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Some Assembly Required: Scientists Piece Together the Largest U.S.-Based Dark Matter ExperimentPress Releasexeno Tue, 07/16/2019 - 10:023019
Major deliveries in June set the stage for the next phase of work on LUX-ZEPLIN project

Lower (left) and upper photomultiplier tube arrays are prepared for LZ at the Sanford Underground Research Facility in Lead, South Dakota. (Credit: Matt Kapust/SURF)

Most of the remaining components needed to fully assemble an underground dark matter-search experiment called LUX-ZEPLIN (LZ) arrived at the project’s South Dakota home during a rush of deliveries in June.

When complete, LZ will be the largest, most sensitive U.S.-based experiment yet that is designed to directly detect dark matter particles. Scientists around the world have been trying for decades to solve the mystery of dark matter, which makes up about 85 percent of all matter in the universe though we have so far only detected it indirectly through observed gravitational effects.

The bulk of the digital components for LZ’s electronics system, which is designed to transmit and record signals from ever-slight particle interactions in LZ’s core detector vessel, were among the new arrivals at the Sanford Underground Research Facility (SURF). SURF, the site of a former gold mine now dedicated to a broad spectrum of scientific research, was also home to a predecessor search experiment called LUX.

A final set of snugly fitting acrylic vessels, which will be filled with a special liquid designed to identify false dark matter signals in LZ’s inner detector, also arrived at SURF in June.

 

Also, the last two of four intricately woven wire grids that are essential to maintain a constant electric field and extract signals from the experiment’s inner detector, also called the time projection chamber, arrived in June (see related article).

“LZ achieved major milestones in June. It was the busiest single month for delivering things to SURF — it was the peak,” said LZ Project Director Murdock Gilchriese of the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab). Berkeley Lab is the lead institution for the LZ project, which is supported by an international collaboration that has about 37 participating institutions and about 250 researchers and technical support crew members.

“A few months from now all of the action on LZ is going to be at SURF — we are already getting close to having everything there,” Gilchriese said.

Mike Headley, executive director at SURF, said, “We’ve been collectively preparing for these deliveries for some time and everything has gone very well. It’s been exciting to see the experiment assembly work progress and we look forward to lowering the assembled detector a mile underground for installation.”

An intricately thin wire grid is visible atop an array of photomultiplier tube. The components are part of the LZ inner detector. (Credit: Matt Kapust/SURF)

 

All of these components will be transported down a shaft and installed in a nearly mile-deep research cavern. The rock above provides a natural shield against much of the constant bombardment of particles raining down on the planet’s surface that produce unwanted “noise.”

LZ components have also been painstakingly tested and selected to ensure that the materials they are made of do not themselves interfere with particle signals that researchers are trying to tease out.

LZ is particularly focused on finding a type of theoretical particle called a weakly interacting massive particle or WIMP by triggering a unique sequence of light and electrical signals in a tank filled with 10 metric tons of highly purified liquid xenon, which is among Earth’s rarest elements. The properties of xenon atoms allow them to produce light in certain particle interactions.

Proof of dark matter particles would fundamentally change our understanding of the makeup of the universe, as our current Standard Model of Physics does not account for their existence.

Assembly of the liquid xenon time projection chamber for LZ is now about 80 percent complete, Gilchriese said. When fully assembled later this month this inner detector will contain about 500 photomultiplier tubes. The tubes are designed to amplify and transmit signals produced within the chamber.

Components for the LUX-ZEPLIN project are stored inside a water tank nearly a mile below ground. The inner detector will be installed on the central mount pictured here, and acrylic vessels (wrapped in white) will fit snugly around this inner detector. (Credit: Matt Kapust/SURF)

 

Once assembled, the time projection chamber will be lowered carefully into a custom titanium vessel already at SURF. Before it is filled with xenon, this chamber will be lowered to a depth of about 4,850 feet. It will be carried in a frame that is specially designed to minimize vibrations, and then floated into the experimental cavern across a temporarily assembled metal runway on air-pumped pucks known as air skates.

Finally, it will be lowered into a larger outer titanium vessel, already underground, to form the final vacuum-insulated cryostat needed to house the liquid xenon.

That daylong journey, planned in September, will be a nail-biting experience for the entire project team, noted Berkeley Lab’s Simon Fiorucci, LZ deputy project manager.

“It will certainly be the most stressful — this is the thing that really cannot fail. Once we’re done with this, a lot of our risk disappears and a lot of our planning becomes easier,” he said, adding, “This will be the biggest milestone that’s left besides having liquid xenon in the detector.”

Project crews will soon begin testing the xenon circulation system, already installed underground, that will continually circulate xenon through the inner detector, further purify it, and reliquify it. Fiorucci said researchers will use about 250 pounds of xenon for these early tests.

Work is also nearing completion on LZ’s cryogenic cooling system that is required to convert xenon gas to its liquid form.

An array of photomultiplier tubes that are designed to detect signals occurring within LZ’s liquid xenon tank. (Credit: Matt Kapust/SURF)

 

LZ digital electronics, which will ultimately connect to the arrays of photomultiplier tubes and enable the readout of signals from particle interactions, were designed, developed, delivered, and installed by University of Rochester researchers and technical staff at SURF in June.

“All of our electronics have been designed specifically for LZ with the goal of maximizing our sensitivity for the smallest possible signals,” said Frank Wolfs, a professor of physics and astronomy at the University of Rochester who is overseeing the university’s efforts.

He noted that more than 28 miles of coaxial cable will connect the photomultiplier tubes and their amplifying electronics – which are undergoing tests at UC Davis – to the digitizing electronics. “The successful installation of the digital electronics and the online network and computing infrastructure in June makes us eager to see the first signals emerge from LZ,” Wolfs added.

Also in June, LZ participants exercised high-speed data connections from the site of the experiment to the surface level at SURF and then to Berkeley Lab. Data captured by the detectors’ electronics will ultimately be transferred to LZ’s primary data center, the National Energy Research Scientific Computing Center (NERSC) at Berkeley Lab via the Energy Sciences Network (ESnet), a high-speed nationwide data network based at Berkeley Lab.

The production of the custom acrylic tanks (see related article), which will contain a fluid known as a liquid scintillator, was overseen by LZ participants at University of California,Santa Barbara.

Researchers from the University of Rochester in June installed six racks of electronics hardware that will be used to process signals from the LZ experiment. (Credit: University of Rochester)

The top three acrylic tanks for the LUX-ZEPLIN outer detector during testing at the fabrication vendor. These tanks are now at the Sanford Underground Research Facility in Lead, South Dakota. (Credit: LZ Collaboration)

“The last five tanks, delivered in June, were fabricated using a novel acrylic molding process to closely fit around the cryostat vessel,” said Harry Nelson, professor of physics at UC Santa Barbara.

The top three acrylic tanks for the LUX-ZEPLIN outer detector during testing at the fabrication vendor. These tanks are now at the Sanford Underground Research Facility in Lead, South Dakota. (Credit: LZ Collaboration)

“The partnership between LZ and SURF is tremendous, as evidenced by the success of the assembly work to date,” Headley said. “We’re proud to be a part of the LZ team and host this world-leading experiment in South Dakota.”

NERSC and ESnet are DOE Office of Science User Facilities.

Major support for LZ comes from the DOE Office of Science, the South Dakota Science and Technology Authority, the U.K.’s Science & Technology Facilities Council, and by collaboration members in the U.S., U.K., South Korea, and Portugal.

 

More:

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DOE’s Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit energy.gov/science.

Founded in 1931 on the belief that the biggest scientific challenges are best addressed by teams, Lawrence Berkeley National Laboratory and its scientists have been recognized with 13 Nobel Prizes. Today, Berkeley Lab researchers develop sustainable energy and environmental solutions, create useful new materials, advance the frontiers of computing, and probe the mysteries of life, matter, and the universe. Scientists from around the world rely on the Lab’s facilities for their own discovery science. Berkeley Lab is a multiprogram national laboratory, managed by the University of California for the U.S. Department of Energy’s Office of Science.

The Sanford Underground Research Facility’s mission is to enable compelling underground, interdisciplinary research in a safe work environment and to inspire our next generation through science, technology, engineering, and math education. For more information, please visit the Sanford Lab website at http://www.sanfordlab.org.

Lawrence Berkeley National Laboratory

Shielding blocks removed exposing the Bevatron. (Courtesy: Lawrence Berkeley National Lab)

In the world of science, Lawrence Berkeley National Laboratory (Berkeley Lab) is synonymous with “excellence.” Thirteen Nobel prizes are associated with Berkeley Lab. Seventy Lab scientists are members of the National Academy of Sciences (NAS), one of the highest honors for a scientist in the United States. Thirteen of our scientists have won the National Medal of Science, our nation’s highest award for lifetime achievement in fields of scientific research. Eighteen of our engineers have been elected to the National Academy of Engineering, and three of our scientists have been elected into the Institute of Medicine. In addition, Berkeley Lab has trained thousands of university science and engineering students who are advancing technological innovations across the nation and around the world.

Berkeley Lab is a multidisciplinary national laboratory located in Berkeley, California on a hillside directly above the campus of the University of California at Berkeley. The site consists of 76 buildings located on 183 acres, which overlook both the campus and the San Francisco Bay.

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510-486-4000

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Contact Info

Glenn Roberts Jr.,
Public Affairs, Lawrence Berkeley National Laboratory
geroberts@lbl.gov  
http://newscenter.lbl.gov/

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LHC experiments present new Higgs results at 2019 EPS-HEP conferencePress releasexeno Mon, 07/15/2019 - 11:492919
The ATLAS and CMS collaborations at the LHC have studied the Higgs boson with the largest sample of proton–proton collision data recorded so far and have made precision measurements of this particle to search for signs of new physics

Candidates for a Higgs produced with a Z. ATLAS (l): both decay ultimately to leptons, leaving two electrons (green) and four muons (red). CMS (r): the Higgs decays to two charm quarks forming jets (cones); the Z decays to electrons (green) (Image: ATLAS/CMS/CERN)

Geneva and Ghent. At the 2019 European Physical Society’s High-Energy Physics conference (EPS-HEP) taking place in Ghent, Belgium, the ATLAS and CMS collaborations presented a suite of new results. These include several analyses using the full dataset from the second run of CERN’s Large Hadron Collider (LHC), recorded at a collision energy of 13 TeV between 2015 and 2018. Among the highlights are the latest precision measurements involving the Higgs boson. In only seven years since its discovery, scientists have carefully studied several of the properties of this unique particle, which is increasingly becoming a powerful tool in the search for new physics.

The results include new searches for transformations (or “decays”) of the Higgs boson into pairs of muons and into pairs of charm quarks. Both ATLAS and CMS also measured previously unexplored properties of decays of the Higgs boson that involve electroweak bosons (the W, the Z and the photon) and compared these with the predictions of the Standard Model (SM) of particle physics. ATLAS and CMS will continue these studies over the course of the LHC’s Run 3 (2021 to 2023) and in the era of the High-Luminosity LHC (from 2026 onwards).

The Higgs boson is the quantum manifestation of the all-pervading Higgs field, which gives mass to elementary particles it interacts with, via the Brout-Englert-Higgs mechanism. Scientists look for such interactions between the Higgs boson and elementary particles, either by studying specific decays of the Higgs boson or by searching for instances where the Higgs boson is produced along with other particles. The Higgs boson decays almost instantly after being produced in the LHC and it is by looking through its decay products that scientists can probe its behaviour.

In the LHC’s Run 1 (2010 to 2012), decays of the Higgs boson involving pairs of electroweak bosons were observed. Now, the complete Run 2 dataset – around 140 inverse femtobarns each, the equivalent of over 10 000 trillion collisions – provides a much larger sample of Higgs bosons to study, allowing measurements of the particle’s properties to be made with unprecedented precision. ATLAS and CMS have measured the so-called “differential cross-sections” of the bosonic decay processes, which look at not just the production rate of Higgs bosons but also the distribution and orientation of the decay products relative to the colliding proton beams. These measurements provide insight into the underlying mechanism that produces the Higgs bosons. Both collaborations determined that the observed rates and distributions are compatible with those predicted by the Standard Model, at the current rate of statistical uncertainty.

An event recorded by ATLAS showing a candidate for a Higgs boson produced in association with two top quarks. The Higgs boson decays to four muons (red tracks). There is an additional electron (green track) and four particle jets (yellow cones) (Image: ATLAS/CERN)

Since the strength of the Higgs boson’s interaction is proportional to the mass of elementary particles, it interacts most strongly with the heaviest generation of fermions, the third. Previously, ATLAS and CMS had each observed these interactions. However, interactions with the lighter second-generation fermions – muons, charm quarks and strange quarks – are considerably rarer. At EPS-HEP, both collaborations reported on their searches for the elusive second-generation interactions.

ATLAS presented their first result from searches for Higgs bosons decaying to pairs of muons (H→μμ) with the full Run 2 dataset. This search is complicated by the large background of more typical SM processes that produce pairs of muons. “This result shows that we are now close to the sensitivity required to test the Standard Model’s predictions for this very rare decay of the Higgs boson,” says Karl Jakobs, the ATLASspokesperson. “However, a definitive statement on the second generation will require the larger datasets that will be provided by the LHC in Run 3 and by the High-Luminosity LHC.”

CMS presented their first result on searches for decays of Higgs bosons to pairs of charm quarks (H→cc). When a Higgs boson decays into quarks, these elementary particles immediately produce jets of particles. “Identifying jets formed by charm quarks and isolating them from other types of jets is a huge challenge,” says Roberto Carlin, spokesperson for CMS. “We’re very happy to have shown that we can tackle this difficult decay channel. We have developed novel machine-learning techniques to help with this task.”

 

An event recorded by CMS showing a candidate for a Higgs boson produced in association with two top quarks. The Higgs boson and top quarks decay leading to a final state with seven jets (orange cones), an electron (green line), a muon (red line) and missing transverse energy (pink line)(Image: CMS/CERN)

 

The Higgs boson also acts as a mediator of physics processes in which electroweak bosons scatter or bounce off each other. Studies of these processes with very high statistics serve as powerful tests of the Standard Model. ATLAS presented the first-ever measurement of the scattering of two Z bosons. Observing this scattering completes the picture for the W and Z bosons as ATLAS has previously observed the WZ scattering process and both collaborations the WW process. CMS presented the first observation of electroweak-boson scattering that results in the production of a Z boson and a photon.

“The experiments are making big strides in the monumental task of understanding the Higgs boson,” says Eckhard Elsen, CERN’s Director of Research and Computing. “After observation of its coupling to the third-generation fermions, the experiments have now shown that they have the tools at hand to address the even more challenging second generation. The LHC’s precision physics programme is in full swing.”

 

 

CERN

At CERN, the European Organization for Nuclear Research, physicists and engineers are probing the fundamental structure of the universe. They use the world's largest and most complex scientific instruments to study the basic constituents of matter – the fundamental particles. The particles are made to collide together at close to the speed of light. The process gives the physicists clues about how the particles interact, and provides insights into the fundamental laws of nature.

Contact information
European Organization for Nuclear Research
CERN
CH-1211 Genève 23
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Organisation Européenne pour
la Recherche Nucléaire
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+ 41 22 76 761 11
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Experimental mini-accelerator achieves record energyPress Releasexeno Thu, 07/11/2019 - 08:062819
Coupled terahertz device significantly improves electron beam quality

The two-stage miniature accelerator is operated with terahertz radiation (shown here in red). In a first step (left) the electron bunches (shown in blue) are compressed, in a second step (right) they are accelerated. The two individual elements are each about two centimetres wide. Credit: DESY, Gesine Born

Scientists at DESY have achieved a new world record for an experimental type of miniature particle accelerator: For the first time, a terahertz powered accelerator more than doubled the energy of the injected electrons. At the same time, the setup significantly improved the electron beam quality compared to earlier experiments with the technique, as Dongfang Zhang and his colleagues from the Center for Free-Electron Laser Science (CFEL) at DESY report in the journal Optica. “We have achieved the best beam parameters yet for terahertz accelerators,” said Zhang.

“This result represents a critical step forward for the practical implementation of terahertz-powered accelerators,” emphasized Franz Kärtner, who heads the ultrafast optics and X-rays group at DESY. Terahertz radiation lies between infrared and microwave frequencies in the electromagnetic spectrum and promises a new generation of compact particle accelerators. “The wavelength of terahertz radiation is about a hundred times shorter than the radio waves currently used to accelerate particles,” explained Kärtner. “This means that the components of the accelerator can also be built to be around a hundred times smaller.” The terahertz approach promises lab-sized accelerators that will enable completely new applications for instance as compact X-ray sources for materials science and maybe even for medical imaging. The technology is currently under development.

Since terahertz waves oscillate so fast, every component and every step has to be precisely synchronized. “For instance, to achieve the best energy gain, the electrons have to hit the terahertz field exactly during its accelerating half cycle,” explained Zhang. In accelerators, particles usually do not fly in a continuous beam, but are packed in bunches. Because of the fast-changing field, in terahertz accelerators these bunches have to be very short to ensure even acceleration conditions along the bunch.

“In previous experiments the electron bunches were too long”, said Zhang. “Since the terahertz field oscillates so quickly, some of the electrons in the bunch were accelerated, while others were even slowed down. So, in total there was just a moderate average energy gain, and, what is more important, a wide energy spread, resulting in what we call poor beam quality.” To make things worse, this effect strongly increased the emittance, a measure for how well a particle beam is bundled transversally. The tighter, the better – the smaller the emittance.

STEAM is a kind of Swiss army knife for electron beams - depending on the operating mode it combines four functions in one device and can compress, focus, analyse and accelerate electron bunches. Credit: DESY, Gesine Born

To improve the beam quality, Zhang and his colleagues built a two-step accelerator from a multi-purpose device they had developed earlier: The Segmented Terahertz Electron Accelerator and Manipulator (STEAM) can compress, focus, accelerate and analyze electron bunches with terahertz radiation. The researchers combined two STEAM devices in line. They first compressed the incoming electron bunches from about 0.3 millimetres in length to just 0.1 millimetres. With the second STEAM device, they accelerated the compressed bunches. “This scheme requires control on the level of quadrillionths of a second, which we achieved,“ said Zhang “This led to a fourfold reduction of the energy spread and improved the emittance sixfold, yielding the best beam parameters of a terahertz accelerator so far.”

The net energy gain of the electrons that were injected with an energy of 55 kiloelectron volts (keV) was 70 keV. “This is the first energy boost greater than 100 percent in a terahertz powered accelerator,” emphasised Zhang. The coupled device produced an accelerating field with a peak strength of 200 million Volts per metre (MV/m) – close to state-of-the-art strongest conventional accelerators. For practical applications this still has to be significantly improved. “Our work shows that even a more than three times stronger compression of the electron bunches is possible. Together with a higher terahertz energy, acceleration gradients in the regime of gigavolts per metre seem feasible,” summarized Zhang. “The terahertz concept thus appears increasingly promising as a realistic option for the design of compact electron accelerators.”

The achieved progress is also central for the ERC funded project AXSIS (frontiers in Attosecond X-ray Science: Imaging and Spectroscopy) at CFEL, which pursues short pulse X-ray spectroscopy and imaging of complex biophysical processes, where the short X-ray pulses are generated with THz based electron accelerators. CFEL is a joint venture of DESY, the University of Hamburg and the Max Planck Society.

 

Reference:
Femtosecond phase control in high field Terahertz driven ultrafast electron sources; Dongfang Zhang, Arya Fallahi, Michael Hemmer, Hong Ye, Moein Fakhari, Yi Hua, Huseyin Cankaya, Anne-Laure Calendron, Luis E. Zapata, Nicholas H. Matlis, Franz X. Kärtner; Optica, 2019; DOI: 10.1364/OPTICA.6.000872

 

Science contact

Dr. Dongfang Zhang
CFEL/DESY
Phone: +49 40 8998-6366
dongfang.zhang@desy.de

Prof. Franz X. Kärtner
CFEL/DESY
Phone: +49 40 8998-6350
franz.kaertner@desy.de

 
Deutsches Elektronen-Synchrotron

DESY is one of the world’s leading accelerator centres. Researchers use the large-scale facilities at DESY to explore the microcosm in all its variety – from the interactions of tiny elementary particles and the behaviour of new types of nanomaterials to biomolecular processes that are essential to life. The accelerators and detectors that DESY develops and builds are unique research tools. The facilities generate the world’s most intense X-ray light, accelerate particles to record energies and open completely new windows onto the universe. That makes DESY not only a magnet for more than 3000 guest researchers from over 40 countries every year, but also a coveted partner for national and international cooperations. Committed young researchers find an exciting interdisciplinary setting at DESY. The research centre offers specialized training for a large number of professions. DESY cooperates with industry and business to promote new technologies that will benefit society and encourage innovations. This also benefits the metropolitan regions of the two DESY locations, Hamburg and Zeuthen near Berlin.

Address

DESY Hamburg
Notkestraße 85
22607Hamburg
Germany

+ 49 40/8998-0

http://www.desy.de/
Contact Info

PR Office
DR Thomas Zoufal
presse@desy.de
Phone: +49 40 8998-1666
 

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3 Sky Surveys Completed in Preparation for Dark Energy Spectroscopic InstrumentPress Releasexeno Mon, 07/08/2019 - 09:352719
Researchers will pick 35 million galaxies and quasars to target during DESI’s 5-year mission

A multicolor mosaic image of the massive galaxy cluster, Abell 370, located in the constellation Cetus – named for a sea monster in Greek mythology. Galaxy clusters are the largest structures in the universe bound by gravity, and consist of thousands of galaxies and large amounts of dark matter. Abell 370 formed when two less massive galaxy clusters merged together billions of years ago. It is more than 6.5 billion light-years away from Earth. The mosaic is approximately 4.5 million light-years across and has been constructed from deep optical imaging in the Legacy Surveys’ eighth data release. (Credit: John Moustakas/Siena College; Legacy Surveys team)

It took three sky surveys – conducted at telescopes in two continents, covering one-third of the visible sky, and requiring almost 1,000 observing nights – to prepare for a new project that will create the largest 3D map of the universe’s galaxies and glean new insights about the universe’s accelerating expansion.

This Dark Energy Spectroscopic Instrument (DESI) project will explore this expansion, driven by a mysterious property known as dark energy, in great detail. It could also make unexpected discoveries during its five-year mission.

The surveys, which wrapped up in March, have amassed images of more than 1 billion galaxies and are essential in selecting celestial objects to target with DESI, now under construction in Arizona.

The latest batch of imaging data from these surveys, known as DR8, was publicly released July 8, and an online Sky Viewer tool provides a virtual tour of this data. A final data release from the DESI imaging surveys is planned later this year.

Scientists will select about 33 million galaxies and 2.4 million quasars from the larger set of objects imaged in the three surveys. Quasars are the brightest objects in the universe and are believed to contain supermassive black holes. DESI will target these selected objects for several measurements after its start, which is expected in February 2020.

DESI will measure each target across a range of different wavelengths of light, known as spectrum, from the selected set of galaxies repeatedly over the course of its mission. These measurements will provide details about their distance and acceleration away from Earth.

A collection of 5,000 swiveling robots, each carrying a fiber-optic cable, will point at sets of pre-selected sky objects to gather their light (see a related video) so it can be split into different colors and analyzed using a series of devices called spectrographs.

 

Three surveys, 980 nights

“Typically, when you apply for time on a telescope you get up to five nights,” said David Schlegel, a DESI project scientist at the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab), which is the lead institution in the DESI collaboration. “These three imaging surveys totaled 980 nights, which is a pretty big number.”

The three imaging surveys for DESI include:

  • The Mayall z-band Legacy Survey (MzLS), carried out at the Mayall Telescope at the National Science Foundation’s Kitt Peak National Observatory near Tucson, Arizona, over 401 nights. DESI is now under installation at the Mayall Telescope.
  • The Dark Energy Camera Legacy Survey (DECaLS) at the Victor Blanco Telescope at NSF’s Cerro Tololo Inter-American Observatory in Chile, which lasted 204 nights.
  • The Beijing-Arizona Sky Survey (BASS), which used the Steward Observatory’s Bok telescope at Kitt Peak National Observatory and lasted 375 nights.
This map shows the sky areas covered (blue) by three surveys conducted in preparation for DESI. (Credit: University of Arizona)

 

On-site survey crews – typically two DESI project researchers per observing night for each of the surveys – served in a sort of “lifeguard” role, Schlegel said. “When something went wrong they were there to fix it – to keep eyes on the sky,” and researchers working remotely also aided in troubleshooting.

 

On the final night of the final survey …

In early March, Eva-Maria Mueller, a postdoctoral researcher at the U.K.’s University of Portsmouth, and Robert Blum, former deputy director at the National Optical Astronomy Observatory (NOAO) that manages the survey sites, were on duty with a small team in the control room of the NSF’s Victor Blanco Telescope on a mile-high Chilean mountain for the final night of DECaLS survey imaging.

An aerial image of the Cerro Tololo Interamerican Observatory in Chile, with the silvery dome of the 4-meter Blanco telescope pictured at lower right. (Credit: NOAO/AURA/NSF)

 

Seated several stories beneath the telescope, Mueller and Blum viewed images in real time to verify the telescope’s position and focus. Mueller, who was participating in a five-night shift that was her first observing stint for the DESI surveys, said, “This was always kind of a childhood dream.”

Blum, who had logged many evenings at the Blanco telescope for DECaLS, said, “It’s really exciting to think about finishing this phase.”

He noted that this final night was focused on “cleaning up little holes” in the previous imaging. Blum is now serving in a new role as acting operations director for the Large Synoptic Survey Telescope under installation in Chile.

New software designed for the DESI surveys, and precise positioning equipment on the telescopes, has helped to automate the image-taking process, setting the exposure time and filters and compensating for atmospheric distortions and other factors that can affect the imaging quality, Blum noted. During a productive evening, it was common to produce about 150 to 200 images for the DECaLS survey.

 

Cool cosmic cartography experiment

The data from the surveys was routed to supercomputers at Berkeley Lab’s National Energy Research Scientific Computing Center (NERSC), which will be the major storehouse for DESI data.

More than 100 researchers participated in night shifts to conduct the surveys, said Arjun Dey, the NOAO project scientist for DESI. Dey served as a lead scientist for the MzLS survey and a co-lead scientist on the DECaLS survey with Schlegel.

“We are building a detailed map of the universe and measuring its expansion history over the last 10 to 12 billion years,” Dey said. “The DESI experiment represents the most detailed – and definitely the coolest – cosmic cartography experiment undertaken to date. Although the imaging was carried out for the DESI project, the data are publicly available so everyone can enjoy the sky and explore the cosmos.”

 

BASS survey supported by global team

Xiaohui Fan, a University of Arizona astronomy professor who was a co-lead on the BASS survey conducted at Kitt Peak’s Bok Telescope, coordinated viewing time by an international group that included co-leads Professor Zhou Xu and Associate Professor Zou Hu, other scientists from the National Astronomical Observatories of China (NAOC), and researchers from the University of Arizona and from across the DESI collaboration.

The Bok (left) and Mayall telescopes at Kitt Peak National Observatory near Tucson, Arizona. DESI is currently under installation at the Mayall telescope. (Credit: Michael A. Stecker)

 

BASS produced about 100,000 images during its four-year run. It scanned a section of sky about 13 times larger than the Big Dipper, part of the Ursa Major constellation.

“This is a good example of how a collaboration is done,” Fan said. “Through this international partnership we were bringing in people from around the world. This is a nice preview of what observing with DESI will be like.”

Fan noted the DESI team’s swift response in updating the telescope’s hardware and software during the course of the survey.

“It improved a lot in terms of automated controls and focusing and data reduction,” he said. Most of the BASS survey imaging concluded in February, with some final images taken in March.

 

Next steps toward DESI’s completion

All of the images gathered will be processed by a mathematical code, called Tractor, that helps to identify all of the galaxies surveyed and measure their brightness.

With the initial testing of the massive corrector barrel, which houses DESI’s package of six large mirrors, in early April, the next major milestone for the project will be the delivery, installation, and testing of its focal plane, which caps the telescope and houses the robotic positioners.

Dey, who participated in formative discussions about the need for an experiment like DESI almost 20 years ago, said,

“It’s pretty amazing that our small and dedicated team was able to pull off such a large survey in such a short time. We are excited to be turning to the next phase of this project!”

NERSC is a DOE Office of Science User Facility.

 

###

 

DESI is supported by the U.S. Department of Energy’s Office of Science; the U.S. National Science Foundation, Division of Astronomical Sciences under contract to the National Optical Astronomy Observatory; the Science and Technologies Facilities Council of the United Kingdom; the Gordon and Betty Moore Foundation; the Heising-Simons Foundation; the National Council of Science and Technology of Mexico; the Ministry of Economy of Spain; the French Alternative Energies and Atomic Energy Commission (CEA); and DESI member institutions. The DESI scientists are honored to be permitted to conduct astronomical research on Iolkam Du’ag (Kitt Peak), a mountain with particular significance to the Tohono O’odham Nation. View the full list of DESI collaborating institutions, and learn more about DESI here: desi.lbl.gov.

Lawrence Berkeley National Laboratory addresses the world’s most urgent scientific challenges by advancing sustainable energy, protecting human health, creating new materials, and revealing the origin and fate of the universe. Founded in 1931, Berkeley Lab’s scientific expertise has been recognized with 13 Nobel prizes. The University of California manages Berkeley Lab for the U.S. Department of Energy’s Office of Science. For more, visit www.lbl.gov.

DOE’s Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit energy.gov/science.

The National Optical Astronomy Observatory (NOAO) is the national center for ground-based nighttime astronomy in the United States and is operated by the Association of Universities for Research in Astronomy (AURA) under a cooperative agreement with the National Science Foundation Division of Astronomical Sciences.

The National Science Foundation (NSF) is an independent federal agency created by Congress in 1950 to promote the progress of science. NSF supports basic research and people to create knowledge that transforms the future.

The Heising-Simons Foundation is a family foundation based in Los Altos, California. The Foundation works with its many partners to advance sustainable solutions in climate and clean energy, enable groundbreaking research in science, enhance the education of our youngest learners, and support human rights for all people.

The Gordon and Betty Moore Foundation fosters path-breaking scientific discovery, environmental conservation, patient care improvements and preservation of the special character of the Bay Area. Visit moore.org and follow @MooreFound.

The Science and Technology Facilities Council (STFC) of the United Kingdom coordinates research on some of the most significant challenges facing society, such as future energy needs, monitoring and understanding climate change, and global security. It offers grants and support in particle physics, astronomy and nuclear physics; visit https://stfc.ukri.org/.

Established in 1958 and aiming at the forefront of astronomical science, the National Astronomical Observatories of the Chinese Academy of Sciences (NAOC) conducts cutting-edge astronomical studies, operates major national facilities and develops state-of the-art technological innovations.

Lawrence Berkeley National Laboratory

Shielding blocks removed exposing the Bevatron. (Courtesy: Lawrence Berkeley National Lab)

In the world of science, Lawrence Berkeley National Laboratory (Berkeley Lab) is synonymous with “excellence.” Thirteen Nobel prizes are associated with Berkeley Lab. Seventy Lab scientists are members of the National Academy of Sciences (NAS), one of the highest honors for a scientist in the United States. Thirteen of our scientists have won the National Medal of Science, our nation’s highest award for lifetime achievement in fields of scientific research. Eighteen of our engineers have been elected to the National Academy of Engineering, and three of our scientists have been elected into the Institute of Medicine. In addition, Berkeley Lab has trained thousands of university science and engineering students who are advancing technological innovations across the nation and around the world.

Berkeley Lab is a multidisciplinary national laboratory located in Berkeley, California on a hillside directly above the campus of the University of California at Berkeley. The site consists of 76 buildings located on 183 acres, which overlook both the campus and the San Francisco Bay.

Address

1 Cyclotron Road
Berkeley, CA94720
United States

510-486-4000

http://www.lbl.gov/
Contact Info

Glenn Roberts Jr.,
Public Affairs, Lawrence Berkeley National Laboratory
geroberts@lbl.gov  
http://newscenter.lbl.gov/

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Dutch and US students win 2019 CERN Beamline for Schools competitionPress Releasexeno Mon, 06/24/2019 - 07:592619

The 2019 CERN Beamline for Schools winners: (from left) Team from the West High School in Salt Lake City, USA (Image: Kara Budge) and team from the Praedinius Gymnasium in Groningen, Netherlands (Image: Martin Mug).

This release is a collaboration between DESY and CERN.

Geneva and Hamburg: Two teams of high-school students, one from the Praedinius Gymnasium in Groningen, Netherlands, and one from the West High School in Salt Lake City, USA, have won the 2019 Beamline for Schools competition (BL4S). In October, these teams will be invited to the DESY1 research centre in Hamburg, Germany, to carry out their proposed experiments together with scientists from CERN and DESY.

Beamline for Schools is a unique international competition that is open to high-school students all over the world. The students are invited to submit a proposal for an experiment that uses a beamline. Beamlines deliver a stream of subatomic particles to any given set-up, making it possible to study a broad variety of properties and processes in various scientific disciplines. They are operated at laboratories such as CERN and DESY.

Since Beamline for Schools was launched in 2014 almost 10,000 students from 84 countries have participated. This year, 178 teams from 49 countries worldwide submitted a proposal for the sixth edition of the competition.

Due to the second Long Shutdown of CERN’s accelerators for maintenance and upgrade, there is currently no beam at CERN, which has opened up opportunities to explore partnerships with other laboratories, namely DESY.

“It is a great honour for us to host the finals of this year’s Beamline for Schools competition at DESY,” said Helmut Dosch, Chairman of the DESY Board of Directors. “We are really looking forward to meeting the extraordinary students who made it through with their proposals and we wish them a successful and rewarding time at the lab. We at DESY are committed to fostering the next generation of scientists, which CERN’s Beamline for Schools project does brilliantly.”

 “We are all very excited to welcome this year’s winners to DESY. This is a new chapter in the history of this competition because, for the first time, we are taking the finals of the competition to another research laboratory. As always, the more then 60 voluntary experts from CERN and DESY evaluated all the proposals for their creativity, motivation, proposed methodology, feasibility and their overall ability to explore some of the concepts of modern particle physics” said Sarah Aretz, BL4S project manager.

The two winning teams of 2019 will look at fundamental differences between matter and antimatter. When electrons at high energies collide with a target, such as a piece of graphite, some of their energy gets transferred into photons. These photons can, in turn, transform into other particles. Eventually, a shower of particles at lower energy will develop. The team “Particle Peers” from the Praedinius Gymnasium, Groningen, Netherlands has proposed to compare the properties of the particle showers originating from electrons with those created from positrons, the antimatter partner of the electron.

"I couldn't stop smiling when I heard the news that we’d won. It's unbelievable that we’ll get the opportunity to conduct our experiment with amazing scientists and meet new students who are just as enthusiastic about physics as I am," said Frederiek de Bruine from the “Particle Peers” team.

The “DESY Chain” team from the West High School, Salt Lake City, USA, focuses on the properties of scintillators in its proposal. These are materials that are used for particle detection. The students aim to study the performance of these scintillators and compare their sensitivity to electrons and positrons. This may lead to more efficient particle detectors for a wide range of applications.

“I’m so excited by the prospect of working at DESY this autumn, it’s such a once-in-a-lifetime opportunity. I’m proud to be a part of the first USA team to win the BL4S competition, especially because it provides access to equipment and systems I would otherwise never have dreamt of even seeing,” said August Muller from the “DESY Chain” team.

The shortlist consisted of 20 teams, ten of which received a special mention. This is the second time that a Dutch team has won the competition. Previous winners came from schools in the Netherlands, Greece, Italy (twice), South Africa, Poland, the United Kingdom, Canada, India and the Philippines.

Beamline for Schools is an Education and Outreach project funded by the CERN & Society Foundation and supported by individual donors, foundations and companies. For 2019, the project is partially funded by the Wilhelm and Else Heraeus Foundation; additional contributions have been received from the Motorola Solutions Foundation, Amgen Switzerland AG and the Ernest Solvay Fund, which is managed by the King Baudouin Foundation.

 

Shortlist drawn up by CERN and DESY experts:

A Light in the Darkness (USA)

Centaurus Warriors (USA)

Cosmic Conquerors (Thailand)

DESY Chain (USA)

DESYners (USA)

JT/High Pawns (Pakistan)

Jubarte Team (Brazil)

Leftover Leptons (India)

Magic Doubly Magic Nuclei (Poland)

My Little Positron(Australia)

Particle peers (The Netherlands)

Raiders of the Lost Quark (UAE)

RAM FAM (Australia)

Salvo Krevas (Malaysia)

Team John Monash Science School (Australia)

The Baryonic Six (Sweden)

The Lumineers (Pakistan)

The Weak Force (South Africa)

Unstoppable SPAS (China)

Young Researchers (Ukraine)

 

Special Mentions:

Antimatter Tracker (Argentina)

Cherenkoviously Brilliant (UK)

EthioCosmos (Ethiopia)

Kics Team (Sudan)

Kleine Wissenschaftler (Iran)

Observers of the microcosm (Ukraine)

Quantum Minds (Mexico)

SolarBeam (Thailand)

Team Pentaquark (Bangladesh)

YKS_Young Kurdish Scientists (Iran)

 

Further information

Video from the team “Particle peers”, Praedinius Gymnasium in Groningen (https://praedinius.nl/index.html), Netherlands: https://youtu.be/va1ZnjllFDk

Video from the team “DESY Chain”, West High School in Salt Lake City  (https://west.slcschools.org), US: https://www.youtube.com/watch?v=sdexfXt2o30

 

Beamline for School

Beamline for Schools 2019 Edition

The evaluation of the sixth Beamline for Schools competition finally starts

Previous winners

1. DESY is one of the world’s leading particle accelerator centres. Researchers use the large‐scale facilities at DESY to explore the microcosm in all its variety – ranging from the interaction of tiny elementary particles to the behaviour of innovative nanomaterials, the vital processes that take place between biomolecules and the great mysteries of the universe. The accelerators and detectors that DESY develops and builds at its locations in Hamburg and Zeuthen are unique research tools. DESY is a member of the Helmholtz Association, and receives its funding from the German Federal Ministry of Education and Research (BMBF) (90 per cent) and the German federal states of Hamburg and Brandenburg (10 per cent).

CERN

At CERN, the European Organization for Nuclear Research, physicists and engineers are probing the fundamental structure of the universe. They use the world's largest and most complex scientific instruments to study the basic constituents of matter – the fundamental particles. The particles are made to collide together at close to the speed of light. The process gives the physicists clues about how the particles interact, and provides insights into the fundamental laws of nature.

Contact information
European Organization for Nuclear Research
CERN
CH-1211 Genève 23
Switzerland

or

Organisation Européenne pour
la Recherche Nucléaire
F-01631 CERN Cedex
France
+ 41 22 76 761 11
+ 41 22 76 765 55 (fax)
 

https://home.cern/
Contact Info

Press Office
Arnaud Marsollier
Arnaud.Marsollier@cern.ch 
Press.office@cern.ch
+41 22 767 34 32
+41 22 767 21 41

 

,
Deutsches Elektronen-Synchrotron

DESY is one of the world’s leading accelerator centres. Researchers use the large-scale facilities at DESY to explore the microcosm in all its variety – from the interactions of tiny elementary particles and the behaviour of new types of nanomaterials to biomolecular processes that are essential to life. The accelerators and detectors that DESY develops and builds are unique research tools. The facilities generate the world’s most intense X-ray light, accelerate particles to record energies and open completely new windows onto the universe. That makes DESY not only a magnet for more than 3000 guest researchers from over 40 countries every year, but also a coveted partner for national and international cooperations. Committed young researchers find an exciting interdisciplinary setting at DESY. The research centre offers specialized training for a large number of professions. DESY cooperates with industry and business to promote new technologies that will benefit society and encourage innovations. This also benefits the metropolitan regions of the two DESY locations, Hamburg and Zeuthen near Berlin.

Address

DESY Hamburg
Notkestraße 85
22607Hamburg
Germany

+ 49 40/8998-0

http://www.desy.de/
Contact Info

PR Office
Christian Mrotzek
christian.mrotzek@DESY.DE
+49 40 8998-1665
+ 49 040 8998 4307 (fax)

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Laser trick produces high-energy terahertz pulsesPress Releasexeno Thu, 06/13/2019 - 10:592519
Milestone for compact particle accelerators

From the colour difference of two slightly delayed laser flashes (left) a non-linear crystal generates an energetic terahertz pulse (right). Credit: DESY, Lucid Berlin

A team of scientists from DESY and the University of Hamburg has achieved an important milestone in the quest for a new type of compact particle accelerator. Using ultra-powerful pulses of laser light, they were able to produce particularly high-energy flashes of radiation in the terahertz range having a sharply defined wavelength (colour). Terahertz radiation is to open the way for a new generation of compact particle accelerators that will find room on a lab bench. The team headed by Andreas Maier and Franz Kärtner from the Hamburg Center for Free-Electron Laser Science (CFEL) is presenting its findings in the journal Nature Communications. CFEL is jointly run by DESY, the University of Hamburg and the Max Planck Society.

The terahertz range of electromagnetic radiation lies between the infrared and microwave frequencies. Air travellers may be familiar with terahertz radiation from the full-body scanners used by airport security to search for objects hidden beneath a person’s garments. However, radiation in this frequency range might also be used to build compact particle accelerators.

“The wavelength of terahertz radiation is about a thousand times shorter than the radio waves that are currently used to accelerate particles,” says Kärtner, who is a lead scientist at DESY. “This means that the components of the accelerator can also be built to be around a thousand times smaller.”

The generation of high-energy terahertz pulses is therefore also an important step for the AXSIS (frontiers in Attosecond X-ray Science: Imaging and Spectroscopy) project at CFEL, funded by the European Research Council (ERC), which aims to open up completely new applications with compact terahertz particle accelerators.

However, chivvying along an appreciable number of particles calls for powerful pulses of terahertz radiation having a sharply defined wavelength. This is precisely what the team has now managed to create.

“In order to generate terahertz pulses, we fire two powerful pulses of laser light into a so-called non-linear crystal, with a minimal time delay between the two,” explains Maier from the University of Hamburg. The two laser pulses have a kind of colour gradient, meaning that the colour at the front of the pulse is different from that at the back. The slight time shift between the two pulses therefore leads to a slight difference in colour. “This difference lies precisely in the terahertz range,” says Maier. “The crystal converts the difference in colour into a terahertz pulse.”

The method requires the two laser pulses to be precisely synchronised. The scientists achieve this by splitting a single pulse into two parts and sending one of them on a short detour so that it is slightly delayed before the two pulses are eventually superimposed again. However, the colour gradient along the pulses is not constant, in other words the colour does not change uniformly along the length of the pulse. Instead, the colour changes slowly at first, and then more and more quickly, producing a curved outline. As a result, the colour difference between the two staggered pulses is not constant. The difference is only appropriate for producing terahertz radiation over a narrow stretch of the pulse.

“That was a big obstacle towards creating high-energy terahertz pulses,” as Maier reports. “Because straightening the colour gradient of the pulses, which would have been the obvious solution, is not easy to do in practice.”

It was co-author Nicholas Matlis who came up with the crucial idea: he suggested that the colour profile of just one of the two partial pulses should be stretched slightly along the time axis. While this still does not alter the degree with which the colour changes along the pulse, the colour difference with respect to the other partial pulse now remains constant at all times.

“The changes that need to be made to one of the pulses are minimal and surprisingly easy to achieve: all that was necessary was to insert a short length of a special glass into the beam,” reports Maier. “All of a sudden, the terahertz signal became stronger by a factor of 13.”

In addition, the scientists used a particularly large non-linear crystal to produce the terahertz radiation, specially made for them by the Japanese Institute for Molecular Science in Okazaki.

“By combining these two measures, we were able to produce terahertz pulses with an energy of 0.6 millijoules, which is a record for this technique and more than ten times higher than any terahertz pulse of sharply defined wavelength that has previously been generated by optical means,” says Kärtner. “Our work demonstrates that it is possible to produce sufficiently powerful terahertz pulses with sharply defined wavelengths in order to operate compact particle accelerators.”

Reference:

Spectral Phase Control of Interfering Chirped Pulses for High-Energy Narrowband Terahertz Generation; Spencer W. Jolly, Nicholas H. Matlis, Frederike Ahr, Vincent Leroux, Timo Eichner, Anne-Laure Calendron, Hideki Ishizuki, Takunori Taira, Franz X. Kärtner, and Andreas R. Maier; „Nature Communications“, 2019; DOI: 10.1038/s41467-019-10657-4

DESY is one of the world’s leading particle accelerator centres. Researchers use the large‐scale facilities at DESY to explore the microcosm in all its variety – ranging from the interaction of tiny elementary particles to the behaviour of innovative nanomaterials and the vital processes that take place between biomolecules to the great mysteries of the universe. The accelerators and detectors that DESY develops and builds at its locations in Hamburg and Zeuthen are unique research tools. DESY is a member of the Helmholtz Association, and receives its funding from the German Federal Ministry of Education and Research (BMBF) (90 per cent) and the German federal states of Hamburg and Brandenburg (10 per cent).

 

Science contact

Dr. Andreas R. Maier
University of Hamburg
+49 40 8998-6687
andreas.maier@desy.de

Prof. Franz X. Kärtner
DESY
+49 40 8998-6350
franz.kaertner@desy.de

Media contact

Dr. Thomas Zoufal
DESY press officer
Phone: +49 40 8998-1666
presse@desy.de

Deutsches Elektronen-Synchrotron

DESY is one of the world’s leading accelerator centres. Researchers use the large-scale facilities at DESY to explore the microcosm in all its variety – from the interactions of tiny elementary particles and the behaviour of new types of nanomaterials to biomolecular processes that are essential to life. The accelerators and detectors that DESY develops and builds are unique research tools. The facilities generate the world’s most intense X-ray light, accelerate particles to record energies and open completely new windows onto the universe. That makes DESY not only a magnet for more than 3000 guest researchers from over 40 countries every year, but also a coveted partner for national and international cooperations. Committed young researchers find an exciting interdisciplinary setting at DESY. The research centre offers specialized training for a large number of professions. DESY cooperates with industry and business to promote new technologies that will benefit society and encourage innovations. This also benefits the metropolitan regions of the two DESY locations, Hamburg and Zeuthen near Berlin.

Address

DESY Hamburg
Notkestraße 85
22607Hamburg
Germany

+ 49 40/8998-0

http://www.desy.de/
Contact Info

PR Office
Christian Mrotzek
christian.mrotzek@DESY.DE
+49 40 8998-1665
+ 49 040 8998 4307 (fax)

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In Granada, the European particle physics community prepares decisions for the future of the fieldPress Releasexeno Mon, 05/13/2019 - 00:272419

Geneva and Granada, 13 May 2019. The European particle physics community is meeting this week in Granada, Spain, to discuss the roadmap for the future of the discipline. The aim of the symposium is to define scientific priorities and technological approaches for the coming years and to consider plans for the medium- and long-term future. An important focus of the discussions will be assessing the various options for the period beyond the lifespan of the Large Hadron Collider.

“The Granada symposium is an important step in the process of updating the European Strategy for Particle Physics1 and aims to prioritise our scientific goals and prepare for the upcoming generation of facilities and experiments,” said the President of the CERN Council, Ursula Bassler. “The discussions will focus on the scientific reach of potential new projects, the associated technological challenges and the resources required.”

The European Strategy Group, which was established to coordinate the update process, has received 160 contributions from the scientific community setting out their views on possible future projects and experiments. The symposium in Granada will provide an opportunity to assess and discuss them.

“The intent is to make sure that we have a good understanding of the science priorities of the community and of all the options for realising them,” said the Chair of the European Strategy Group, Professor Halina Abramowicz. “This will ensure that the European Strategy Group is well informed when deciding about the strategy update.”

The previous update of the European Strategy, approved in May 2013, recommended that design and feasibility studies be conducted in order for Europe “to be in a position to propose an ambitious post-LHC accelerator project.” Over the last few years, in collaboration with partners from around the world, Europe has therefore been engaging in R&D and design projects for a range of ambitious post-LHC facilities under the CLIC and FCC umbrellas. A study to investigate the potential to build projects that are complementary to high-energy colliders, exploiting the opportunities offered by CERN’s unique accelerator complex, was also launched by CERN in 2016. These contributions will feed into the discussion, which will also take into account the worldwide particle physics landscape and developments in related fields.

“At least two decades will be needed to design and build a new collider to succeed the LHC. Such a machine should maximise the potential for new discoveries and enable major steps forward in our understanding of fundamental physics” said CERN Director-General, Fabiola Gianotti. “It is not too early to start planning for it as it will take time to develop the new technologies needed for its implementation.”

The Granada symposium will be followed up with the compilation of a “briefing book” and with a Strategy Drafting Session, which will take place in Bad Honnef, Germany, from 20 to 24 January 2020. The update of the European Strategy for Particle Physics is due to be completed and approved by the CERN Council in May 2020.

An online Q&A session will be held on Thursday 16 May – 4pm CEST
Reporters interested in participating are invited to register by sending an e-mail to press@cern.ch

1. The European Strategy for Particle Physics is the cornerstone of Europe’s decision-making process for the long-term future of the field. In accordance with the mandate set by the CERN Council, it is formed through broad consultation of the grass-roots particle physics community, actively solicits the opinions of physicists from around the world and is developed in close coordination with similar processes in the US and Japan in order to ensure coordination between regions and optimal use of global resources.

About CERN
CERN, the European Organization for Nuclear Research, is one of the world's leading laboratories for particle physics. The Organization is located on the French-Swiss border, with its headquarters in Geneva. Its Member States are: Austria, Belgium, Bulgaria, Czech Republic, Denmark, Finland, France, Germany, Greece, Hungary, Israel, Italy, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Spain, Sweden, Switzerland and United Kingdom. Cyprus and Slovenia are Associate Member States in the pre-stage to Membership. India, Lithuania, Pakistan, Turkey and Ukraine are Associate Member States. The European Union, Japan, JINR, the Russian Federation, UNESCO and the United States of America currently have Observer status.

CERN

At CERN, the European Organization for Nuclear Research, physicists and engineers are probing the fundamental structure of the universe. They use the world's largest and most complex scientific instruments to study the basic constituents of matter – the fundamental particles. The particles are made to collide together at close to the speed of light. The process gives the physicists clues about how the particles interact, and provides insights into the fundamental laws of nature.

Contact information
European Organization for Nuclear Research
CERN
CH-1211 Genève 23
Switzerland

or

Organisation Européenne pour
la Recherche Nucléaire
F-01631 CERN Cedex
France
+ 41 22 76 761 11
+ 41 22 76 765 55 (fax)
 

https://home.cern/
Contact Info

Press Office
Arnaud Marsollier
Arnaud.Marsollier@cern.ch 
Press.office@cern.ch
+41 22 767 34 32
+41 22 767 21 41

 

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BESIII Observes Polarization of Baryons in J/ψ DecayPress Releasexeno Tue, 05/07/2019 - 08:472319

The BESIII collaboration observed baryon polarization in baryon-antibaryon (matter-antimatter particle) events from J/ψ particles produced at the BEPCII collider. The paper was published in Nature Physics on May 6.

Fig. 1 Graphical illustration of the e+e-→J/ψ→ΛΛ-bar reaction (Image by BESIII Collaboration)

 

The reaction e+e−→J/ψ→ΛΛ-bar , is illustrated in Fig. 1.  The baryons used in the study are Λ hyperons. Their weak decay into proton and negative pion, Λ→pπ-, makes it possible to determine the hyperon polarization, providing a convenient hyperon polarimeter. An example of the e+e−→J/ψ→ΛΛ-bar event with the subsequent decays Λ→pπ- and Λ-bar→p-bar π+ observed in the BESIII detector is shown in Fig. 2. With BESIII data from 2009 and 2012 (corresponding to 1.3 billion J/ψ events), the number of such reconstructed events is 420K.

The Λ hyperons in the reaction were polarized in the y direction (defined in Fig. 1) and BESIII has determined the precise value of the polarization, which depends on the production angle θΛ as shown in Fig. 3, with the maximum reaching 25%. The observed polarization makes it possible to determine new values for the parameters of hyperon decays. The BESIII result corrects by 17% the value used in many experiments for decades. This calls for reinterpretation of all Λ hyperon polarization results.

Finally, BESIII made a direct comparison of the decay parameters of the Λ hyperon to those of its antiparticle – Λ-bar antihyperon. This is the most sensitive test of matter-antimatter symmetry (CP symmetry) involving Lambda particles. This offers prospects for the further search for new sources of CP symmetry violation in baryon decay, using the large J/ψ data sample accumulated at BESIII and possibly even larger data samples at future experiments.

 

Fig. 2. An e+e-→J/ψ→ΛΛ-bar event as seen in the BESIII detector (Image by BESIII Collaboration)

Fig. 3. Polarization of Λ particle as a function of the production angle θΛ (Image by BESIII Collaboration)

 About BESIII:

The BESIII experiment at the Beijing Electron Positron Collider is composed of about 500 physicists from 67 institutions from 14 countries. The BESIII experiment contributes to China’s world-leading role in τ-charm physics. To date, the collaboration has published more than 250 papers.

 

Media Contacts:

Mr. Guo Lijun
Press Officer, International Office, IHEP
E-mail: ljguo@ihep.ac.cn

Institute of High Energy Physics, Chinese Academy of Sciences

The Institute of High Energy Physics (IHEP), a Chinese Academy of Sciences research institute, is China’s biggest laboratory for the study of particle physics. We want to understand the universe better at the most fundamental level – from the smallest subatomic particles to the large-scale structure of the cosmos. We also want to use the knowledge and technology that comes from our research for the good of humanity. As well as theoretical and experimental research into particle and astroparticle physics, we have a broad range of research in related fields such as accelerator technologies and nuclear analysis techniques. The Institute also provides beam facilities for researchers in other fields of study.

Working at IHEP are over 1400 full-time staff, as well as over 500 postdocs and graduate students. Particle physics is a very collaborative and a very international field, and we have partnerships and experiment collaborations with dozens of universities and research institutions across China and worldwide.

IHEP’s main campus is at Yuquan Road in the west part of Beijing. The Beijing campus hosts the Beijing Electron-Positron Collider, the BESIII experiment, the Beijing Synchrotron Radiation Facility, and most of IHEP’s research and administrative staff.  

The Dongguan campus, in Guangdong province in the south of China, is home to the China Spallation Neutron Source facility (currently under construction). In addition, IHEP runs experiment sites at Daya Bay and Jiangmen (both in Guangdong Province), Yangbajing (Tibet) and Daocheng (Sichuan).

Address

19B Yuquan Road
Shijingshan Qu
Beijing Shi, 100049
China

86-10-88233093

Contact Info

Institute of High Energy Physics, Chinese Academy of Sciences
19B Yuquan Road, Shijingshan District, Beijing, China, 100049
Email: ihep@ihep.ac.cn
FAX: 86-10-88233374
TEL: 86-10-88233093

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XENON1T Scientists Observe the Rarest Decay Process Ever Measured in the UniversePress Releasexeno Wed, 04/24/2019 - 11:512219

The universe is almost 14 billion years old. An inconceivable length of time by human standards – yet compared to some physical processes, it is but a moment. There are radioactive nuclei that decay on much longer time scales. An international team of scientists has now directly measured the rarest decay process ever recorded in a detector. Using the XENON1T detector which mainly searches for dark matter at the INFN Gran Sasso National Laboratory, the researchers were able to observe the decay of Xenon-124 atomic nuclei for the first time. The half-life of a process is the time after which half of the radioactive nuclei present in a sample have decayed away. The half-life measured for Xenon-124 is about one trillion times longer than the age of the universe. This makes the observed radioactive decay, the so-called double electron capture of Xenon-124, the rarest process ever seen happening in a detector. 

“The fact that we managed to observe this process directly demonstrates how powerful our detection method actually is – also for signals which are not from dark matter,” says Prof. Christian Weinheimer from the University of Münster (Germany) whose group lead the study. 

In addition, the new result provides information for further investigations on neutrinos, the lightest of all elementary particles whose nature is still not fully understood. XENON1T is a joint experimental project of about 160 scientists from Europe, the US and the Middle East. The results were published in the science journal “Nature”.

A sensitive dark matter detector

The Gran Sasso Laboratory of the National Institute for Nuclear Physics (INFN) in Italy, where scientists are currently searching for dark matter particles is located about 1,400 meters beneath the Gran Sasso massif, well protected from cosmic rays which can produce false signals. Theoretical considerations predict that dark matter should very rarely “collide” with the atoms of the detector. This assumption is fundamental to the working principle of the XENON1T detector: its central part consists of a cylindrical tank of about one meter in length filled with 3,200 kilograms of liquid xenon at a temperature of –95° C. When a dark matter particle interacts with a xenon atom, it transfers energy to the atomic nucleus which subsequently excites other xenon atoms. This leads to the emission of faint signals of ultraviolet light which are detected by means of sensitive light sensors located in the upper and lower parts of the cylinder. The same sensors also detect a minute amount of electrical charge which is released by the collision process. 

The new study shows that the XENON1T detector is also able to measure other rare physical phenomena, such as double electron capture. To understand this process, one should know that an atomic nucleus normally consists of positively charged protons and neutral neutrons, which are surrounded by several atomic shells occupied by negatively charged electrons. Xenon-124, for example, has 54 protons and 70 neutrons. In double electron capture, two protons in the nucleus simultaneously “catch” two electrons from the innermost atomic shell, transform into two neutrons, and emit two neutrinos. The other atomic electrons reorganize themselves to fill in the two holes in the innermost shell. The energy released in this process is carried away by X-rays and so-called Auger electrons. However, these signals are very hard to detect, as double electron capture is a very rare process which is hidden by signals from the omnipresent natural radioactivity.

The measurement

This is how the XENON collaboration succeeded with this measurement: The X-rays from the double electron capture in the liquid xenon produced an initial light signal as well as free electrons. The electrons were moved towards the gas-filled upper part of the detector where they generated a second light signal. The time difference between the two signals corresponds to the time it takes the electrons to reach the top of the detector. Scientists used this interval and the information provided by the sensors measuring the signals to reconstruct the position of the double electron capture. The energy released in the decay was derived from the strength of the two signals. All signals from the detector were recorded over a period of more than one year, however, without looking at them at all as the experiment was conducted in a “blind” fashion. This means that the scientists could not access the data in the energy region of interest until the analysis was finalized to ensure that personal expectations did not skew the outcome of the study. Thanks to the detailed understanding of all relevant sources of background signals it became clear that 126 observed events in the data were indeed caused by the double electron capture of Xenon-124. 

Using this first-ever measurement, the physicists calculated the enormously long half-life of 1.8×1022 years for the process. This is the slowest process ever measured directly. It is known that the atom Tellurium-128 decays with an even longer half-life, however, its decay was never observed directly and the half-life was inferred indirectly from another process. The new results show how well the XENON1T detector can detect rare processes and reject background signals. While two neutrinos are emitted in the double electron capture process, scientists can now also search for the so-called neutrino-less double electron capture which could shed light on important questions regarding the nature of neutrinos. 

Status and outlook

XENON1T acquired data from 2016 until December 2018 when it was switched off. The scientists are currently upgrading the experiment for the new “XENONnT” phase which will feature a three times larger active detector mass. Together with a reduced background level this will boost the detector’s sensitivity by an order of magnitude.

LINKS

The Nature article
The print version of the Nature article
The XENON1T Experiment
The XENON Experiment at INFN Gran Sasso National Laboratory
Short movie of the XENON1T construction at LNGS

CONTACTS

INFN Communications Office | Antonella Varaschin
antonella.varaschin@presid.infn.it
+39 349 5384481

LNGS-INFN Outreach Office | Roberta Antolini
roberta.antolini@lngs.infn.it
+39 0862 437216

The XENON spokesperson

Prof. Elena Aprile, Columbia University, New York, US
age@astro.columbia.edu

Tel. +39 3494703313 Tel. +1 212 854 3258 

In Italy

XENON National Leader for INFN

Marco Selvi, INFN Bologna
selvi@bo.infn.it
Tel. +39 3283178626 Tel. +39 0512091120

Laboratori Nazionali del Gran Sasso - INFN

INFN Gran Sasso National Laboratory. (Courtesy: INFN)

Gran Sasso National Laboratory (LNGS) is one of the four national laboratories of INFN (National Institute for Nuclear Physics).

The other laboratories of INFN are based in Catania, Frascati (Rome) and Legnaro (Padua); the whole network of laboratories house large equipment and infrastructures available for use by the national and international scientific community.

The National Institute for Nuclear Physics (INFN) is the Italian research agency dedicated to the study of the fundamental constituents of matter and the laws that govern them, under the supervision of the Ministry of Education, Universities and Research (MIUR). It conducts theoretical and experimental research in the fields of subnuclear, nuclear and astroparticle physics.

Address

Via G. Acitelli, 22
67100Assergi AQ
Italy

+ 39 0862 4371

http://www.lngs.infn.it/en
Contact Info

XENON spokesperson
Prof. Elena Aprile, Columbia University, New York, US.
Tel. +39 3494703313
Tel. +1 212 854 3258
age@astro.columbia.edu

INFN spokesperson
Roberta Antolini
+ 39 0862 437216
Roberta.antolini@lngs.infn.it

 

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CERN unveils its Science Gateway projectPress Releasexeno Mon, 04/08/2019 - 07:382019

Artistic view of the Science Gateway. (Image: RPBW)

CERN is launching the Science Gateway, a new scientific education and outreach centre targeting the general public of all ages. The building will be designed by world-renowned architects, Renzo Piano Building Workshop. The project will be funded through external donations, with the leading contribution coming from FCA Foundation, a charitable foundation created by Fiat Chrysler Automobiles. Construction is planned to start in 2020 and to be completed in 2022.

As part of its mission to educate and engage the public in science, and to share knowledge and technology with society, CERN is launching the Science Gateway, a new facility for scientific education and outreach. The purpose of the project is to create a hub of scientific education and culture to inspire younger generations with the beauty of science. Aimed at engaging audiences of all ages, the Science Gateway will include inspirational exhibition spaces, laboratories for hands-on scientific experiments for children and students from primary to high-school level, and a large amphitheatre to host science events for experts and non-experts alike.

With a footprint of 7000 square metres, the iconic Science Gateway building will offer a variety of spaces and activities, including exhibitions explaining the secrets of nature, from the very small (elementary particles) to the very large (the structure and evolution of the universe). The exhibitions will also feature CERN’s accelerators, experiments and computing, how scientists use them in their exploration and how CERN technologies benefit society. Hands-on experimentation will be a key ingredient in the Science Gateway’seducational programme, allowing visitors to get first-hand experience of what it’s like to be a scientist. The immersive activities available in the Science Gateway will foster critical thinking, evidence-based assessment and use of the scientific method, important tools in all walks of life.

“The Science Gateway will enable CERN to expand significantly its education and outreach offering for the general public, in particular the younger generations. We will be able to share with everybody the fascination of exploring and learning how matter and the universe work, the advanced technologies we need to develop in order to build our ambitious instruments and their impact on society, and how science can influence our daily life,” says CERN Director-General Fabiola Gianotti. “I am deeply grateful to the donors for their crucial support in the fulfilment of this beautiful project.”

The overall cost of the Science Gateway is estimated at 79 million Swiss Francs, entirely funded through donations. As of today, 57 million Swiss Francs have been already secured, allowing construction to start on schedule, thanks in particular to a very generous contribution of 45 million Swiss Francs from the FCA Foundation, which will support the project as it advances through the construction phases. Other donors include a private foundation in Geneva and Loterie Romande, which distributes its profits to public utility projects in various areas including research, culture and social welfare. CERN is looking for additional donations in order to cover the full cost of the project.

John Elkann, Chairman of FCA and the FCA Foundation, said: “The new Science Gateway will satisfy the curiosity of 300,000 visitors every year – including many researchers and students, but also children and their families – providing them with access to tools that will help them understand the world and improve their lives, whatever career paths they eventually choose. At FCA we’re delighted to be supporting this project as part of our social responsibility which also allows us to honour the memory of Sergio Marchionne: in an open and stimulating setting, it will teach us how we can work successfully together, even though we may have diverse cultures and perspectives, to discover the answers to today’s big questions and to those of tomorrow”.

As part of the educational portfolio of the Science Gateway, CERN and FCA Foundation will develop a programme for schools, with the advice of Fondazione Agnelli. The main goal will be to transmit concepts of science and technology in an engaging way, in order to encourage students to pursue careers in STEM (Science, Technology, Engineering and Mathematics). According to the approach of enquiry-based learning, students will be involved in hands-on educational modules and experiments in physics. Special kits will be delivered to classes, containing all necessary materials and instructions to run modules throughout the school year. As a follow-up, classes will be invited to take part in a contest, with the winners awarded a 2-3 day visit to the Science Gateway and CERN. There will be an initial period of experimentation, with a pilot programme in Italy focusing on junior high schools and involving up to 550,000 students. After the pilot, CERN plans to extend this initiative to all its Member States. 

The Science Gateway will be hosted in a new, iconic building, designed by world-renowned architects Renzo Piano Building Workshop, on CERN’s Meyrin site adjacent to another of CERN’s iconic buildings, the Globe of Science and Innovation. The vision for the Science Gateway is inspired by the fragmentation and curiosity already intrinsic to the nature of the CERN site and buildings, so it is made up of multiple elements, embedded in a green forest and interconnected by a bridge spanning the main road leading to Geneva.

“It’s a place where people will meet,” says Renzo Piano. “Kids, students, adults, teachers and scientists, everybody attracted by the exploration of the Universe, from the infinitely vast to the infinitely small. It is a bridge, in the metaphorical and real sense, and a building fed by the energy of the sun, nestling in the midst of a newly grown forest.”

Also inspired by CERN’s unique facilities, such as the Large Hadron Collider (LHC), the world’s largest particle accelerator, the architecture of the Science Gateway celebrates the inventiveness and creativity that characterise the world of research and engineering. Architectural elements such as tubes that seem to be suspended in space evoke the cutting-edge technology underpinning the most advanced research that is furthering our understanding of the origins of the universe.

A bridge over the Route de Meyrin will dominate the brand-new Esplanade des Particules and symbolise the inseparable link between science and society. Construction is planned to start in 2020 and be completed in 2022.

About FCA Foundation
The FCA Foundation, the charitable arm of FCA, supports charitable organizations and initiatives that help empower people, build strong, resilient communities and generate meaningful and measurable societal impacts particularly in the field of education.

About FCA
Fiat Chrysler Automobiles (FCA) is a global automaker that designs, engineers, manufactures and sells vehicles in a portfolio of brands including Abarth, Alfa Romeo, Chrysler, Dodge, Fiat, Fiat Professional, Jeep®, Lancia, Ram and Maserati. It also sells parts and services under the Mopar name and operates in the components and production systems sectors under the Comau and Teksid brands. FCA employs nearly 200,000 people around the globe. For more information regarding FCA, please visit www.fcagroup.com.    

About RPBW         
The Renzo Piano Building Workshop (RPBW) was established in 1981 by Renzo Piano with offices in Genoa, Italy and Paris, France. The practice has since expanded and now also operates from New York.
RPBW is led by 10 partners, including founder and Pritzker Prize laureate, architect Renzo Piano. The practice permanently employs about 130 architects together with a further 30 support staff including 3D visualization artists, model makers, archivers, administrative and secretarial staff.
RPBW has successfully undertaken and completed over 140 projects around the world.
Currently, among the main projects in progress are: the Academy Museum of Motion Pictures in Los Angeles; the École normale supérieure Paris-Saclay and; the GES 2 Center for the Arts in Moscow.
Major projects already completed include: the Centre Georges Pompidou in Paris; the Kanak Cultural Center in Nouméa, New Caledonia; the Beyeler Foundation Museum in Basel; the New York Times Building in New York; the California Academy of Sciences in San Francisco; the Chicago Art Institute expansion in Chicago, Illinois; The Shard in London; Columbia University’s Manhattanville development project in New York City; the Whitney Museum of American Art in New York; the Valletta City Gate in Malta; the Stavros Niarchos Cultural Center in Athens; the New Paris Courthouse and others throughout the world.

Exhibitions of Renzo Piano and RPBW’s works have been held in many cities worldwide, including at the Royal Academy of Arts in London in 2018.

The Science Gateway involves Renzo Piano Building Workshop, architects, in collaboration with Brodbeck Roulet Architectes Associés (Geneva)

Design team: A.Belvedere, L.Piazza (partner and associate in charge)

Consultants: Arup / EDMS (structure); Transsolar (sustainability); SRG (MEP); Müller BBM (acoustics); Emmer Pfenninger (façades); Changement à vue (A/V, heater equipment); Arup (lighting); Charpente Concept (fire prevention); Atelier Descombes Rampini (landscaping)

About Fondazione Agnelli
The Fondazione Agnelli is an independent, non-profit research organisation in the fields of human and social sciences, established in 1966 and named after founder of Fiat, the Senator Giovanni Agnelli. Its mission is “to further understanding of change in contemporary society in Italy and in Europe”. Since 2008 the Fondazione’s focus is on education, as a powerful lever for an individual’s fulfilment, an important channel of social mobility, and a key factor for a country’s economic growth and social cohesiveness. It runs wide ranging studies to improve the Italian education system, works with schools to renew the teaching methodologies, and helps families in the school choice. www.fondazioneagnelli.it

CERN

At CERN, the European Organization for Nuclear Research, physicists and engineers are probing the fundamental structure of the universe. They use the world's largest and most complex scientific instruments to study the basic constituents of matter – the fundamental particles. The particles are made to collide together at close to the speed of light. The process gives the physicists clues about how the particles interact, and provides insights into the fundamental laws of nature.

Contact information
European Organization for Nuclear Research
CERN
CH-1211 Genève 23
Switzerland

or

Organisation Européenne pour
la Recherche Nucléaire
F-01631 CERN Cedex
France
+ 41 22 76 761 11
+ 41 22 76 765 55 (fax)
 

https://home.cern/
Contact Info

Press Office
Arnaud Marsollier
Arnaud.Marsollier@cern.ch 
Press.office@cern.ch
+41 22 767 34 32
+41 22 767 21 41

 

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