The Global Community of Particle Physics
This account brings you hot items from public particle physics news sources, including CERN, SymmetryMagazine.org, and Interactions.org.
The Milky Way’s satellites help reveal link between dark matter halos and galaxy formation
2020-03-31T19:27:59Z via NavierStokesApp To: Public
"The Milky Way’s satellites help reveal link between dark matter halos and galaxy formation"https://www6.slac.stanford.edu/taxonomy/term/805/feed )
10 years of LHC physics, in numbers
2020-03-31T13:28:08Z via NavierStokesApp To: Public
"10 years of LHC physics, in numbers"
How do you measure a decade of LHC research?
In 2010, the Large Hadron Collider research program jumped into full swing as scientists started collecting physics data from particle collisions in the LHC for the first time.
How has this gigantic, global scientific effort affected the world? Symmetry pulled together a few numbers to find out.
petabytes of data
In the last decade, LHC experiments collected almost 280 petabytes of data, which scientists recorded on tape. You would need to stream Netflix 24/7 for more than 15,000 years to eventually use that much data! But from another perspective, platforms like Facebook (which has 2.5 billion users) collect that much data in 70 days!
While it’s impossible to know the actual number of Higgs bosons the LHC has produced (see Accounting for the Higgs), scientists can use the Standard Model’s equations to predict how many Higgs bosons the LHC should have produced. Scientists consider all the different ways Higgs bosons can be made, the likelihood of each process, and the energy and total number of collisions. Studying those Higgs bosons, scientists have precisely defined the mass, charge, spin and half-life of the Higgs. They continue to examine the many different ways the Higgs interacts with other particles and use it as a tool to search for new physics beyond the Standard Model.
Every week the number of scientific papers that LHC scientists have published steadily increases as they comb through the data to study rare phenomena and search for new physics. This includes work by thousands of graduate students on their way to earning their PhDs.
Worldwide LHC Computing Grid requests
Physicists need a huge amount of computing power to do their research—much more than a standard laptop can support. Every day several thousand physicists submit a total of about 2 million “jobs” to the WLCG. Each “job” is an important brick in the growing body of scientific work.
The number of collisions recorded by the four main experiments at the LHC is close to 4 quadrillion, or, as physicists say it, 395 “inverse femtobarns.” (Each inverse femtobarn corresponds to about 100 trillion collisions.) For reference, the LHC’s predecessor—the Tevatron particle collider at the US Department of Energy’s Fermi National Accelerator Laboratory—delivered a then-unprecedented more than 20 fb-1 to its two experiments over the course of 25 years of proton-antiproton collisions. Now the number of LHC collisions recorded by just the ATLAS or CMS experiment (~190 fb-1) is equivalent to the total number of ants on Earth.
CERN is governed by 23 member states, but scientists from more than 600 institutions around the world work on the experiments and projects it hosts. Since 2010, CERN has formally added 15 new countries—Albania, Bangladesh, Costa Rica, Kazakhstan, Latvia, Lebanon, Mongolia, Nepal, Palestine, Paraguay, the Philippines, Qatar, Sri Lanka, Thailand and Tunisia—to its research community through official bilateral cooperation agreements. Today, the total number of collaborating countries is around 80. US institutions are supported by the Department of Energy’s Office of Science.
microgram of protons
When running, the LHC has more than 300 trillion protons circling through its two beampipes. But they’re so tiny that even if you combined all the protons accelerated in the machine since 2010, they would only amount to a pile about the size of a speck of pollen.
CERN has hosted more than 45,000 guided tours in 32 languages through its public visit program, allowing more than 1 million visitors to discover the work of the world’s biggest physics laboratory. And for two special Open Day weekends—one in 2013 and another in 2019—CERN welcomed an average of 36,000 visitors a day! That’s roughly the same daily average as Disneyland Paris. Open Day visitors had access to numerous sites such as the LHC tunnel that are normally only accessible to authorized personnel.
Each year the Arts at CERN program invites artists to work alongside particle physicists and engineers at CERN. The resulting installations, choreography and multimedia projects travel the world and inspire countless art and science enthusiasts. In 2019, for example, more than 80,000 visitors took in the traveling exhibit Quantum/Broken Symmetries, which featured pieces by 10 artists who did work at CERN.
The Globe of Science and Innovation at CERN isn’t just an iconic landmark; it’s also a venue for conferences, shows, panels, film screenings and artistic performances. Since 2010, about 40,000 visitors have attended an event hosted by CERN inside the Globe. CERN also organizes events in the local community, including talks at schools, science fairs and panel discussions at movie theaters.
Since 2010, CERN openlab has set up over 50 collaborative projects through which CERN computer scientists work with leading tech companies on joint R&D. The companies get to test their latest products in CERN’s cutting-edge research environment, and CERN gets the chance to try out emerging technologies. For example, current projects with companies Intel and Micron are exploring how machine learning can be used to further improve the processing of data from particle collisions. At the same time, projects with Oracle and Siemens are using such technologies to help improve control systems for the LHC.
knowledge transfer projects
CERN’s Knowledge Transfer department collaborates with academic and industrial organizations to find new uses outside of particle physics research for technology developed at CERN. Since 2010, CERN has signed more than 300 knowledge transfer contracts with universities and companies working in fields such as safety, medtech and aerospace engineering. A notable collaboration is a father-and-son medical team who used CERN Medipix read-out chips to develop the world’s first 3D color X-ray in 2018.
CERN’s national and international teacher programs welcome groups of educators to the lab for anywhere between three days and two weeks. During their stays, teachers visit experiments, talk with physicists, and discuss ways to bring modern physics into their classrooms. More than 10,000 educators have participated.
Since 2010 almost 3,000 undergraduates have participated in the CERN summer student programs, including more than 150 students from the United States. These students receive training, tutoring and mentorship as they dip their toes into real scientific research and learn what particle physics is all about.
Week 11 at the Pole
2020-03-27T20:27:55Z via NavierStokesApp To: Public
"Week 11 at the Pole"
It finally happened—the lowering sun disappeared below the horizon at the South Pole, leaving everything in dusk.http://icecube.wisc.edu/news/feed )
Why some diseases come and go with the seasons, and how to develop smarter, safer chemicals
2020-03-26T18:27:57Z via NavierStokesApp To: Public
"Why some diseases come and go with the seasons, and how to develop smarter, safer chemicals"
On this week’s show, host Joel Goldberg gets an update on the coronavirus pandemic from Senior Correspondent Jon Cohen. In addition, Cohen gives a rundown of his latest feature, which highlights the relationship between diseases and changing seasons—and how this relationship relates to a potential coronavirus vaccine. Also this week, from a recording made at this year’s AAAS annual meeting in Seattle, host Meagan Cantwell speaks with Alexandra Maertens, director of the Green Toxicology initiative at Johns Hopkins University, Baltimore, about the importance of incorporating nonanimal testing methods to study the adverse effects of chemicals. This week’s episode was edited by Podigy. Listen to previous podcasts. About the Science Podcast [Image: Let Ideas Compete/Flickr; Music: Jeffrey Cook]http://www.sciencemag.org/rss/podcast.xml )
I vincitori della selezione locale di L'Aquila FameLab 2020
2020-03-26T11:28:29Z via NavierStokesApp To: Public
"I vincitori della selezione locale di L'Aquila FameLab 2020"
Quest’anno la selezione locale FameLab 2020, organizzata dai Laboratori Nazionali del Gran Sasso dell’INFN, dall’Università degli Studi dell’Aquila e dal Gran Sasso Science Institute, si è svolta in maniera virtuale.http://www.lngs.infn.it/en/news/rss )
Three national laboratories achieve record magnetic field for accelerator focusing magnet
2020-03-25T17:28:15Z via NavierStokesApp To: Public
"Three national laboratories achieve record magnetic field for accelerator focusing magnet"
Three national laboratories achieve record magnetic field for accelerator focusing magnetPress Releasexeno Thu, 03/19/2020 - 11:011220
In a multiyear effort involving three national laboratories from across the United States, researchers have successfully built and tested a powerful new magnet based on an advanced superconducting material. The eight-ton device — about as long as a semi-truck trailer — set a record for the highest field strength ever recorded for an accelerator focusing magnet and raises the standard for magnets operating in high-energy particle colliders.
The Department of Energy’s Fermilab, Brookhaven National Laboratory and Lawrence Berkeley National Laboratory designed, built and tested the new magnet, one of 16 they will provide for operation in the High-Luminosity Large Hadron Collider at CERN laboratory in Europe. The 16 magnets, along with another eight produced by CERN, serve as “optics” for charged particles: They will focus beams of protons into a tiny, infinitesimal spot as they approach collision inside two different particle detectors.
The ingredient that sets these U.S.-produced magnets apart is niobium-tin – a superconducting material that produces strong magnetic fields. These will be the first niobium-tin quadrupole magnets ever to operate in a particle accelerator.
“This accomplishment is a major milestone for the High-Luminosity LHC project, which relies heavily on the success of the niobium-tin superconducting magnet technology,” said Lucio Rossi, project leader of the High-Luminosity LHC project.
The ingredient that sets these U.S.-produced magnets apart is niobium-tin – a superconducting material that produces strong magnetic fields.
Like the current Large Hadron Collider, its high-luminosity successor will smash together beams of protons cruising around the 17-mile ring at close to the speed of light. The High Luminosity LHC will pack an additional punch: It will provide 10 times the collisions that are possible at the current LHC. With more collisions come more opportunities to discover new physics.
And the machine’s new focusing magnets will help it achieve that leap in delivered luminosity.
“We’ve demonstrated that this first quadrupole magnet behaves successfully and according to design, based on the multiyear development effort made possible by DOE investments in this new technology,” said Fermilab scientist Giorgio Apollinari, head of the U.S. Accelerator Upgrade Project, which leads the U.S.-based focusing-magnet project.
“It’s a very cutting-edge magnet, really on the edge of magnet technology,” said Brookhaven National Laboratory scientist Kathleen Amm, the Brookhaven representative for the Accelerator Upgrade Project.
What makes it successful is its impressive ability to focus.
Focus, magnets, focus
In circular colliders, two beams of particles race around the ring in opposite directions. An instant before they reach the collision point, each beam passes through a series of magnets that focus the particle beams into a tiny, infinitesimal spot, much the way lenses focus light rays to a point. Now packed as tightly with particles as the magnets can get them — smash! — the beams collide.
The scientific fruitfulness of that smash depends on how dense the beam is. The more particles that are crowded into the collision point, the greater the chance of particle collisions.
You get those tightly packed beams by sharpening the magnet’s focus. One way to do that is to widen the lens. Consider light:
“If you try to focus the light from the sun using a magnifying glass at a small point, you want to have a more ‘powerful’ magnifying glass,” said Ian Pong, Berkeley Lab scientist and one of the control account managers.
A larger magnifying glass focuses more of the sun’s rays than a smaller one. However, the light rays at the outer rim of the lens have to be bent more sharply in order to approach the same focal point.
Or consider a group of archers shooting arrows at an apple: More arrows will stick if the archers shoot from above, below and either side of the apple than if they are stationed at one post, firing from the same position.
The analog of the magnifying glass size and the archer array is the magnet’s aperture — the opening of the passageway the beam takes as it barrels through the magnet’s interior. If the particle beam is allowed to start wide before being focused, more particles will arrive at the intended focal point — the center of the particle detector.
The U.S. team widened the LHC focusing magnet’s aperture to 150 millimeters, more than double the current aperture of 70 millimeters.
But of course, a wider aperture isn’t enough. There is still the matter of actually focusing the beam, which means forcing a dramatic change in the beam’s size, from wide to narrow, by the time the beam reaches the collision point. And that requires an exceptionally strong magnet.
“The magnet has to squeeze the beam more powerfully than the LHC’s present magnets in order to create the luminosity needed for the HL-LHC,” Apollinari said.
“The magnet has to squeeze the beam more powerfully than the LHC’s present magnets in order to create the luminosity needed for the HL-LHC,” Apollinari said.
To meet the demand, scientists designed and constructed a muscular focusing magnet, calculating that, at the required aperture, it would have to generate a field exceeding 11.4 teslas. This is up from the current 7.5-tesla field generated by the niobium-titanium-based LHC quadrupole magnets. (For accelerator experts: The HL-LHC integrated luminosity goal is 3,000 inverse femtobarns.)
In January, the three-lab team’s first HL-LHC focusing magnet delivered above the goal performance, achieving an 11.5-tesla field and running continuously at this strength for five straight hours, just as it would operate when the High-Luminosity LHC starts up in 2027.
“These magnets are the currently highest-field focusing magnets in accelerators as they exist today,” Amm said. “We’re really pushing to higher fields, which allows us to get to higher luminosities.”
The new focusing magnet was a triumph, thanks to niobium-tin.
Niobium-tin for the win
The focusing magnets in the current LHC are made with niobium-titanium, whose intrinsic performance limit is generally recognized to have been reached at 8 to 9 teslas in accelerator applications.
The HL-LHC will need magnets with around 12 teslas, about 250,000 times stronger than the Earth’s magnetic field at its surface.
“So what do you do? You need to go to a different conductor,” Apollinari said.
Accelerator magnet experts have been experimenting with niobium-tin for decades. Electrical current coursing through a niobium-tin superconductor can generate magnetic fields of 12 teslas and higher — but only if the niobium and tin, once mixed and heat-treated to become superconductive, can stay intact.
“Once they’re reacted, it becomes a beautiful superconductor that can carry a lot of current, but then it also becomes brittle,” Apollinari said.
“If you bend it too much, even a little bit, once it’s a reacted material, it sounds like corn flakes,” Amm said. “You actually hear it break.”
Over the years, scientists and engineers have figured out how to produce niobium-tin superconductor in a form that is useful. Guaranteeing that it would hold up as the star of an HL-LHC focusing magnet was another challenge altogether.
Berkeley, Brookhaven and Fermilab experts made it happen. Their assembly process is a delicate, involved operation balancing niobium-tin’s fragility against the massive changes in temperature and pressure it undergoes as it becomes the primary player in a future collider magnet.
The process starts with wires containing niobium filaments surrounding a tin core, provided by an outside manufacturer. The wires are then fabricated into cables at Berkeley in just the right way. The teams at Brookhaven and Fermilab then wind these cables into coils, careful to avoid deforming them excessively. They heat the coils in a furnace in three temperature stages, a treatment that takes more than a week. During heat treatment the tin reacts with the filaments to form the brittle niobium-tin.
Having been reacted in the furnace, the niobium-tin is now at its most fragile, so it is handled with care as the team cures it, embedding it in a resin to become a solid, strong coil.
That coil is now ready to serve as one of the focusing magnet’s four poles. The process takes several months for each pole before the full magnet can be assembled.
“Because these coils are very powerful when they are energized, there is a lot of force trying to push the magnet apart,” Pong said. “Even if the magnet is not deforming, at the conductor level there will be a strain, to which niobium-tin’s performance is very sensitive. The management of the stress is very, very important for these high-field magnets.”
Heat treating the magnet coils — one of the intermediate steps in the magnet’s assembly — is also a subtle science. Each of the four coils of an HL-LHC focusing magnet weighs about one ton and has to be heat-treated evenly — inside and out.
“You have to control the temperature well. Otherwise the reaction will not give us the best performance. It’s a bit like cooking,” Pong said.
“You have to control the temperature well. Otherwise the reaction will not give us the best performance,” Pong said. “It’s a bit like cooking. It’s not just to achieve the temperature in one part of the coil but in the entire coil, end to end, top to bottom, the whole thing.”
And the four coils have to be aligned precisely with one another.
“You need very high field precision, so we have to have very high precision in how they align these to get good magnetic-field uniformity, a good quadrupole field,” Amm said.
The fine engineering that goes into the U.S. HL-LHC magnets has sharpened over decades, with a payoff that is energizing the particle accelerator community.
“This will be the first use of niobium-tin in accelerator focusing magnets, so it will be pretty exciting to see such a complex and sophisticated technology get implemented into a real machine,” Amm said.
“We were always carrying the weight of responsibility, the hope in the last 10, 20 years — and if you want to go further, 30, 40 years — focusing on these magnets, on conductor development, all the work,” Pong said. “Finally, we are coming to it, and we really want to make sure it is a lasting success.”
The many moving parts of an accelerator collaboration
Ensuring lasting success has as much to do with operational choreography as it does with exquisite engineering. Conducting logistics that span years and a continent requires painstaking coordination.
“Planning and scheduling are very important, and they’re quite challenging,” Pong said. “For example, transportation communication: We have to make sure that things are well-protected. Otherwise these expensive items can be damaged, so we have to foresee issues and prevent them. Delays also have an impact on the whole project, so we have to ensure components are shipped to destination in a timely schedule.”
Amm, Apollinari, Pong and Rossi acknowledge that the three-U.S.-lab team and CERN have met the challenges capably, operating as a well-oiled machine.
“The technologies developed at Fermilab, Brookhaven and Berkeley helped make the original LHC a success. And now again, these technologies out of the U.S. are really helping CERN be successful. It’s a dream team, and it’s an honor to be a part of it,” Amm said.
“This full-length, accelerator-ready magnet performance record is a real textbook case for international collaboration in the accelerator domain: Since the very beginning, the U.S. labs and CERN teamed up and managed to have a common and very synergic R&D, particularly for the quadrupole magnet that is the cornerstone of the upgrade,” Rossi said. “This has resulted in substantial savings and improved output.”
From now until about 2025, the U.S. labs will continue to build the large, hulking tubes, starting with fine strands of niobium and tin. They plan to begin delivering in 2022 the first of 16 magnets, plus four spares, to CERN. Installation will take place over the three years following.
“This success in the U.S. is a very good omen for the test of the CERN quadrupole magnet, a twin companion of the U.S. quadrupole. It also nicely complements the successful test in July 2019 at CERN of the 11.2-tesla dipole, which will be the first high field niobium-tin magnet to be installed for HL-LHC, in the upcoming months,” Rossi said.
“Our magnets are massive superconducting devices, focusing tiny invisible particle beams that are flying close to the speed of light through the bore. It’s quite magical,” Pong said.
“People say that ‘touchdown’ is a very beautiful word to describe the landing of an airplane, because you have a huge metal object weighing hundreds of tons, descending from the sky, touching a concrete runway very gently,” Pong said. “These magnets are not too different from that. Our magnets are massive superconducting devices, focusing tiny invisible particle beams that are flying close to the speed of light through the bore. It’s quite magical.”
The magic starts in 2027, when the High-Luminosity LHC comes online.
“We are doing today the work that future young researchers will use in 10 or 20 years from now to push the frontier of human knowledge, just like it happened when I was a young researcher here at Fermilab, using the Tevatron,” Apollinari said. “It’s a generational passing of the baton. We need to make the machines for the future generations, and with this technology, obviously what we can enable for the future generation is a lot.”
- Karen McNulty Walsh, Brookhaven National Laboratory, email@example.com, 631-344-8350, 917-699-0501
- Laurel Kellner, Lawrence Berkeley National Laboratory, firstname.lastname@example.org, 510-590-8034
- Leah Hesla, Fermilab, email@example.com, 630-840-3351
Fermilab is America’s premier national laboratory for particle physics and accelerator research. A U.S. Department of Energy Office of Science laboratory, Fermilab is located near Chicago, Illinois, and operated under contract by the Fermi Research Alliance LLC, a joint partnership between the University of Chicago and the Universities Research Association, Inc. Visit Fermilab’s website at www.fnal.gov and follow us on Twitter at @Fermilab.
This accelerator magnet work is supported by the Department of Energy Office of Science.
Fermilab is supported by the Office of Science of the U.S. Department of Energy. The 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.http://www.interactions.org/index.rss )
Fermi National Accelerator Laboratory
Fermilab is America's particle physics and accelerator laboratory. Founded in 1967, Fermilab drives discovery by investigating the smallest building blocks of matter using world-leading particle accelerator and detector facilities. We also use the universe as a laboratory, making measurements of the cosmos to the mysteries of dark matter and dark energy. Fermilab is located near Chicago, Illinois, and is managed by Fermi Research Alliance, LLC for the U.S. Department of Energy Office of Science.
What are we made of? How did the universe begin? What secrets do the smallest, most elemental particles of matter hold, and how can they help us understand the intricacies of space and time?
Since 1967, Fermilab has worked to answer these and other fundamental questions and enhance our understanding of everything we see around us. As the United States' premier particle physics laboratory, we do science that matters. We work together with our international partners on the world's most advanced particle accelerators and dig down to the smallest building blocks of matter. We also probe the farthest reaches of the universe, seeking out the nature of dark matter and dark energy.
Fermilab's 6,800-acre site is located in Batavia, Illinois, and is managed by the Fermi Research Alliance LLC for the U.S. Department of Energy Office of Science. FRA is a partnership of the University of Chicago and Universities Research Association Inc., a consortium of 89 research universities.
P.O. Box 500
+ 1 630 840 3000,
+ 1 630 840 4343 (fax)http://www.fnal.gov/
CERN in the coming weeks
2020-03-25T15:27:54Z via NavierStokesApp To: Public
"CERN in the coming weeks"
CERN in the coming weeks cagrigor Wed, 03/25/2020 - 11:56http://home.web.cern.ch/about/updates/feed )
A lot of our activities are continuing (e.g. physics data analysis, software development, technical studies, administration and so forth), and some teams have actually seen a surge e.g. the IT team that is working hard to provide videoconferencing support for everyone. Our communications team is also very busy!
As of last Friday, CERN has now reduced all activities on-site to those that are essential for the safety and security of the sites and equipment. The number of people with access to the CERN sites is limited; it is considered safe to be on site with regard to COVID-19 as long as people respect the safety measures.
As CERN was moving into the final stage of a long shutdown (Long Shutdown 2 – LS2), no accelerators were operational. The goal of last week was to safely stop all the maintenance, consolidation, and upgrade work that was in progress. The approach is to keep baseline services at CERN running (e.g., ventilation, cooling, electrical supply, safety systems), whilst leaving all material and equipment in a secure state, so that things are ready to restart quickly when operations can begin again. Monitoring during this phase will include on-site checks, with technical infrastructure operators maintaining their usual 24/7 physical presence in our main control room. Extensive on-call support is in place in case of problems.
Now that all activities have been reduced, CERN is now working on how the impact of the COVID-19 pandemic will affect the LS2 schedule and other activities and how best to recover when the time comes. The global COVID-19 situation is still evolving; we will continue to monitor ongoing events, and adapt according to what happens in our Host States and across the world.
As we enter safe-mode and prepare to plan for a return to full activity, our thoughts go out to all those touched by the virus.
A demonstrator magnet produces a record magnet field
2020-03-25T15:27:54Z via NavierStokesApp To: Public
"A demonstrator magnet produces a record magnet field"
A demonstrator magnet produces a record magnet fieldcmenard Wed, 03/25/2020 - 10:06http://home.web.cern.ch/about/updates/feed )
One of the keys to pushing the energy limits of accelerators is being able to reach higher magnetic fields. CERN and several other laboratories around the world have launched R&D programmes aimed at improving existing magnet technology. In February, a demonstrator magnet using superconducting niobium-tin, cooled to 1.9 kelvins, achieved a peak magnetic field of 16.5 tesla on the conductor, exceeding the previous record of 16.2 tesla in 2015.
The demonstrator, known as an enhanced Racetrack Model Coil (eRMC) magnet, consists of two superimposed flat coils in the shape of a racetrack, hence its name. The coils are produced using a cable composed of multifilament composite wire made of niobium-tin, a superconductor that can reach higher magnetic fields than the niobium-titanium superconductor currently used for the magnets of the Large Hadron Collider (LHC). The dipole magnets in the LHC operate at a nominal field of 8.3 tesla.
Niobium-tin is the material being used for some of the new magnets in the High-Luminosity LHC, the successor to the LHC, which will make use of dipole and quadrupole magnets generating a magnetic field of around 12 tesla. This increase is already significant in comparison with what can be achieved with niobium-titanium, but niobium-tin will allow even higher magnetic fields to be produced. This potential is now being explored further, notably as part of the Future Circular Collider (FCC) study. To reach a collision energy of 100 TeV using a ring with a circumference of 100 km, dipole magnets generating magnetic fields of 16 tesla are needed.
Even though the eRMC demonstrator isn’t an accelerator magnet, its configuration allows the performance of niobium-tin conductors to be tested. During the tests, the eRMC magnet, cooled to 1.9 kelvins (the LHC’s operating temperature), reached a peak magnetic field on the conductor of 16.5 tesla. At 4.5 kelvins, this field peaked at 16.3 tesla, which corresponds to 98% of the maximum estimated performance of the superconducting cable.
“These results and recent advances with niobium-tin magnets demonstrate the potential of this technology for a next-generation hadron collider,” emphasises Luca Bottura, leader of the Magnets, Superconductors and Cryostats (TE-MSC) group at CERN. This record is just one of many promising advances at several laboratories. Another magnet, FRESCA2, which has a 100 mm aperture, reached a magnetic field of 14.6 tesla in 2018 at CERN. FRESCA2 was developed for integration into a test station for superconducting cables. Last year, Fermilab in the United States tested an accelerator-type short model dipole magnet, with a 60 mm aperture, which reached a field of 14.1 tesla at 4.5 kelvins.
The CERN teams will continue their work to develop an accelerator magnet configuration. The eRMC demonstrator will therefore be dismantled and reassembled with a third coil on the median plane to create a 50 mm cavity.
Scientists search for origin of proton mass
2020-03-24T18:27:41Z via NavierStokesApp To: Public
"Scientists search for origin of proton mass"
Only 1% of the mass of the proton comes from the Higgs field. ALICE scientists examine a process that could help explain the rest.
When protons and nuclei inside the Large Hadron Collider smash directly into each other, their energy can transform into new types of matter such as the famed Higgs boson, known for its association with a field that gives fundamental particles mass. But when nuclei merely graze each other, a different amazing thing happens: They generate some of the strongest magnetic fields in the universe.
These ultra-intense magnetic fields are enabling scientists to peer inside atoms to answer a fundamental question: How do protons get most of their mass?
Protons are made up of fundamental particles called quarks and gluons. Quarks are very light, and, as far as scientists know, gluons have no mass at all. Yet protons are much heavier than the combined masses of the three quarks they each contain.
“There is a lot of publicity about the origin of mass because of the Higgs boson,” says Dmitri Kharzeev, a theorist with a joint appointment at Stony Brook University and the Department of Energy’s Brookhaven National Laboratory. “But the Higgs is responsible for the mass of the quarks. The rest of it has a different origin.”
The origin of mass
Quarks are very light, accounting for only about 1% of the proton’s overall mass. The plausible—yet still unproven—theoretical explanation for this discrepancy is related to how quarks move through the vacuum.
This vacuum is not empty, says Sergei Voloshin, a professor at Wayne State University and a member of the ALICE experiment at CERN. The vacuum is actually filled with undulating fields that constantly burp particle-antiparticle pairs into and out of existence.
The three quarks that give protons their identity are forever jostling with these ethereal particle-antiparticle pairs. When one of these quarks gets too close to a vacuum-produced antiquark, it is annihilated and disappears in a burst of energy.
But the proton doesn’t wither and die when its quark is zapped out of existence; rather, the partner quark from the vacuum-produced particle-antiparticle pair steps in and takes the annihilated quark’s place (a plot twist straight out of The Talented Mr. Ripley).
Scientists think that this incessant interchange of quarks is responsible for making a proton appear more massive than the sum of its quarks.
“Ninety-nine percent of mass might originate from this process of chirality-flipping in the vacuum.”
A matter of handedness
From the outside, not much appears to change in this swap. The annihilated quark is immediately replaced by a seemingly identical twin, making this process difficult to observe. Luckily for LHC scientists, they are not exactly identical: Quarks, like people, can be left- or right-handed, a concept called chirality.
Chirality is related to a quantum mechanical property called spin and roughly translates to whether the quark spins clockwise or counterclockwise as it moves along a particular direction through space. (Visualize beads spinning as they slide along a wire.)
Because of the properties of the vacuum, the replacement quark will always have the opposite handedness from the original. That constant flipping of quarks from one handedness to the other is how theorists explain the majority of the proton’s mass.
“Ninety-nine percent of mass might originate from this process of chirality flipping in the vacuum,” Kharzeev says. “When we step on a scale, the number we see might be the result of these chirality-flipping transitions.”
Physics inside a magnetic field
In 2004, when Kharzeev was the head of the Nuclear Theory Group at Brookhaven Lab, he had an idea for how they could experimentally search for evidence of quark chirality flipping, which had never been observed.
Because quarks are charged, they should interact with a magnetic field. “Normally, we never think about this interaction, because the magnetic fields we can create in the laboratory are extremely weak compared to the strength of quarks’ interactions with each other,” Kharzeev says. “However, we realized that when charged ions are colliding, they are accompanied by an electromagnetic field, and this field can be used to probe the chirality of quarks.”
When they did the math, they found that positively charged ions grazing each other inside a particle collider like the LHC will generate a magnetic field two orders of magnitude stronger than the one at the surface of the strongest magnetic field known to exist. This would be enough to override the quarks’ strong attraction to each other.
“Measuring the magnetic field’s strength and its lifetime was the primary goal of a recent ALICE data analysis,” says Voloshin. “The study yielded somewhat unexpected results, but they were still consistent with the existence of the strong magnetic field required for sorting of quarks according to their handedness.”
Within a strong magnetic field, a quark’s motion is no longer random. The magnetic field automatically sorts quarks according to their chirality, with their handedness steering them toward either the field’s north or south pole.
A hearty, hot soup of quarks
It’s nearly impossible to catch a quark flipping its chirality inside a proton, Kharzeev says.
“Inside a proton, left-handed quarks transition into right-handed quarks, and right-handed quarks transition back into left-handed quarks,” he says. “We will always see a mixture of left- and right-handed quarks.”
To study whether quark chirality flipping happens, physicists need to catch several large and unexpected imbalances between the number of right- and left-handed quarks.
Luckily, heavy nuclei collisions produce the perfect conditions for quarks to change their handedness. When two nuclei hit each other at high speeds, their protons and neutrons melt into a quark-gluon plasma, which is one of the hottest and densest materials known to exist in the universe. The liberated quarks swimming through this plasma can shift their identities with ease.
“It’s like pretzels before they’re baked,” Kharzeev says. “You can easily mold the dough and change the twist.”
The vacuum of space is not homogeneous—there are knots of gluon field that preferentially twist these doughy quarks one way or the other. If chirality flipping is happening, then scientists should catch an imbalance in the number of left- and right-handed quarks that shoot out from the plasma.
“The average handedness over all the collisions should be the same,” Kharzeev says, “but the fluctuations from collision to collision should be very large; we should see some quark-gluon plasmas that are preferentially righted-handed and others that are preferentially left-handed.” Due to the presence of magnetic field, the handedness of the plasma translates into observable charge asymmetry of produced particles—this is the “chiral magnetic effect” proposed by Kharzeev.
Shortly after Kharzeev proposed the idea of sorting quarks according to their handedness in the strong magnetic field of colliding nuclei, Voloshin designed a way to test this theory using the ALICE experiment, whose US participation is funded by the Department of Energy. The initial results show evidence for quarks sorting themselves according to chirality. But more research needs to be done before scientists can be sure.
Color with IceCube
2020-03-23T15:27:19Z via NavierStokesApp To: Public
Week 10 at the Pole
2020-03-20T21:27:30Z via NavierStokesApp To: Public
SOSPENSIONE TERMINI PROCEDIMENTALI DI GARE PER EMERGENZA COVID-19 COME DA D.L. N.18/2020
2020-03-20T12:27:41Z via NavierStokesApp To: Public
"SOSPENSIONE TERMINI PROCEDIMENTALI DI GARE PER EMERGENZA COVID-19 COME DA D.L. N.18/2020"
Come previsto dall'art. 103 del D. L. n. 18 del 17.03.2020, si informa che i termini di tutti i procedimenti di gara pendenti alla data del 23 febbraio 2020 o iniziati successivamente a tale data sono sospesi dal 23 febbraio al 15 aprile 2020. Salvo nuove disposizioni di legge, i termini anzidetti riprenderanno a decorrere dal 16 aprile 2020 per la parte residua.http://www.lngs.infn.it/en/news/rss )
Ancient artifacts on the beaches of Northern Europe, and how we remember music
2020-03-19T18:27:35Z via NavierStokesApp To: Public
"Ancient artifacts on the beaches of Northern Europe, and how we remember music"
On this week’s show, host Joel Goldberg talks with science journalist Andrew Curry about archaeological finds from thousands of years ago along the shores of Northern Europe. Curry outlines the rich history of the region that scientists, citizen scientists, and energy companies have helped dredge up. Also this week, from a recording made at this year’s AAAS annual meeting in Seattle, host Meagan Cantwell speaks with Elizabeth Margulis, a professor at Princeton University, about musical memory. Margulis explains what research tells us about how our brains process music, and dives into her own study on how Western and non-Western audiences interpret the same song differently. This week’s episode was edited by Podigy. Listen to previous podcasts. About the Science Podcast [Image: Sebastian Reinecke/Flickr; Music: Jeffrey Cook]http://www.sciencemag.org/rss/podcast.xml )
New Call for GSSI PhD Applications 2020/21 now open
2020-03-18T14:27:37Z via NavierStokesApp To: Public
"New Call for GSSI PhD Applications 2020/21 now open"
The GSSI – Gran Sasso Science Institute offers 30 PhD scholarships in the following fields: Astroparticle Physics (8 scholarships), Mathematics in Natural, Social and Life Sciences (8), Computer Science (7), Regional Science and Economic Geography (7).http://www.lngs.infn.it/en/news/rss )
Looking for dark matter in the center of the Milky Way
2020-03-17T14:27:32Z via NavierStokesApp To: Public
"Looking for dark matter in the center of the Milky Way"
Dark matter is one of the biggest mysteries in science today, and neutrinos might be able to help. IceCube and ANTARES Collaborations recently probed a known dark matter hotspot—the center of the Milky Way—by combining data from their respective neutrino telescopes. They did not find any unusual excesses of neutrinos, but they put stronger constraints on the dark matter annihilation cross-section averaged over the dark matter velocity. The results of the analysis are outlined in a paper submitted today to Physical Review D.http://icecube.wisc.edu/news/feed )
Annullamento concorso Anch'Io Scienziato - A.S. 2019-2020
2020-03-16T14:28:23Z via NavierStokesApp To: Public
"Annullamento concorso Anch'Io Scienziato - A.S. 2019-2020"
I Laboratori Nazionali del Gran Sasso a seguito dell'emergenza COVID-19 e della chiusura delle scuole di ogni ordine e grado comunicano la sospensione del concorso "Anch'Io Scienziato" 2019-2020 dando appuntamento a tutti gli studenti abruzzesi al prossimo anno scolastico. In bocca al lupo a tutti per un rapido ritorno alla normalitàhttp://www.lngs.infn.it/en/news/rss )
Week 9 at the Pole
2020-03-13T17:28:34Z via NavierStokesApp To: Public
Science’s leading role in the restoration of Notre Dame, and the surprising biology behind how our body develops its tough skin
2020-03-12T18:28:40Z via NavierStokesApp To: Public
"Science’s leading role in the restoration of Notre Dame, and the surprising biology behind how our body develops its tough skin"
On this week’s show, freelance writer Christa Lesté-Lasserre talks with host Sarah Crespi about the scientists working on the restoration of Notre Dame, from testing the changing weight of wet limestone, to how to remove lead contamination from four-story stained glass windows. As the emergency phase of work winds down, scientists are also starting to use the lull in tourist activity to investigate the mysteries of the cathedral’s construction. Also this week, Felipe Quiroz, an assistant professor in the biomedical engineering department at the Georgia Institute of Technology and Emory University, talks with Sarah about his paper on the cellular mechanism of liquid-liquid phase separation in the formation of the tough outer layer of the skin. Liquid-liquid phase separation is when two liquids “demix,” or separate, like oil and water. In cells, this process created membraneless organelles that are just now starting to be understood. In this work, Quiroz and colleagues create a sensor for phase separation in the cell that works in living tissue, and show how phase separation is tied to the formation of the outer layers of skin in mice. Read the related Insight. This week’s episode was produced with help from Podigy. Listen to previous podcasts. About the Science Podcast Download a transcript (PDF). [Image: r. nial bradshaw/Flickr; Music: Jeffrey Cook]http://www.sciencemag.org/rss/podcast.xml )
CERN updates its Open Hardware Licence
2020-03-12T10:28:36Z via NavierStokesApp To: Public
"CERN updates its Open Hardware Licence"
CERN updates its Open Hardware Licenceachintya Mon, 03/09/2020 - 12:33http://home.web.cern.ch/about/updates/feed )
Nine years after publishing the first version of the CERN Open Hardware Licence (CERN-OHL) – which governs the use, copying, modification and distribution of hardware designs and the manufacture and distribution of any resulting products – CERN has now released version 2.0 of the licence. The latest version uses simpler terminology, introduces three variants of the licence, and broadens its range to include designs that go from artistic to mechanical to electronic, as well as adapting the licence to cases such as application-specific integrated circuits (ASICs) and field-programmable gate arrays (FPGAs). It can even be used to license software.
“The CERN-OHL is to hardware what the free and open-source licences are to software,” explains Myriam Ayass, legal adviser for the CERN Knowledge Transfer group and one of the authors of the CERN-OHL. “It defines the conditions under which a licensee will be able to use or modify the licensed material. It shares the same principles as free software or open-source software: anyone should be able to see the source – the design documentation in the case of hardware – study it, modify it and share it.” ‘Source’ includes schematic diagrams, designs, circuit or circuit-board layouts, mechanical drawings, flow charts and descriptive texts, as well as other explanatory material.
“Open hardware gives designers and users the freedom to share hardware designs, modify them, manufacture products based on the design files and commercialise those products. This freedom enables collaboration among engineers, scientists, researchers, hobbyists and companies without the risk of vendor lock-in or other issues present in proprietary development,” explains Javier Serrano, an engineer in the Beams Department at CERN and the founder of the Open Hardware Repository (OHR).
Version 2.0 of the CERN-OHL introduces three variants of the licence – strongly reciprocal, weakly reciprocal and permissive – which aim to address specific constraints caused by different collaboration models currently used in open-hardware projects. The first two variants mean that if any product is made using an open hardware design, the design of that product, including any improvements or modifications, should be made available under the same licence as that of the original product. Permissive licences do not impose this condition.
Andrew Katz, a lawyer and “open” specialist from Moorcrofts LLP, who has also been involved in the drafting process, said he believes the new drafts adopt best practices from the world of open-source software, while adapting to the specific and uniquely complex challenges presented by open hardware. “We’re particularly excited by the enthusiastic response we’ve had to the drafts from members of communities in all sectors of open hardware, and we’ve been very grateful for their valuable comments and input.”
Summer at the South Pole: 2019-2020 season recap
2020-03-11T15:28:35Z via NavierStokesApp To: Public
"Summer at the South Pole: 2019-2020 season recap"
This summer season, IceCube sent more than 30 people from 12 institutions to the Pole to work on a variety of tasks to maintain and upgrade the observatory. Despite a number of delays, the IceCube team got a lot done in a short amount of time.http://icecube.wisc.edu/news/feed )