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  • MicroBooNE experiment’s first results show no hint of a sterile neutrino

    2021-10-27T15:27:28Z via NavierStokesApp To: Public

    "MicroBooNE experiment’s first results show no hint of a sterile neutrino" Four complementary analyses by Fermilab’s MicroBooNE show no signs of a theorized fourth kind of neutrino. New results from the MicroBooNE experiment at the US Department of Energy’s Fermi National Accelerator Laboratory deal a blow to a theoretical particle known as the sterile neutrino. For more than two decades, this proposed fourth neutrino has remained a promising explanation for anomalies seen in earlier physics experiments. Finding a new particle would be a major discovery and a radical shift in our understanding of the universe. However, four complementary analyses released by the international MicroBooNE collaboration and presented during a seminar today all show the same thing: no sign of the sterile neutrino. Instead, the results align with the Standard Model of Particle Physics, scientists’ best theory of how the universe works. The data is consistent with what the Standard Model predicts: three kinds of neutrinos—no more, no less. “MicroBooNE has made a very comprehensive exploration through multiple types of interactions, and multiple analysis and reconstruction techniques,” says Bonnie Fleming, physics professor at Yale University and co-spokesperson for MicroBooNE. “They all tell us the same thing, and that gives us very high confidence in our results that we are not seeing a hint of a sterile neutrino.” MicroBooNE is a 170-ton neutrino detector roughly the size of a school bus that has operated since 2015. The international experiment has close to 200 collaborators from 36 institutions in five countries. They used cutting-edge technology to record spectacularly precise 3D images of neutrino events and examine particle interactions in detail—a much-needed probe into the subatomic world. Neutrinos are one of the fundamental particles in nature. They’re neutral, incredibly tiny, and the most abundant particle with mass in our universe—though they rarely interact with other matter. They’re also particularly intriguing to physicists, with a number of unanswered questions surrounding them. These puzzles include why their masses are so vanishingly small and whether they are responsible for matter's dominance over antimatter in our universe. This makes neutrinos a unique window into exploring how the universe works at the smallest scales. MicroBooNE’s new results are an exciting turning point in neutrino research. With sterile neutrinos further disfavored as the explanation for anomalies spotted in neutrino data, scientists are investigating other possibilities. These include things as intriguing as light created by other processes during neutrino collisions or as exotic as dark matter, unexplained physics related to the Higgs boson, or other physics beyond the Standard Model. First hints of sterile neutrinos Neutrinos come in three known types—the electron, muon and tau neutrino—and can switch between these flavors in a particular way as they travel. This phenomenon is called “neutrino oscillation.” Scientists can use their knowledge of oscillations to predict how many neutrinos of any kind they expect to see when measuring them at various distances from their source. Neutrinos are produced by many sources, including the sun, the atmosphere, nuclear reactors and particle accelerators. Starting around two decades ago, data from two particle beam experiments threw researchers for a loop. In the 1990s, the Liquid Scintillator Neutrino Detector experiment at Los Alamos National Laboratory saw more particle interactions than expected. In 2002, the follow-up MiniBooNE experiment at Fermilab began gathering data to investigate the LSND result in more detail. MiniBooNE scientists also saw more particle events than calculations predicted. These strange neutrino beam results were followed by reports of missing electron neutrinos from radioactive sources and reactor neutrino experiments. Sterile neutrinos emerged as a popular candidate to explain these odd results. While neutrinos are already tricky to detect, the proposed sterile neutrino would be even more elusive, responding only to the force of gravity. But because neutrinos flit between the different types, a sterile neutrino could impact the way neutrinos oscillate, leaving its signature in the data. But studying the smallest things in nature isn’t straightforward. Scientists never see neutrinos directly; instead, they see the particles that emerge when a neutrino hits an atom inside a detector. The MiniBooNE detector had a particular limitation: It was unable to tell the difference between electrons and photons (particles of light) close to where the neutrino interacted. This ambiguity painted a muddled picture of what particles were emerging from collisions. You can think of it like having a box of chocolates—MiniBooNE could tell you it contains a dozen pieces, but MicroBooNE could tell you which ones have almonds, and which have caramel. If MiniBooNE were truly seeing more electrons than predicted, it would indicate extra electron neutrinos causing the interactions. That would mean something unexpected was happening in the oscillations that researchers hadn’t accounted for: sterile neutrinos. But if photons were causing the excess, it would likely be a background process rather than oscillations gone wild and a new particle. It was clear that researchers needed a more nuanced detector. In 2007, the idea for MicroBooNE was born. MicroBooNE: precision detector The MicroBooNE detector is built on state-of-the-art techniques and technology. It uses special light sensors and more than 8000 painstakingly attached wires to capture particle tracks. It’s housed in a 40-foot-long cylindrical container filled with 170 tons of pure liquid argon. Neutrinos bump into the dense, transparent liquid, releasing additional particles that the electronics can record. The resulting pictures show detailed particle paths and, crucially, distinguish electrons from photons. MicroBooNE’s first three years of data show no excess of electrons—but they also show no excess of photons from a background process that might indicate an error in MiniBooNE’s data. “We’re not seeing what we would have expected from a MiniBooNE-like signal, neither electrons nor the most likely of the photon suspects,” says Fermilab scientist Sam Zeller, who served as MicroBooNE co-spokesperson for eight years. “But that earlier data from MiniBooNE doesn’t lie. There’s something really interesting happening that we still need to explain.” MicroBooNE ruled out the most likely source of photons as the cause of MiniBooNE’s excess events with 95% confidence and ruled out electrons as the sole source with greater than 99% confidence, and there is more to come. MicroBooNE still has half of its data to analyze and more ways yet to analyze it. The granularity of the detector enables researchers to look at particular kinds of particle interactions. While the team started with the most likely causes for the MiniBooNE excess, there are additional channels to investigate—such as the appearance of an electron and positron, or different outcomes that include photons. “Being able to look in detail at these different event outcomes is a real strength of our detector,” Zeller says. “The data is steering us away from the likely explanations and pointing toward something more complex and interesting, which is really exciting.” While the first analyses weighed in on the sterile neutrino, additional analyses could provide more information about exotic explanations, including dark matter, axion-like particles, the hypothetical Z-prime boson and beyond. There’s even a chance it could still be a sterile neutrino, hiding in even more unexpected ways. Future neutrino exploration Neutrinos are surrounded by mysteries. The anomalous data seen by the earlier MiniBooNE and LSND experiments still need an explanation. So too does the very phenomenon of neutrino oscillation and the fact that neutrinos have mass, neither of which is predicted by the Standard Model. There are also tantalizing hints that neutrinos could help explain why there is so much matter in the universe, as opposed to a universe full of antimatter or nothing at all. MicroBooNE is one of a suite of neutrino experiments searching for answers. Crucially, it’s also a long-running testbed for the liquid argon technology that will be used in upcoming detectors. “We’ve built and tested the hardware, and we’ve also developed the infrastructure to process our enormous dataset,” says Justin Evans, a scientist at the University of Manchester and MicroBooNE co-spokesperson. “That includes the simulations, calibrations, reconstruction algorithms, analysis strategies and automation through techniques like machine learning. This groundwork is essential for future experiments.” Liquid argon is the material of choice for the ICARUS detector set to begin gathering physics data soon and the Short-Baseline Near Detector coming online in 2023. Together with MicroBooNE, the three experiments form the Short-Baseline Neutrino Program at Fermilab and will produce a wealth of neutrino data. For example, in one month, SBND will record more data than MicroBooNE collected in two years. Today’s results from MicroBooNE will help guide some of the research in the trio’s broad portfolio. “Every time we look at neutrinos, we seem to find something new or unexpected,” says Evans. “MicroBooNE’s results are taking us in a new direction, and our neutrino program is going to get to the bottom of some of these mysteries.” Liquid argon will also be used in the Deep Underground Neutrino Experiment, a flagship international experiment hosted by Fermilab that already has more than 1000 researchers from over 30 countries. DUNE will study oscillations by sending neutrinos 800 miles through the earth to detectors at the mile-deep Sanford Underground Research Facility. The combination of short- and long-distance neutrino experiments will give researchers insights into the workings of these fundamental particles. “We have some big, unanswered questions in physics that many experiments are trying to address,” Fleming says. “And neutrinos may be telling us where to find some of those answers. I think if you want to understand how the universe works, you have to understand neutrinos.” Editor’s note: This article was originally published as a Fermilab press release.;_medium=rss&utm;_campaign=main_feed&utm;_content=click ( Feed URL: )
  • Siglata la convenzione tra l’I.I.S. "A. D'Aosta" e i Laboratori Nazionali del Gran Sasso

    2021-10-27T14:27:24Z via NavierStokesApp To: Public

    "Siglata la convenzione tra l’I.I.S. "A. D'Aosta" e i Laboratori Nazionali del Gran Sasso" Nella mattinata di oggi 27 ottobre, presso l’Aula Magna dell’Istituto d’Istruzione Superiore D’Aosta dell’Aquila, è stata siglata la convenzione tra l’Istituto e i Laboratori Nazionali del Gran Sasso dell’INFN. Read More ... ( Feed URL: )
  • BICEP3 tightens the bounds on cosmic inflation

    2021-10-26T17:27:23Z via NavierStokesApp To: Public

    "BICEP3 tightens the bounds on cosmic inflation" A new analysis of the South Pole-based telescope’s observations has all but ruled out several popular models of inflation. Physicists looking for signs of primordial gravitational waves by sifting through the earliest light in the cosmos—the cosmic microwave background—have reported their findings: still nothing.  But far from being a dud, the latest results from the BICEP3 experiment at the South Pole have tightened the bounds on models of cosmic inflation, a process that in theory explains several perplexing features of our universe and which should have produced gravitational waves shortly after the universe began.  “Once-promising models of inflation are now ruled out,” says Chao-Lin Kuo, a BICEP3 principal investigator and a physicist at Stanford University and the Department of Energy’s SLAC National Accelerator Laboratory.  The results were published Oct. 4 in Physical Review Letters. Blowing up the universe Cosmic inflation is the idea that very early in the history of the universe, the amount of space in the universe exploded from roughly the size of a hydrogen atom to about a light-year across, in about the time it would take light to travel one-trillionth of the way across the same atom. Inflation can explain a lot—notably, why the universe appears to be fairly smooth and look the same in all directions, why space is flat and why there are no magnetic monopoles. Still, physicists have not succeeded in working out the exact details, and they have come up with many different ways inflation might have occurred.  One way to sort out which, if any, of these inflationary models is correct is to look for gravitational waves that would have been produced as space expanded and the matter and energy in it shifted. In particular, those waves should leave an imprint on the polarization of light in the cosmic microwave background.   Polarizing gravitational waves This polarized light has two components: B-modes, which swirl around the sky, and E-modes, which are arranged in more orderly lines. Although the details depend on which model of inflation is correct, primordial gravitational waves should show up as particular patterns of B and E modes.  Starting in the mid-2000s, researchers began studying B-mode polarization in the CMB, searching for evidence of primordial gravitational waves. Over time, the particulars of the experiments have changed considerably, says SLAC lead scientist Zeeshan Ahmed, who has worked on a few incarnations of the BICEP experiment at the South Pole.  The first BICEP experiment deployed about 50 machined metal horns that detect tiny differences in microwave radiation, each equipped with thermal sensors and polarizing grids to measure polarization. The next generation, BICEP2, required a technological leap—new, superconducting detectors that could be more densely packed into the same area as previous telescopes. The successor Keck Array was essentially several BICEP2 telescopes in one.  To get to the next level, BICEP3, “we had to invent some things along the way,” Ahmed says.  The BICEP project is supported by grants from the National Science Foundation, the Keck Foundation, NASA’s Jet Propulsion Laboratory, NASA, the Gordon and Betty Moore Foundation, the Canada Foundation for Innovation, the UK Science and Technology Facilities Council and the US Department of Energy Office of Science.  With support from a SLAC Laboratory Directed Research and Development grant, Kuo, Ahmed and other SLAC scientists developed a number of new systems and materials. Among those are detector components that are more modular and easier to replace and lenses and filters that are more transparent to microwaves while blocking more infrared light, which helps keep the temperature-sensitive superconducting microwave detectors cool.  Those advances, Ahmed says, combined with data from prior experiments including BICEP2, Keck, WMAP and Planck, have allowed researchers to put the tightest bounds yet on what kinds of primordial gravitational waves could be out there—and hence the tightest bounds yet on models of cosmic inflation. The search continues “The experimentalists are doing heroic work,” says Stanford theoretical physicist Eva Silverstein, who studies cosmic inflation. “It’s great progress.” The results rule out a number of inflation models, including some popular older models and some versions of newer ones motivated by string theory, says Silverstein. The findings suggest that the correct model will be slightly more complicated that those that have been ruled out, although there is still a wide range of viable alternatives. “It’s not as though we’re going back to the drawing board,” Silverstein says, but the results “help us focus.” As more data comes in from BICEP3 and its immediate successor, the BICEP Array, as well as from other projects, physicists will start to get clues that will help focus their search for better models of inflation even more. Still, Ahmed says, they may have to wait until CMB-S4, a project currently under review at the Department of Energy, to get clearer answers. CMB-S4 will deploy the equivalent of 18 BICEP3 experiments—or more, Ahmed says—and will draw heavily on Department of Energy laboratory researchers and expertise, including ideas developed for BICEP3. “It’ll take a decade to build up this thing,” he says, “but it’s starting to take shape.” Editor’s note: A version of this article was originally published by SLAC.;_medium=rss&utm;_campaign=main_feed&utm;_content=click ( Feed URL: )
  • Countdown to Dark Matter Day

    2021-10-26T09:27:24Z via NavierStokesApp To: Public

    "Countdown to Dark Matter Day" Countdown to Dark Matter Day Ana Lopes abelchio Thu, 10/21/2021 - 12:55 Simulation of the dark-matter distribution in the universe. (V. Springel et al. 2005) On and around 31 October, CERN and other laboratories around the world will celebrate the global hunt for the universe’s missing matter – the dark matter that is thought to make up most of the matter in space. Experiments worldwide are searching for this unseen matter using many different tools, such as telescopes in space and on the ground, particle beams and deep underground detectors. CERN is home to several experiments that seek out the particles that may make up dark matter. These include experiments based at the Large Hadron Collider (LHC), such as ATLAS and CMS, which have broken new ground in the search for dark-matter particles, and non-LHC experiments such as CAST and NA64, which too have added new knowledge about the properties of these hypothetical particles. The Laboratory also hosts the control centre of AMS, a detector that was assembled at CERN and installed on the International Space Station to measure cosmic rays and try to shed light on their nature, as well as that of dark matter and antimatter. Between 25 October and 4 November, Dark Matter Day activities, in physical or virtual form, will share what we know and don’t know about dark matter with audiences worldwide. CERN will take part, hosting several activities: a production uniting the arts and the sciences at the Laboratory’s Globe of Science and Innovation on 27 October; a virtual booth in an online exhibition space where anyone from anywhere can freely explore the different booths and learn about dark matter; and a series of social-media activities on CERN’s Facebook, Twitter and Instagram channels featuring CERN scientists answering questions from followers across the globe, like those in last year’s event (see video below). Check out the Dark Matter Day website to find out more and follow #DarkMatterDay and #DarkMatterDay2021. Dark Matter Day is sponsored by the Interactions Collaboration, and this year’s event is dedicated to the memory of Glenn Roberts of Lawrence Berkeley National Laboratory, who founded Dark Matter Day and passed away earlier this year. ( Feed URL: )
  • “Ask me anything” features panel of dark matter experts

    2021-10-25T16:27:36Z via NavierStokesApp To: Public

    "“Ask me anything” features panel of dark matter experts" “Ask me anything” features panel of dark matter expertsPress ReleaseLauren Mon, 10/25/2021 - 08:562821In a Universe filled with the light from our sun and distant stars, it is difficult to conceive of it as mostly dark. When we look around our world and into space, we see enormous variety—trees, birds, planets, asteroids and stars. This visible matter accounts for about 15 percent of all the matter in the Universe. The rest is called dark matter. Although it doesn’t interact with light and may interact weakly with normal matter, scientists believe it exists because of its gravitational effects in the Universe. Think of dark matter as an enormous iceberg floating in the ocean—what you see is a mere fraction of what lies beneath the water.Since the late 1800s, scientists have postulated that there’s more to the Universe than what is visible—even using the most powerful tools of the day. For the past 100 years, there has been a growing body of evidence to indicate our universe and most of the matter in it is, indeed, dark. So, what is that evidence?To find out, join the “Ask me anything” virtual event on Monday, Nov. 1, at 19:00 GMT where you can learn more about how scientists are trying to detect the invisible in one of three ways: “make it, shake it, or break it!” The event takes place in conjunction with the Interactions Collaboration Dark Matter Day, a series of events taking place around the world between Oct. 25 and Nov. 4. A panel of four dark matter experts will be standing by to answer your questions about this mysterious material that makes up a huge portion of the Universe.Featured speakers for “Ask me anything” include:Catherine Heymans, Astronomer Royal for Scotland, Professor of Astrophysics at the University of Edinburgh and Director of the GCCL Institute in Bochum Germany. Heymans specializes in observing the dark side of our Universe, using deep sky observations to test whether we need to go beyond Einstein with our current theory of gravity. She has received the 2017 Royal Astronomical Society Darwin Lectureship and the 2018 Max-Planck Humboldt Research Award.Alex Murphy, professor of nuclear and particle astrophysicist at the University of Edinburgh. Murphy’s interest lies in the origin and nature of matter in the Universe. Ongoing projects include experimental and computational determination of the most important nuclear reactions involved in stellar nucleosynthesis, and the direct search for dark matter in deep underground laboratories. He has a keen interest in public engagement, where he was once identified as Professor of Impossible Physics.Tracy Slatyer, theoretical physicist at MIT. Slatyer works in particle physics, cosmology and astrophysics. She was born in the Solomon Islands and grew up in Australia and Fiji. She completed her undergraduate degree in Australia. Since then, she has been studying the astrophysical and cosmological signals of dark matter and other new physics at the Institute for Advanced Study in Princeton (2010-2013) and as a professor at MIT (2013-present). She won the 2021 New Horizons Prize from the Breakthrough Foundation.Nigel Smith, director of TRIUMF. Smith has undertaken astroparticle physics research in extreme locations, including studying astronomical sources of ultra-high energy gamma rays at the South Pole, searching for Galactic dark 1.1 km underground at the Boulby Underground Laboratory, and overseeing dark matter and neutrinos studies 2 km underground at the SNOLAB facility. He now leads TRIUMF, Canada’s particle accelerator centre.How to participate in “Ask me anything”Sign up for the Zoom webinar at to the Interactions Collaboration Facebook page: learn more about Dark Matter Day, go to“Ask me anything” will also be recorded. To view it later, please register for the webinar then click the “I would like to receive a recording” box. Send your questions to before or after the event and we will do our best to answer! The event is hosted in partnership with Scio. To learn more go to Interactions Collaboration AddressXeno Media18W100 22nd StSuite #103AOakbrook Terrace, IL60181United States 6305991550 https://www.xenomedia.comContact ( Feed URL: )
  • Al via le operazioni di svuotamento di BOREXINO

    2021-10-22T11:27:24Z via NavierStokesApp To: Public

    "Al via le operazioni di svuotamento di BOREXINO" Ieri 21 Ottobre, con l’inizio delle operazioni di svuotamento ed il trasporto dello scintillatore, si è dato il via al processo di dismissione di Borexino. Borexino è stato un esperimento di fisica delle particelle che ha analizzato il funzionamento del Sole, ha studiato le proprietà dei neutrini e misurato il calore proveniente dal cuore del nostro pianeta. Read More ... ( Feed URL: )
  • Soil science goes deep, and making moldable wood

    2021-10-20T18:27:37Z via NavierStokesApp To: Public

    "Soil science goes deep, and making moldable wood" There are massive telescopes that look far out into the cosmos, giant particle accelerators looking for ever tinier signals, gargantuan gravitational wave detectors that span kilometers of Earth—what about soil science? Where’s the big science project on deep soil? It’s coming soon. Staff Writer Erik Stokstad talks with host Sarah Crespi about plans for a new subsoil observatory to take us beyond topsoil. Wood is in some ways an ideal building material. You can grow it out of the ground. It’s not very heavy. It’s strong. But materials like metal and plastic have one up on wood in terms of flexibility. Plastic and metal can be melted and molded into complicated shapes. Could wood ever do this? Liangbing Hu, a professor in the department of materials science and engineering and director of the Center for Materials Innovation at the University of Maryland, College Park, talked with Sarah about making moldable wood in a new way. In a sponsored segment from Science/AAAS Custom Publishing Office, Sean Sanders, director and senior editor for the Custom Publishing office, interviews Michael Brehm, associate professor at UMass Chan Medical School Diabetes Center of Excellence, about how he is using humanized mouse models to study ways to modulate the body’s immune system as a pathway to treating type 1 diabetes. This segment is sponsored by the Jackson Laboratory.  This week’s episode was produced with help from Podigy. [Image: Xiao et al., Science 2021; Music: Jeffrey Cook] [Alt text:  honeycomb structure made from moldable wood] Authors: Sarah Crespi; Erik Stokstad See for privacy information. ( Feed URL: )
  • Eyes on the sky

    2021-10-19T17:27:33Z via NavierStokesApp To: Public

    "Eyes on the sky" There’s no one best way to build a telescope. On a mountaintop in the Atacama Desert of Chile, a gargantuan new eye on the cosmos is taking shape.  When completed in the late 2020s, the aptly named Extremely Large Telescope will be the largest optical telescope on the planet. With a nearly 40-meter-wide mirror—roughly four times as wide as the current record holder—it will search for Earth-like planets, seek out the first generation of galaxies and produce images up to 16 times sharper than the Hubble Space Telescope (depending on the wavelength). Meanwhile, NASA is preparing to launch what it dubs Hubble’s successor: the James Webb Space Telescope. It won’t be as big as the ELT; its 6.5-meter-wide mirror is middling compared to ground-based telescopes. But from its stable perch beyond Earth’s atmosphere, JWST’s infrared eyes will glimpse light from the first stars, peek into the atmospheres of worlds beyond the solar system and lift the veil on dust-enshrouded stellar nurseries. Telescopes in space. Telescopes on the ground. Each have their place in the exploration of the cosmos. But over the four centuries that have elapsed since Galileo pointed a handheld spyglass skyward, the telescope’s job has remained the same. “I would describe it as a photon bucket,” says Elizabeth George, a telescope detector engineer at the European Southern Observatory.  Illustration by Sandbox Studio, Chicago with Steve Shanabruch Photons, tiny packets of light, are the main currency in astronomy. Light, in its many guises, is often the only intel we have from far-off locales. A telescope’s job is straightforward: collect more photons than our eyes alone can see.  Generally, that means going big. In the same way that a large bucket collects more rain than a small pail, a telescope with a larger mirror or lens ensnares more photons, allowing astronomers to see fainter things. And for a given wavelength of light, a wide mirror or lens creates a sharper image, letting researchers see those faint things in better detail.  This holds true whether a telescope sits on the ground or lives in space, whether it focuses on visible light or expands beyond our human senses to collect radio waves or X-rays. The choice of whether to erect a telescope on land or lob one into orbit is the result of balancing several factors. “In space, there's no atmosphere, that's really the benefit,” George says.  Telescopes on Earth must peer through shifting parcels of air that blur images and make stars twinkle.  Space offers an incredibly stable environment. With minimal temperature swings and no mechanical stress from gravity, the precision of a telescope in space outperforms anything on the ground. “Earth is incredibly noisy, it turns out,” George says. Earth’s atmosphere also blocks many types of light from reaching the ground. Visible light and radio waves get through fine, but gamma rays, X-rays, most ultraviolet light and some infrared wavelengths don’t make it. Each of these wavelength ranges probe vastly different physical phenomena.  “The electromagnetic spectrum is so diverse …  we need many different types of telescopes in order to really fully understand the whole universe,” says Regina Caputo, an astrophysicist at NASA’s Goddard Space Flight Center.  Illustration by Sandbox Studio, Chicago with Steve Shanabruch Space comes with caveats. It’s phenomenally expensive to put a telescope in orbit, and most are impossible to repair or update once they’ve escaped the atmosphere. “On the ground, you can make things really big, for cheaper and faster, and you can constantly upgrade,” George says. “The benefit of ground-based is you can try out new things.” Telescopes on the ground can grow as big as humans dare to build them. While Hubble, the largest optical space telescope, measures 2.4 meters across, the widest optical scope on the ground—the Gran Telescopio Canarias on the Canary Island of La Palma—spans 10.4 meters. Some radio telescopes are bigger still: The largest single telescope of any kind is FAST, the Five-hundred-meter Aperture Spherical radio Telescope, a radio dish in China that spans half a kilometer.  With the flexibility to try new things on the ground, astronomers have gotten clever about boosting image resolution while gazing through a turbulent atmosphere. Many of the largest optical telescopes come equipped with adaptive optics: A deformable mirror—used to correct distortions—and reference points of light in the sky—bright stars or marks created by lasers—help these scopes regain much of the clarity they otherwise would have lost.  Some ground-based observatories achieve resolution that far surpasses that of any one telescope by combining the light of many smaller scopes observing in sync. The ALMA observatory in Chile, for example, links up 66 radio dishes to produce images with the clarity (though not the sensitivity to faint light) of a single telescope 16 kilometers across.  But whether in space or on the ground, big or small, sensitive to one type of light or another, no one telescope is the best. “You identify the physics question you're trying to ask, and then that will dictate what kind of telescope you need,” says Marc Postman, an astronomer at Space Telescope Science Institute in Baltimore.  To study ultracold interstellar gas, a radio telescope on the ground is the right tool; those clouds are home to molecules and hydrogen atoms that emit specific radio wavelengths. But to probe 10-million-degree plasma that pervades clusters of galaxies, an X-ray telescope in space is the best bet; it can detect the high-energy photons emitted by electrons decelerating in those ionized gases.  Even a single telescope can fare better or worse than another, depending on the metric. The Extremely Large Telescope and the JWST, for example, will have some overlap in the wavelengths of light they can see. At those wavelengths, the ELT will produce much sharper images, thanks to its sheer size and adaptive optics. But JWST, despite being much smaller, will see far fainter things, because there’s no infrared glow from a warm atmosphere to compete with in space.  And sometimes, tiny is king. When Postman and colleagues wanted to measure the cosmic optical background, a feeble glow of visible light coming from all directions in space, they didn’t use a big telescope. They turned to a 21-centimeter-wide instrument—smaller than many backyard telescopes—on the New Horizons spacecraft, which buzzed Pluto in 2015. Out at the solar system’s edge, that telescope was beyond the light pollution caused by a haze of interplanetary dust particles that scatter sunlight.  “The sky is so dark out there that even a small telescope can make observations that would be difficult for a much bigger telescope much closer to the sun,” Postman says. In the coming years, new ground-based observatories will push the limits of what we can see. The ELT, under construction in the southern hemisphere, and the Thirty Meter Telescope, proposed to be built in the northern hemisphere, are planned to be the largest optical eyes humans have ever trained on the sky. And when the Vera C. Rubin Observatory comes online in 2023, it will have an exceptionally wide field of view that will let it scan the entire sky visible from northern Chile every few days. It will create a time-lapse movie that will help astronomers discover anything that flashes or moves: supernovae, passing asteroids or even undiscovered planets in the remote parts of our solar system.  In space, all eyes are on the JWST, which completed its final prelaunch tests on August 26 and is scheduled for launch December 18. In the early 2030s, the European Space Agency’s Athena observatory will give astronomers powerful new X-ray vision, which will let them probe deeper into some of the hotter, more energetic locales in the universe. And in between, a medley of specialized space telescopes will zero in on specific science questions such as the nature of dark matter and dark energy as well as the continued hunt for more planets in the galaxy. All these telescopes—and too many others to name—will continue their 400-plus-year legacy of expanding our view of cosmos. It’s a legacy that Galileo himself would be glad to hear. In his 1610 publication The Starry Messenger, where he documented the wonders his telescope revealed, he pondered his device’s future: “Perchance other discoveries still more excellent will be made from time to time by me or by other observers, with the assistance of a similar instrument.”;_medium=rss&utm;_campaign=main_feed&utm;_content=click ( Feed URL: )
  • The four LHC experiments are getting ready for pilot beams

    2021-10-18T13:27:35Z via NavierStokesApp To: Public

    "The four LHC experiments are getting ready for pilot beams" The four LHC experiments are getting ready for pilot beams Cristina Agrigoroae cagrigor Mon, 10/18/2021 - 15:16 First Physics at CERN Control Room (Image: CERN) Since 2019, many places at CERN have been operating like beehives to complete the scheduled upgrades for the second long shutdown (LS2) of the accelerator complex. This period of intense work is now coming to an end with the injection of the first pilot beams into the LHC. This major milestone will be featured during a live event on CERN’s social media channels on 20 October at 4 pm (CEST). The pilot beams are part of the commissioning of the LHC machine in preparation for its Run 3, starting in 2022. With an integrated luminosity equal to the two previous runs combined, the four LHC experiments will be able to perform even more precise measurements. Yet, to stay apace with the accelerator’s improved vigour, all of them had to undergo a series of upgrades and transformations. After the refurbished Time Projection Chamber (TPC) and the revamped Miniframe joined the ALICE detector in the cavern, the reinstallation of its new Muon Forward Tracker subdetector followed. In May, a new Inner Tracking System (ITS), the largest pixel detector ever built, took the seat of the previous one, between the beam pipe and the TPC. The final piece of the ALICE puzzle – the Fast Interaction Trigger (FIT) – was installed in July. At ATLAS, among the ongoing works, the muon spectrometer was upgraded, notably with the installation of one of the two New Small Wheels, which uses new technologies such as the novel small-strip Thin Gap Chambers (sTGC) and the Micromegas detectors. Its twin will be lowered into the detector’s cavern in November. In 2020, the CMS experiment completed the installation of the first GEM (Gas Electron Multiplier) station, the brand new sub-detector system for detecting muons in the region closest to the beam pipe. This year, a new, redesigned beam pipe with a new vacuum pumping group was installed. Over the summer, after its design was improved and its innermost layer replaced, the Pixel Tracker was installed at the centre of the CMS detector, followed by the Beam Radiation, Instrumentation and Luminosity (BRIL) sub-detectors. As for the LHCb experiment, an important metamorphosis happened during these two years. A new scintillating-fibre particle-tracking detector (SciFi) and upgraded ring-imaging Cherenkov detectors, RICH1 and RICH2, were installed this year, before the recommissioning of the beam pipe. The installation of a faster Vertex Locator (VELO) is planned for the coming months. The first proton beams circulated in CERN’s accelerator chain in December last year, with the first beam being injected into the PS Booster (PSB), connecting it for the first time to the new Linac4. The Proton Synchrotron followed, accelerating its first beam in March, while the Super Proton Synchrotron (SPS) saw its first beams accelerated in May. Now, with the LHC at its nominal temperature (1.9 K), the first pilot beams will be circulated on 18 October. Join the live event on YouTube and Facebook to follow the first injection of proton beams into the LHC after a two-year-long shutdown. ( Feed URL: )
  • Successful beam pipe installation at LHCb

    2021-10-18T09:27:37Z via NavierStokesApp To: Public

    "Successful beam pipe installation at LHCb" Successful beam pipe installation at LHCb cagrigor Mon, 10/18/2021 - 10:51 The stainless-steel section of the LHCb beam pipe is lifted up to the beamline with a crane and put in place between the filters of the muon system. (Image: CERN) The LHC experiments are nearing the completion of maintenance and upgrade works carried out in the framework of the second long shutdown of CERN’s accelerator complex. Of all the experiments, LHCb is undergoing the most significant metamorphosis during these two years, namely the installation of a faster Vertex Locator (VELO), a new scintillating-fibre particle-tracking detector (SciFi), and upgraded ring-imaging Cherenkov detectors, RICH1 and RICH2. While the installation of LHCb’s subdetectors and infrastructure in preparation for commissioning is still under way, its beampipe was successfully reinstalled over the summer, marking a milestone in the detector’s preparation for Run 3 of the LHC. The LHCb beam pipe has a conical shape through the whole of the LHCb detector, which makes it different from that of the other experiments. Along its total length of 19 m, its diameter ranges from 50 mm close to the LHCb interaction point to 380 mm in the experiment’s muon system. The beam pipe is composed of four sections, all of different lengths. Three of these sections are made of beryllium and measure 11.6 m, giving LHCb the longest beryllium beam pipe of all the LHC experiments. The last and biggest section is made of stainless steel. Both the shape and material of the beam pipe were chosen to optimise its transparency to particles emerging from the collisions that take place at the LHC.  The beam pipe has a spider-web-like support structure in the aperture of the LHCb magnet, with beryllium collars and carbon-fibre ropes and rods ensuring that the amount of material is kept to a minimum. Installed during the first long shutdown, it was the first such structure ever used in an experiment and remains unique in the world today. The support structure may seem fragile, but is able to keep the beam pipe in place under the huge force that it exerts on itself when under vacuum. The smallest of the beryllium sections is slid inside its spider-web-like support (Image: CERN)The installation of the LHCb beam pipe, which involved engineers and technicians across multiple departments, started in April. The first smaller section was inserted through the RICH1 subdetector and connected to the VELO vacuum tank surrounding the interaction point. The installation and careful alignment of the spider-web-like structure followed in mid-July. The remaining sections were installed afterwards in a well-defined order: first, the longest (7 m) beryllium section was slid through the inner cylindrical sheath of the RICH2 subdetector. Then, the stainless-steel cone, the heaviest (160 kg) and biggest section, was lifted up to the beamline with a crane and then slid into place in the centre of the muon system. Finally, the lightest beryllium section (about 4 kg) was carefully installed by hand, sliding it into place on its spider-web support in the magnet. Once the sections had been connected with bellows and checks had been carried out to make sure that there were no leaks in the connections, the bake-out procedure to improve the quality of the vacuum started in mid-August. For this step, the beam pipe was wrapped in heating blankets, allowing it to be heated up to 250 °C. The VELO vacuum tank and the very thin radio-frequency foil that separates the LHCb detector vacuum from the LHC beam vacuum were also heated at the same time as the beam pipe. After final checks of the vacuum quality, the heating blankets were removed and the beam pipe was filled with neon gas at atmospheric pressure to keep it ready for beams to circulate in October. ( Feed URL: )
  • The ripple effects of mass incarceration, and how much is a dog’s nose really worth?

    2021-10-14T18:27:33Z via NavierStokesApp To: Public

    "The ripple effects of mass incarceration, and how much is a dog’s nose really worth?" This week we are covering the Sciencespecial issue on mass incarceration. Can a dog find a body? Sometimes. Can a dog indicate a body was in a spot a few months ago, even though it’s not there now? There’s not much scientific evidence to back up such claims. But in the United States, people are being sent to prison based on this type of evidence. Host Sarah Crespi talks with Peter Andrey Smith, a reporter and researcher based in Maine, about the science—or lack thereof—behind dog-sniff evidence. With 2 million people in jail or prison in the United States, it has become incredibly common to have a close relative behind bars. Sarah talks with Hedwig Lee, a sociologist at Washington University in St. Louis, about the consequences of mass incarceration for families of the incarcerated, from economic to social.  This week’s episode was produced with help from Podigy. [Image:  Adrian Brandon; Music: Jeffrey Cook] [Alt text: illustration from the special issue on mass incarceration by Adrian Brandon. He writes: “This illustration shines a light on the structural role of the prison system and how deeply embedded it is in the fabric of this country.”] Authors: Sarah Crespi; Peter Andrey Smith     See for privacy information. ( Feed URL: )
  • CERN Quantum Technology Initiative unveils strategic roadmap shaping CERN’s role in next quantum revolution

    2021-10-14T13:27:33Z via NavierStokesApp To: Public

    "CERN Quantum Technology Initiative unveils strategic roadmap shaping CERN’s role in next quantum revolution" CERN Quantum Technology Initiative unveils strategic roadmap shaping CERN’s role in next quantum revolution sandrika Wed, 10/13/2021 - 13:31 The picture is a modified variant of the original Veronika McQuade's computer centre shot. (Image: CERN) Geneva, 14 October 2021. The CERN Quantum Technology Initiative (CERN QTI) reaches its next milestone today, with the unveiling of a first roadmap defining its medium- and long-term quantum research programme. The roadmap details the CERN QTI goals and strategy, and outlines its governing structure and the composition of its international advisory board, as well as the activities to support the exchange of knowledge and innovation with the high-energy physics community and beyond in the extensive field of quantum technologies. Through CERN QTI, CERN is disseminating its enabling technologies – such as quantum state sensors, time synchronisation protocols, and many more from the cryogenics, electronics, quantum theory and computing domains – to accelerate the development of quantum technologies. Today’s information and communication technology grew out of the knowledge and development of quantum mechanics during the last century. CERN QTI will see the CERN community play their part in a global effort to bring about the “next quantum revolution” – whereby counterintuitive phenomena such as superposition and entanglement are exploited to build novel computing, communication, and sensing and simulation devices. “As an international, open and neutral platform, and building on its collaborative culture and proven track record of innovation, CERN is uniquely positioned to act as an “honest broker” between CERN Member States and to foster innovative ideas in the field of high-energy physics and beyond,” says Professor Joachim Mnich, CERN Director for Research and Computing. “This is underpinned by several concrete R&D projects that are already under way at CERN.” Composed of prominent international experts nominated by the 23 CERN Member States, the recently formed advisory board contributed to the roadmap being published today. “The roadmap builds on high-quality research projects already ongoing at CERN, with top-level collaborations, to advance a vision and concrete steps to explore the potential of quantum information science and technologies for high-energy physics,” reported Kerstin Borras and Yasser Omar, co-chairs of the CERN QTI advisory board, in a statement unanimously approved by the board members. “CERN can play a key role as a facilitator of cross-disciplinary discussions about the role of quantum technologies in science, advancing the development of use cases and enabling technologies, promoting co-development, as well as being a key early-adopter of quantum technologies. The members of the advisory board will promote the collaboration between the quantum technologies and the high-energy physics communities in their respective countries, with CERN and its roadmap being a very important forum and instrument to develop fruitful cross-fertilisation.” The board will work together with the CERN QTI management team to guide the activities and create as many synergies as possible with national and international initiatives related to quantum technologies. A year on from its launch, CERN QTI has already established collaborations and projects to explore how quantum technologies can best benefit high-energy physics and beyond in four main quantum research areas: quantum computing and algorithms; quantum theory and simulation; quantum sensing, metrology and materials; and quantum communication and networks. The current projects span multiple research topics and target applications such as quantum graph neural networks for track reconstruction, quantum support vector machines for particle classification, quantum anomaly detection for beyond the Standard Model searches, quantum generative adversarial networks for physics simulation, new sensors and materials for future detectors, and secure quantum key distribution protocols for distributed data analysis. Education and training are also at the core of CERN QTI. Building on the success of its first online course on quantum computing, CERN QTI will be extending its academia–industry training programme to accelerate the process of cultivating competencies across various R&D and engineering activities for the new generation of scientists, from high-school students to senior researchers. “CERN has demonstrated excellence in scientific research for many years, and has fostered great innovation in computing technologies. Building on its unique expertise and strong collaborative culture, CERN is in a distinctive position today to foster quantum developments in the European high-energy physics community and beyond,” concludes Alberto Di Meglio, Coordinator of the CERN Quantum Technology Initiative. --------------------------------------------About CERN QTI The CERN Quantum Technology Initiative (CERN QTI) is a comprehensive R&D, academic and knowledge-sharing initiative to exploit quantum advantage for high-energy physics and beyond. Given CERN's increasing information and communications technology and computing demands, as well as the significant national and international interest in quantum-technology activities, CERN QTI aims to provide dedicated mechanisms for the exchange of both knowledge and innovation. Find out more at and on Twitter and LinkedIn. Link to roadmap: ( Feed URL: )
  • Direct Photons Offer Glimpse of Gluons' Dynamic Motion

    2021-10-12T21:27:32Z via NavierStokesApp To: Public

    "Direct Photons Offer Glimpse of Gluons' Dynamic Motion" Direct Photons Offer Glimpse of Gluons' Dynamic MotionPress ReleaseLauren Tue, 10/12/2021 - 14:262521PHENIX data validate approach for future studies of proton spin and structureThe PHENIX detector at the Relativistic Heavy Ion Collider at Brookhaven National LaboratoryUPTON, NY—Scientists seeking to explore the teeming microcosm of quarks and gluons inside protons and neutrons report new data delivered by particles of light. The light particles, or photons, come directly from interactions of a quark in one proton colliding with a gluon in another at the Relativistic Heavy Ion Collider (RHIC). By tracking these “direct photons,” members of RHIC’s PHENIX Collaboration say they are getting a glimpse—albeit a blurry one—of gluons’ transverse motion within the building blocks of atomic nuclei.“We show experimentally for the first time the potential that direct photon measurements are sensitive to the transverse motion of gluons and that we can use such measurements to start constraining things—to reduce the huge uncertainties in our knowledge of how gluons behave,” said Alexander Bazilevsky, deputy spokesperson of the PHENIX Collaboration and a physicist at the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory.The data, published in Physical Review Letters, come from collisions between beams of polarized protons at RHIC, a DOE Office of Science user facility for nuclear physics research located at Brookhaven Lab. RHIC is the only facility in the world capable of colliding protons with their spin directions aligned in a controlled way.“RHIC’s spin polarization is a crucial requirement for this research. It gives us a way to establish which way is up so we can measure the motions of other particles relative to that reference direction,” explained Brookhaven Lab physicist Nicole Lewis, whose work on this analysis formed the basis of her Ph.D. thesis.As Lewis explained in an invited talk at the 2021 Fall Meeting of the American Physical Society’s Division of Nuclear Physics on October 12, understanding the origin of proton spin is also one of the main research goals.A proton’s spin, or intrinsic angular momentum, makes it act like a tiny bar magnet with two poles. This property is used every day in magnetic resonance imaging (MRI), where a powerful external magnet changes the alignment of protons’ spins in our bodies so doctors can see features inside. But where spin comes from is still a mystery.Studies at RHIC and elsewhere show that quark spins and gluon spins both make substantial contributions to proton spin, but not enough. The motions of these fundamental particles within protons are expected to also play a role. Using direct photons to measure how gluons’ transverse motion is correlated with overall proton spin is expected to help solve this puzzle.In addition, studying the motion of quarks and gluons within a proton will help reveal details of the interactions between these particles. Those interactions are governed by the strong nuclear force—the strongest force in nature—which is carried by gluons and binds the quarks within the protons and neutrons of atomic nuclei. So, studying gluons and the strong force is really about understanding the “glue” that binds visible matter—everything made of atoms.The newly analyzed data from PHENIX reveal that direct photons can be used to study gluons’ motions inside a proton.The PHENIX measurements are 50 times more precise than the only previously published direct photon data—about 30 years ago from an experiment at DOE’s Fermi National Accelerator Laboratory.“Our results help to validate the use of this approach for future studies at RHIC—including at an upgraded sPHENIX detector currently being installed in the location of the original PHENIX detector, which ended its experimental run in 2016. sPHENIX is expected to be operational in 2023 and will have even better capabilities to detect direct photons,” Bazilevsky said.The direct photon data from proton-proton collisions will also provide important cross-checking for experiments using electrons to probe the inner structure of protons at the future Electron-Ion Collider (EIC).“Proton-proton and electron-proton collisions give us different, complementary ways to ‘see’ inside a proton to construct the final picture of how things look,” Bazilevsky said.How to peer inside a protonProton-proton collisions can produce a range of interactions. A quark in one proton can interact with either a quark or gluon in the other. And a gluon also can interact with a quark or gluon. So, these collisions produce a mixture of quark-quark, gluon-gluon, and quark-gluon events.But only one of those possible interactions—quark-gluon scattering—is a major source of photons (quantized particles of light) emitted directly from the collision zone. And because photons have no electric charge or “color” charge (the type of charge carried by quarks and gluons) they don’t interact with anything on their way out. By measuring these direct photons, scientists can zero in on the gluons involved in these interactions.To tell whether the gluons are moving, the scientists align the spins in one proton beam transversely—that is, pointing “up” relative to their forward direction of motion. Then they measure whether there are more photons emerging to the left or the right of the forward-going proton’s up point of reference.“The up is the spin, and the left or right gives you the momentum of the gluons in the transverse direction,” Lewis explained. That helps physicists expand beyond a one-dimensional view of quarks or gluons only moving in the same direction as the proton they are in.“From this we are able to probe a more three-dimensional picture of the proton and study internal transverse dynamics of the quarks and gluons. If we were to measure a very large left to right asymmetry, that would indicate that there are large internal dynamics going on inside the proton, which would in turn contribute to the proton’s spin.”Picking out direct photonsFiguring out which photons come directly from a quark-gluon interaction isn’t so simple.“There are so many other photons present in these collisions that come from the decays of other particles or radiative processes,” Lewis said. “Trying to isolate the photons that came directly from the collision, that’s the hard part.”The scientists use a process of elimination. If a photon picked up in the detector is surrounded by other particles with similar energy, it likely came from radiative processes that happened after the collision—so those photons are not direct. Likewise, if the energy and angles of a pair of photons can be reconstructed to have originated from the decay of a parent particle—a pi zero meson, say—then those photons are also not direct photons. After all the eliminations, the photons with no other obvious source are assumed to have originated from a quark-gluon scattering event.“PHENIX has the resolution and other characteristics that enable it to do these measurements,” Bazilevsky said.“Another reason why this is hard is because direct photon production is a pretty rare process,” said Lewis. “It doesn’t happen frequently, and it has a large background—which makes the signal hard to detect. We need many collisions to have enough occurrences to be able to do the analysis.”Now for the first time, Bazilevsky said, “we show that a collider like RHIC can produce enough collisions for such measurements.”Coming into focusBut even with the detector and collider capabilities, the PHENIX results did not show an asymmetry in the number of direct photons emerging left or right of the transversely polarized proton. “We got something that was consistent with zero,” Lewis said.But that does not mean that the gluons involved in these interactions were not moving, because the uncertainties in the measurements are still somewhat large.“The models based on previous measurements give only a blurry picture,” Bazilevsky said. “Within the large uncertainties of these models, we show that direct photons are starting to be sensitive to gluon motions and reducing the uncertainties. So, our picture is still blurry, but we are zooming in a bit.”“We are looking forward to the next step—building and using the sPHENIX detector, which will be able to track many more collisions and pick out direct photons emerging from wider angles around the collision zone. Then we may start to see something that’s not zero,” he said.This research and RHIC operations are funded by the DOE Office of Science (NP). Additional funders are listed in the scientific paper.Brookhaven National Laboratory is supported by the U.S. Department of Energy’s Office of Science. 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, visit @BrookhavenLab on Twitter or find us on Facebook.Related Links Online version of this news release with related graphics [] Scientific paper: "Probing gluon spin-momentum correlations in transversely polarized protons through midrapidity isolated direct photons in p↑+p collisions at s√=200 GeV" [] DOE Explains: quarks and gluons [] DOE Explains: nuclei [] Brookhaven National Laboratory We advance fundamental research in nuclear and particle physics to gain a deeper understanding of matter, energy, space, and time; apply photon sciences and nanomaterials research to energy challenges of critical importance to the nation; and perform cross-disciplinary research on climate change, sustainable energy, and Earth’s ecosystems.    AddressBrookhaven National LaboratoryP.O. Box 5000Upton, NY11973-5000United States + 1 631 344 8000 InfoMedia and Communications Office  Karen McNulty Walsh +1 (631) Peter Genzer +1 (631) 344-3174genzer@bnl.govLinksBrookhaven photo databasePress releasesLinkedInYouTubeTwitterFunding - DOE Office of ScienceFacebook ( Feed URL: )
  • Watch the renovation of CERN’s East Area

    2021-10-12T17:27:26Z via NavierStokesApp To: Public

    "Watch the renovation of CERN’s East Area" Watch the renovation of CERN’s East Area Naomi Dinmore thortala Tue, 10/12/2021 - 18:53 CERN’s East Area has hosted a variety of fixed-target experiments since the 1950s, using four beamlines from the Proton Synchrotron (PS). Over the past two years, the experimental area – CERN’s second largest – has undergone a complete makeover. New instrumentation and beamline configuration have improved the precision of data collection, and new magnets and power convertors have drastically reduced the area’s energy consumption. As the beams return to the accelerator complex, the East Area’s experiments are taking physics measurements again and the facility’s central role in the modern physics landscape has been restored. Watch a time-lapse video condensing two years of the East Area renovations into two minutes below. (Video: CERN) ( Feed URL: )
  • I Laboratori Nazionali del Gran Sasso a BergamoScienza

    2021-10-12T15:27:19Z via NavierStokesApp To: Public

    "I Laboratori Nazionali del Gran Sasso a BergamoScienza" I Laboratori Nazionali del Gran Sasso dell’INFN saranno protagonisti, mercoledì 13 ottobre alle 18.30 del tour virtuale organizzato in occasione di BergamoScienza, festival di divulgazione scientifica organizzato dall’Associazione BergamoScienza giunto alla XIX edizione. Read More ... ( Feed URL: )
  • Is dark matter cold, warm or hot?

    2021-10-12T13:27:36Z via NavierStokesApp To: Public

    "Is dark matter cold, warm or hot?" The answer has to do with dark matter’s role in shaping the cosmos. Half a century after Vera Rubin and Kent Ford confirmed that a form of invisible matter—now called dark matter—is required to account for the rotation of galaxies, the evidence for its existence is overwhelming.  Although it is known to interact with ordinary matter only through gravity, there is such a massive amount of dark matter out there—85% of all the matter in the universe—that it has played a pivotal behind-the-scenes role in shaping all the stuff we can see, from our own Milky Way galaxy to the wispy filaments of gas that link galaxies across vast distances.  “We think it exists because there’s evidence for it on many, many scales,” says Kevork Abazajian, a theoretical physicist and astrophysicist at the University of California, Irvine.  There have been a lot of ideas about what form dark matter might take, from planet-sized objects called MACHOs to individual particles like WIMPs—weakly interacting massive particles roughly the size of a proton—and even tinier things like axions and sterile neutrinos.  In the 1980s, scientists came up with a way to make sense of this growing collection: They started classifying proposed dark-matter particles as cold, warm or hot. These categories are based on how fast each type of dark matter would have traveled through the early universe—a speed that depended on its mass—and on how hot its surroundings were when it popped into existence.  Light, fast particles are known as hot dark matter; heavy, slow ones are cold dark matter; and warm dark matter falls in between.  In this way of seeing things, WIMPs are cold, sterile neutrinos are warm, and relic neutrinos from the early universe are hot. (Axions are a special case—both light and extremely cold. We’ll get to them later.) Why is their speed so important? “If a dark matter particle is lighter and faster, it can travel farther in a given time, and it will smooth out any structure that already exists along the way,” Abazajian says.  On the other hand, slower, colder forms of dark matter would have helped build structure, and based on what we know and see today it must have been part of the mix. Illustration by Sandbox Studio, Chicago with Corinne Mucha Building galaxies Although there are theories about when and how each type of dark-matter candidate would have formed, the only thing scientists know for sure is that dark matter was already around about 75,000 years after the Big Bang. It was then that matter started to dominate over radiation and little seeds of structure started to form, says Stanford theoretical physicist Peter Graham.  Most types of dark-matter particles would have been created by collisions between other particles in the hot, dense soup of the infant universe, in much the same way that high-energy particle collisions at places like the Large Hadron Collider give rise to exotic new types of particles. As the universe expanded and cooled, dark-matter particles would have wound up being hot, warm or cold—and, in fact, there could have been more than one type.  Scientists describe them as freely “streaming” through the universe, although this term is a little misleading, Abazajian says. Unlike leaves floating on a river, all headed in the same direction in a coordinated way, “these things are not just in one place and then in another place,” he says. “They’re everywhere and going in every direction.” As it streamed, each type of dark matter would have had a distinctive impact on the growth of structure along the way—either adding to its clumpiness, and thus to the building of galaxies, or thwarting their growth. Cold dark matter, such as the WIMP, would have been a clump-builder. It moved slowly enough to glom together and form gravitational wells, which would have captured nearby bits of matter. Hot dark matter, on the other hand, would have been a clump-smoother, zipping by so fast that it could ignore those gravitational wells. If all dark matter were hot, none of those seeds could have grown into bigger structures, says Silvia Pascoli, a theoretical physicist at the University of Bologna in Italy. That’s why scientists now believe that hot dark-matter particles, such as relic neutrinos from the early days of the cosmos, could not constitute more than a sliver of dark matter as a whole. Despite their tiny contribution, Pascoli adds, “I say these relic neutrinos are currently the only known component of dark matter. They have an important impact on the evolution of the universe.”  You might think that warm dark matter would be the best dark matter, filling the universe with a Goldilocks bowl of just-right structure. Sterile neutrinos are considered the top candidate in this category, and in theory they could indeed constitute the vast majority of dark matter. But most of the parameter space—the sets of conditions—where they could exist have been ruled out, says Abazajian, who as a graduate student researched how specific types of neutrino oscillations in the early universe could have produced sterile neutrino dark matter. Although those same oscillations could be happening today, he says, the probability that a regular neutrino would turn into a sterile one through standard oscillations in the vacuum of space are thought to be very small, with estimates ranging from 1 in 100,000 to 1 in 100 trillion.  “You’d have to have a very good counting mechanism to count up to 100 trillion hits in your detector without missing the one hit from a sterile neutrino,” Abazajian says.  That said, there are a few experiments out there that are giving it a try, using new approaches that don’t rely on direct hits. Then there’s the axion. Unlike the other dark-matter candidates, axions would be both extremely light—so light that they are better described as waves whose associated fields can spread over kilometers—and extremely cold, Graham says. They are so weakly coupled to other forms of matter that the frantic collisions of particles in the thermal bath of the early universe would have produced hardly any. “They would have been produced in a different way than the other dark matter candidates,” Graham says. “Even though the universe was very hot at the time, axions would have been very cold at birth and would stay cold forever, which means that they are absolutely cold dark matter.”  Even though axions are very light, Graham says, “because they exist at close to absolute zero, the temperature where all motion stops, they are essentially not moving. They’re kind of this ghostly fluid, and everything else moves through it.” Illustration by Sandbox Studio, Chicago with Corinne Mucha Searching for dark matter of all kinds Some scientists think it will take more than one type of dark matter to account for all the things we see in the universe. And in the past few years, as experiments aimed at detecting WIMPs and producing dark matter particles through collisions at the Large Hadron Collider have so far come up empty-handed, the search for dark matter has broadened. The proliferation of ideas for searches has been helped by technological advances and clever approaches that could force much lighter and even more exotic dark-matter particles out of hiding. Some of those efforts make use of the very clumpiness that dark matter was instrumental in creating.  Simona Murgia, an experimentalist at the University of California, Irvine, led a team looking for signs of collisions between WIMPs and their antiparticles with the Fermi Gamma-ray Space Telescope while a postdoc at the US Department of Energy’s SLAC National Accelerator Laboratory. Now she’s joined an international team of scientists who will conduct a vast survey of the Southern sky from the Vera C. Rubin Observatory in Chile using the world’s biggest digital camera, which is under construction at SLAC. One of the things this survey will do is get a much better handle on the distribution of dark matter in the universe by looking at how it bends light from the galaxies we can see. “It will tell us something about the nature of dark matter in a totally different way,” Murgia says. “The more clumpy its distribution is, the more consistent it is with theories that tell you dark matter is cold.” The camera is expected to snap images of about 20 billion galaxies over 10 years, and from those images scientists hope to infer the fundamental nature of the dark matter that shaped them.   “We don’t only want to know the dark matter is there,” Murgia says. “We do want to understand the cosmology, but we also really want to know what dark matter is.”;_medium=rss&utm;_campaign=main_feed&utm;_content=click ( Feed URL: )
  • CERN working with WHO to improve understanding of COVID-19 airborne transmission risk in indoor spaces

    2021-10-11T13:27:33Z via NavierStokesApp To: Public

    "CERN working with WHO to improve understanding of COVID-19 airborne transmission risk in indoor spaces" CERN working with WHO to improve understanding of COVID-19 airborne transmission risk in indoor spaces Priyanka Dasgupta thortala Mon, 10/11/2021 - 14:27 As the response to the pandemic evolves and people step back into the office, it is necessary to monitor continuously the risk of disease transmission and be prepared to make quick, evidence-based decisions to ensure that everyone can work safely. CERN has developed the COVID Airborne Risk Assessment tool (CARA) to help personnel return to work safely by assessing the risk of COVID-19 infection in enclosed spaces like offices or meeting rooms. In accordance with CERN’s knowledge-transfer strategy, CERN has made the CARA software open-source, and the tool is freely available to all on GitLab.  The tool has attracted the attention of many international organisations, including the World Health Organization (WHO) and the United Nations Office at Geneva (UNOG). In June 2021, CERN shared its approach to risk assessment of occupational hazards, presenting CARA to WHO’s COVID Expert Panel. As a result, WHO has now invited CERN to become a member of a multidisciplinary working group of international experts, which will work to define a standardised algorithm to quantify airborne transmission risk in indoor settings. The collaboration takes place within CERN’s wide-ranging engagement with other international organisations, promoting shared solutions to societal challenges. “Since the beginning of the COVID-19 pandemic, WHO has worked closely with a wide range of experts from diverse technical disciplines and organisations on gathering evidence, developing and updating guidance, including on the research on modes of transmission of SARS-CoV-2, and related infection prevention and control recommendations. The CARA tool developed by CERN is an innovative approach to estimating the risk and informing space-management decisions for a safe return to work,” says Maria Van Kerkhove, WHO COVID-19 Technical Lead. “With the expertise and competence of medical and health professionals from the WHO worldwide community, it could eventually be possible to harness CERN’s CARA tool for wider applications that benefit society,” says Archana Sharma, Senior Adviser for Relations with International Organisations, who coordinates CERN’s relations with WHO. The CARA tool models the concentration profile of potential airborne viruses when people breathe or speak in enclosed spaces, producing clear and intuitive graphs. The user can set a number of parameters, including room volume, exposure time, activity type, mask-wearing and ventilation. The report generated by the tool indicates how to avoid exceeding critical concentrations and break chains of airborne transmission in spaces such as individual offices, meeting rooms and labs. The tool can scientifically assess the risk for different factors like: Is there a need for filtration systems in the room? What if a speaker at a meeting removes their mask? This information is then used by space managers and safety officers to implement the necessary safety measures and invest in targeted technical solutions. “Even with the vaccination campaigns in full swing in many countries, we are still seeing high numbers of positive cases and we must not forget that the virus is still out there. CARA is an easy-to-use tool that can be pivotal in helping people return safely to social spaces,” says Benoît Delille, Head of the Occupational Health, Safety and Environmental Protection (HSE) unit at CERN. The software is constantly being improved with the help of experts at CERN and across the world. “CARA has a lot of potential and we are exploring its biomedical applications with other collaborators like the Institute of Global Health at the University of Geneva,” says Alessandro Raimondo from the CERN Knowledge Transfer group. Learning from such synergetic experiences, CERN’s hope is to make the tool’s use and integration simpler and smoother in various places worldwide as part of the collective effort to take a firm stand against the pandemic. ___________________________ CERN’s technologies and expertise are available for scientific and commercial purposes through a variety of technology transfer opportunities. The CERN Knowledge Transfer group can help you tap into this potential and find solutions for you based on CERN’s many areas of expertise. Visit the KT website or write to us at ( Feed URL: )
  • Swarms of satellites could crowd out the stars, and the evolution of hepatitis B over 10 millennia

    2021-10-07T18:27:37Z via NavierStokesApp To: Public

    "Swarms of satellites could crowd out the stars, and the evolution of hepatitis B over 10 millennia" In 2019, a SpaceX rocket released 60 small satellites into low-Earth orbit—the first wave of more than 10,000 planned releases. At the same time, a new field of environmental debate was also launched—with satellite companies on one side, and astronomers, photographers, and stargazers on the other. Contributing Correspondent Joshua Sokol joins host Sarah Crespi to talk about the future of these space-based swarms. Over the course of the first 18 months of the coronavirus pandemic, different variants of the virus have come and gone. What would such changes look like over 10,000 years? Arthur Kocher, a researcher at the Max Planck Institute for the Science of Human History, talks with Sarah about watching the evolution of the virus that causes hepatitis B—over 10 millennia—and how changes in the disease’s path match up with shifts in human history. This week’s episode was produced with help from Podigy. ( Feed URL: )
  • Si conclude oggi Borexino, l’esperimento che ha permesso di conoscere meglio il Sole

    2021-10-07T12:27:40Z via NavierStokesApp To: Public

    "Si conclude oggi Borexino, l’esperimento che ha permesso di conoscere meglio il Sole" Laboratori Nazionali del Gran Sasso, 7 ottobre 2021 - Termina oggi la grande avventura scientifica di Borexino. Attivo dal 2007, l’esperimento dei Laboratori Nazionali del Gran Sasso (LNGS) dell’Istituto Nazionale di Fisica Nucleare (INFN) ha permesso di accrescere la nostra conoscenza sul funzionamento del Sole, e sui neutrini prodotti dalle reazioni di fusione che avvengono nel suo nucleo. Read More ... ( Feed URL: )
  • Collide residency award launches new call for entries

    2021-10-07T09:27:32Z via NavierStokesApp To: Public

    "Collide residency award launches new call for entries" Collide residency award launches new call for entries mailys Wed, 10/06/2021 - 20:22 Collide Residency Award poster (Image: CERN) Today, Arts at CERN launches a new call for Collide, its flagship residency programme, in partnership with the City of Barcelona. Artists from all around the world are invited to submit their proposals for a research-led residency. The laureate, an individual artist or artistic collective, will be invited to spend three months dedicated to artistic research and exploration between CERN and Barcelona. Artists interested in the dialogue between art and science can apply with a project proposal to develop during the residency working side by side with particle physicists, engineers, IT experts and laboratory staff. The selected artist or artistic collective will receive a three-month fully funded residency award that will allow them to spend two months at CERN in Geneva, followed by one month in Barcelona where they can expand their research and engage with the scientific laboratories of the city while being hosted at Hangar Centre for Art Research and Production in Barcelona. Arts at CERN focuses on the interactions between artists, scientists and engineers around the Laboratory’s rich culture through residency programmes, art commissions, and exhibitions. The Collide residency programme was established in 2012 to foster networks with international organisations and create new connections between art and fundamental science worldwide. Following last year’s successful response, the Collide Info Day on the 4 November 2021 will give the opportunity to applicants to find out more about the residency award and ask questions to the Collide team of scientists, curators, and winning artists of the past edition. “Arts at CERN is celebrating its tenth anniversary this year, and has served to strengthen the interaction and links between art and science. Collide is an opportunity to promote the importance of fundamental research and its positive impact on society thanks to artists who offer innovative perspectives on the scientific activities and technology development here at CERN,” says Charlotte Lindberg Warakaulle, CERN Director for International Relations. “Since 2012, Collide has brought together art and science at CERN in unique ways. After some exceptional times for all of us, I am very happy to be able to invite artists to the Laboratory once more, and to receiving ambitious artistic proposals inspired by physics and fundamental science,” declares Mónica Bello, Head of Arts at CERN. “The success of the previous two editions of the Collide residency award and its renewal for a third year highlight the vitality of the field of art and science globally as well as in Barcelona. Projects like Collide help support the growth and consolidation of the rich artistic ecosystem working at the intersection of science and technology, at an international level, ” says Jordi Martí, Sixth Deputy Mayor, Director of the Area of Culture, Education, Science and Community of the Barcelona City Council. Online applications for Collide are open from 7 October until the 22 November 2021. A jury of cultural experts and scientists will select the winning artist or artistic collective who will start their residencies in 2022. You can access the application here:  Further Twitter / Facebook / Instagram ( Feed URL: )