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  • richardmitnick 8:12 pm on May 26, 2022 Permalink | Reply
    Tags: "Researchers hunt for one-pole magnets by combining cosmic rays and particle accelerators", , , , By re-analyzing data from a wide range of experimental monopole searches the researchers identified novel limits on monopoles across a wide range of masses., , Neutrino physics, Paul Dirac theorized the existence of one-pole “magnetic monopoles" – particles comparable to electrons but with a magnetic charge., , The interdisciplinary research required bringing together expertise from several distinct corners of science - including accelerator physics; neutrino interactions and cosmic rays., , These results and source of monopoles studied by the researchers will serve as a useful benchmark for interpreting subsequent future monopole searches at terrestrial laboratories.   

    From The Kavli Institute for the Physics and Mathematics of the Universe (IPMU) [カブリ数物連携宇宙研](JP) at The University of Tokyo [東京大学](JP): “Researchers hunt for one-pole magnets by combining cosmic rays and particle accelerators” 

    KavliFoundation

    From The Kavli Institute for the Physics and Mathematics of the Universe (IPMU) [カブリ数物連携宇宙研](JP) at The University of Tokyo [東京大学](JP)

    Kavli IPMU

    May 26, 2022

    Research contact
    Volodymyr Takhistov
    Project Researcher / Kavli IPMU Fellow
    Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU), The University of Tokyo
    E-mail:volodymyr.takhistov@ipmu.jp

    Media contact
    Motoko Kakubayashi
    Press officer
    Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU), The University of Tokyo
    E-mail:press@ipmu.jp

    Some of the world’s most powerful particle accelerators have helped researchers draw new leading limits on the existence of long theorized magnetic monopoles from the collisions of energetic cosmic rays bombarding the Earth’s atmosphere, reports a new study published in Physical Review Letters.

    1
    Figure 1. Schematic illustration of magnetic compass and hypothetical magnetic monopole (Credit: Kavli IPMU)

    Magnets are intimately familiar to everyone, with wide-ranging applications within daily life, from TVs and computers to kids toys. However, breaking any magnet, such as a navigation compass needle consisting of north and south poles in half, will result in just two smaller two-pole magnets. This mystery has eluded researchers for decades since 1931, when physicist Paul Dirac theorized the existence of one-pole “magnetic monopoles” – particles comparable to electrons but with a magnetic charge.

    To explore whether magnetic monopoles exist, an international team of researchers, including the University of Tokyo’s Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU) Fellow Volodymyr Takhistov, studied available data from a variety of terrestrial experiments and have carried out the most sensitive searches to date for monopoles over a broad range of possible masses. The researchers focused on an unusual source of monopoles – atmospheric collisions of cosmic rays that have been occurring for eons.

    The interdisciplinary research required bringing together expertise from several distinct corners of science – including accelerator physics, neutrino interactions and cosmic rays.

    Cosmic ray collisions with the atmosphere have already played a central role in advancing science, especially the exploration of ghostly neutrinos. This lead to Kavli IPMU Senior Fellow Takaaki Kajita’s 2015 Nobel Prize in Physics for the discovery by the Super-Kamiokande experiment that neutrinos oscillate in flight, implying that they have mass.

    Partially inspired by the results of Super-Kamiokande, the team set to work on monopoles. Particularly intriguing were light monopoles with masses around the electroweak scale, which can be readily accessible to conventional particle accelerators.

    By carrying out simulations of cosmic ray collisions, analogously to particle collisions at the LHC at CERN, the researchers obtained a persistent beam of light monopoles raining down upon different terrestrial experiments.

    2
    Figure 2. A schematic illustration of magnetic monopole (M) production from collisions of cosmic rays with the Earth’s atmosphere. (Credit: Volodymyr Takhistov)

    This unique source of monopoles is especially interesting, as it is independent of any pre-existing monopoles such as those potentially left over as relics from the early Universe, and covers a broad range of energies.

    By re-analyzing data from a wide range of previous experimental monopole searches, the researchers identified novel limits on monopoles across a wide range of masses, including those beyond the reach of conventional collider monopole searches.

    These results and source of monopoles studied by the researchers will serve as a useful benchmark for interpreting subsequent future monopole searches at terrestrial laboratories.

    Details of their study were published in Physical Review Letters on 17 May, 2022.

    See the full article here .

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    Please help promote STEM in your local schools.

    Stem Education Coalition

    The Kavli Institute for the Physics and Mathematics of the Universe (IPMU) [カブリ数物連携宇宙研](JP) at The University of Tokyo [東京大学](JP) is an international research institute with English as its official language. The goal of the institute is to discover the fundamental laws of nature and to understand the Universe from the synergistic perspectives of mathematics, astronomy, and theoretical and experimental physics. The Institute for the Physics and Mathematics of the Universe (IPMU) was established in October 2007 under the World Premier International Research Center Initiative (WPI) of the Ministry of Education, Sports, Science and Technology in Japan with the University of Tokyo as the host institution. IPMU was designated as the first research institute within the University of Tokyo Institutes for Advanced Study (UTIAS) in January 2011. It received an endowment from The Kavli Foundation and was renamed the “Kavli Institute for the Physics and Mathematics of the Universe” in April 2012. Kavli IPMU is located on the Kashiwa campus of the University of Tokyo, and more than half of its full-time scientific members come from outside Japan.

    The Kavli Foundation, based in Oxnard, California, is dedicated to the goals of advancing science for the benefit of humanity and promoting increased public understanding and support for scientists and their work.

    The Foundation’s mission is implemented through an international program of research institutes, professorships, and symposia in the fields of astrophysics, nanoscience, neuroscience, and theoretical physics as well as prizes in the fields of astrophysics, nanoscience, and neuroscience.

     
  • richardmitnick 8:43 am on February 28, 2022 Permalink | Reply
    Tags: "Local nuclear reactor helps UChicago scientists catch and study neutrinos", , , Neutrino physics, ,   

    From The University of Chicago (US): “Local nuclear reactor helps UChicago scientists catch and study neutrinos” 

    U Chicago bloc

    From The University of Chicago (US)

    Feb 24, 2022
    Louise Lerner

    1
    University of Chicago graduate student Mark Lewis observes the compact neutrino detector (visible as the black cube on top of a silver platform) next to the containment wall of a reactor at Constellation’s Dresden Generating Station. Photo courtesy Collar lab.

    ‘Ghost particles’ research could bolster physics, nuclear nonproliferation.

    A nuclear reactor at an Illinois energy plant is helping University of Chicago scientists learn how to catch and understand the tiny, elusive particles known as neutrinos.

    At Constellation’s (formerly Exelon) Dresden Generating Station in Morris, Illinois, the team took the first measurements of neutrinos coming off a nuclear reactor with a tiny detector. These particles are extremely hard to catch because they interact so rarely with matter, but power reactors are one of the few places on Earth with a high concentration of them.

    “This was an exciting opportunity to benefit from the enormous neutrino production from a reactor, but also a challenge in the noisy industrial environment right next to a reactor,” said Prof. Juan Collar, a particle physicist who led the research. “This is the closest that neutrino physicists have been able to get to a commercial reactor core. We gained unique experience in operating a detector under these conditions, thanks to Constellation’s generosity in accommodating our experiment.”

    With this knowledge, the group is planning to take more measurements that may be able to tease out answers to questions about the fundamental laws governing particle and nuclear interactions.

    The technique may also be useful in nuclear nonproliferation, because the neutrinos can tell scientists about what’s going on in the core of the reactor. Detectors could be placed next to reactors as a safeguard to monitor whether the reactor is being used for energy production or to make weapons.

    “Orders of magnitude”

    Neutrinos are sometimes called “ghost particles” because they pass invisibly through almost all matter.

    (Billions have already zipped through your body today without your notice, en route from elsewhere in outer space.) But if you can catch them, they can tell you about what’s happening where they came from, and about the fundamental properties of the universe.

    In particular, scientists would like to learn about specific aspects of neutrino behavior—whether they have electromagnetic properties (for instance, a “magnetic moment”), and whether they interact with as yet unknown particles hiding from our notice, or in new ways with known particles. Taking extensive measurements of as many neutrinos as possible can help narrow down these possibilities.

    The need for many neutrinos is what drew Collar’s team to nuclear reactors. “Commercial reactors are the largest source of neutrinos on Earth by orders of magnitude,” he said. In the normal course of operation, nuclear reactors produce astronomical numbers of neutrinos per second. They occur when atoms inside the reactor break up into lighter elements, and release some of the energy in the form of neutrinos.

    However, there’s a problem. Because neutrinos are so lightweight, and interact so rarely, scientists normally have to find them by filling an enormous tank with detecting fluids and then search for the telltale signal that a passing particle has produced one of a number of known reactions in it.

    But there’s no room inside a commercial nuclear reactor for a multi-ton detector. The researchers needed something much, much smaller. Luckily, Collar is an expert in building such devices; he previously lead a team that built the world’s smallest neutrino detector.

    2
    The international COHERENT Collaboration, which includes physicists at UChicago use a detector that’s small and lightweight enough for a researcher to carry. Their findings, which confirm the theory of The DOE’s Fermi National Accelerator Laboratory (US)’s Daniel Freedman, were reported Aug. 3 in the journal Science.

    In a second stroke of luck, Illinois is one of the leading nuclear energy states—about half the state’s electricity is generated at nuclear reactors. Constellation granted Collar permission to test the detector at Dresden Generating Station, one of the first-ever commercial nuclear plants in the nation.

    4
    An exterior view of Commonwealth Edison Company’s Dresden nuclear power station near Morris, Illinois.
    Credit: The Department of Energy (US).

    Previously, Collar and his team had tested their tiny detectors at a particle accelerator in The DOE’s Oak Ridge National Laboratory in Tennessee, where they were able to carefully control much of the environment in order to get a good signal. But in order for the detector to work at Dresden, they had to build a new version adapted to deal with the much noisier environment of an operating commercial reactor.

    “You’re getting radiation, heat, vibration from the turbines, radiofrequency noise from the pumps and other machinery,” Collar said. “But we managed to work around all the challenges that were thrown our way.”

    They designed the detector with a complex multi-layered shielding to protect it from other stray particles that would contaminate the data. Eventually, they were able to leave the detector in place to function unattended for several months, taking data all the while.

    The team next hopes to take data at another reactor down the road at Constellation’s Braidwood Generating Station, or at the Vandellòs nuclear plant in coastal Spain. “This method can really contribute to our understanding of neutrino properties,” Collar said. “A lot of theoretical knowledge can be extracted from our data.”

    The knowledge about operating small detectors in such noisy environments is also in high demand. “There is an interest in the nuclear nonproliferation community to set detectors next to reactors, because they can tell you what’s going on in the core—revealing any deviations from the declared use,” Collar said.

    The output of neutrinos changes according to what kind of fuel the reactor is burning and what it’s producing, so detectors should be able to monitor for warning signs of weapons production, or whether fuel is being secretly diverted elsewhere. But to make this goal a reality, such detectors would have to be small, robust and easy to use; Collar said the Dresden work helps gather valuable data to make such detectors possible.

    There may also be many other uses for neutrino detectors. “For example, once we have sufficiently sensitive neutrino detectors, you could use them to map the interior of the Earth—perhaps even detect oil or other useful deposits,” Collar said. “A lot of thinking along these lines has been done, but it is still in the future.”

    While working on the design, Collar was reminded that his laboratory on campus continues a line of work initiated by Prof. Willard Libby in the 1950s to discover how to use carbon-dating to tell the age of an object.

    “These pioneers had to come up with techniques that we still use today to find a relatively small signal amongst a great deal of background noise,” he said. “It’s rewarding to think our work is part of a long local tradition. And Illinois is a special place for nuclear power generation, for similar reasons.”

    Science papers:

    Physical Review D

    Suggestive evidence for Coherent Elastic Neutrino-Nucleus Scattering from reactor antineutrinos

    See the full article here .

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    Please help promote STEM in your local schools.

    Stem Education Coalition

    U Chicago Campus

    The University of Chicago (US) is an urban research university that has driven new ways of thinking since 1890. Our commitment to free and open inquiry draws inspired scholars to our global campuses, where ideas are born that challenge and change the world.

    We empower individuals to challenge conventional thinking in pursuit of original ideas. Students in the College develop critical, analytic, and writing skills in our rigorous, interdisciplinary core curriculum. Through graduate programs, students test their ideas with University of Chicago scholars, and become the next generation of leaders in academia, industry, nonprofits, and government.

    University of Chicago research has led to such breakthroughs as discovering the link between cancer and genetics, establishing revolutionary theories of economics, and developing tools to produce reliably excellent urban schooling. We generate new insights for the benefit of present and future generations with our national and affiliated laboratories: DOE’s Argonne National Laboratory (US), DOE’s Fermi National Accelerator Laboratory (US), and the Marine Biological Laboratory in Woods Hole, Massachusetts.
    The University of Chicago is enriched by the city we call home. In partnership with our neighbors, we invest in Chicago’s mid-South Side across such areas as health, education, economic growth, and the arts. Together with our medical center, we are the largest private employer on the South Side.

    In all we do, we are driven to dig deeper, push further, and ask bigger questions—and to leverage our knowledge to enrich all human life. Our diverse and creative students and alumni drive innovation, lead international conversations, and make masterpieces. Alumni and faculty, lecturers and postdocs go on to become Nobel laureates, CEOs, university presidents, attorneys general, literary giants, and astronauts. The University of Chicago is a private research university in Chicago, Illinois. Founded in 1890, its main campus is located in Chicago’s Hyde Park neighborhood. It enrolled 16,445 students in Fall 2019, including 6,286 undergraduates and 10,159 graduate students. The University of Chicago is ranked among the top universities in the world by major education publications, and it is among the most selective in the United States.

    The university is composed of one undergraduate college and five graduate research divisions, which contain all of the university’s graduate programs and interdisciplinary committees. Chicago has eight professional schools: the Law School, the Booth School of Business, the Pritzker School of Medicine, the School of Social Service Administration, the Harris School of Public Policy, the Divinity School, the Graham School of Continuing Liberal and Professional Studies, and the Pritzker School of Molecular Engineering. The university has additional campuses and centers in London, Paris, Beijing, Delhi, and Hong Kong, as well as in downtown Chicago.

    University of Chicago scholars have played a major role in the development of many academic disciplines, including economics, law, literary criticism, mathematics, religion, sociology, and the behavioralism school of political science, establishing the Chicago schools in various fields. Chicago’s Metallurgical Laboratory produced the world’s first man-made, self-sustaining nuclear reaction in Chicago Pile-1 beneath the viewing stands of the university’s Stagg Field. Advances in chemistry led to the “radiocarbon revolution” in the carbon-14 dating of ancient life and objects. The university research efforts include administration of DOE’s Fermi National Accelerator Laboratory(US) and DOE’s Argonne National Laboratory(US), as well as the U Chicago Marine Biological Laboratory in Woods Hole, Massachusetts (MBL)(US). The university is also home to the University of Chicago Press, the largest university press in the United States. The Barack Obama Presidential Center is expected to be housed at the university and will include both the Obama presidential library and offices of the Obama Foundation.

    The University of Chicago’s students, faculty, and staff have included 100 Nobel laureates as of 2020, giving it the fourth-most affiliated Nobel laureates of any university in the world. The university’s faculty members and alumni also include 10 Fields Medalists, 4 Turing Award winners, 52 MacArthur Fellows, 26 Marshall Scholars, 27 Pulitzer Prize winners, 20 National Humanities Medalists, 29 living billionaire graduates, and have won eight Olympic medals.

    The University of Chicago is enriched by the city we call home. In partnership with our neighbors, we invest in Chicago’s mid-South Side across such areas as health, education, economic growth, and the arts. Together with our medical center, we are the largest private employer on the South Side.

    In all we do, we are driven to dig deeper, push further, and ask bigger questions—and to leverage our knowledge to enrich all human life. Our diverse and creative students and alumni drive innovation, lead international conversations, and make masterpieces. Alumni and faculty, lecturers and postdocs go on to become Nobel laureates, CEOs, university presidents, attorneys general, literary giants, and astronauts.

    Research

    According to the National Science Foundation (US), University of Chicago spent $423.9 million on research and development in 2018, ranking it 60th in the nation. It is classified among “R1: Doctoral Universities – Very high research activity” and is a founding member of the Association of American Universities (US) and was a member of the Committee on Institutional Cooperation from 1946 through June 29, 2016, when the group’s name was changed to the Big Ten Academic Alliance. The University of Chicago is not a member of the rebranded consortium, but will continue to be a collaborator.

    The university operates more than 140 research centers and institutes on campus. Among these are the Oriental Institute—a museum and research center for Near Eastern studies owned and operated by the university—and a number of National Resource Centers, including the Center for Middle Eastern Studies. Chicago also operates or is affiliated with several research institutions apart from the university proper. The university manages DOE’s Argonne National Laboratory(US), part of the United States Department of Energy’s national laboratory system, and co-manages DOE’s Fermi National Accelerator Laboratory (US), a nearby particle physics laboratory, as well as a stake in the Apache Point Observatory (US) in Sunspot, New Mexico.
    _____________________________________________________________________________________

    SDSS Telescope at Apache Point Observatory, near Sunspot NM, USA, Altitude 2,788 meters (9,147 ft).

    Apache Point Observatory (US), near Sunspot, New Mexico Altitude 2,788 meters (9,147 ft).
    _____________________________________________________________________________________

    Faculty and students at the adjacent Toyota Technological Institute at Chicago collaborate with the university. In 2013, the university formed an affiliation with the formerly independent Marine Biological Laboratory in Woods Hole, Mass. Although formally unrelated, the National Opinion Research Center (US) is located on Chicago’s campus.

     
  • richardmitnick 10:25 am on December 26, 2021 Permalink | Reply
    Tags: "2021 A year physicists asked 'What lies beyond the Standard Model?'", , , , , , , Neutrino physics, Neutrinos [tau;muon;electron] represent three of the 17 fundamental particles in the Standard Model., , , ,   

    From The Conversation (AU) via phys.org : “2021 A year physicists asked ‘What lies beyond the Standard Model?'” 

    From The Conversation (AU)

    via

    phys.org

    December 23, 2021
    Aaron McGowan, The Conversation

    1
    Experiments at the Large Hadron Collider in Europe, like the ATLAS calorimeter seen here, are providing more accurate measurements of fundamental particles. Credit: Maximilien Brice, CC BY-NC.

    European Organization for Nuclear Research [Organisation européenne pour la recherche nucléaire] [Europäische Organisation für Kernforschung](CH) [CERN].

    “If you ask a physicist like me to explain how the world works, my lazy answer might be: ‘It follows the Standard Model.’

    Standard Model of Particle Physics, Quantum Diaries

    The Standard Model explains the fundamental physics of how the universe works. It has endured over 50 trips around the Sun despite experimental physicists constantly probing for cracks in the model’s foundations.

    With few exceptions, it has stood up to this scrutiny, passing experimental test after experimental test with flying colors. But this wildly successful model has conceptual gaps that suggest there is a bit more to be learned about how the universe works.

    I am a neutrino physicist. Neutrinos represent three of the 17 fundamental particles in the Standard Model. They zip through every person on Earth at all times of day. I study the properties of interactions between neutrinos and normal matter particles.

    In 2021, physicists around the world ran a number of experiments that probed the Standard Model. Teams measured basic parameters of the model more precisely than ever before. Others investigated the fringes of knowledge where the best experimental measurements don’t quite match the predictions made by the Standard Model. And finally, groups built more powerful technologies designed to push the model to its limits and potentially discover new particles and fields. If these efforts pan out, they could lead to a more complete theory of the universe in the future.

    Filling holes in Standard Model

    In 1897, J.J. Thomson discovered the first fundamental particle, the electron, using nothing more than glass vacuum tubes and wires. More than 100 years later, physicists are still discovering new pieces of the Standard Model.

    2
    The Standard Model of physics allows scientists to make incredibly accurate predictions about how the world works, but it doesn’t explain everything. Credit: CERN, CC BY-NC.

    The Standard Model is a predictive framework that does two things. First, it explains what the basic particles of matter are. These are things like electrons and the quarks that make up protons and neutrons. Second, it predicts how these matter particles interact with each other using “messenger particles.” These are called bosons—they include photons and the famous Higgs boson—and they communicate the basic forces of nature. The Higgs boson wasn’t discovered until 2012 after decades of work at The European Organization for Nuclear Research [Organisation européenne pour la recherche nucléaire](CH), the huge particle collider in Europe.

    European Organization for Nuclear Research [Organisation européenne pour la recherche nucléaire] [Europäische Organisation für Kernforschung](CH) CMS Higgs Event May 27, 2012.

    European Organization for Nuclear Research [Organisation européenne pour la recherche nucléaire] [Europäische Organisation für Kernforschung](CH) ATLAS Higgs Event June 18, 2012.

    Peter Higgs – University of Edinburgh [Oilthigh Dhùn Èideann] (SCT).

    The Standard Model is incredibly good at predicting many aspects of how the world works, but it does have some holes.

    Notably, it does not include any description of gravity. While Albert Einstein’s Theory of General Relativity describes how gravity works, physicists have not yet discovered a particle that conveys the force of gravity [Quantum Mechanics’ ‘graviton’]. A proper “Theory of Everything” would do everything the Standard Model can, but also include the messenger particles that communicate how gravity interacts with other particles.

    Another thing the Standard Model can’t do is explain why any particle has a certain mass—physicists must measure the mass of particles directly using experiments. Only after experiments give physicists these exact masses can they be used for predictions. The better the measurements, the better the predictions that can be made.

    Recently, physicists on a team at CERN measured how strongly the Higgs boson feels itself.

    4
    Twice the Higgs, twice the challenge
    ATLAS searches for pairs of Higgs bosons in the rare bbɣɣ decay channel, 29 March 2021.

    Another CERN team also measured the Higgs boson’s mass more precisely than ever before.

    4
    A new result by the CMS Collaboration narrows down the mass of the Higgs boson to a precision of 0.1%.

    And finally, there was also progress on measuring the mass of neutrinos.

    KATRIN experiment aims to measure the mass of the neutrino using a huge device called a spectrometer (interior shown)KIT Karlsruhe Institute of Technology [Karlsruher Institut für Technologie] (DE).

    Physicists know neutrinos have more than zero mass but less than the amount currently detectable. A team in Germany has continued to refine the techniques that could allow them to directly measure the mass of neutrinos.

    Hints of new forces or particles

    In April 2021, members of the Muon g-2 experiment at Fermilab announced their first measurement of the magnetic moment of the muon.

    DOE’s Fermi National Accelerator Laboratory(US) Muon g-2 studio. As muons race around a ring at the Muon g-2 studio, their spin axes twirl, reflecting the influence of unseen particles.

    The muon is one of the fundamental particles in the Standard Model, and this measurement of one of its properties is the most accurate to date. The reason this experiment was important was because the measurement didn’t perfectly match the Standard Model prediction of the magnetic moment. Basically, muons don’t behave as they should. This finding could point to undiscovered particles that interact with muons.

    But simultaneously, in April 2021, physicist Zoltan Fodor and his colleagues showed how they used a mathematical method called Lattice QCD to precisely calculate the muon’s magnetic moment. Their theoretical prediction is different from old predictions, still works within the Standard Model and, importantly, matches experimental measurements of the muon.

    The disagreement between the previously accepted predictions, this new result and the new prediction must be reconciled before physicists will know if the experimental result is truly beyond the Standard Model.

    Upgrading the tools of physics

    Physicists must swing between crafting the mind-bending ideas about reality that make up theories and advancing technologies to the point where new experiments can test those theories. 2021 was a big year for advancing the experimental tools of physics.

    First, the world’s largest particle accelerator, the Large Hadron Collider at CERN, was shut down and underwent some substantial upgrades. Physicists just restarted the facility in October, and they plan to begin the next data collection run in May 2022. The upgrades have boosted the power of the collider so that it can produce collisions at 14 TeV, up from the previous limit of 13 TeV. This means the batches of tiny protons that travel in beams around the circular accelerator together carry the same amount of energy as an 800,000-pound (360,000-kilogram) passenger train traveling at 100 mph (160 kph). At these incredible energies, physicists may discover new particles that were too heavy to see at lower energies.

    SixTRack CERN LHC particles.

    Some other technological advancements were made to help the search for dark matter. Many astrophysicists believe that dark matter particles, which don’t currently fit into the Standard Model, could answer some outstanding questions regarding the way gravity bends around stars—called gravitational lensing—as well as the speed at which stars rotate in spiral galaxies. Projects like the Cryogenic Dark Matter Search have yet to find dark matter particles, but the teams are developing larger and more sensitive detectors to be deployed in the near future.

    Gravitational Lensing Gravitational Lensing National Aeronautics Space Agency (US) and European Space Agency [Agence spatiale européenne][Europäische Weltraumorganisation](EU).


    Super Cryogenic Dark Matter Search at DOE’s SLAC National Accelerator Laboratory (US) at Stanford University (US) at SNOLAB (Vale Inco Mine, Sudbury, Canada).

    Particularly relevant to my work with neutrinos is the development of immense new detectors like Hyper-Kamiokande and DUNE.

    Hyper-Kamiokande [(神岡宇宙素粒子研究施設](JP) a neutrino physics laboratory to be located underground in the Mozumi Mine of the Kamioka Mining and Smelting Co. near the Kamioka section of the city of Hida in Gifu Prefecture, Japan.

    DOE’s Fermi National Accelerator Laboratory(US) DUNE LBNF (US) from FNAL to Sanford Underground Research Facility, Lead, South Dakota, USA.

    DOE’s Fermi National Accelerator Laboratory(US) DUNE LBNF (US) Caverns at Sanford Underground Research Facility.

    Using these detectors, scientists will hopefully be able to answer questions about a fundamental asymmetry in how neutrinos oscillate. They will also be used to watch for proton decay, a proposed phenomenon that certain theories predict should occur.

    2021 highlighted some of the ways the Standard Model fails to explain every mystery of the universe. But new measurements and new technology are helping physicists move forward in the search for the Theory of Everything.”

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    The Conversation (AU) launched as a pilot project in October 2014. It is an independent source of news and views from the academic and research community, delivered direct to the public.
    Our team of professional editors work with university and research institute experts to unlock their knowledge for use by the wider public.
    Access to independent, high quality, authenticated, explanatory journalism underpins a functioning democracy. Our aim is to promote better understanding of current affairs and complex issues. And hopefully allow for a better quality of public discourse and conversation.

     
  • richardmitnick 8:57 am on August 31, 2021 Permalink | Reply
    Tags: , , , Neutrino oscillation, Neutrino physics, , , , Solar Neutrino Problem   

    From Sanford Underground Research Facility-SURF: “The neutrino puzzle” 

    SURF-Sanford Underground Research Facility, Lead, South Dakota, USA.

    From Sanford Underground Research Facility-SURF

    Homestake Mining, Lead, South Dakota, USA.


    Homestake Mining Company

    August 30, 2021
    Constance Walter

    Researchers continue to piece together information about the ghostly particle.

    Imagine trying to put together a jigsaw puzzle that has no picture for reference, is missing several pieces and, of the pieces you do have, some don’t quite fit together.

    Welcome to the life of a neutrino researcher.

    Vincente Guiseppe began his neutrino journey 15 years ago as a post-doc at DOE’s Los Alamos National Laboratory (US). He worked with germanium detectors and studied radon while a graduate student and followed the scientific community’s progress as the Solar Neutrino Problem was solved. The so-called Solar Neutrino Problem was created when Dr. Ray Davis Jr., who operated a solar neutrino experiment on the 4850 Level of the Homestake Gold Mine, discovered only one-third of the neutrinos that had been theorized. Nearly 30 years after Davis began his search, the problem was solved with the discovery of neutrino oscillation.

    “I began to understand that neutrinos had much more in store for us. That led me to move to neutrino physics and set me up to transition to the Majorana Demonstrator (Majorana) project,” said Guiseppe, who is now a co-spokesperson for Majorana, located nearly a mile underground at SURF, and a senior research staff member at DOE’s Oak Ridge National Lab (ORNL).

    Majorana uses germanium crystals in a search for the theorized Majorana particle—a neutrino that is believed to be its own antiparticle. Its discovery could help unravel mysteries about the origins of the universe and would add yet another piece to this baffling neutrino puzzle.

    We caught up with Guiseppe recently to talk about neutrinos—what scientists know (and don’t know), why neutrinos behave so strangely and why scientists keep searching for this ghost-like particle.

    SURF: What are neutrinos?

    Guiseppe: Let’s start with what we know. Of all the known fundamental particles that have mass, neutrinos are the most abundant—only the massless photon, which we see as light, is more abundant. We know their mass is quite small, but not zero—much lighter than their counterparts in the Standard Model of Physics—and we know there are three types and that they can change flavors. They also rarely interact with matter, which makes them difficult to study.

    All of these data points are pieces of that neutrino puzzle. But every piece is important if we want to complete the picture.

    SURF: Why should we care about the neutrino?

    Guiseppe: We care because they are so abundant. It’s almost embarrassing to have something that is so prevalent all around us and to not fully understand it. Think of it this way: You see a forest and the most abundant thing in that forest is a tree. But that’s all you know. You don’t know anything about how a tree operates. You don’t know how it grows, you don’t know why it’s green, you don’t know why it’s alive. It would be embarrassing to not know that. But that’s not the case with trees. Something so abundant as what we see in nature—animal species, trees, plants—we understand them completely, there’s nothing surprising. So, the fact that they are so abundant, and yet we know so little about them, brings a sort of duty to understand them.

    SURF: What intrigues you most about neutrino research?

    Guiseppe: Most? I would say the breadth of research and the big questions that can be answered by a single particle. While similar claims could be made about other particle research, the experimental approach is wide open. We look for neutrinos from nuclear reactors, particle accelerators, the earth, our atmosphere, the sun, from supernovae, and some experiments are only satisfied if we find no neutrinos, as in the case of neutrinoless double-beta decay searches. Neutrino research places detectors in underground caverns, at the South Pole, in the ocean, and even in a van for drive-by neutrino monitoring for nuclear safeguard applications. It’s a diverse field with big and unique questions.

    SURF: What is oscillation?

    Guiseppe: Oscillation is the idea that neutrinos can co-exist in a mixture of types or “flavors.” While they must start out as a particular flavor upon formation, they can evolve into a mixture of other flavors while traveling before falling into one flavor upon interaction with matter or detection. Hence, they are observed to oscillate between flavors from formation to detection.

    SURF: It’s a fundamental idea that a thing can’t become another thing unless acted upon by an outside force or material. How can something spontaneously become something it wasn’t a split second ago? And why are we OK with that?

    Guiseppe: Are people really okay with the idea of neutrinos changing flavors? I think we are, inasmuch as we are really okay with the implications of quantum mechanics? (As an aside, this reminds me of a question I asked my undergraduate quantum mechanics professor. I felt I was doing fine in the class and could work the problems but was worried that I really didn’t understand quantum mechanics. He responded with a slight grin: “Oh, no one really ‘understands’ quantum mechanics.”).

    It is quantum mechanics at work that makes this flavor change possible. Since neutrinos come in three separate flavors and three separate masses (and more importantly, each flavor does not come as a definite mass), they can exist in a quantum mechanical mixture of flavors. The root of your concern stems from the idea of its identify—what does it mean to change this identity?

    The comforting aspect is that neutrinos are not found to change speed, direction, mass, shape, or anything else that would require an outside force or energy in the usual sense. By changing flavor, the neutrino is only changing its personality and the rules by which it should follow at a given time.

    While this bit of personification is probably not comforting, it is only how the neutrino must interact with other particles that changes over time. You could think of the neutrino as being formed as one type, but then realizing it is not forced into that identity. It then remains in an indecisive state while being swayed to one type over another before finally making a decision upon detection or other interaction. In that sense, it is not a spontaneous change, but the result of a well thought-out (or predictable) decision process.

    SURF: What is a Majorana Particle and why is it important?

    Guiseppe: A Majorana particle is one that is indistinguishable from its antimatter partner. This sets it apart from all other particles. With the Majorana Demonstrator, we are looking for this particle in a process called neutrinoless double-beta decay.

    Neutrinoless double-beta decay is a nuclear process whereby two neutrons transform into two protons and electrons (aka, beta particles), but without the emission of two anti-neutrinos. This is in contrast to the two neutrino double-beta decay process where the two anti-neutrinos are emitted; a process that has been observed.

    SURF: Why neutrinoless double-beta decay?

    Guiseppe: Neutrinoless double-beta decay experiments offer the right mix of simplicity, experimental challenges, and the potential for a fascinating discovery. The signature for neutrinoless double-beta decay is simple: a measurement made at a specific energy and at a fixed point in the detector. But it’s a rare occurrence that is easily obscured so reducing all background (interferences) that can partially mimic this signature and foil the measurement is critical. Searching for this decay requires innovative detectors, as well as the ability to control the ubiquitous radiation found in everything around us.

    SURF: After so many years, how do you stay enthusiastic about neutrino research?

    Guiseppe: Its book isn’t finished yet. We have more to learn and more questions to answer—we only need the means to do so. I stay enthused due to the likelihood of some new surprises (or comforting discoveries) that await. Along the way, we can continue to make advances in detector technology and develop new (or cleaner) materials, which inevitably lead to applications outside of physics research. In the end, chasing down neutrino properties and the secrets they may hold remains exciting due to clever ideas that keep the next discovery within reach.

    See the full article here .


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    About us: The Sanford Underground Research Facility-SURF in Lead, South Dakota, advances our understanding of the universe by providing laboratory space deep underground, where sensitive physics experiments can be shielded from cosmic radiation. Researchers at the Sanford Lab explore some of the most challenging questions facing 21st century physics, such as the origin of matter, the nature of dark matter and the properties of neutrinos. The facility also hosts experiments in other disciplines—including geology, biology and engineering.

    The Sanford Lab is located at the former Homestake gold mine, which was a physics landmark long before being converted into a dedicated science facility. Nuclear chemist Ray Davis earned a share of the Nobel Prize for Physics in 2002 for a solar neutrino experiment he installed 4,850 feet underground in the mine.

    Homestake closed in 2003, but the company donated the property to South Dakota in 2006 for use as an underground laboratory. That same year, philanthropist T. Denny Sanford donated $70 million to the project. The South Dakota Legislature also created the South Dakota Science and Technology Authority to operate the lab. The state Legislature has committed more than $40 million in state funds to the project, and South Dakota also obtained a $10 million Community Development Block Grant to help rehabilitate the facility.

    In 2007, after the National Science Foundation named Homestake as the preferred site for a proposed national Deep Underground Science and Engineering Laboratory (DUSEL), the South Dakota Science and Technology Authority (SDSTA) began reopening the former gold mine.

    In December 2010, the National Science Board decided not to fund further design of DUSEL. However, in 2011 the Department of Energy, through the Lawrence Berkeley National Laboratory, agreed to support ongoing science operations at Sanford Lab, while investigating how to use the underground research facility for other longer-term experiments. The SDSTA, which owns Sanford Lab, continues to operate the facility under that agreement with Berkeley Lab.

    The first two major physics experiments at the Sanford Lab are 4,850 feet underground in an area called the Davis Campus, named for the late Ray Davis. The Large Underground Xenon (LUX) experiment is housed in the same cavern excavated for Ray Davis’s experiment in the 1960s.

    In October 2013, after an initial run of 80 days, LUX was determined to be the most sensitive detector yet to search for dark matter—a mysterious, yet-to-be-detected substance thought to be the most prevalent matter in the universe. The The U Washington MAJORANA Neutrinoless Double-beta Decay Experiment Demonstrator experiment (US), also on the 4850 Level, is searching for a rare phenomenon called “neutrinoless double-beta decay” that could reveal whether subatomic particles called neutrinos can be their own antiparticle. Detection of neutrinoless double-beta decay could help determine why matter prevailed over antimatter. The Majorana Demonstrator experiment is adjacent to the original Davis cavern.

    The LUX Xenon dark matter detector | Sanford Underground Research Facility mission was to scour the universe for WIMPs, vetoing all other signatures. It would continue to do just that for another three years before it was decommissioned in 2016.

    In the midst of the excitement over first results, the LUX collaboration was already casting its gaze forward. Planning for a next-generation dark matter experiment at Sanford Lab was already under way. Named LUX-ZEPLIN (LZ), the next-generation experiment would increase the sensitivity of LUX 100 times.

    SLAC National Accelerator Laboratory(US) physicist Tom Shutt, a previous co-spokesperson for LUX, said one goal of the experiment was to figure out how to build an even larger detector.

    “LZ will be a thousand times more sensitive than the LUX detector,” Shutt said. “It will just begin to see an irreducible background of neutrinos that may ultimately set the limit to our ability to measure dark matter.”

    We celebrate five years of LUX, and look into the steps being taken toward the much larger and far more sensitive experiment.

    Another major experiment, the Long Baseline Neutrino Experiment (LBNE)—a collaboration with Fermi National Accelerator Laboratory (Fermilab) and Sanford Lab, is in the preliminary design stages. The project got a major boost last year when Congress approved and the president signed an Omnibus Appropriations bill that will fund LBNE operations through FY 2014. Called the “next frontier of particle physics,” LBNE will follow neutrinos as they travel 800 miles through the earth, from FermiLab in Batavia, Ill., to Sanford Lab.

    FNAL DUNE LBNF (US) from FNAL to SURF, Lead, South Dakota, USA

    FNAL DUNE LBNF (US) Caverns at Sanford Lab.

    The MAJORANA DEMONSTRATOR will contain 40 kg of germanium; up to 30 kg will be enriched to 86% in 76Ge. The DEMONSTRATOR will be deployed deep underground in an ultra-low-background shielded environment in the Sanford Underground Research Facility (SURF) in Lead, SD. The goal of the DEMONSTRATOR is to determine whether a future 1-tonne experiment can achieve a background goal of one count per tonne-year in a 4-keV region of interest around the 76Ge 0νββ Q-value at 2039 keV. MAJORANA plans to collaborate with Germanium Detector Array (or GERDA) experiment is searching for neutrinoless double beta decay (0νββ) in Ge-76 at the underground Laboratori Nazionali del Gran Sasso (LNGS) for a future tonne-scale 76Ge 0νββ search.

    CASPAR is a low-energy particle accelerator that allows researchers to study processes that take place inside collapsing stars.

    The scientists are using space in the Sanford Underground Research Facility (SURF) in Lead, South Dakota, to work on a project called the Compact Accelerator System for Performing Astrophysical Research (CASPAR). CASPAR uses a low-energy particle accelerator that will allow researchers to mimic nuclear fusion reactions in stars. If successful, their findings could help complete our picture of how the elements in our universe are built. “Nuclear astrophysics is about what goes on inside the star, not outside of it,” said Dan Robertson, a Notre Dame assistant research professor of astrophysics working on CASPAR. “It is not observational, but experimental. The idea is to reproduce the stellar environment, to reproduce the reactions within a star.”

     
  • richardmitnick 11:54 am on February 1, 2021 Permalink | Reply
    Tags: "Andreas Ekström will explore the secrets of the strong force in atomic nuclei", , , Neutrino physics, , , , , ,   

    From Chalmers University of Technology [ tekniska högskola ](SE): “Andreas Ekström will explore the secrets of the strong force in atomic nuclei” 

    From Chalmers University of Technology [ tekniska högskola ](SE)

    25 Aug 2017 [Brought forward 1.31.21. Why now?]

    1
    For the next five years, Andreas Ekström will lead a research project funded with 1,5 M€ from the European Research Council (ERC). The goal is to establish new methods and theories to model atomic nuclei. Credit: Mia Halleröd Palmgren.

    All visible matter in the universe consists of atoms. The constituents of the atomic nucleus are held together by a force called the strong force. Despite its central importance, we do not yet know how it works. Researchers from Chalmers University of Technology will therefore try to reveal new information about atomic nuclei.

    “We need to create a solid theoretical framework to describe the strong force between protons and neutrons in atomic nuclei. Today’s theories form an incomplete patchwork”, says Andreas Ekström, researcher at the Department of Physics at Chalmers University of Technology.

    For the next five years, he will lead a research project funded with 1,5 M€ from the European Research Council (ERC). The goal is to establish new methods and theories to model atomic nuclei. He will focus on heavy, unstable, and exotic nuclei that so far have eluded researchers all over the world.

    ” To generate new knowledge about the strong force, I will investigate heavy atomic nuclei such as oxygen and calcium. A heavy nucleus typically contains more information than a light nucleus such as helium. However, it’s a greater challenge to analyze heavy nuclei”, says Andreas Ekström.

    1

    In his project, he will introduce new ways to exploit data from existing experiments and theoretically disassemble atomic nuclei to better understand the strong force. More or less laying the puzzle backwards. Since a heavy nucleus consists of considerably more neutrons and protons than a light one, it will be a tricky puzzle with many pieces to keep track of.

    But the research project is not only about describing the strong force in nuclei. It is also essential to work out methods for calculating the uncertainties in the models.

    “Many fields of research are based on input from fundamental . It is also very expensive and time consuming to conduct large experiments. Therefore, it is important that we can offer predictions with great precision.”

    The basic research that is conducted by Andreas Ekström is essential for understanding stellar physics and fusion processes in the sun as well as neutrino physics. The aim is to solve one of the great mysteries of our universe.

    “The strong force affects everything – from the smallest atomic nucleus to the biggest star – and a well-functioning society is based on understanding the world we live in. We need fundamental research as a pillar of society. Even though we will not have all the answers in five years, I hope that we can make important progress. My previous research has shown that the proposed method of laying the puzzle backwards is a possible way ahead”, says Andreas Ekström.

    See the full article here .

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    Chalmers University of Technology [tekniska högskola](SE) is a Swedish university located in Gothenburg that focuses on research and education in technology, natural science, architecture, maritime and other management areas

    The University was founded in 1829 following a donation by William Chalmers, a director of the Swedish East India Company. He donated part of his fortune for the establishment of an “industrial school”. Chalmers was run as a private institution until 1937, when the institute became a state-owned university. In 1994, the school was incorporated as an aktiebolag under the control of the Swedish Government, the faculty and the Student Union. Chalmers is one of only three universities in Sweden which are named after a person, the other two being Karolinska Institutet and Linnaeus University.

     
  • richardmitnick 4:51 pm on December 22, 2020 Permalink | Reply
    Tags: "Welcome to Neutrino Alley- Q&A with ORNL’s Marcel Demarteau", , , Neutrino physics, ,   

    From DOE’s Oak Ridge National Laboratory: “Welcome to Neutrino Alley- Q&A with ORNL’s Marcel Demarteau” 

    From DOE’s Oak Ridge National Laboratory

    December 22, 2020

    1
    ORNL’s Marcel Demarteau inspects experiments along Neutrino Alley at the Spallation Neutron Source, which makes neutrinos as a byproduct. Credit: Genevieve Martin/ORNL, U.S. Dept. of Energy.

    ORNL Spallation Neutron Source.


    ORNL Spallation Neutron Source.

    Marcel Demarteau is director of the Physics Division at the Department of Energy’s Oak Ridge National Laboratory. For topics from nuclear structure to astrophysics, he shapes ORNL’s physics research agenda. One of his challenges is advancing knowledge of neutrinos – electrically neutral particles that interact only weakly with matter, making their detection difficult.

    For four major neutrino collaborations, ORNL plays key roles. The lab leads the Majorana Demonstrator at the Sanford Underground Research Facility in South Dakota.

    U Washington Majorana Demonstrator Experiment at SURF

    It hosts the PROSPECT experiment at ORNL’s High Flux Isotope Reactor, or HFIR, and the COHERENT experiment at ORNL’s Spallation Neutron Source, or SNS. HFIR and SNS are DOE Office of Science User Facilities. ORNL is also leading the development of the LEGEND experiment as follow-up to the Majorana Demonstrator.

    Yale PROSPECT—A Precision Oscillation and Spectrum Experiment


    Yale PROSPECT Neutrino experiment


    ORNL High Flux Isotope Reactor

    LEGEND experiment at Gran Sasso

    Neutrinos are a byproduct of neutron production. Each year, hundreds of researchers rely on the 1.4 megawatt pulsed neutron source at SNS, the world’s brightest accelerator-based neutrino source, for scientific research and industrial development. The COHERENT experiment makes the most of SNS’s neutrino factory with five detectors sited along a 164-foot, or 50-meter, long hallway that has come to be called Neutrino Alley.

    Here, Demarteau explains its successes and possibilities.

    Q: What is Neutrino Alley and how did it come to be?

    A: Neutrino Alley is a service corridor at the Spallation Neutron Source that we discovered is ideally suited for neutrino experiments. As SNS’s name says, it is a facility to create neutrons; but in the process, a lot of other particles are created, especially pions. Pions are stopped very quickly in the liquid mercury target and decay at rest to give us three different neutrinos: promptly emitted muon neutrinos with a precise energy, and delayed electron and antimuon neutrinos.

    Q: Where is Neutrino Alley in relation to SNS’s target?

    A: The closest point in Neutrino Alley is about 20 meters from the SNS target. The irony is that neutrino experiments don’t like neutrons, which are SNS’s primary goal. Neutrons can induce spurious signals that look like neutrino interactions. We need a lot of shielding to remove the neutrons, and that’s why the 20 meters from the target is so beneficial. What’s in between is mainly concrete.

    Q: What experiments are going on there now?

    A: The COHERENT experiment measures coherent elastic neutrino-nucleus scattering, or CEvNS, which is pronounced “sevens.” This is a collective process in which a neutrino interacts with the nucleus as a whole, rather than with individual components of that nucleus. Eleven neutrino experiments at spallation and reactor sources worldwide are looking for this interaction.

    Scientists predicted this process about 50 years ago. However, it has been very difficult to observe because of the small interaction probability and because the energy to be detected is tiny. A frequent analogy is a mosquito bouncing off an elephant and measuring the movement of the elephant. We designed COHERENT to look for this process, and nearly three years ago we were the first to observe it. We provided experimental evidence for the process sought for 50 years. The COHERENT collaboration, comprising 20 institutions from four countries, conducts the experiment at the SNS. Jason Newby is the enthusiastic principal investigator at ORNL, which itself has nearly a dozen participants.

    The first target that we used to measure and discover the CEvNS process was a cesium iodide crystal. We have recently also measured this process on argon nuclei; that detector uses liquid argon as the detection medium. Moreover, we have other experiments in preparation – one with a detector of sodium iodide crystals and the other one with a detector of germanium crystals. Measuring the interaction rate for different nuclei provides us with insight into the fundamental physics processes occurring in these target materials.

    Q: What questions do you hope to answer with these detectors?

    A: The neutrino is one of the more interesting particles in particle physics. Currently, the Standard Model of Particle Physics tells us what matter is made of – quarks and leptons interacting through the electromagnetic, weak nuclear, strong nuclear and gravitational forces. The model was completed in 2012 with the discovery of the Higgs boson.

    Standard Model of Particle Physics via http://www.plus.maths.org .

    CERN CMS Higgs Event May 27, 2012.


    CERN ATLAS Higgs Event
    June 12, 2012.

    This model has been extremely successful in enabling us to calculate a lot of the phenomena that we see in nature. We can calculate some phenomena to a precision of better than one in a billion. However, we know that this model is incomplete. One salient new discovery that demonstrates that the Standard Model is incomplete is the fact that neutrinos have mass. Because neutrinos have mass, they can oscillate. They can change identity between the three known types of neutrinos, and that does not fit in our current description of the Standard Model.

    The high flux of neutrinos at the SNS also enables us to look for deviations from theoretical predictions, which could point to the existence of a completely new form of matter, such as sterile neutrinos. That would inform our understanding of the origin of dark matter, which would be absolutely transformational. Furthermore, we believe that neutrinos can provide insight into the matter-antimatter asymmetry in the universe. Neutrinos provide a unique window that will help us probe and uncover the new physics that we don’t know yet, that is not part of our Standard Model, our current description. That’s why neutrinos are such fascinating particles to study.

    Also, by mapping the fundamentals of neutrino interactions with liquid argon, our measurements inform the flagship Office of High Energy Physics experiment called DUNE, the Deep Underground Neutrino Experiment, which uses liquid argon as the detection medium.

    SURF-Sanford Underground Research Facility, Lead, South Dakota, USA.


    FNAL LBNF/DUNE from FNAL to SURF, Lead, South Dakota, USA.


    SURF DUNE LBNF Caverns at Sanford Lab.


    FNAL DUNE Argon tank at SURF.

    One goal of the DUNE experiment is to measure the neutrino flux from a supernova explosion in our galaxy. It just so happens that the energy spectrum of the neutrinos at the SNS is very similar to the energy spectrum expected from a supernova explosion. Our measurements thus provide the foundational measurements to enable extraction of information about the processes inside a supernova explosion.

    Q: How has having a neutrino factory been a game changer?

    A: The SNS is a game changer because it is a test beam for neutrinos. I can select a single type of neutrino with a well-defined energy with no background to probe a physics phenomenon. The SNS is a pulsed source for neutron production with a repetition rate of 60 hertz. This timing structure, combined with the physics of pion decay, enables me to select background-free, promptly emitted muon neutrinos with a very well-defined energy or a mixture of only electron and muon antineutrinos. This is unique in the world. No other source can provide that. That is the breakthrough that the SNS provides.

    Q: Why is it important to have only one flavor of neutrino?

    A: In everyday life we constantly deal with noise. How delightful it is to go to the symphony, and before the orchestra starts playing, you can hear a pin drop. Absolute quiet, no noise. And as soon as the orchestra starts playing, you are able to discern every nuance of every instrument for every measure during the performance. That is exactly the environment the SNS provides us: a pure, almost serene environment to study neutrino interactions. A pure muon neutrino source with a well-defined energy, shielded from most neutrons and other backgrounds, that enables you to probe the subtlest of effects of fundamental physics. There’s no other facility in the world that even comes close to providing that unique feature of neutrino physics.

    Q: How many neutrinos does COHERENT catch?

    A: The other unique feature of Neutrino Alley is the very high flux of neutrinos. Because neutrinos interact very weakly, you need a lot of them to carry out your experiments. The number of neutrinos coming from the SNS is approximately 4.3 ×10^7 neutrinos per second per square centimeter at a distance of 20 meters from the target. It’s an enormous number. What we end up detecting is a few hundred events. That huge reduction in data gives you a feel for the very small interaction rate of neutrinos. But given that we have such a very large and well-controlled neutrino flux, neutrinos can be used as a portal to other types of physics.

    Q: Neutrinos have been the topic of many Nobel Prizes. What more can they show us?

    A: Who knows? Neutrinos have surprised us many times before, and I’m convinced that they still have many surprises in store for us. We know that there is dark matter in the universe. We observe its gravitational interaction through the motions of the galaxies, but we have no clue what that is. Neutrinos can provide us clues to what the nature of dark matter really is. If dark matter has a particle nature, it could be that there are other types of neutrinos that we have not discovered yet. So far, we have found only three types of neutrinos, but there may also be other kinds of neutrinos, such as so-called sterile neutrinos. They could be candidate particles to help explain the nature of dark matter. At SNS, with the upcoming Second Target Station, further windows of opportunity will be opened with no impact to the base neutron science program.

    Q: What is the future of neutrino research?

    A: With the abundant availability and capabilities to study neutrinos, we’ve learned something about their nature. But at the same time, because the flux is so high and the source so pure, we have other windows to the universe.

    Neutrinos are fascinating and mysterious particles that we know so little about. For example, we don’t know if a neutrino is its own antiparticle. To probe that property of neutrinos, we are involved in a flagship experiment, called LEGEND – the Large Enriched Germanium Experiment for Neutrinoless double-beta Decay. If we can establish that a neutrino is its own antiparticle, it will tell us something about the matter/antimatter asymmetry in the universe. If the universe started out in equilibrium, there should be equal amounts of matter and antimatter. However, that’s not what we see. We see only matter around us. So, the question that has been plaguing us for a while is, where did all the antimatter go? If a neutrino is its own antiparticle, it provides a mechanism for the antimatter to disappear. That’s another reason neutrinos are thought to be a probe to help us further understand fundamental interactions in nature and, in the end, the energy and matter distribution in the universe.

    Resources at the SNS are funded by DOE’s Office of Science.

    See the full article here .


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    ORNL is managed by UT-Battelle for the Department of Energy’s Office of Science. DOE’s Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time.

    i2

     
  • richardmitnick 1:13 pm on April 15, 2020 Permalink | Reply
    Tags: , , , , Matter and Antmatter, Neutrino physics, , , ,   

    From University of Colorado Boulder via phys.org: “Why didn’t the universe annihilate itself? Neutrinos may hold the answer” 

    U Colorado

    From University of Colorado Boulder

    via


    phys.org

    April 15, 2020
    Daniel Strain, University of Colorado at Boulder

    1
    Event display for a candidate electron neutrino. Credit: T2K

    Alysia Marino and Eric Zimmerman, physicists at CU Boulder, have been on the hunt for neutrinos for the last two decades.

    That’s no easy feat: Neutrinos are among the most elusive subatomic particles known to science. They don’t have a charge and are so lightweight—each one has a mass many times smaller than the electron—that they interact only on rare occasions with the world around them.

    They may also hold the key to some of physics’ deepest mysteries.

    In a study published today in the journal Nature, Marino, Zimmerman and more than 400 other researchers on an experiment called T2K come closer to answering one of the big ones: Why didn’t the universe annihilate itself in a humungous burst of energy not long after the Big Bang?

    The new research suggests that the answer comes down to a subtle discrepancy in the way that neutrinos and their evil twins, the antineutrinos, behave—one of the first indications that phenomena called matter and antimatter may not be the exact mirror images many scientists believed.

    The group’s findings showcase what scientists can learn by studying these unassuming particles, said Zimmerman, a professor in the Department of Physics.

    “Even 20 years ago, the field of neutrino physics was much smaller than it is today,” he said.

    Marino, an associate professor of physics, agreed. “There’s still a lot we’re trying to understand about how neutrinos interact,” she said.

    Big Bang

    Neutrinos, which weren’t directly detected until the 1950s, are often produced deep within stars and are among the most common particles in the universe. Ever second, trillions of them pass through your body, although few if any will react with a single one of your atoms.

    2
    A graphic showing neutrinos emitted from the sun over a period of 1500 days. Credit: T2K Experiment.

    To understand why this cosmic dandelion fluff is important, it helps to go back to the beginning—the very beginning.

    Based on their calculations, physicists believe that the Big Bang must have created a huge amount of matter alongside an equal quantity of antimatter. These particles behave exactly like, but have opposite charges from, the protons, electrons and all the other matter that makes up everything you can see around you.

    There’s just one problem with that theory: Matter and antimatter obliterate each other on contact.

    “Our universe today is dominated by matter and not antimatter,” Marino said. “So there had to be some process in physics that distinguished matter from antimatter and could have given rise to a small excess of protons or electrons over their antiparticles.”

    Over time, that small excess became a big excess until there was virtually no antimatter left in the cosmos. According to one popular theory, neutrinos underly that discrepancy.

    Zimmerman explained that these subatomic particles come in three different types, which scientists call “flavors,” with unique interactions. They are the muon neutrino, electron neutrino and tau neutrino. You can think of them as the physicist’s Neapolitan ice cream.

    These flavors, however, don’t stay put. They oscillate. If you give them enough time, for example, the odds that a muon neutrino will stay a muon neutrino can shift. Imagine opening your freezer and not knowing whether the vanilla ice cream you left behind will now be chocolate or strawberry, instead.

    But is the same true for antineutrinos? Proponents of the theory of “leptogenesis” argue that if there were even a small difference in how these mirror images behave, it could go a long way toward explaining the imbalance in the universe.

    “The next big step in neutrino physics is to understand whether neutrino oscillations happen at the same rate as antineutrino oscillations,” Zimmerman said.

    T2K map, T2K Experiment, Tokai to Kamioka, Japan

    T2K Experiment, Tokai to Kamioka, Japan

    Traveling Japan

    That, however, means observing neutrinos up close.

    The T2K, or Tokai to Kamioka, Experiment goes to extreme lengths to do just that. In this effort, scientists use a particle accelerator to shoot beams made up of neutrinos from a research site in Tokai, Japan, to detectors in Kamioka—a distance of more than 180 miles or the entire width of Japan’s largest island, Honshu.

    Zimmerman and Marino have both participated in the collaboration since the 2000s. For the last nine years, the duo and their colleagues from around the world have traded off studying beams of muon neutrinos and muon antineutrinos.

    In their most recent study, the researchers hit pay dirt: These bits of matter and antimatter seem to behave differently. Muon neutrinos, Zimmerman said, are more inclined to oscillate into electron neutrinos than their antineutrino counterparts.

    The results come with major caveats. The team’s findings are still quite a bit shy of the physics community’s gold standard for a discovery, a measure of statistical significance called “five-sigma.” The T2K collaboration is already upgrading the experiment so that it can collect more data and faster to reach that mark.

    But, Marino said, the results provide one of the most tantalizing hints to date that some kinds of matter and antimatter may act differently—and not by a trivial amount.

    “To explain the T2K results, the difference needs to be almost the largest amount that you could possibly get” based on theory, she said.

    Marino sees the study as one window to the fascinating world of neutrinos. There are many more pressing questions around these particles, too: How much, for example, does each flavor of neutrino weigh? Are neutrinos, in a really weird twist, actually their own antiparticles? She and Zimmerman are taking part in a second collaboration, an upcoming effort called the Deep Underground Neutrino Experiment (DUNE), that will aid the upgraded T2K in finding those answers.

    “There are still things we’re figuring out because neutrinos are so hard to produce in a lab and require such complicated detectors,” Marino said. “There’s still room for more surprises.”

    See the full article here .

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    U Colorado Campus

    As the flagship university of the state of Colorado CU-Boulder is a dynamic community of scholars and learners situated on one of the most spectacular college campuses in the country. As one of 34 U.S. public institutions belonging to the prestigious Association of American Universities (AAU) – and the only member in the Rocky Mountain region – we have a proud tradition of academic excellence, with five Nobel laureates and more than 50 members of prestigious academic academies.

    CU-Boulder has blossomed in size and quality since we opened our doors in 1877 – attracting superb faculty, staff, and students and building strong programs in the sciences, engineering, business, law, arts, humanities, education, music, and many other disciplines.

    Today, with our sights set on becoming the standard for the great comprehensive public research universities of the new century, we strive to serve the people of Colorado and to engage with the world through excellence in our teaching, research, creative work, and service.

     
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