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  • richardmitnick 4:25 pm on July 16, 2019 Permalink | Reply
    Tags: , , Michigan State University, Neutrinos, , ,   

    From U Wisconsin IceCube Collaboration: A Flock of Articles on NSF Grant to Upgrade IceCube 

    U Wisconsin ICECUBE neutrino detector at the South Pole

    From From U Wisconsin IceCube Collaboration

    From U Wisconsin: “UW lab gears up for another Antarctic drilling campaign”

    With news that the National Science Foundation (NSF) and international partners will support an upgrade to the IceCube neutrino detector at the South Pole, the UW–Madison lab that built the novel drill used to bore mile-deep holes in the Antarctic ice is gearing up for another drilling campaign.

    The UW’s Physical Sciences Laboratory (PSL), which specializes in making customized equipment for UW–Madison researchers, will once again lead drilling operations. The $37 million upgrade announced this week (July 16, 2019) will expand the IceCube detector by adding seven new strings of 108 optical modules each to study the basic properties of neutrinos, phantom-like particles that emanate from black holes and exploding stars, but that also cascade through Earth’s atmosphere as a result of colliding subatomic particles.

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    “It takes a crew of 30 people to run this 24/7. It’s the people that make it work,” says Bob Paulos, director of the Physical Sciences Lab. Photo: Bryce Richter

    See the full article here .

    From U Wisconsin: “IceCube: Antarctic neutrino detector to get $37 million upgrade”

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    The IceCube Neutrino Observatory is located at NSF’s Amundsen-Scott South Pole Station. Management and operation of the observatory is through the Wisconsin IceCube Particle Astrophysics Center at UW–Madison. Raffaela Busse, IceCube / NSF

    IceCube, the Antarctic neutrino detector that in July of 2018 helped unravel one of the oldest riddles in physics and astronomy — the origin of high-energy neutrinos and cosmic rays — is getting an upgrade.

    This month, the National Science Foundation (NSF) approved $23 million in funding to expand the detector and its scientific capabilities. Seven new strings of optical modules will be added to the 86 existing strings, adding more than 700 new, enhanced optical modules to the 5,160 sensors already embedded in the ice beneath the geographic South Pole.

    The upgrade, to be installed during the 2022–23 polar season, will receive additional support from international partners in Japan and Germany as well as from Michigan State University and the University of Wisconsin–Madison. Total new investment in the detector will be about $37 million.

    See the full article here .

    From Niels Bohr Institute: “A new Upgrade for the IceCube detector”

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    Illustration of the IceCube laboratory under the South Pole. The sensors detecting neutrinos are attached to the strings lowered into the ice. The upgrade will take place in the Deep Core area. Illustration: IceCube/NSF

    Neutrino Research:

    The IceCube Neutrino Observatory in Antarctica is about to get a significant upgrade. This huge detector consists of 5,160 sensors embedded in a 1x1x1 km volume of glacial ice deep beneath the geographic South Pole. The purpose of the installation is to detect neutrinos, the “ghost particles” of the Universe. The IceCube Upgrade will add more than 700 new and enhanced optical sensors in the deepest, purest ice, greatly improving the observatory’s ability to measure low-energy neutrinos produced in the Earth’s atmosphere. The research in neutrinos at the Niels Bohr Institute, University of Copenhagen is led by Associate Professor Jason Koskinen

    See the full article here .

    From Michigan State University: “Upgrade for neutrino detector, thanks to NSF grant”

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    The IceCube Neutrino Observatory, the Antarctic detector that identified the first likely source of high-energy neutrinos and cosmic rays, is getting an upgrade. Courtesy of IceCube

    The IceCube Neutrino Observatory, the Antarctic detector that identified the first likely source of high-energy neutrinos and cosmic rays, is getting an upgrade.

    The National Science Foundation is upgrading the IceCube detector, extending its scientific capabilities to lower energies, and bridging IceCube to smaller neutrino detectors worldwide. The upgrade will insert seven strings of optical modules at the bottom center of the 86 existing strings, adding more than 700 new, enhanced optical modules to the 5,160 sensors already embedded in the ice beneath the geographic South Pole.

    The upgrade will include two new types of sensor modules, which will be tested for a ten-times-larger future extension of IceCube – IceCube-Gen2. The modules to be deployed in this first extension will be two to three times more sensitive than the ones that make up the current detector. This is an important benefit for neutrino studies, but it becomes even more relevant for planning the larger IceCube-Gen2.

    The $37 million extension, to be deployed during the 2022-23 polar field season, has now secured $23 million in NSF funding. Last fall, the upgrade office was set up, thanks to initial funding from NSF and additional support from international partners in Japan and Germany as well as from Michigan State University and the University of Wisconsin-Madison.

    See the full article here .

    From U Wisconsin IceCube: “The IceCube Upgrade: An international effort”

    The IceCube Upgrade project is an international collaboration made possible not only by support from the National Science Foundation but also thanks to significant contributions from partner institutions in the U.S. and around the world. Our national and international collaborators play a huge role in manufacturing new sensors, developing firmware, and much more. Learn more about a few of our partner institutions below.

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    The Chiba University group poses with one of the new D-Egg optical detectors. Credit: Chiba University

    Chiba University is responsible for the new D-Egg optical detectors, 300 of which will be deployed on the new Upgrade strings. A D-Egg is 30 percent smaller than the original IceCube DOM, but its photon detection effective area is twice as large thanks to two 8-inch PMTs in the specially designed egg-shaped vessel made of UV-transparent glass. Its up-down symmetric detection efficiency is expected to improve our precision for measuring Cherenkov light from neutrino interactions. The newly designed flasher devices in the D-Egg will also give a better understanding of optical characteristics in glacial ice to improve the resolution of arrival directions of cosmic neutrinos.

    See the full article here .

    From DESY: “Neutrino observatory IceCube receives significant upgrade”

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    Deep down in the perpetual ice of Antarctica IceCube watches out for a faint bluish glow that indicates a rare collision of a cosmic neutrino within the ice. Artist’s concept: DESY, Science Communication Lab

    Particle detector at the South Pole will be expanded to comprise a neutrino laboratory

    The international neutrino observatory IceCube at the South Pole will be considerably expanded in the coming years. In addition to the existing 5160 sensors, a further 700 optical modules will be installed in the perpetual ice of Antarctica. The National Science Foundation in the USA has approved 23 million US dollars for the expansion. The Helmholtz Centres DESY and Karlsruhe Institute of Technology (KIT) are supporting the construction of 430 new optical modules with a total of 5.7 million euros (6.4 million US dollars), which will turn the observatory into a neutrino laboratory. IceCube, for which Germany with a total of nine participating universities and the two Helmholtz Centres is the most important partner after the USA, had published convincing indications last year of a first source of high-energy neutrinos from the cosmos.

    See the full article here .

    See the full articles above .

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    IceCube is a particle detector at the South Pole that records the interactions of a nearly massless sub-atomic particle called the neutrino. IceCube searches for neutrinos from the most violent astrophysical sources: events like exploding stars, gamma ray bursts, and cataclysmic phenomena involving black holes and neutron stars. The IceCube telescope is a powerful tool to search for dark matter, and could reveal the new physical processes associated with the enigmatic origin of the highest energy particles in nature. In addition, exploring the background of neutrinos produced in the atmosphere, IceCube studies the neutrinos themselves; their energies far exceed those produced by accelerator beams. IceCube is the world’s largest neutrino detector, encompassing a cubic kilometer of ice.

    IceCube employs more than 5000 detectors lowered on 86 strings into almost 100 holes in the Antarctic ice NSF B. Gudbjartsson, IceCube Collaboration

    Lunar Icecube

    IceCube DeepCore annotated

    IceCube PINGU annotated


    DM-Ice II at IceCube annotated

     
  • richardmitnick 12:11 pm on May 30, 2019 Permalink | Reply
    Tags: , , , , Neutrinos   

    From Fermi National Accelerator Lab: “Long-Baseline Neutrino Facility pre-excavation work is in full swing” 

    FNAL Art Image
    FNAL Art Image by Angela Gonzales

    From Fermi National Accelerator Lab , an enduring source of strength for the US contribution to scientific research world wide.

    May 2, 2019
    Kurt Riesselmann

    Unlocking the mysteries of neutrinos in order to get a clearer picture of the universe and understand why we are here at all, is a monumental undertaking. However, before the international Deep Underground Neutrino Experiment, hosted by the Department of Energy’s Fermilab, can start solving those mysteries, a massive construction project is required to provide the necessary infrastructure, named the Long-Baseline Neutrino Facility.

    The LBNF construction in Lead, South Dakota is under way, and a fleet of yellow pickup trucks has become the talk of the town and evidence of the beehive of construction activity that Fermilab is managing at the Sanford Underground Research Facility.

    These trucks are owned by the company Kiewit, part of the Kiewit-Alberici Joint Venture, who are preparing the construction site at Sanford Lab for the excavation of about 800,000 tons of rock to create the huge caverns for the South Dakota-portion of the Long-Baseline Neutrino Facility. (Prep work for the Illinois-portion of the Long-Baseline Neutrino Facility, to be built at Fermilab, will start early next year.)

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    The excavation of LBNF/DUNE caverns requires the transport of about 800,000 tons of rock from a mile underground to the surface, and then transporting it to its final resting place in a former mining area known as the Open Cut. Credit: Fermilab

    The excavation will create the three LBNF caverns that vary in length between 500 and 625 feet long, up to 70 feet wide and 95 feet tall. These caverns will house DUNE’s massive particle detectors and the necessary utilities.

    FNAL DUNE Argon tank at SURF

    Excavating such an enormous amount of rock a mile underground, bringing it to the surface, and then transporting it to its final resting place is a huge job. And creating the infrastructure for that job is a huge amount of work by itself—and is going on right now. Fortunately, the mile-deep shaft that workers will use to bring rock to the surface—known as the Ross Shaft—already exists and the seven-year-long shaft renovation project will soon wrap up. But other pre-excavation work remains to be done. The main tasks are (see photo gallery):

    Renovating the area at the bottom of the mile-deep Ross Shaft, where rock will be loaded into large buckets, called skips, that will travel up the shaft;
    Strengthening the Ross headframe—the structure that holds and operates the hoist that conveys the skips filled with rock to the surface;
    Refurbishing the three-story-tall rock crushing system next to the Ross headframe; it was last used in 2001 when the Ross Shaft was still used by the Homestake gold mine.
    Building and installing the three-quarter-mile-long conveyor system that will transport the crushed rock to the Open Cut, an open pit mining area excavated by the Homestake mining company in the 1980s. Despite the massive amount of rock to be excavated for the LBNF caverns, the deposited rock will fill less than one percent of the Open Cut.
    Rehabbing the existing tramway tunnel to prepare it for the installation of the conveyor system;
    Establishing the power infrastructure for operating the LBNF/DUNE experiment, which will include 70,000 tons of liquid argon cooled to minus 300 degrees Fahrenheit (minus 184 degrees Celsius).

    And remember, this massive construction project will enable some truly groundbreaking science. DUNE, hosted by Fermilab, will be the world’s most advanced experiment dedicated to studying the properties of mysterious subatomic particles called neutrinos.

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

    The DUNE detectors will enable scientists to study a neutrino beam generated at Fermilab. The DUNE collaboration includes more than 1,000 scientists from more than 30 countries around the world. A large prototype detector for the experiment, constructed at the European research center CERN, successfully began recording particle tracks in September.

    CERN Proto Dune

    For more information on LBNF/DUNE, see http://www.fnal.gov/dune.

    See the full article here.


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    FNAL Icon

    Fermi National Accelerator Laboratory (Fermilab), located just outside Batavia, Illinois, near Chicago, is a US Department of Energy national laboratory specializing in high-energy particle physics. Fermilab is America’s premier laboratory for particle physics and accelerator research, funded by the U.S. Department of Energy. Thousands of scientists from universities and laboratories around the world collaborate at Fermilab on experiments at the frontiers of discovery.

    FNAL MINERvA front face Photo Reidar Hahn

    FNAL DAMIC

    FNAL Muon g-2 studio

    FNAL Short-Baseline Near Detector under construction

    FNAL Mu2e solenoid

    Dark Energy Camera [DECam], built at FNAL

    FNAL DUNE Argon tank at SURF

    FNAL/MicrobooNE

    FNAL Don Lincoln

    FNAL/MINOS

    FNAL Cryomodule Testing Facility

    FNAL MINOS Far Detector in the Soudan Mine in northern Minnesota

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

    FNAL/NOvA experiment map

    FNAL NOvA Near Detector

    FNAL ICARUS

    FNAL Holometer

     
  • richardmitnick 12:00 pm on May 25, 2019 Permalink | Reply
    Tags: ARCA or Astroparticle Research with Cosmics in the Abyss, , , , , Cubic Kilometre Neutrino Telescope or KM3NeT, Neutrinos, ORCA or Oscillation Research with Cosmics in the Abyss   

    From Discover Magazine: “Why Scientists Are Putting a Telescope on the Bottom of the Ocean” 

    DiscoverMag

    From Discover Magazine

    May 23, 2019
    Korey Haynes

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    The telescope, once complete, will be made of hundreds of spherical detectors suspended at the bottom of the sea. (Credit: KM3NeT)

    Deep under the Mediterranean Sea, hundreds of watchful eyes hang suspended on cables, waiting for a rare and valuable flash. Their quarry are ghostly neutrino particles, capable of tunneling through light-years of space and a planet’s worth of rock without ever coming into contact with matter.

    But, here, under the ocean, they just might hit a detector from the Cubic Kilometre Neutrino Telescope, or KM3NeT.

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    Cubic Kilometre Neutrino Telescope, or KM3NeT

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    KM3NeT Digital Optical Module (DOM) in the laboratory.

    While the international collaboration is still in the early stages of construction, it hopes to soon begin tracking some of the most elusive particles in the universe.

    Neutrinos are nearly massless particles produced in the sun and in energetic events like supernovas, colliding stars, and gamma-ray bursts. Because the particles barely interact with the rest of the universe, they are notoriously difficult to study, though trillions pass through your body every second.

    Researchers have tended to bury neutrino detectors in vats of supercooled liquids or miles underground, hoping that neutrinos will be the only particles that make it through.

    This time, researchers are hiding the detectors at the bottom of the sea, on the other side of the planet from the skies they hope to study, to block everything but neutrinos from hitting their detectors.

    Hidden Detectors

    Most neutrino detectors look for the rare flashes of energy the particles give off when they collide with the nuclei of atoms. But because these interactions don’t happen very often, neutrino detectors have to cover a lot of ground – quite literally. KM3Net, as its name implies, will one day occupy a cubic kilometer of seawater – about 400,000 Olympic swimming pools worth.

    Neutrino detectors also have to be protected from the onslaught of regular radiation, which would otherwise drown out the fainter gleam of neutrino interactions. So researchers build them deep underground, in abandoned mines or underneath Antarctic ice sheets.

    SNOLAB


    SNOLAB, a Canadian underground physics laboratory at a depth of 2 km in Vale’s Creighton nickel mine in Sudbury, Ontario

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

    IceCube neutrino detector interior


    U Wisconsin ICECUBE neutrino detector at the South Pole

    Now, they are trying one at the bottom of the sea – and the other side of the world. “The underwater telescope is bombarded by millions of different particles but only neutrinos can pass through the Earth to reach the detector from below,” said Clancy James, a researcher at the Curtin Institute of Radio Astronomy in Australia, a KM3Net partner.

    Each telescope is actually made up of hundreds of spherical detectors a little bigger than a basketball. These are suspended on vertical lines, and each node is connected by cables that run along the sea floor. The first test components were installed in 2013, with another round of construction in 2015 and 2018. Scientists are currently testing a limited number of detectors, and they are still searching for funding to make the full array a reality.

    Two telescopes comprise KM3Net. One is called ARCA, or Astroparticle Research with Cosmics in the Abyss [no image available] , and it sits off the coast of Italy. It will study the higher-energy cosmic neutrinos produced by the universe’s most energetic events, like gamma-ray bursts, and provide scientists with a greater understanding of powerful astrophysical events. Its partner is ORCA, or Oscillation Research with Cosmics in the Abyss [above], located closer to France. This telescope will study the lower-energy particles produced by cosmic rays striking Earth’s atmosphere.

    So far, the telescope’s operations have been for testing purposes, proving that the setup is successful using only a few of the eventual hundreds of detectors. The team is in the process of adding more. The completion of the telescopes will mean that astronomers don’t have to get very, very lucky to spot a neutrino signal. Instead, the large array should open new windows into the hard-to-view world of barely-there particles.

    See the full article here .

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  • richardmitnick 4:18 pm on April 16, 2019 Permalink | Reply
    Tags: , , , , , MINOS, Neutrinos,   

    From Fermi National Accelerator Lab: “Search for sterile neutrinos in MINOS and MINOS+” 

    FNAL Art Image
    FNAL Art Image by Angela Gonzales

    From Fermi National Accelerator Lab , an enduring source of strength for the US contribution to scientific research world wide.

    April 16, 2019

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    MINOS far detector as seen in 2012. Photo: Reidar Hahn

    The MINOS+ collaboration at the Department of Energy’s Fermilab has published a paper in Physical Review Letters about their latest results: new constraints on the existence of sterile neutrinos. The collaboration has exploited new high-statistics data and a new analysis regime to set more stringent boundaries on the possibility of sterile neutrinos mixing with muon neutrinos. They have significantly improved on their previous results published in 2016. With close to 40 publications that have garnered more than 6,000 citations, MINOS has been at the forefront of studying neutrino oscillations physics since its first data-taking days in 2005.

    The experiment uses two iron-scintillator sampling-and-tracking calorimetric particle detectors: The near detector is placed 1.04 kilometers from the neutrino source at Fermilab, and the far detector is placed 735 kilometers away in Minnesota.

    FNAL MINOS near detector

    FNAL MINOS Far Detector in the Soudan Mine in northern Minnesota

    The MINOS experiment collected data using a low-energy neutrino beam from May 1, 2005, to April 29, 2012, and MINOS+ collected data with a medium-energy neutrino beam from Sept. 4, 2013 to June 29, 2016.

    The detectors have accumulated high-statistics samples of muon neutrino interactions. Using a Fermilab neutrino beam composed of almost 100 percent muon neutrinos, they measured the disappearance of muon neutrinos as the particles arrived at the far detector. The collaboration used these data to obtain some of the most precise to-date measurements of standard three-neutrino mixings. These data also restrict phenomena beyond the Standard Model, including the hypothetical light sterile neutrinos.

    The analysis has simultaneously employed the energy spectra of charged-current (W boson exchange) and neutral-current (Z boson exchange) interactions between the neutrinos and the atoms inside the detector.

    Using a neutrino oscillation model that assumed the existence of the three known kinds of neutrinos plus a fourth type of neutrino referred to as a single sterile neutrino, the MINOS+ collaboration found no evidence of sterile neutrinos. Instead, the collaboration was able to set rigorous limits on the mixing parameter sin2θ24 for the mass splitting Δm241 > 10−4 eV2.

    The results significantly increase the tension with results obtained by experiments conducted with single detectors studying electron neutrino appearance in a muon neutrino beam. The LSND and MiniBooNE techniques and limited statistics present challenges that are now being tackled by the MicroBooNE experiment at Fermilab, designed specifically for this task.

    LSND experiment at Los Alamos National Laboratory and Virginia Tech

    FNAL/MiniBooNE

    FNAL/MicrobooNE

    Scientists from 33 institutions in five countries — the United States, UK, Brazil, Poland and Greece — are members of the MINOS+ collaboration. More information can be found on the MINOS+ website.

    This work is supported by the U.S. Department of Energy Office of Science.

    See the full article here.


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    FNAL Icon

    Fermi National Accelerator Laboratory (Fermilab), located just outside Batavia, Illinois, near Chicago, is a US Department of Energy national laboratory specializing in high-energy particle physics. Fermilab is America’s premier laboratory for particle physics and accelerator research, funded by the U.S. Department of Energy. Thousands of scientists from universities and laboratories around the world collaborate at Fermilab on experiments at the frontiers of discovery.

    FNAL MINERvA front face Photo Reidar Hahn

    FNAL DAMIC

    FNAL Muon g-2 studio

    FNAL Short-Baseline Near Detector under construction

    FNAL Mu2e solenoid

    Dark Energy Camera [DECam], built at FNAL

    FNAL DUNE Argon tank at SURF

    FNAL/MicrobooNE

    FNAL Don Lincoln

    FNAL/MINOS

    FNAL Cryomodule Testing Facility

    FNAL MINOS Far Detector in the Soudan Mine in northern Minnesota

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

    FNAL/NOvA experiment map

    FNAL NOvA Near Detector

    FNAL ICARUS

    FNAL Holometer

     
  • richardmitnick 12:19 pm on April 9, 2019 Permalink | Reply
    Tags: All the miners get very dirty but all the SNOLAB people are clean so the difference between them is stark., , , Neutrinos, Paul Dirac won the Nobel Prize in 1933 after calculating that every particle in the universe must have a corresponding antiparticle., , SNO-Sudbury Neutrino Observatory, , SNOLAB researchers share the elevator with miners on their way to work in the Vale's Creighton nickel mine., The question of what happened to all the antimatter has remained unanswered.,   

    From University of Pennsylvania: “Answering big questions by studying small particles” 

    U Penn bloc

    From University of Pennsylvania

    April 8, 2019

    Erica K. Brockmeier-Writer
    Eric Sucar- Photographer

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    A view inside the SNO detector, a 40-foot acrylic sphere that’s covered with thousands of photodetectors. The facility is located in SNOLAB, a research facility located 2km underground near in the Vale’s Creighton nickel mine, Sudbury, Canada (Photo credit: SNO+ Collaboration).

    Neutrinos are extremely lightweight subatomic particles that are produced during nuclear reactions both here on Earth and in the center of stars. But neutrinos aren’t harmful or radioactive: In fact, nearly 100 trillion neutrinos bombard Earth every second and usually pass through the world without notice.

    Joshua Klein is an experimental particle physicist who studies neutrinos and dark matter. His group, along with retired professor Eugene Beier, collaborates with the Sudbury Neutrino Observatory (SNO), an international research endeavor focused on the study of neutrinos. Klein and Beier’s groups previously designed and now maintain the electronics at SNOLAB that collect data on these subatomic particles.

    Klein is fascinated by neutrinos and how they could help answer fundamental questions about the nature of the universe. “They may explain why the universe is made up of matter and not equal parts matter and anti-matter, they may be responsible for how stars explode, they may even tell us something about the laws of physics at the highest energy scales,” says Klein.

    Previous research on neutrinos has already led to groundbreaking discoveries in particle physics. The SNO collaboration was awarded the 2016 Breakthrough Prize in Fundamental Physics for solving the “solar neutrino problem.” The problem was that the number of neutrinos being produced by the sun was only a third of what was predicted by theoretical physicists, a discrepancy that had puzzled researchers since the 1970s.

    To solve this, researchers went about 1.2 miles underground to study neutrinos in order to avoid the cosmic radioactive particles that could interfere with their minute and precise measurements. The SNOLAB facility in Sudbury, Canada, which houses a a 40-foot wide acrylic vessel surrounded by photodetectors, allowed physicists to measure the three different types of neutrinos at the same time. Physicists found that neutrinos were able to change from one type into another.

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    The exterior of the SNO Detector as seen from the ground at SNOLAB (Photo credit: SNOLAB).

    Today, 15 years later, researchers are looking for an incredibly rare process involving neutrinos that, if found, could revolutionize the field of fundamental physics. “Now that we know that neutrinos can change form, along with the fact that neutrinos have mass but no charge, we can hypothesize that they can be their own antiparticle. If this is true, it could explain why the universe is made of only matter,” says Klein.

    The question of what happened to all the antimatter has remained unanswered since Paul Dirac won the Nobel Prize in 1933 after calculating that every particle in the universe must have a corresponding antiparticle. But the majority of the universe is made of ordinary matter, not equal parts matter and anti-matter, and scientists are trying to figure out why.

    The photodetectors at SNOLAB are now being upgraded as part of SNO+ [Physical Review D] in order to search for a rare type of radioactive decay known as a neutrinoless double beta decay, a never-before seen process that would prove that neutrinos and anti-neutrinos are actually the same particle. Witnessing a neutrinoless double-beta decay event is so rare, if it even exists, and would give off such a small signal that the only way to detect it is through the combination of powerful equipment, refined analyses, and a lot of patience.

    Instead of sitting around waiting for a rare event to happen, researchers are actively taking advantage of this state-of-the-art underground facility. “One of the selling points of SNO+ is that it’s a multipurpose detector,” says graduate student Eric Marzec. “A lot of detectors are produced with a singular goal, like detecting dark matter, but SNO+ has a lot of other interesting physics that it can probe.”

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    Here at Penn, students from the Klein lab conduct key maintenance and repairs on the electronic components that are instrumental to the success of SNO+. They also conduct research on new materials that can help increase the sensitivity of the detector, providing more chances of seeing a rare neutrinoless double-beta decay event. (Four photos, no individual descriptions.)

    Marzec and Klein were part of a recent study using SNO+’s upgraded capabilities to collect new data on solar neutrinos [Physical Review D]. Before the detector vessel is filled with scintillator, a soap-like liquid that will help them detect rare radioactive decays, it was briefly filled with water. This enabled researchers to collect data on what direction the neutrinos came from, which then allowed them to focus their efforts on studying neutrinos that came from the Sun.

    The solar neutrino problem may be solved, but new data on solar neutrinos is still incredibly useful, especially since data from SNO+ have very low background signals from things like cosmic radiation. “There’s only a few experiments that have ever been able to measure neutrinos coming from the sun,” says Marzec. “People might someday want to look at whether the neutrino production of the sun varies over time, so it’s useful to have as many time points and as many measurements over the years as possible.”

    Marzec has spent a considerable amount of time working at the SNOLAB facility in northern Ontario. He describes a typical day as starting with a 6 a.m. underground elevator ride that travels more than a mile underground. SNOLAB researchers share the elevator with miners on their way to work in the Vale’s Creighton nickel mine. “All the miners get very dirty, but all the SNOLAB people are clean, so the difference between them is stark. It’s very obvious who is the nerd underground and who the miners are,” says Marzec.

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    After traveling 6,800 floors underground, researchers walk more than half a mile through a series of tunnels to reach the entrance of SNOLAB (Photo credit: SNOLAB).

    After arriving at the –6,800th floor, researchers walk more than a half mile from the cage shaft to the SNOLAB through underground dirt tunnels. When they reach the lab, they have to shower and change into threadless uniforms to prevent any microscopic threads from getting inside the sensitive detector. After air quality checks are completed, the researchers are free to begin their work on the detector.

    When asked what it’s like to work more than a mile underground, Marzec comments that he got used to the strangeness after a few visits. “The first time, it feels very much like you’re underground because the pressure is very noticeable, and you feel exhausted at the end of the day.” Thankfully, Marzec and his colleagues don’t have to travel a mile underground every time they want to collect data from SNO+ since they can remotely collect and analyze the hundreds of terabytes of data generated by the detector.

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    To do any repair work or cleaning inside the detector, researchers must be lowered into the 40 foot tall sphere using a harness (Photo credit: SNOLAB).

    As Marzec is in the final stages of preparing his Ph.D. thesis, he says he will miss his time working on SNO+. “It’s kind of monastic,” Marzec says about his time working at SNOLAB. “You go there and mediate on physics while you’re there. But it’s also kind of a social thing as well: There are a lot of people you know who are working on the same stuff.”

    Klein and his group, including four graduate students and two post-docs, recently returned from a SNOLAB collaboration meeting, where upwards of 100 physicists met to present and discuss recent results and the upcoming plans for the next phase of the project. Klein is excited, and, admittedly, a little bit nervous, to see how everything comes together. “Putting in the liquid scintillator will change everything—there’s never been a detector being converted from a water-based detector to a scintillator detector. Here at Penn, for us, it’s big because we designed upgrades to the electronics to handle the fact that we will be getting data at a rate that’s about 100 times higher,” says Klein.

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    A scientist works inside the SNO+ detector while it is partially filled with deuterated water. Each one of the gold-colored circles is an individual photodetector (Photo credit: SNOLAB).

    Despite the numerous technical and logistical challenges ahead, researchers are enthusiastic about the potential that SNO+ can bring to particle physics research. Other areas of study include learning how neutrinos change form, studying low-energy neutrinos to figure out why the Sun seems to have less “heavy” elements than astronomers expect, and measuring geoneutrinos to figure out why Earth is hotter than other nearby planets like Mars.

    But for Klein, the prospect of finding a rare neutrinoless double beta decay event remains the most thrilling aspect of this research, which, if discovered, could turn the Standard Model of particle physics on its head. “After the question of what is dark energy and what is dark matter, the question of whether neutrinos are their own antiparticle is the most important question for particle physics to answer,” Klein says. “And if neutrinos are their own antiparticle, the simplest piece you can put into the equation [within the Standard Model] blows up: It doesn’t work, it’s mathematically inconsistent. And we don’t know how we would fix that. It is a completely experimental question, so that’s why we’re excited.”

    See the full article here .

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    U Penn campus

    Academic life at Penn is unparalleled, with 100 countries and every U.S. state represented in one of the Ivy League’s most diverse student bodies. Consistently ranked among the top 10 universities in the country, Penn enrolls 10,000 undergraduate students and welcomes an additional 10,000 students to our world-renowned graduate and professional schools.

    Penn’s award-winning educators and scholars encourage students to pursue inquiry and discovery, follow their passions, and address the world’s most challenging problems through an interdisciplinary approach.

     
  • richardmitnick 4:27 pm on April 5, 2019 Permalink | Reply
    Tags: "MINERvA successfully completes its physics run", , , , , Neutrinos, Neutrinos could hold the answer to one of the most pressing mysteries in physics: why matter was not completely annihilated by antimatter after the Big Bang., ,   

    From Fermi National Accelerator Lab: “MINERvA successfully completes its physics run” 

    FNAL Art Image
    FNAL Art Image by Angela Gonzales

    From Fermi National Accelerator Lab , an enduring source of strength for the US contribution to scientific research world wide.

    April 5, 2019
    Caitlyn Buongiorno

    FNAL MINERvA front face Photo Reidar Hahn

    On Feb. 26, a crowd of engineers, technicians and analysts crowded around a computer screen as Fermilab scientist Deborah Harris pressed “stop” on the data collection for the MINERvA neutrino experiment.

    “We’re all just really excited by what we’ve accomplished,” said Harris, MINERvA co-spokesperson and future professor at York University. “The detector worked wonderfully, we collected the data we need, and we did it on schedule.”

    MINERvA studies how neutrinos and their antimatter twins, antineutrinos, interact with the nuclei of different atoms. Scientists use that data to help discover the best models of these interactions. Now, after nine years of operation, the data taking has come to an end, but the analysis will continue for a while. MINERvA scientists have published more than 30 scientific papers so far, with more to come. As of today, 58 students have obtained their master’s or Ph.D. degrees doing research with this experiment.

    Neutrinos could hold the answer to one of the most pressing mysteries in physics: why matter was not completely annihilated by antimatter after the Big Bang. That imbalance from 13.7 billion years ago led the universe to develop into what we see today. Studying neutrinos (and antineutrinos) could uncover the mystery and help us understand why we are here at all.

    1
    The MINERvA collaboration gathers to celebrate the end of data taking. MINERvA co-spokesperson Laura Fields, kneeling at center, holds a 3-D-printed model of the MINERvA neutrino detector. Photo: Reidar Hahn

    A number of neutrino experiments investigate this mystery, including Fermilab’s NOvA experiment and the upcoming international Deep Underground Neutrino Experiment, hosted by Fermilab.

    FNAL/NOvA experiment map


    FNAL NOvA Near Detector

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


    FNAL DUNE Argon tank at SURF


    SURF DUNE LBNF Caverns at Sanford Lab

    To be as successful as possible, these experiments need precise models that describe what happens before and after a neutrino collides with an atom.

    Every time a neutrino collides with part of an atom inside a detector, a spray of new particles flies off and travels through the rest of the detector. In order to understand the nuances of neutrinos, scientists need to know the energy of the neutrino when it first enters the detector and the energy of all the particles produced after the interaction. This task is complicated by the fact that some of the outgoing particles are invisible to the detector — and must still be accounted for.

    Imagine you’re playing pool and you shoot the cue ball at another ball. You can easily predict where that second ball will go. That prediction, however, gets much more complex when your cue ball strikes a collection of balls. After the break shot, they scatter in all directions, and it’s hard to predict where each will go. The same thing is true when a neutrino interacts with a lone particle: You can easily predict where the lone ball will go. But when a neutrino interacts with an atom’s nucleus — a collection of protons and neutrons — the calculation is much more difficult because, like the pool balls, particles may go off in many different directions.

    “It’s actually worse than that,” said Kevin McFarland, former MINERvA co-spokesperson and professor of physics at the University of Rochester. “All the balls in the break shot are also connected by springs.”

    MINERvA provides a neutrino-nucleus interaction guidebook for neutrino researchers. The experiment measured neutrino interactions with polystyrene, carbon, iron, lead, water and helium. Without MINERvA’s findings, researchers at other experiments would have a much tougher time understanding the outcomes of these interactions and how to interpret their data.

    “I really am proud of what we’ve been able to accomplish so far,” said Laura Fields, Fermilab scientist and co-spokesperson for MINERvA. “Already the world has a much greater understanding of these interactions.”

    See the full article here.


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    FNAL Icon

    Fermi National Accelerator Laboratory (Fermilab), located just outside Batavia, Illinois, near Chicago, is a US Department of Energy national laboratory specializing in high-energy particle physics. Fermilab is America’s premier laboratory for particle physics and accelerator research, funded by the U.S. Department of Energy. Thousands of scientists from universities and laboratories around the world collaborate at Fermilab on experiments at the frontiers of discovery.

    FNAL MINERvA front face Photo Reidar Hahn

    FNAL DAMIC

    FNAL Muon g-2 studio

    FNAL Short-Baseline Near Detector under construction

    FNAL Mu2e solenoid

    Dark Energy Camera [DECam], built at FNAL

    FNAL DUNE Argon tank at SURF

    FNAL/MicrobooNE

    FNAL Don Lincoln

    FNAL/MINOS

    FNAL Cryomodule Testing Facility

    FNAL MINOS Far Detector in the Soudan Mine in northern Minnesota

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

    FNAL/NOvA experiment map

    FNAL NOvA Near Detector

    FNAL ICARUS

    FNAL Holometer

     
  • richardmitnick 8:24 am on March 29, 2019 Permalink | Reply
    Tags: , , , Neutrinos, Null result,   

    From CERN Courier for FNAL: “MINOS squeezes sterile neutrino’s hiding ground” 


    From CERN Courier

    1
    Null result

    Newly published results from the MINOS+ experiment at Fermilab in the US cast fresh doubts on the existence of the sterile neutrino – a hypothetical fourth neutrino flavour that would constitute physics beyond the Standard Model. MINOS+ studies how muon neutrinos oscillate into other neutrino flavours as a function of distance travelled, using magnetised-iron detectors located 1 and 735 km downstream from a neutrino beam produced at Fermilab.

    Neutrino oscillations, predicted more than 60 years ago, and finally confirmed in 1998, explain the observed transmutation of neutrinos from one flavour to another as they travel. Tantalising hints of new-physics effects in short-baseline accelerator-neutrino experiments have persisted since 1995, when the Liquid Scintillator Neutrino Detector (LSND) at Los Alamos National Laboratory reported an 88±23 excess in the number of electron antineutrinos emerging from a muon–antineutrino beam.

    LSND experiment at Los Alamos National Laboratory and Virginia Tech

    This suggested that muon antineutrinos were oscillating into electron antineutrinos along the way, but not in the way expected if there are only three neutrino flavours.

    The plot thickened in 2007 when another Fermilab experiment, MiniBooNE, an 818 tonne mineral-oil Cherenkov detector located 541 m downstream from Fermilab’s Booster neutrino beamline, began to see a similar effect.

    FNAL/MiniBooNE

    The excess grew, and last November the MiniBooNE collaboration reported a 4.5σ deviation from the predicted event rate for the appearance of electron neutrinos in a muon neutrino beam. In the meantime, theoretical revisions in 2011 meant that measurements of neutrinos from nuclear reactors also show deviations suggestive of sterile-neutrino interference: the so-called “reactor anomaly”.

    Tensions have been running high. The latest results from MINOS+, first reported in 2017 and recently accepted for publication in Physical Review Letters, fail to confirm the MiniBooNE signal. The MINOS+ results are also consistent with those from a comparable analysis of atmospheric neutrinos in 2016 by the IceCube detector at the South Pole.

    U Wisconsin ICECUBE neutrino detector at the South Pole

    “LSND, MiniBooNE and the reactor data are fairly compatible when interpreted in terms of sterile neutrinos, but they are in stark conflict with the null results from MINOS+ and IceCube,” says theorist Joachim Kopp of CERN. “It might be possible to come up with a model that allows compatibility, but the simplest sterile neutrino models do not allow this.” In late February, the long-baseline T2K experiment in Japan joined the chorus of negative searches for the sterile neutrino, although excluding a different region of parameter space.

    T2K Experiment, Tokai to Kamioka, Japan


    T2K Experiment, Tokai to Kamioka, Japan

    Whereas MiniBooNE and LSND sought to observe a second-order flavour transition (in which a muon neutrino morphs into a sterile and then electron neutrino), MINOS+ and IceCube are sensitive to a first-order muon-to-sterile transition that would reduce the expected flux of muon neutrinos. Such “disappearance” experiments are potentially more sensitive to sterile neutrinos, provided systematic errors are carefully modelled.

    “The MiniBooNE observations interpreted as a pure sterile neutrino oscillation signal are incompatible with the muon-neutrino disappearance data,” says MINOS+ spokesperson Jenny Thomas of University College London. “In the event that the most likely MiniBooNE signal were due to a sterile neutrino, the signal would be unmissable in the MINOS/MINOS+ neutral-current and charged-current data sets.” Taking into account simple unitarity arguments, adds Thomas, the latest MINOS+ analysis is incompatible with the MiniBooNE result at the 2σ level and at 3σ sigma below a “mass-splitting” of 1 eV2 (see figure 1).

    See the full article here .


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    THE FOUR MAJOR PROJECT COLLABORATIONS

    ATLAS

    CERN/ATLAS detector

    ALICE

    CERN/ALICE Detector


    CMS
    CERN CMS New

    LHCb
    CERN LHCb New II

    LHC

    CERN map

    CERN LHC Grand Tunnel

    CERN LHC particles

     
  • richardmitnick 8:52 pm on March 28, 2019 Permalink | Reply
    Tags: , , , , , , , Neutrinos, ,   

    From insideHPC: “Nor-Tech Powers LIGO and IceCube Nobel-Physics Prize-Winning Projects” 

    From insideHPC

    March 28, 2019

    Today HPC integrator Nor-Tech announced participation in two recent Nobel Physics Prize-Winning projects. The company’s HPC gear will help power the Laser Interferometer Gravitational-Wave Observatory (LIGO) project as well as the IceCube neutrino detection experiment.


    VIRGO Gravitational Wave interferometer, near Pisa, Italy

    Caltech/MIT Advanced aLigo Hanford, WA, USA installation


    Caltech/MIT Advanced aLigo detector installation Livingston, LA, USA

    Cornell SXS, the Simulating eXtreme Spacetimes (SXS) project

    Gravitational waves. Credit: MPI for Gravitational Physics/W.Benger

    Gravity is talking. Lisa will listen. Dialogos of Eide

    ESA/eLISA the future of gravitational wave research

    Localizations of gravitational-wave signals detected by LIGO in 2015 (GW150914, LVT151012, GW151226, GW170104), more recently, by the LIGO-Virgo network (GW170814, GW170817). After Virgo came online in August 2018


    Skymap showing how adding Virgo to LIGO helps in reducing the size of the source-likely region in the sky. (Credit: Giuseppe Greco (Virgo Urbino group)

    U Wisconsin IceCube neutrino observatory

    U Wisconsin ICECUBE neutrino detector at the South Pole

    U Wisconsin IceCube experiment at the South Pole



    U Wisconsin ICECUBE neutrino detector at the South Pole


    IceCube Gen-2 DeepCore PINGU


    IceCube reveals interesting high-energy neutrino events

    “We are excited about the amazing discoveries these enhanced detectors will reveal,” said Nor-Tech Executive Vice President Jeff Olson. “This is an energizing time for all of us at Nor-Tech—knowing that the HPC solutions we are developing for two Nobel projects truly are changing our view of the world.”

    LIGO just announced that their detectors are about to come online after a one-year shutdown for hardware upgrades. In preparation for this, LIGO Consortium member University of Wisconsin-Milwaukee upgraded their clusters with Nor-Tech hardware to assist with the computing demands. At UWM they design, build and maintain computational tools, such as Nor-Tech’s supercomputer, that handle LIGO’s massive amounts of data. Nor-Tech completed the most recent update-including Intel Skylake processors-in 2018. The new Skylake-equipped technology is proving to be almost 10 times faster.

    LIGO was awarded a Nobel Prize in 2017. Prior to this, at a Feb. 11, 2016 national media conference, National Science Foundation (NSF) researchers announced the first direct observation of a gravitational wave. This was a paradigm-shifting achievement in the science community. Subsequent gravitational wave detections have confirmed those results.

    In 2018, the LIGO team announced the first visible detection of a neutrino event. This was made possible, in part, by the powerful HPC technology Nor-Tech has been providing to multiple LIGO Consortium institutions since 2005.

    The first Nor-Tech client to win a Nobel Prize in Physics was the IceCube research team, headquartered at the University of Wisconsin-Madison. IceCube is designed specifically to identify neutrinos from space. It’s a cubic kilometer of ice, laced with photo-detectors, located at a dedicated Antarctic research facility.

    Nor-Tech has been working with several of the world’s leading research institutions involved with the IceCube project for more than 10 years; designing, building, and upgrading HPC technology that made exciting neutrino discoveries possible.

    See the full article here .

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    Founded on December 28, 2006, insideHPC is a blog that distills news and events in the world of HPC and presents them in bite-sized nuggets of helpfulness as a resource for supercomputing professionals. As one reader said, we’re sifting through all the news so you don’t have to!

    If you would like to contact me with suggestions, comments, corrections, errors or new company announcements, please send me an email at rich@insidehpc.com. Or you can send me mail at:

    insideHPC
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    Phone: (503) 877-5048

     
  • richardmitnick 9:08 am on March 28, 2019 Permalink | Reply
    Tags: , , , , , Neutrinos,   

    From Fermi National Accelerator Lab: “Waiting for neutrinos” 

    FNAL Art Image
    FNAL Art Image by Angela Gonzales

    From Fermi National Accelerator Lab , an enduring source of strength for the US contribution to scientific research world wide.

    March 26, 2019
    Jim Daley

    On Feb. 24, 1987, light from a supernova that exploded 168,000 years ago in the Large Magellanic Cloud, a neighbor of the Milky Way, reached Earth.

    Large Magellanic Cloud. Adrian Pingstone December 2003

    Astronomers Ian Shelton and Oscar Duhalde at the Las Campanas Observatory in Chile first reported the supernova, called SN 1987A (or simply 87A), which was one of the brightest in nearly four centuries.

    SN1987a fromNASA/ESA Hubble Space Telescope in Jan. 2017 using its Wide Field Camera 3 (WFC3).

    Carnegie Las Campanas Observatory in the southern Atacama Desert of Chile in the Atacama Region approximately 100 kilometres (62 mi) northeast of the city of La Serena,near the southern end and over 2,500 m (8,200 ft) high

    A supernova such as 87A occurs when a star many times larger than our sun runs out of fuel in its core. At this point, the core is made of iron, and its fate hinges on the battle between two forces: Gravity tries to collapse it while electrons effectively repel each other, thanks to the Pauli exclusion principle, a quantum-mechanical effect. For a while, equilibrium is maintained, but the mass of the iron core keeps increasing, because of nuclear burning in the shell above it. Eventually, the core mass reaches a critical value called the Chandrasekhar limit, and the relentless pull of gravity wins. The core collapses on itself in near free fall, and a shockwave forms around it. Heated by the energy of escaping neutrinos, the shockwave ejects the outer layers of the star in a catastrophic blast that can briefly shine more brightly than entire galaxies. After losing its energy to neutrino emission, the core finally settles into what is known as a neutron star, effectively a giant nucleus made primarily of neutrons.

    By the time Duhalde and Shelton saw light from 87A, three neutrino detectors around the world had already picked up evidence of the supernova. Most of the energy released in a supernova is emitted as neutrinos, nearly massless subatomic particles that react rarely with ordinary matter. Because they are so weakly interacting, neutrinos can slip out of the envelope of a collapsing supernova hours before particles of light, which ride the explosion’s shockwave, are ejected.

    Neutrinos produced by 87A arrived on Earth just before the light from the explosion did. Irvine-Michigan-Brookhaven (IMB), a neutrino observatory in Ohio on the shore of Lake Erie, detected eight neutrino events.

    Irvine–Michigan–Brookhaven (detector) located in a Morton Salt company’s Fairport mine on the shore of Lake Erie in the United States 600 meters underground

    Baksan Neutrino Observatory in Russia detected five more, and Kamiokande II, a neutrino detector deep underground in a Japanese mine, saw 11.

    INR RAS – Baksan Neutrino Observatory (BNO). The Underground Scintillation Telescope in Baksan Gorge at the Northern Caucasus
    (Kabarda-Balkar Republic)

    Kamiokande-II operated 1985-1990

    It was the first time that neutrinos from a supernova had been detected – although the neutrino scientists didn’t realize it until after Duhalde and Shelton announced their observation. They found the neutrino events in their data only when they looked for them upon hearing the news about the supernova.

    1
    A supernova is born when the burnt out stellar core collapses, releasing a shockwave, which speeds toward the outer layers of the star. Most of the energy released in a supernova is emitted as neutrinos, nearly massless subatomic particles that react rarely with ordinary matter. Image: Max Planck Institute for Astrophysics

    Max Planck Institute for Astrophysics

    Something incredible waiting to be known?

    More than 30 years later, scientists are building the international Deep Underground Neutrino Experiment (DUNE), hosted by Fermilab.

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


    FNAL DUNE Argon tank at SURF


    SURF DUNE LBNF Caverns at Sanford Lab

    Its 70,000-ton liquid-argon detector will be located almost a mile underground at Sanford Underground Research Facility [SURF] in South Dakota, waiting for another burst of supernova neutrinos to arrive.

    The discovery would portend a new exploding star somewhere in the Milky Way.

    Kate Scholberg, a particle physicist at Duke University, says supernova neutrinos could teach us a lot about supernovae and particle physics if we detect them the next time an event like 87A occurs. That’s because the neutrinos carry information about the supernova with them as they travel across space. The signals the neutrinos make in particle detectors like DUNE would allow physicists to draw conclusions about the conditions in which the neutrinos were made and provide evidence for the fate of the exploding star.

    “You can actually see the processes that are happening in real time as the neutron star is being born,” said Scholberg, who studies neutrinos as part of DUNE.

    These processes could point to new physics. For example, if exotic particles are produced in a supernova, traces of their existence would be apparent in the signal made by the neutrinos. That’s because physicists can calculate the total energy produced by a supernova, and they can estimate how much of it was emitted as neutrinos from the measurement. If the total energy detected doesn’t add up to the total expected, it could hint at new particles being produced.

    “The detection of a supernova in 1987 from Kamiokande was, to me, one of the most impressive detections for particle physics,” said Inés Gil Botella, a scientist at Spain’s Center for Energy, Environment and Technology, or CIEMAT, and one of the leads on DUNE’s supernova search. “It opened a way to understanding the universe through particles other than photons. This new multimessenger era of astrophysics really started with the detection of supernova neutrinos.”

    3
    A supernova’s shockwave ejects the outer layers of the star in a catastrophic blast that can briefly shine more brightly than entire galaxies. Image: NASA

    The DUNE dimension

    While detectors captured only 24 of the neutrinos emitted from 87A, hundreds of peer-reviewed papers were published as a result of the discovery and subsequent research. When DUNE is completed, it could see far more neutrinos and contribute to a similar – and entirely novel – flurry of research.

    “DUNE has several capabilities that are truly unique among all large neutrino detectors when it comes to studies of supernova neutrinos,” said Steven Gardiner, a Fermilab scientist who works on simulating what occurs when a supernova neutrino enters a detector.

    DUNE is different from Cherenkov detectors such as Kamiokande in several ways, including that it uses liquid argon instead of water as the target medium. Liquid-argon detectors spot neutrinos when they collide with argon nuclei. Argon’s nucleus is composed of protons and neutrons that are arranged in various energy states. When a neutrino collides with an argon nucleus, a proton or neutron in a lower energy state can be elevated to a higher energy state and lead to the emission of particles from the argon nucleus via its de-excitation. Some of these particles can be observed by the detector.

    “When the nucleus de-excites, a few different things can happen,” Gardiner said. “The nucleus can emit gamma rays, neutrons, protons or heavier nuclear fragments. You can potentially see gamma rays in liquid argon, because they’ll scatter electrons in the argon, and you’ll see little blips that come from them.”

    Cherenkov detectors, which look primarily for electron antineutrinos striking bare protons, can’t reconstruct gamma rays with as much detail as liquid-argon detectors can.

    Because of the complicated nature of the energy reconstruction, it’s quite a challenge to reconstruct supernova neutrino events in a liquid-argon detector. Gardiner is currently building computer simulations that can model the various signatures that can occur when a neutrino interacts with the liquid argon in DUNE.

    “The difficulty is, because you have so many argon excited states available, you have all sorts of different signatures that could be produced in your detector,” he said. “And you have to deal with that level of complexity to fully reconstruct the energy from a neutrino collision.”

    Then there’s the challenge of teasing out the signal from the noise. Supernova neutrinos carry far less energy than, say, neutrinos produced by a particle accelerator, so the signals they produce in the argon are weaker. Unearthing these low-energy interactions requires both a sensitive detector and a knowledge of the interaction’s various signatures.

    “High-energy neutrinos are easier to detect, and their interactions are well-known. We know how they behave,” Gil Botella said. “But at these low, supernova-neutrino energies, the interactions with argon are not very well-known. We don’t have much experimental data to say what happens when a low-energy neutrino interacts with argon.”

    And scientists at the world’s other neutrino projects are looking to change that, planning experiments that would paint a clearer picture of low-energy neutrinos.

    “Studying neutrinos is a tricky business, and we have more work to do, but DUNE’s technological capabilities make those challenges far more tractable,” Gardiner said. “The physics payoffs will be huge. If we’re going to tackle these questions, DUNE is a good way to do it.”

    FNAL DUNE can capture neutrinos from supernovae

    Oscillation station

    DUNE could also help inform our understanding of neutrino oscillation in a way that other detectors cannot. In Cherenkov detectors, the signal is produced mostly by electron antineutrinos interacting with water molecules. Conversely, liquid argon also samples electron neutrinos from the supernova’s ejecta.

    “We need both electron neutrinos and antineutrinos to disentangle oscillation scenarios,” said Alex Friedland, a particle physicist and senior staff scientist at SLAC National Accelerator Laboratory in California. DUNE, because it will be the only detector that can see electron neutrinos, adds a missing piece to that puzzle.

    Neutrinos oscillate between three flavors (electron, muon or tau) as they move through space. Physicists have studied neutrino oscillations in neutrinos produced in the sun, in ­­Earth’s atmosphere, from nuclear reactors and in high-energy particle beams created by particle accelerators. But they haven’t been able to study them in supernovae, where the number of neutrinos produced is simply off the charts compared to other sources.

    “This is the ultimate intensity frontier,” Friedland said. “Nature does it for us, so we just have to take advantage of that. The supernova is a laboratory on the other side of the galaxy. It carries out experiments, and we ‘just’ have to build the detector and make a measurement. Of course, it’s useful to keep in mind that this measurement ‘just’ happens to be one of the most challenging tasks that DUNE, the most advanced neutrino detector ever built, will undertake.”

    Neutrino oscillation typically describes a single particle changing flavors, but under the right circumstances — such as in a collapsing supernova — many neutrinos can oscillate collectively.

    “Collective oscillation means that you have neutrinos that go through the background of other neutrinos, and a flavor state of a given neutrino knows about what all the other neutrinos that it passes are doing in terms of flavor,” Friedland said.

    With enough neutrino signals – which a detector such as the giant DUNE could amass – physicists can reconstruct the energy spectrum of the electron neutrinos arriving at Earth. This spectrum can have striking features imprinted on it by collective oscillations of neutrinos inside the supernova. With that information, they can see how the neutrinos evolved collectively in the dying star.

    The information can give them clues about what happened to the star itself, as well. The neutrino density is so high in a core-collapse supernova like 87A that it affects how the star explodes. The shockwave of the explosion is propelled by what physicists call the neutrino-driven wind.

    Other core-collapse events might not produce a supernova that we can see easily from Earth, but we’ll know they occurred when the neutrino detectors register a burst.

    “When a star collapses into a black hole, you likely don’t get any fireworks,” Scholberg explained. “The observers might see nothing, or just see a star wink out. Those kinds of events would be seen brightly in neutrinos.”

    Once the DUNE detectors are in place, they’ll be used to take measurements of neutrinos coming from Fermilab accelerators and wait patiently for a supernova to explode. This happens in our galaxy on average once every 30 to 50 years.

    “That’s the drawback of the supernova neutrino world; we’re always waiting,” Scholberg said. “You better not miss anything.”

    When it does occur, a core-collapse supernova will be a major event that will affect multiple fields of research, including particle physics and astrophysics.

    “It’s so impressive: Supernovae produce a huge number of neutrinos, they travel such a long distance, and you get a signal directly from something that’s kiloparsecs away,” Gil Botella said. “It’s really amazing to get access to information inside a star like that. It’s the connection with the objects in the universe — the unknown of the universe.”

    Members of the public can sign up to receive alerts from the SuperNova Early Warning System (SNEWS). The automated system currently includes seven neutrino experiments in Canada, China, Italy, Japan and at the South Pole. When neutrinos produced in a supernova reach Earth, SNEWS will send out email alerts to announce their arrival, which would captivate the research community.

    “Once the supernova happens, you can forget about everything else that we were thinking about,” Friedland said. “The world of science will be talking about that for at least a year or more.”

    The Deep Underground Neutrino Experiment is supported in part by the U.S. Department of Energy Office of Science.

    See the full article here.


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    FNAL Icon

    Fermi National Accelerator Laboratory (Fermilab), located just outside Batavia, Illinois, near Chicago, is a US Department of Energy national laboratory specializing in high-energy particle physics. Fermilab is America’s premier laboratory for particle physics and accelerator research, funded by the U.S. Department of Energy. Thousands of scientists from universities and laboratories around the world collaborate at Fermilab on experiments at the frontiers of discovery.

    FNAL MINERvA front face Photo Reidar Hahn

    FNAL DAMIC

    FNAL Muon g-2 studio

    FNAL Short-Baseline Near Detector under construction

    FNAL Mu2e solenoid

    Dark Energy Camera [DECam], built at FNAL

    FNAL DUNE Argon tank at SURF

    FNAL/MicrobooNE

    FNAL Don Lincoln

    FNAL/MINOS

    FNAL Cryomodule Testing Facility

    FNAL MINOS Far Detector in the Soudan Mine in northern Minnesota

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

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    FNAL Holometer

     
  • richardmitnick 8:35 am on March 15, 2019 Permalink | Reply
    Tags: "How Much Of The Dark Matter Could Neutrinos Be?", , , , , , , Neutrinos, Neutrinos are the only Standard Model particles that behave like dark matter should. But they can’t be the full story   

    From Ethan Siegel: “How Much Of The Dark Matter Could Neutrinos Be?” 

    From Ethan Siegel
    Mar 14, 2019

    They’re the only Standard Model particles that behave like dark matter should. But they can’t be the full story.

    1
    While the web of dark matter (purple) might seem to determine cosmic structure formation on its own, the feedback from normal matter (red) can severely impact galactic scales. Both dark matter and normal matter, in the right ratios, are required to explain the Universe as we observe it. Neutrinos are ubiquitous, but standard, light neutrinos cannot account for most (or even a significant fraction) of the dark matter. (ILLUSTRIS COLLABORATION / ILLUSTRIS SIMULATION)

    All throughout the Universe, there’s more than what we’re capable of seeing. When we look out at the stars moving around within galaxies, the galaxies moving withing groups and clusters, or the largest structures of all that make up the cosmic web, everything tells the same disconcerting story: we don’t see enough matter to explain the gravitational effects that occur. In addition to the stars, gas, plasma, dust, black holes and more, there must be something else in there causing an additional gravitational effect.

    Traditionally, we’ve called this dark matter, and we absolutely require it to explain the full suite of observations throughout the Universe. While it cannot be made up of normal matter — things made of protons, neutrons, and electrons — we do have a known particle that could have the right behavior: neutrinos. Let’s find out how much of the dark matter neutrinos could possibly be.

    2
    The neutrino was first proposed in 1930, but was not detected until 1956, from nuclear reactors. In the years and decades since, we’ve detected neutrinos from the Sun, from cosmic rays, and even from supernovae. Here, we see the construction of the tank used in the solar neutrino experiment in the Homestake gold mine from the 1960s.(BROOKHAVEN NATIONAL LABORATORY)

    At first glance, neutrinos are the perfect dark matter candidate. They barely interact at all with normal matter, and neither absorb nor emit light, meaning that they won’t generate an observable signal capable of being picked up by telescopes. At the same time, because they interact through the weak force, it’s inevitable that the Universe created enormous numbers of them in the extremely early, hot stages of the Big Bang.

    We know that there are leftover photons from the Big Bang, and very recently we’ve also detected indirect evidence that there are leftover neutrinos as well. Unlike the photons, which are massless, it’s possible that neutrinos have a non-zero mass. If they have the right value for their mass based on the total number of neutrinos (and antineutrinos) that exist, they could conceivably account for 100% of the dark matter.

    3
    The largest-scale observations in the Universe, from the cosmic microwave background [CMB]to the cosmic web to galaxy clusters to individual galaxies, all require dark matter to explain what we observe. The large-scale structure requires it, but the seeds of that structure, from the Cosmic Microwave Background, require it too. (CHRIS BLAKE AND SAM MOORFIELD)

    CMB per ESA/Planck


    ESA/Planck 2009 to 2013

    So how many neutrinos are there? That depends on the number of types (or species) of neutrino.

    Although we can detect neutrinos directly using enormous tanks of material designed to capture their rare interactions with matter, this is both incredibly inefficient and is only going to capture a tiny fraction of them. We can see neutrinos that are the result of particle accelerators, nuclear reactors, fusion reactions in the Sun, and cosmic rays interacting with our planet and atmosphere. We can measure their properties, including how they transform into one another, but not the total number of types of neutrino.

    4
    In this illustration, a neutrino has interacted with a molecule of ice, producing a secondary particle — a muon — that moves at relativistic speed in the ice, leaving a trace of blue light behind it. Directly detecting neutrinos has been a herculean but successful effort, and we are still trying to puzzle out the full suite of their nature. (NICOLLE R. FULLER/NSF/ICECUBE)

    U Wisconsin ICECUBE neutrino detector at the South Pole


    But there is a way to make the critical measurement from particle physics, and it comes from a rather unexpected place: the decay of the Z-boson. The Z-boson is the neutral boson that mediates the weak interaction, enabling certain types of weak decays. The Z couples to both quarks and leptons, and whenever you produce one in a collider experiment, there’s a chance that it will simply decay into two neutrinos.

    Those neutrinos are going to be invisible! We cannot typically detect the neutrinos we create from particle decays in colliders, as it would take a detector with the density of a neutron star to capture them. But by measuring what percentage of the decays produce “invisible” signals, we can infer how many types of light neutrino (whose mass is less than half the Z-boson mass) there are. It’s a spectacular and unambiguous result known for decades now: there are three.

    Standard Model of Particle Physics (LATHAM BOYLE AND MARDUS OF WIKIMEDIA COMMONS)


    This diagram displays the structure of the Standard Model, illustrating the key relationships and patterns. In particular, this diagram depicts all of the particles in the Standard Model, the role of the Higgs boson, and the structure of electroweak symmetry breaking, indicating how the Higgs vacuum expectation value breaks electroweak symmetry, and how the properties of the remaining particles change as a consequence. Note that the Z-boson couples to both quarks and leptons, and can decay through neutrino channels. (LATHAM BOYLE AND MARDUS OF WIKIMEDIA COMMONS)

    Coming back to dark matter, we can calculate, based on all the different signals we see, how much extra dark matter is necessary to give us the right amount of gravitation. In every way we know how to look, including:

    from colliding galaxy clusters,
    from galaxies moving within X-ray emitting clusters,
    from the fluctuations in the cosmic microwave background,
    from the patterns found in the large-scale structure of the Universe,
    and from the internal motions of stars and gas within individual galaxies,

    we find that we require about five times the abundance of normal matter to exist in the form of dark matter. It’s a great success of dark matter for modern cosmology that just by adding one ingredient to solve one puzzle, a whole slew of other observational puzzles are also solved.

    5
    Four colliding galaxy clusters, showing the separation between X-rays (pink) and gravitation (blue), indicative of dark matter. On large scales, cold dark matter is necessary, and no alternative or substitute will do.(X-RAY: NASA/CXC/UVIC./A.MAHDAVI ET AL. OPTICAL/LENSING: CFHT/UVIC./A. MAHDAVI ET AL. (TOP LEFT); X-RAY: NASA/CXC/UCDAVIS/W.DAWSON ET AL.; OPTICAL: NASA/ STSCI/UCDAVIS/ W.DAWSON ET AL. (TOP RIGHT); ESA/XMM-NEWTON/F. GASTALDELLO (INAF/ IASF, MILANO, ITALY)/CFHTLS (BOTTOM LEFT); X-RAY: NASA, ESA, CXC, M. BRADAC (UNIVERSITY OF CALIFORNIA, SANTA BARBARA), AND S. ALLEN (STANFORD UNIVERSITY) (BOTTOM RIGHT))

    NASA/Chandra X-ray Telescope



    CFHT Telescope, Maunakea, Hawaii, USA, at Maunakea, Hawaii, USA,4,207 m (13,802 ft) above sea level

    NASA/ESA Hubble Telescope

    ESA/XMM Newton

    If you have three species of light neutrino, it would only take a relatively small amount of mass to account for all the dark matter: a few electron-Volts (about 3 or 4 eV) per neutrino would do it. The lightest particle found in the Standard Model besides the neutrino is the electron, and that has a mass of about 511 keV, or hundreds of thousands of times the neutrino mass we want.

    Unfortunately, there are two big problems with having light neutrinos that are that massive. When we look in detail, the idea of massive neutrinos is insufficient to make up 100% of the dark matter.

    6
    A distant quasar will have a big bump (at right) coming from the Lyman-series transition in its hydrogen atoms. To the left, a series of lines known as a forest appears. These dips are due to the absorption of intervening gas clouds, and the fact that the dips have the strengths they do place constraints on the temperature of dark matter. It cannot be hot. (M. RAUCH, ARAA V. 36, 1, 267 (1998))

    The first problem is that neutrinos, if they are the dark matter, would be a form of hot dark matter. You might have heard the phrase “cold dark matter” before, and what it means is that the dark matter must be moving slowly compared to the speed of light at early times.

    Why?

    If dark matter were hot, and moving quickly, it would prevent the gravitational growth of small-scale structure by easily streaming out of it. The fact that we form stars, galaxies, and clusters of galaxies so early rules this out. The fact that we see the weak lensing signals we do rules this out. The fact that we see the pattern of fluctuations in the cosmic microwave background rules this out. And direct measurements of clouds of gas in the early Universe, through a technique known as the Lyman-α forest, definitively rule this out. Dark matter cannot be hot.

    7
    The dark matter structures which form in the Universe (left) and the visible galactic structures that result (right) are shown from top-down in a cold, warm, and hot dark matter Universe. From the observations we have, at least 98%+ of the dark matter must be cold. (ITP, UNIVERSITY OF ZURICH)

    A number of collaborations have measured the oscillations of one species of neutrinos to another, and this enables us to infer the mass differences between the different types. Since the 1990s, we’ve been able to infer that the mass difference between two of the species are on the order of about 0.05 eV, and the mass difference between a different two species is approximately 0.009 eV. Direct constraints on the mass of the electron neutrino come from tritium decay experiments, and show that the electron neutrino must be less massive than about 2 eV.

    8
    A neutrino event, identifiable by the rings of Cerenkov radiation that show up along the photomultiplier tubes lining the detector walls, showcase the successful methodology of neutrino astronomy. This image shows multiple events, and is part of the suite of experiments paving our way to a greater understanding of neutrinos. (SUPER KAMIOKANDE COLLABORATION)

    Super-Kamiokande experiment. located under Mount Ikeno near the city of Hida, Gifu Prefecture, Japan

    Beyond that, the cosmic microwave background [CMB [above] (from Planck [above]) and the large-scale structure data (from the Sloan Digital Sky Survey) tells us that the sum of all the neutrino masses is at most approximately 0.1 eV, as too much hot dark matter would definitively affect these signals. From the best data we have, it appears that the mass values that the known neutrinos have are very close to the lowest values that the neutrino oscillation data implies.

    In other words, only a tiny fraction of the total amount of dark matter is allowed to be in the form of light neutrinos. Given the constraints we have today, we can conclude that approximately 0.5% to 1.5% of the dark matter is made up of neutrinos. This isn’t insignificant; the light neutrinos in the Universe have about the same mass as all the stars in the Universe. But their gravitational effects are minimal, and they cannot make up the needed dark matter.

    THE The Sudbury neutrino observatory, which was instrumental in demonstrating neutrino oscillations and the massiveness of neutrinos. With additional results from atmospheric, solar, and terrestrial observatories and experiments, we may not be able to explain the full suite of what we’ve observed with only 3 Standard Model neutrinos, and a sterile neutrino could still be very interesting as a cold dark matter candidate. (A. B. MCDONALD (QUEEN’S UNIVERSITY) ET AL.,SUDBURY NEUTRINO OBSERVATORY INSTITUTE

    There is an exotic possibility, however, that means we might still have a chance for neutrinos to make a big splash in the world of dark matter: it’s possible that there’s a new, extra type of neutrino. Sure, we have to fit in with all the constraints from particle physics and cosmology that we have already, but there’s a way to make that happen: to demand that if there’s a new, extra neutrino, it’s sterile.

    A sterile neutrino has nothing to do with its gender or fertility; it merely means that it doesn’t interact through the conventional weak interactions today, and that a Z-boson won’t couple to it. But if neutrinos can oscillate between the conventional, active types and a heavier, sterile type, it could not only behave as though it were cold, but could make up 100% of the dark matter. There are experiments that are completed, like LSND and MiniBooNe, as well as experiments planned or in process, like MicroBooNe, PROSPECT, ICARUS and SBND, that are highly suggestive of sterile neutrinos being a real, important part of our Universe.

    LSND experiment at Los Alamos National Laboratory and Virginia Tech>

    FNAL/MiniBooNE

    FNAL/MicrobooNE

    Yale PROSPECT Neutrino experiment


    Yale PROSPECT—A Precision Oscillation and Spectrum Experiment

    INFN Gran Sasso ICARUS, since moved to FNAL


    FNAL/ICARUS

    FNAL Short Baseline Neutrino Detector [SBND]

    Scheme of the MiniBooNE experiment at FNAL

    A high-intensity beam of accelerated protons is focused onto a target, producing pions that decay predominantly into muons and muon neutrinos. The resulting neutrino beam is characterized by the MiniBooNE detector. (APS / ALAN STONEBRAKER)

    If we restrict ourselves to the Standard Model alone, we simply cannot account for the dark matter that must be present in our Universe. None of the particles we know of have the right behavior to explain all of the observations. We can imagine a Universe where neutrinos have relatively large amounts of mass, and that would result in a Universe with significant quantities of dark matter. The only problem is that dark matter would be hot, and lead to an observably different Universe than the one we see today.

    Still, the neutrinos we know of do behave like dark matter, although it only makes up about 1% of the total dark matter out there. That’s not totally insignificant; it equals the mass of all the stars in our Universe! And most excitingly, if there truly is a sterile neutrino species out there, a series of upcoming experiments ought to reveal it over the next few years. Dark matter might be one of the greatest mysteries out there, but thanks to neutrinos, we have a chance at understanding it at least a little bit.

    See the full article here .

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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    “Starts With A Bang! is a blog/video blog about cosmology, physics, astronomy, and anything else I find interesting enough to write about. I am a firm believer that the highest good in life is learning, and the greatest evil is willful ignorance. The goal of everything on this site is to help inform you about our world, how we came to be here, and to understand how it all works. As I write these pages for you, I hope to not only explain to you what we know, think, and believe, but how we know it, and why we draw the conclusions we do. It is my hope that you find this interesting, informative, and accessible,” says Ethan

     
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