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  • richardmitnick 11:19 am on July 3, 2015 Permalink | Reply
    Tags: , Neutrinos,   

    From Symmetry: “How do you solve a puzzle like neutrinos?” 


    June 30, 2015
    Lauren Biron

    When it comes to studying particles that zip through matter as though it weren’t even there, you use every method you can think of.

    Artwork by Sandbox Studio, Chicago with Ana Kova

    Sam Zeller sounds borderline embarrassed by scientists’ lack of understanding of neutrinos—particularly how much mass they have.

    “I think it’s a pretty sad thing that we don’t know,” she says. “We know the masses of all the particles except for neutrinos.” And that’s true even for the Higgs, which scientists only discovered in 2012.

    Ghostly neutrinos, staggeringly abundant and ridiculously aloof, have held onto their secrets long past when they were theorized in the 1930s and detected in the 1950s. Scientists have learned a few things about them:

    They come in three flavors associated with three other fundamental particles (the electron, muon and tau).
    They change, or oscillate, from one type to another.
    They rarely interact with anything, and trillions upon trillions stream through us every minute.
    They have a very small mass.

    But right now, there are still more questions than answers.

    Zeller, one of thousands of neutrino researchers around the world and co-spokesperson for the neutrino experiment MicroBooNE based at Fermilab, says the questions about neutrinos don’t stop at mass.

    FNAL MicroBooNE

    She writes down a shopping list of things physicists want to find out:

    Is one type of neutrino much heavier than the other two, or much lighter?
    What is the absolute mass of the neutrino?
    Are there more than three types of neutrinos?
    Do neutrinos and antineutrinos behave differently?
    Is the neutrino its own antiparticle?
    Is our picture of neutrinos correct?

    No single experiment can answer all of these questions. Instead, there are dozens of experiments looking at neutrinos from different sources, each contributing a piece to the puzzle. Some neutrinos stream unimpeded from far away, born in supernovae, the sun, the atmosphere or cosmic sources. Others originate closer to home, in the Earth, nuclear reactors, radioactive decays or particle accelerators. Their different birthplaces imbue them with different flavors and energies—a range so great, it spans at least 16 orders of magnitude. Armed with the knowledge of where and how to look, scientists are entering an exhilarating experimental time.

    “That’s why neutrino physics is so exciting right now,” Zeller says. “It’s not as if we’re shooting in the dark or we don’t know what we’re doing. Worldwide, we’re embarking on a program to answer these questions. That path will make use of these many different sources, and in the end you put it all together and hope the story makes sense.”


    Neutrinos from nuclear reactors

    The first confirmation that neutrinos were more than just a theory came from nuclear reactors, where neutrinos are produced in a process called beta decay. A team of scientists led by Clyde Cowan and Frederick Reines found neutrinos spewing in a steady stream from reactors at the Hanford Site in Washington and the Savannah River Plant in South Carolina between 1953 and 1959.

    Reactors have been useful for neutrino physics ever since, particularly because they produce only one kind of neutrino: electron antineutrinos. When studying the way particles change from one type to another, it’s invaluable to know exactly what you’re starting with.

    Reactor experiments such as KamLAND, which studied particles from 53 nuclear reactors in Japan, echoed results from projects examining solar and atmospheric neutrinos. All of them found that neutrinos changed flavor over time.


    “Once we know that neutrinos are oscillating, that gives us the strongest evidence that neutrinos are massive,” says Dan Dwyer, a scientist at Lawrence Berkeley National Laboratory and researcher on the international Daya Bay Reactor Neutrino Experiment based in China.

    Daya Bay
    Daya Bay

    Such projects now look for the way neutrinos change and for hints about their relative masses.

    Because reactor experiments allow for precision, they’re also ideal to hunt for a fourth type of particle—the yet unobserved sterile neutrino, thought to interact only through gravity.


    Neutrinos from accelerators

    Reactor neutrinos aren’t the only way to look for additional neutrinos. That’s where the powerhouse of neutrino research—the accelerator—comes in.

    Scientists can use a beam of easier-to-control particles such as protons to create a beam of neutrinos.

    First, they accelerate the protons and smash them into a target. The energy released in this collision converts to mass in the form of a flood of new massive particles. Those particles decay into less massive particles, including neutrinos.

    Before the massive particles decay, scientists use magnets to focus them into a beam. Afterward, they use blocking material to skim off unwanted bits while the neutrinos—which can pass through a light-year of lead without even noticing it’s there—flow freely through.

    Neutrino beams from accelerators are typically made of muon neutrinos and antineutrinos, but the experiments that use accelerators split into two main groups: short-baseline experiments, which look at oscillations over smaller distances, and long-baseline experiments, which study neutrinos that have traveled over hundreds of miles.

    Both types of experiments look at how neutrinos oscillate. At short distances, neutrinos are less likely to have changed flavors, though the influence of undiscovered new particles or forces might affect that rate. At long distances, neutrinos are more likely to have changed after traveling for a few milliseconds at nearly the speed of light. Oscillation patterns can give scientists clues as to the masses of the different types of neutrinos.

    Oscillation studies over long distances, like Japan’s T2K experiment or the United States’ NOvA experiment and proposed DUNE experiment, can help researchers find how neutrinos relate to antineutrinos. One method is to search for charge parity violation.



    This complicated-sounding term essentially asks whether matter and antimatter can pull off “the old switcheroo”—that is, whether the universe treats matter and antimatter particles identically. If the oscillations of neutrinos are fundamentally different from the oscillations of antineutrinos, then CP is broken.

    Scientists already know that CP is violated for one major building block of the universe: the quarks. Does the same happen for the other major family, the leptons? Neutrinos might hold the key.


    Studying neutrinos without neutrinos

    It’s odd that one of the most important questions regarding neutrinos can be answered only by looking for a process apparently lacking in neutrinos.

    In neutrinoless double beta decay, a particle would decay into electrons and neutrinos, but the neutrinos would annihilate one another within the nucleus.

    “If you see it, it tells you that neutrinos are different in a fundamental way,” says Boris Kayser, a theorist at Fermilab.

    Neutrinoless double beta decay would occur only if neutrinos and their antiparticles were one and the same. No other fundamental particle of matter has this property.

    “Neutrinos are very special,” Kayser says. “It could be that they violate rules that other particles don’t violate.”

    Several experiments worldwide are under way to search for this process, with future generations planned.

    A different experiment, KATRIN, hopes to find the masses of the neutrinos by looking at particular electrons. As a radioactive kind of hydrogen decays, it spits out an antineutrino and a partner electron. Scientists will use the world’s largest spectrometer to measure the energy of these electrons to learn about the neutrino.

    KATRIN Experiment



    Unperturbed by magnetism or mass in their paths, neutrinos are perhaps the ultimate messengers of the universe. Once found, the particles point back to their origins, places scientists can’t otherwise see. Investigating these neutrinos provides insight into the particles themselves and is a useful way to probe the unknown.

    Take the Earth as an example. Scientists can use detectors to capture geoneutrinos, typically low-energy electron antineutrinos, to learn about the composition of our planet without trying to drill miles below the surface. Because we’ve learned that neutrinos are born of particle decay, the number of geoneutrinos tells researchers how much potassium, thorium and uranium lurk below, heating our world.


    Solar neutrinos

    Neutrinos are also created in processes in the sun. But when Ray Davis built a solar neutrino detector filled with dry cleaning fluid, his experiment picked up only a third of the predicted neutrinos.

    This solar neutrino problem hinted that we didn’t understand our sun; in reality, we didn’t understand neutrinos. Solar neutrino experiments after Davis’ showed that neutrinos from the sun were changing flavor, and a reactor experiment later confirmed that the flavor change was caused by neutrino oscillation.

    Modern solar neutrino experiments such as Italy’s Borexino provide insight into the core of the sun and help put limits on sterile neutrinos.

    Others, like Japan’s Super-Kamiokande detector, can look at how solar neutrinos change when traveling through the earth versus neutrinos oscillating primarily in the vacuum of space.

    Super-Kamiokande experiment Japan

    “The reason that’s important is that if the neutrino interacts with matter in new, unknown ways, which is possible, then this effect would be changed,” says Josh Klein, professor of physics at the University of Pennsylvania. “It’s a very sensitive measure of new physics.”


    Cosmic neutrinos

    Cosmic neutrinos illuminate powerful phenomena occurring within our galaxy and beyond. Massive extragalactic neutrino hunting experiments, such as the IceCube experiment that sprawls across a cubic kilometer of ice in Antarctica, can find neutrinos that have oscillated over much longer distances than we can test with accelerators.

    ICECUBE neutrino detector
    IceCube neutrino detector interior

    “We see neutrinos [with energies] from below 10 [billion electronvolts] to above a thousand [trillion electronvolts],” says Francis Halzen, physicist at the University of Wisconsin, Madison, and leader of IceCube. “Nobody has ever built something that covers this energy range of particles.”

    Giant neutrino detectors like this one can look for sterile neutrinos and gather information on oscillations and mass hierarchy.

    They’re also useful for understanding dark matter and supernovae, analyzing atmospheric neutrinos that form when cosmic rays hit our atmosphere and telling other astronomers where to point their telescopes if neutrinos from a supernova burst hit. Physicists learn properties of neutrinos, but the neutrinos in turn unlock secrets of the universe.

    “Whenever we have made a picture of the universe in a different wavelength region of light, we have always seen things we didn’t expect,” Halzen says. “We’re doing now what astronomers have been doing for decades: looking at the sky in different ways.”

    Neutrinos matter for matter

    At the end of the day, why go to all this trouble for such a tiny particle? In addition to helping scientists probe the interior of the Earth or the far-off corners of the cosmos, neutrinos could hold the key to why matter exists today.

    Scientists know that antimatter and matter are produced in equal parts and should ultimately have annihilated one another, leaving a dark and empty universe. But here we stand, matter in all its glory.

    Sometime early in the universe’s history, an imbalance arose and shifted the scales toward a matter-dominated universe. If physicists find that neutrinos have certain characteristics—including CP violation—it could help explain why the universe turned out the way it did.

    “They’re the most abundant massive particle in the universe,” Zeller says. “If you find out something weird about neutrinos, it’s bound to tell you something about how the universe evolved or how it came to be the way we observe today.”

    See the full article here.

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    Symmetry is a joint Fermilab/SLAC publication.

  • richardmitnick 7:42 am on June 10, 2015 Permalink | Reply
    Tags: , Hyper-K, Neutrinos,   

    From Symmetry: “Japan’s next big neutrino project” 


    June 09, 2015
    Glenn Roberts Jr.

    Artwork by Sandbox Studio, Chicago

    The proposed Hyper-K experiment would dwarf its predecessor.

    In 1998, the Super-K detector in Japan revealed that ubiquitous, almost massless particles called neutrinos have the ability to morph from one type to another. That landmark finding has become one of the most heavily cited scientific results in particle physics.

    Super-Kamiokande experiment Japan

    Now scientists have proposed to build a successor to the still-operating Super-K: Hyper-K, a detector with an active volume 25 times its size.

    Part microscope and part telescope, the proposed Hyper-K experiment could fill in some of the blanks in our understanding of our universe. It could help explain why the universe favors matter over antimatter. It could provide new details about the fluctuating “flavors” or types of neutrinos. It could help elucidate whether there is any difference between neutrinos and their anti-particles.

    It could also provide a better understanding of dark matter and exploding stars and could reveal whether protons—a main ingredient in all atoms—have an expiration date.

    The proposed experiment would be complementary to DUNE, a planned long-baseline neutrino experiment in the United States that will use different technology.


    The “K” in Super-K and Hyper-K stands for a play on the word Kamioka, the name of a mountainous area about 200 miles west of Tokyo that houses multiple particle physics experiments.

    “The uniqueness of Hyper-K is its size and resolution,” says Tsuyoshi Nakaya of Kyoto University, who leads the Hyper-K steering committee and has been a part of Super-K since 1999.

    The central component in the Hyper-K project would be a massive cylindrical tank measuring about 248 meters long and 54 meters high, filled with 1.1 million tons of highly purified water. An alternate Hyper-K design calls for an egg-shaped tank.

    Courtesy of: © Hyper-Kamiokande Collaboration

    Hyper-K would consist of an array of photo-detectors that would measure flashes of light produced in particle events and processes occurring in the tank. The mountain above Hyper-K would help to shield the detectors from the “noise” of other particles such as cosmic rays.

    Hyper-K would study a beam of neutrinos produced at the Japan Proton Accelerator Research Complex about 180 miles away in Tokai, and it would be able to detect neutrinos produced even farther away in Earth’s atmosphere and beyond. Hyper-K could also detect particles produced in the decay of a proton, something scientists have yet to see.

    “The discovery of proton decays would be revolutionary,” says Masato Shiozawa, Hyper-K project leader who works at the Institute for Cosmic Ray Research in Japan.

    Hyper-K has already won international support from institutions in 13 countries, with the largest groups coming from Japan, the United Kingdom, the United States, Switzerland and Canada. In January the ICCR announced a cooperative agreement to pursue Hyper-K with the Institute of Particle and Nuclear Studies in Japan’s High Energy Accelerator Research Organization.

    About 200 researchers are already working on the design of Hyper-K, and the collaboration is still welcoming new members. They hope to begin construction in 2018.

    See the full article here.

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    Symmetry is a joint Fermilab/SLAC publication.

  • richardmitnick 7:15 pm on May 19, 2015 Permalink | Reply
    Tags: , Neutrinos,   

    From Symmetry: “Looking to the heavens for neutrino masses” 


    May 19, 2015
    Matthew R. Francis

    Artwork by Sandbox Studio, Chicago

    Neutrinos may be the lightest of all the particles with mass, weighing in at a tiny fraction of the mass of an electron. And yet, because they are so abundant, they played a significant role in the evolution and growth of the biggest things in the universe: galaxy clusters, made up of hundreds or thousands of galaxies bound together by mutual gravity.

    Thanks to this deep connection, scientists are using these giants to study the tiny particles that helped form them. In doing so, they may find out more about the fundamental forces that govern the universe.

    Curiously light

    When neutrinos were first discovered, scientists didn’t know right away if they had any mass. They thought they might be like photons, which carry energy but are intrinsically weightless.

    But then they discovered that neutrinos came in three different types [flavors] and that they can switch from one type to another, something only particles with mass could do.

    Scientists know that the masses of neutrinos are extremely light, so light that they wonder whether they come from a source other than the Higgs field, which gives mass to the other fundamental particles we know. But scientists have yet to pin down the exact size of these masses.

    It’s hard to measure the mass of such a tiny particle with precision.

    In fact, it’s hard to measure anything about neutrinos. They are electrically neutral, so they are immune to the effects of magnetic fields and related methods physicists use to detect particles. They barely interact with other particles at all: Only a more-or-less direct hit with an atomic nucleus can stop a neutrino, and that doesn’t happen often.

    Roughly a trillion neutrinos pass through your body each second from the sun alone, and almost none of those end up striking any of your atoms. Even the densest matter is nearly transparent to neutrinos. However, by creating beams of neutrinos and by building large, sensitive targets to catch neutrinos from nuclear reactors and the sun, scientists have been able to detect a small portion of the particles as they pass through.

    In experiments so far, scientists have estimated that the total mass of the three types of neutrinos together is roughly between 0.06 electronvolts and 0.2 electronvolts. For comparison, an electron’s mass is 511 thousand electronvolts and a proton weighs in at 938 million electronvolts.

    Because the Standard Model—the theory describing particles and the interactions governing them—predicts massless neutrinos, finding the exact neutrino mass value will help physicists modify their models, yielding new insights into the fundamental forces of nature.

    Standard Model of Particle Physics. The diagram shows the elementary particles of the Standard Model (the Higgs boson, the three generations of quarks and leptons, and the gauge bosons), including their names, masses, spins, charges, chiralities, and interactions with the strong, weak and electromagnetic forces. It also depicts the crucial role of the Higgs boson in electroweak symmetry breaking, and shows how the properties of the various particles differ in the (high-energy) symmetric phase (top) and the (low-energy) broken-symmetry phase (bottom).

    Studying galaxy clusters could provide a more precise answer.

    Footprints of a neutrino

    One way to study galaxy clusters is to measure the cosmic microwave background [CMB], the light traveling to us from 380,000 years after the big bang.

    Cosmic Background Radiation Planck
    CMB per ESA Planck

    ESA Planck

    During its 13.8-billion-year journey, this light passed through and near all the galaxies and galaxy clusters that formed. For the most part, these obstacles didn’t have a big effect, but taken cumulatively, they filtered the CMB light in a unique way, given the galaxies’ number, size and distribution.

    The filtering affected the polarization—the orientation of the electric part of light—and originated in the gravitational field of galaxies. As CMB light traveled through the gravitational field, its path curved and its polarization twisted very slightly, an effect known as gravitational lensing. (This is a less dramatic version of lensing familiar from the beautiful Hubble Space Telescope images.)

    NASA Hubble Telescope
    NASA/ESA Hubble

    The effect is similar to the one that got everyone excited in 2014, when researchers with the BICEP2 telescope announced they had measured the polarization of CMB light due to primordial gravitational waves, which subsequent study showed to be more ambiguous.

    BICEP 2BICEP 2 interior

    That ambiguity won’t be a problem here, says Oxford University cosmologist Erminia Calabrese, who studies the CMB on the Atacama Cosmology Telescope [ACT] Polarization project.

    Princeton Atacama Technology Telescope

    “There is one pattern of CMB polarization that is generated only by the deflection of the CMB radiation.” That means we won’t easily mistake gravitational lensing for anything else.

    Small and mighty

    Manoj Kaplinghat, a physicist at the University of California at Irvine, was one of the first to work out how neutrino mass could be estimated from CMB data alone. Neutrinos move very quickly relative to stuff like atoms and the invisible dark matter that binds galaxies together. That means they don’t clump up like other forms of matter, but their small mass still contributes to the gravitational field.

    Enough neutrinos, even fairly low-mass ones, can deprive a newborn galaxy of a noticeable amount of mass as they stream away, possibly throttling the growth of galaxies that can form in the early universe. It’s nearly as simple as that: Heavier neutrinos mean galaxies must grow more slowly, while lighter neutrinos mean faster galaxy growth.

    Kaplinghat and colleagues realized the polarization of the CMB provides a measure the total amount of gravity from galaxies in the form of gravitational lensing, which working backward will constrain the mass of neutrinos. “When you put all that together, what you realize is you can do a lot of cool neutrino physics,” he says.

    Of course the CMB doesn’t provide a direct measurement of the neutrino mass. From the point of view of cosmology, the three types of neutrinos are indistinguishable. As a result, what CMB polarization gives us is the total mass of all three types together.

    However, other projects are working on the other end of this puzzle. Experiments such as the Main Injector Neutrino Oscillation Search, managed by Fermilab, have determined the differences in mass between the different neutrino types.

    Depending on which neutrino is heaviest, we know how the masses of the other two types of neutrinos relate. If we can figure out the total mass, we can figure out the masses of each one. Together, cosmological and terrestrial measurements will get us the individual neutrino masses that neither is able to alone.

    The space-based Planck observatory and POLARBEAR project in northern Chile have yielded preliminary results in this search already.

    POLARBEAR McGill Telescope
    POLARBEAR telescope

    And scientists at ACTPol, located at high elevation in Chile’s Atacama Desert, are working on this as well. They will determine the neutrino mass as well as the best estimates we have, down to the lowest possible values allowed, once the experiments are running at their highest precision, Calabrese says.

    Progress is necessarily slow: The gravitational lensing pattern comes from seeing small patterns emerging from light captured across a large swath of the sky, much like the image in an Impressionist painting arises from abstract brushstrokes that look like very little by themselves.

    In more scientific terms, it’s a cumulative, statistical effect, and the more data we have, the better chance we have to measure the lensing effect—and the mass of a neutrino.

    See the full article here.

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    Symmetry is a joint Fermilab/SLAC publication.

  • richardmitnick 10:59 am on May 7, 2015 Permalink | Reply
    Tags: , , Neutrinos,   

    From Sanford via KDLT: “Unlocking Mysteries of Dark Matter & Neutrinos in South Dakota” 

    Sanford Underground Research facility

    Sanford Underground levels

    Sanford Underground Research facility


    May 06, 2015
    Tom Hanson, KDLT News Anchor

    The former Homestake Gold Mine in Lead closed in 2002. It is now the Sanford Underground Research Facility Funded by the state of South Dakota, the U.S. Department of Energy and a donation from T. Denny Sanford the lab is drawing some of the sharpest minds in science to South Dakota.

    The search for dark matter and the study of neutrinos are at the heart of two of the underground labs biggest projects. The equipment used in this research is so sensitive it has to be shielded from cosmic rays on the earth’s surface.

    Located almost a mile underground the LUX is a dark matter detector.

    Lux Dark Matter 2
    LUX Dark matter

    The two men behind the project Simon Fiorucci (left) and Harry Nelson are hunting something so rare, no one has ever seen it, in fact no one really knows exactly what it is.

    “We are trying to detect a new form of matter which we are absolutely sure constitutes about 85 percent of the matter in the universe,” said Nelson. “And the fabulous thing is no one knows what it is. So there are a bunch of conjectures and so the gadget behind us is dedicated to the most popular conjecture of what this dark matter of the universe is.”

    The gadget is the Large Underground Xenon Detector or LUX, a phone booth sized container holding liquid xenon, cooled to -160 degrees F and surrounded by thousands of gallons of specially treated water. And according to Sanford Underground Lab officials the LUX has the reputation as the most sensitive detector ever built. Nelson has a nack for taking a very complicated process and simplifying it.

    “Our detector occasionally should see a little touch of the dark matter and it will make the atoms in our detector recoil and emit a little bit of light and also make a little bit of electric charge, that’s what we are trying to do here,” said Nelson.

    But according to Fiorucci so far that hasn’t happened.

    “We’ve seen nothing at all, which at first glance you might think well that’s not great, actually what that means is we’ve eliminated quite a number of possibilities, said Fiorucci.


    Possibilities surround the other big project currently underway at the Sanford lab. The Majorana Demonstrator is looking at neutrinos.

    Majorano Demonstrator Experiment

    Particles so small there are billions of them passing through your body as you read this story. Professor John Wilkerson and his team are searching for a rare form of radioactive decay.

    “If we see this rare decay it would actually tell us that neutrinos can be their own anti particle and it might explain why we exist, why there’s so much matter and why there’s not anti-matter in the universe,” said Wilkerson.

    The vast majority of the observable universe from our planet seems to be made of matter and not antimatter. Why? Is one of the most interesting questions facing scientists.

    Building on the success of the LUX and Majorana Demonstrator, the next generations of projects are coming to the underground facility.
    The LZ project will continue the search for dark matter and will be 30 times larger than the LUX.

    LZ project
    LZ Project

    However the Deep Underground Neutrino Experiment or DUNE will be the biggest of all.


    The $1.5 billion project will try to find out how neutrinos change from point A to point B. It involves shooting neutrinos through the earth from Fermilab in Illinois to a huge detector at the Sanford Underground Lab.

    The man in charge of the facility, executive director Brookings native Mike Headley says they are excited to be a part of the project.

    “This will really be a big deal”, said Headley. “It’s an international collaboration that has close to 150 institutions worldwide and over 700 collaborators. The Long Base Neutrino Experiment (also called DUNE) is basically a $1.5 billion project. It is 1/3 funded international 2/3 funded in U.S. About 300 million of that $1.5 Billion will be facility construction here in South Dakota, so it’s going to be one of the biggest construction projects we’ve ever had in the state.”

    Construction on DUNE will begin next year. Scientists behind the project say neutrinos could hold clues about how the universe began and why matter greatly outnumbers antimatter, allowing us to exist.

    See the full article here.

    Please help promote STEM in your local schools.
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    About us.
    The Sanford Underground Research Facility 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 Majorana Demonstrator experiment, 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.

    Another major experiment, the Long Baseline Neutrino Experiment (LBNE) [being replaced by DUNE]—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 [DUNE] will follow neutrinos as they travel 800 miles through the earth, from FermiLab in Batavia, Ill., to Sanford Lab.

    Fermilab LBNE

  • richardmitnick 1:17 pm on April 23, 2015 Permalink | Reply
    Tags: , , Neutrinos,   

    From Symmetry: “Extreme cold and shipwreck lead” 


    April 23, 2015
    Lauren Biron

    Scientists have proven the concept of the CUORE experiment, which will study neutrinos with the world’s coldest detector and ancient lead.

    Courtesy of the CUORE collaboration

    Scientists on an experiment in Italy are looking for a process so rare, it is thought to occur less than once every trillion, trillion years. To find it, they will create the single coldest cubic meter in the universe.

    The experiment, the Cryogenic Underground Observatory for Rare Events, will begin by the end of the year, scientists recently announced after a smaller version demonstrated the feasibility of the design.

    The project, based at Gran Sasso National Laboratory, will examine a property of ghostly neutrinos by looking for a process called neutrinoless double beta decay. If scientists find it, it could be a clue as to why there is more matter than antimatter in the universe–and show that neutrinos get their mass in a way that’s different from all other particles.

    The full CUORE experiment requires 19 towers of tellurium dioxide crystals, each made of 52 blocks just smaller than a Rubik’s cube. Physicists will place these towers into a refrigerator called a cryostat and cool it to 10 millikelvin, barely above absolute zero. The cryostat will eclipse even the chill of empty space, which registers a toasty 2.7 Kelvin (minus 455 degrees Fahrenheit).

    CUORE uses the cold crystals to search for a small change in temperature caused by these rare nuclear decays. Unlike ordinary beta decays, in which electrons and antineutrinos share energy, the neutrinoless double beta decay produces two electrons, but no neutrinos at all. It is as if the two antineutrinos that should have been produced annihilate one another inside the nucleus.

    “This would be really cool because it would mean that the neutrino and the antineutrino are the same particle, and most of the time we just can’t tell the difference,” says Lindley Winslow, a professor at MIT and one of over 160 scientists working on CUORE.

    Neutrinos could be the only fundamental particles of matter to have this strange property.

    For the past two years, scientists collected data on just one of the crystal towers housed in a smaller cryostat, a project called CUORE-0. The most recent result establishes the most sensitive limits for seeing neutrinoless beta decay in tellurium crystals. In addition, the researchers verified that the techniques developed to construct CUORE work well and reduce background radiation prior to the full experiment coming online.

    “It’s a great result for Te-130, We are also very excited that we were able to demonstrate that what’s coming online with CUORE is what we hoped it would be,” says Reina Maruyama, professor of physics at Yale University and a member of the CUORE Physics Board. “We look forward to shattering our own result from CUORE-0 once CUORE comes to life”

    Avoiding radioactive contamination and shielding the experiment from outside sources that might mimic the telltale energy signature CUORE is searching for is a priority. The mountains at Gran Sasso will provide one layer of shielding from cosmic bombardment, but the CUORE cryostat will also get a second layer of protection against the minor radiation of the mountain itself. Ancient Roman lead ingots, salvaged from a shipwreck that occurred more than 2000 years ago, have been melted down into a shield that will cocoon the crystal towers.

    Lead excels at blocking radiation but can itself become slightly radioactive when hit by cosmic rays. The ingots that sat at the bottom of the sea for two millennia have been spared cosmic bombardment and provide very clean, if somewhat exotic, shielding material.

    The next step for CUORE will be to finish commissioning the powerful refrigerator, the largest of its kind. The cryostat must remain stable even with the tons of material inside. After the detector is installed and the cryostat cooled, it will likely take between six months and a year to find the ultimate sensitivity, measure contamination (if there is any), and show that the detector works perfectly, says Yury Kolomensky, professor of physics at the University of California, Berkeley, and the US spokesperson for the CUORE collaboration. Then it will take data for five years.

    “And then we hope to come back with either a discovery [of neutrinoless double beta decay]–or not. And if not, that means we have shrunk the size of the haystack by a factor of 20,” Kolomensky says.

    If CUORE goes well, it could find itself a contender for the next generation of neutrinoless double beta decay experiments, something Kolomensky says the nuclear physics community plans to decide over the next two to three years. CUORE uses tellurium, a plentiful isotope that has good energy resolution, meaning scientists can tell precisely where the peak is and what caused it. Other large-scale neutrinoless double beta decay experiments use germanium or xenon instead.

    “The worldwide community is looking at all the technologies very carefully,” Kolomensky says. “If our detector works as advertised at this scale, we’ll be in a very strong position to build an even better detector.”

    CUORE’s journey has already been more than 30 years in the making, according to Oliviero Cremonesi, spokesperson for the collaboration.

    “It’s very emotional for me. We started in the ‘80s with milligram prototypes, and now we have a ton-size detector and a unique cryogenic system,” Cremonesi says. “Even more exciting is the knowledge that this adventure could continue in the future.”

    See the full article here.

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    Symmetry is a joint Fermilab/SLAC publication.

  • richardmitnick 11:21 am on April 22, 2015 Permalink | Reply
    Tags: , FNAL ICARUS, Neutrinos,   

    From FNAL: “ICARUS neutrino experiment to move to Fermilab” 

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    Fermilab is an enduring source of strength for the US contribution to scientific research world wide.

    April 22, 2015

    Andre Salles, Fermilab Office of Communication, 630-840-3351, media@fnal.gov
    Vincenzo Napolano, INFN Communication Office, +39066868162, +393472994985, vincenzo.napolano@presid.infn.it, comunicazione@presid.infn.it
    CERN Press Office, +41227673432, +41227672141, press.office@cern.ch

    A view of the top of the ICARUS detector in place at INFN’s Gran Sasso National Laboratory in Italy. The 760-ton detector has been removed from Gran Sasso and shipped to CERN for upgrades, and will come to Fermilab in 2017 to become part of the laboratory’s short-baseline neutrino program. Photo: INFN.

    A group of scientists led by Nobel laureate Carlo Rubbia will transport the world’s largest liquid-argon neutrino detector across the Atlantic Ocean to its new home at the U.S. Department of Energy’s Fermi National Accelerator Laboratory.

    The 760-ton, 65-foot-long detector took data for the ICARUS experiment at the Italian Institute for Nuclear Physics’ (INFN) Gran Sasso National Laboratory in Italy from 2010 to 2014, using a beam of neutrinos sent through the Earth from CERN. The detector is now being refurbished at CERN, where it is the first beneficiary of a new test facility for neutrino detectors.

    INFN Gran Sasso ICARUS
    ICARUS at INFN Gran Sasso

    When it arrives at Fermilab, the detector will become part of an on-site suite of three experiments dedicated to studying neutrinos, ghostly particles that are all around us but have given up few of their secrets.

    All three detectors will be filled with liquid argon, which enables the use of state-of-the-art time projection technology, drawing charged particles created in neutrino interactions toward planes of fine wires that can capture a 3-D image of the tracks those particles leave. Each detector will contribute different yet complementary results to the hunt for a fourth type of neutrino.

    “The liquid-argon time projection chamber is a new and very promising technology that we originally developed in the ICARUS collaboration from an initial table-top experiment all the way to a large neutrino detector,” Rubbia said. “It is expected that it will become the leading technology for large liquid-argon detectors, with its ability to record ionizing tracks with millimeter precision.”

    Fermilab operates two powerful neutrino beams and is in the process of developing a third, making it the perfect place for the ICARUS detector to continue its scientific exploration. Scientists plan to transport the detector to the United States in 2017.

    A planned sequence of three liquid-argon detectors will provide new insights into the three known types of neutrinos and seek a yet unseen fourth type, following hints from other experiments over the past two decades.

    Many theories in particle physics predict the existence of a so-called “sterile” neutrino, which would behave differently from the three known types and, if it exists, could provide a route to understanding the mysterious dark matter that makes up 25 percent of the universe. Discovering this fourth type of neutrino would revolutionize physics, changing scientists’ picture of the universe and how it works.

    “The arrival of ICARUS and the construction of this on-site research program is a lofty goal in itself,” said Fermilab Director Nigel Lockyer. “But it is also the first step forward in Fermilab’s plan to host a truly international neutrino facility, with the help of our partners from around the world. The future of neutrino research in the United States is bright.”

    Fermilab’s proposed suite of experiments includes a new 260-ton Short Baseline Neutrino Detector (SBND), which will sit closest to the source of the particle beam. This detector is under construction by a team of scientists and engineers from universities and national laboratories in the United States and Europe.

    The neutrino beam will then encounter the already-completed 170-ton MicroBooNE detector, which will begin operation next year.

    FNAL MicroBooNE

    The final piece is the ICARUS detector, which will be housed in a new building to be constructed on site.

    Construction on the ICARUS and SBND buildings is scheduled to begin later this year, and the three experiments should all be operational by 2018. The three collaborations include scientists from 45 institutions in six countries.

    The move of the ICARUS detector is a sterling example of cooperation between countries (and between three scientific collaborations) to achieve a global physics goal. The current European strategy for particle physics, adopted by the CERN Council, recommends that Europe play an active part in neutrino experiments in other parts of the world, rather than carry them out at CERN.

    The U.S. particle physics community has adopted the P5 (Particle Physics Project Prioritization Panel) plan, which calls for a world-class long-distance neutrino facility to be built at Fermilab and operated by an international collaboration. Fermilab, CERN, INFN and many other international institutions are expected to partner in this endeavour.

    Knowledge gained by operating the suite of three liquid-argon experiments will be important in the development of the DUNE experiment at the planned long-distance facility at Fermilab. DUNE will be the largest neutrino oscillation experiment ever built, sending particles 800 miles from Fermilab to a 40,000-ton liquid-argon detector at the Sanford Underground Research Facility in South Dakota.

    Sanford Underground Research Facility Interior
    Sanford Underground Research Facility

    For more information, read this article from symmetry magazine.

    “The journey of ICARUS from Italy to CERN to the U.S. is a great example of the global planning in particle physics,” said CERN Director General Rolf Heuer. “U.S. participation in the LHC and European participation in Fermilab’s neutrino program are integral parts of both European and U.S. strategies. I am pleased that CERN has been able to provide the glue that is allowing DUNE to get off the ground with the transport of ICARUS.”

    “The ICARUS T600 is the only detector in the world with more than 600 tons of argon to have been successfully operated,” said INFN’s deputy president Antonio Masiero “ICARUS uses a high-precision, innovative technique to detect neutrinos artificially produced in an accelerator. This technique, developed at INFN and first successfully put into operation in the ICARUS experiment at the INFN’s Gran Sasso National Laboratory, will make in the new dedicated facility at Fermilab a fundamental contribution to neutrino research.”

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

    CERN, the European Organization for Nuclear Research, is the world’s leading laboratory for particle physics. It has its headquarters in Geneva. At present, its Member States are Austria, Belgium, Bulgaria, the Czech Republic, Denmark, Finland, France, Germany, Greece, Hungary, Israel, Italy, the Netherlands, Norway, Poland, Portugal, Slovakia, Spain, Sweden, Switzerland and the United Kingdom. Romania is a Candidate for Accession. Serbia is an Associate Member in the pre-stage to Membership. India, Japan, the Russian Federation, the United States of America, Turkey, the European Union, JINR and UNESCO have Observer Status.

    The Italian Institute for Nuclear Physics (INFN) manages and supports theoretical and experimental research in the fields of subnuclear, nuclear, astroparticle physics in Italy under the supervision of the Ministry of Education, Universities and Research (MIUR). INFN carries out research activities at four national laboratories, in Catania, Frascati, Legnaro and Gran Sasso and 20 divisions, based at university physics departments in different cities of Italy. http://www.infn.it

    See the full article here.

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    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.

  • richardmitnick 10:43 am on April 22, 2015 Permalink | Reply
    Tags: , , Neutrinos   

    From FNAL: “From the Neutrino Division – A collaborative platform for neutrino science” 

    FNAL Home

    Fermilab is an enduring source of strength for the US contribution to scientific research world wide.

    April 22, 2015
    Regina Rameika, head of the Neutrino Division, wrote this column.

    As the new Neutrino Division continues to define and refine its mission, we work to ensure that the activities across the laboratory related to the neutrino program are coherent and relevant to the laboratory’s strategic goals. To this end we have developed the Fermilab Neutrino Platform, which spans across laboratory organizations. Today I would like to highlight just a few of the areas where our colleagues outside of the Neutrino Division are playing key roles in the neutrino program.

    A key aspect of the Neutrino Platform is to deliver neutrino beams to neutrino detectors. Currently the Accelerator Division is delivering record-setting beam power to the NuMI beam, which provides neutrinos to the NOvA, MINERvA and MINOS+ experiments.

    FNAL NUMI Tunnel project




    In the near future, beam will be delivered to the Booster Neutrino Beamline for the MicroBooNE experiment.

    FNAL MicroBooNE

    The Neutrino Beam Group of the Neutrino Division works closely with the External Beams and High Power Targetry groups within the Accelerator Division. The design of the LBNF beamline for DUNE and improvements to the Booster Neutrino Beamline are currently high-priority items for these groups. The targetry group has also embarked on a dedicated R&D effort to more fully understand how high-energy beams affect potential target materials.


    Another important aspect of the Neutrino Platform is the support of test beams for detector development and calibration. The Particle Physics Division manages the Fermilab Test Beam Facility, where LArIAT, a liquid-argon detector, will use one of the facility’s test beams to characterize the response to charged particles in the energy range relevant to current and upcoming neutrino experiments. The MINERvA collaboration is using a different test beam to characterize their detector performance with beams being collected in medium-energy mode.

    Finally, software activities of the Neutrino Platform fall largely within the Scientific Computing Division. The artdaq framework, used for data acquisition in the current generation of neutrino experiments, is a key element of the support provided by scientific computing. Fermilab has also invested strongly in the GENIE neutrino generator and intends to extend that support in the future. And LArSoft, based on the artdaq framework, is designed for use in all analysis of data from liquid-argon-based neutrino experiments.

    These activities — just a few of many — demonstrate the wide range of strong support for neutrino science at Fermilab.

    See the full article here.

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    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.

  • richardmitnick 1:10 pm on April 9, 2015 Permalink | Reply
    Tags: , , , Neutrinos   

    From LBL: “For Ultra-cold Neutrino Experiment, a Successful Demonstration” 

    Berkeley Logo

    Berkeley Lab

    April 9, 2015
    Kate Greene

    Bottom view of a CUORE tower. Credit: CUORE Collaboration

    The CUORICINO Tower during the construction, before the installation of the copper shields. The 13 layers of TeO2 detectors are visible. Credit: CUORE Collaboration

    Today an international team of nuclear physicists announced the first scientific results from the Cryogenic Underground Observatory for Rare Events (CUORE) experiment. CUORE, located at the INFN Gran Sasso National Laboratories in Italy, is designed to confirm the existence of the Majorana neutrino, which scientists believe could hold the key to why there is an abundance of matter over antimatter. Or put another way: why we exist in this universe.

    The results of the experiment, called CUORE-0, were announced at INFN Gran Sasso Laboratories (LNGS) in Italy, the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab), and at other institutions in the US.

    The findings are twofold. First, the CUORE-0 results place some of the most sensitive constraints on the mass of the elusive Majorana neutrino to date. With these new constraints, the CUORE team is essentially shrinking the size of the haystack that hides the Majorana needle, making it much more likely to be found.

    Second, the experiment, successfully demonstrates the performance of CUORE’s novel design—a detector made of towers of Rubik’s cube-sized crystals of tellurium dioxide. These towers are placed in a high-tech refrigerator that has been painstakingly decontaminated, shielded from cosmic rays, and cooled to near absolute zero.

    Today’s results represent data collected over two years from just one tower of tellurium dioxide crystals. By the end of the year, all 19 towers, each containing 52 crystals, will be online, increasing CUORE’s sensitivity by a factor of 20.

    “CUORE-0 is so far the largest detector operating at a temperature very close to absolute zero,” says Dr. Oliviero Cremonesi of INFN-Milano Bicocca, spokesperson for the CUORE collaboration. “CUORE is presently in its final stages of construction, and when completed, it will study the nuclear processes associated with the Majorana neutrino with unprecedented sensitivity.”

    “With the CUORE-0 results, we’ve proven that our experimental design, materials, and processes, which include extremely clean surfaces, pure materials, and precision assembly, are paying off,” says Yury Kolomensky, senior faculty scientist in the Physics Division at Berkeley Lab, professor of physics at UC Berkeley, and U.S. spokesperson for the CUORE collaboration.

    Annihilations in the Early Universe

    To pin down the Majorana neutrino, the researchers are looking for a telltale indicator, a rare nuclear process called neutrinoless double-beta decay. This process is expected to occur infrequently, if at all: less than once every septillion (a trillion trillion, or, a 1 followed by 24 zeros) years per nucleus.

    Unlike regular double-beta decay, which emits two anti-neutrinos, neutrinoless double-beta decay emits no neutrinos at all. It’s as if one of the anti-neutrinos has transformed into a neutrino and cancelled—or annihilated—its sibling inside the nucleus.

    “In 1937, Ettore Majorana predicted that neutrinos and anti-neutrinos could be two manifestations of the same particle – in modern language, they are called Majorana particles,” says Reina Maruyama, assistant professor of physics at Yale University, and a member of the CUORE Physics Board, which guided the analysis of the data. “Detecting neutrinoless double-beta decay would lead us directly to the Majorana particle, and give us hints as to why the universe has so much more matter than antimatter.”

    Known laws of physics forbid such matter-antimatter transformations for normal electrically charged particles like electrons and protons. But neutrinos, which are electrically neutral, may be a special kind of matter with special capabilities.

    The proposed matter-antimatter transitions, while extraordinarily rare now, if they happen at all, may have been common in the universe just after the big bang. The remainder of existence, then, after all the annihilations, would be the matter-full universe we see today.

    Tower assembly. Credit: CUORE Collaboration

    Crystal Clarity

    The CUORE crystals of tellurium dioxide are packed with more than 50 septillion nuclei of tellurium-130, a naturally occurring isotope that can produce double-beta decay and possibly neutrinoless double-beta decay. For the experiment, the crystal towers sit in an extremely cold refrigerator called a cryostat that’s cooled to about 10 milliKelvin or -273.14 degrees Celsius. Last year, the CUORE cryostat set a record for being the coldest volume of its size.

    In the very cold CUORE crystals, presence of both nuclear processes would produce small but precisely measured temperature rises, observable by highly sensitive temperature detectors within the cryostat. These temperature increases correspond to spectra—essentially the amount of energy given off—from the nuclear event. Two-neutrino double-beta decay produces a broad spectrum. In contrast, neutrinoless double-beta decay would create a characteristic peak at the energy of 2528 kiloelectron-volts. This peak is what the researchers are looking for.

    The CUORE experiment sits about a kilometer beneath the tallest mountain of the Apennine range in Italy, where rock shields it from cosmic rays. This location, as well as the experimental design, enables the sensitivity required to detect neutrinoless double-beta decay.

    “The sensitivity demonstrated by the results today is outstanding,” says Stefano Ragazzi, director of the INFN Gran Sasso National Laboratories. “The INFN Gran Sasso Laboratories offers a worldwide unique environment to search for ultra-rare interactions of Majorana neutrinos and dark matter particles and is proud to host the most sensitive experiments in these fields of research.”

    “While there’s no direct evidence of the Majorana neutrino yet, our team is optimistic that CUORE is well positioned to find it,” says Ettore Fiorini, professor emeritus of physics at the University of Milano-Bicocca and founding spokesperson emeritus of the experiment. “There is a competition of sorts, with other experiments using complementary techniques to CUORE turning on at about the same time. The next few years will be tremendously exciting.”

    CUORE is supported jointly by the Italian National Institute for Nuclear Physics Istituto Nazionale di Fisica Nucleare (INFN) in Italy, and the Department of Energy’s Office of Science and the National Science Foundation in the US. The CUORE collaboration is made of 157 scientists from Italy, U.S., China, France, and Spain, and is based in the underground Italian facility called INFN Gran Sasso National Laboratories(LNGS) of the INFN.

    U.S. CUORE team was lead by late Prof. Stuart Freedman until his untimely passing in 2012. Other current and former Berkeley Lab members of the CUORE collaboration not previously mentioned include US Contractor Project Manager Sergio Zimmermann (Engineering Division), former US Contractor Project Manager Richard Kadel (Physics Division, retired), Prof. Eugene Haller (UCB and Materials Science Division), staff scientists Jeffrey Beeman (MSD), Brian Fujikawa (Nuclear Science Division), Sarah Morgan (Engineering), Alan Smith (EH&S), postdocs Jacob Feintzeig (NSD). Raul Hennings-Yeomans (UCB and NSD), Ke Han (NSD, now Yale), Yuan Mei (NSD), and Vivek Singh (UCB and NSD), graduate students Alexey Drobizhev and Sachi Wagaarachchi (UCB and NSD), and engineers David Biare, Lucio di Paolo (NSD and LNGS), and Joseph Wallig (Engineering). Researcher Thomas Banks, postdoc Thomas O’Donnell, graduate student Jonathan Ouellet, all at physics department at UC Berkeley and NSD, NSD staff member Brian Fujikawa, and a former NSD postdoc Ke Han (now at Yale) made especially significant contributions to the analysis of CUORE-0 data and preparation of the results for the publication.

    See the full article here.

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  • richardmitnick 3:36 pm on March 31, 2015 Permalink | Reply
    Tags: , , Neutrinos   

    From FNAL: “Director’s Corner – Welcome, DUNE” 

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    Fermilab is an enduring source of strength for the US contribution to scientific research world wide.

    Fermilab Director
    Nigel Lockyer

    Significant progress has been made on the new international neutrino collaboration. Last week, scientists from 148 institutions around the world chose DUNE (Deep Underground Neutrino Experiment) as the name of the experiment that will use the Long-Baseline Neutrino Facility (LBNF) neutrino beam. And, the group elected André Rubbia, ETH Zurich, and Mark Thomson, University of Cambridge, as the collaboration’s spokespeople. Congratulations to both André and Mark.

    The DUNE collaboration, which includes participation from Asia, Europe, and North and South America, represents a significant milestone in the implementation of P5 report recommendations. More than 700 scientists from 23 countries currently belong to the collaboration, and the group seeks further international partners to participate in this world-class experiment.

    From April 16 to 18, the first DUNE collaboration meeting will be held at Fermilab, when funding agencies and research institutions come together for the first time. In the meantime, much work is already in progress.

    The collaboration is assembling work groups that will tackle different tasks, with the goal of defining the final design for the first 10-kiloton underground detector in South Dakota.

    Sanford Underground levels
    Sanford Underground Research Facility Interior
    Sanford Underground Research Facility

    CERN will build two large prototype detectors to advance the engineering aspects of liquid-argon technology. Here at Fermilab, DUNE scientists will soon be able to take data with a smaller, 35-ton liquid-argon prototype detector. In July, funding agencies will review the updated project plans for LBNF/DUNE.

    At the same time, we are working with the Department of Energy to advance cavern excavation plans for the detector in South Dakota. This spring, DOE will release its draft environmental assessment of LBNF and hold public meetings at Fermilab and in South Dakota. In addition, discussions are happening with other funding agencies about how they can benefit from the neutrino program at Fermilab and contribute to the construction of the DUNE detectors.

    Thank you to the all the individuals and organizations who have helped us get to this point. There is still much work to be done, but we have made excellent progress on the world’s most ambitious neutrino experiment.

    See the full article here.

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    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.

  • richardmitnick 3:35 pm on March 25, 2015 Permalink | Reply
    Tags: , , , Neutrinos   

    From DESY: “Latest result from neutrino observatory IceCube opens up new possibilities for particle physics” 


    No Writer Credit

    South Pole detector measures neutrino oscillations with high precision

    The South Pole observatory IceCube has recorded evidence that elusive elementary particles called neutrinos changing their identity as they travel through the Earth and its atmosphere.

    The IceCube laboratory at the Scott Amundsen South Pole station hosts the computers collecting the detector data (picture: Felipe Pedreros. IceCube/NSF)

    IceCube neutrino detector interior
    IceCube Neutrino Experiment interior

    The observation of these neutrino oscillations, first announced in 1998 by the Super Kamiokande experiment in Japan, opens up new possibilities for particle physics with the Antarctic telescope that was originally designed to detect neutrinos from faraway sources in the cosmos.

    Super-Kamiokande experiment Japan
    Super Kamiokande experiment

    “We are very pleased that the IceCube detector with its DeepCore array can be used to observe neutrino oscillations with high precision,” says Olga Botner, Spokesperson of the IceCube experiment. “DeepCore was designed on the initiative of Per Olof Hulth who sadly passed away recently, to significantly lower IceCube’s energy threshold. The results show that IceCube can contribute to nailing down the oscillation parameters and motivate us to pursue our plans for an IceCube upgrade called PINGU to measure neutrino properties.”

    IceCube DeepCore
    IceCube DeepCore

    IceCube PINGU
    IceCube PINGU

    “IceCube records over one hundred thousand atmospheric neutrinos every year, most of them muon neutrinos produced by the interaction of fast cosmic particles with the atmosphere,” says Rolf Nahnhauer, leading scientist at DESY. The subdetector DeepCore allows for detecting neutrinos with energies down to 10 giga-electronvolts (GeV). “According to our understanding of neutrino oscillations, IceCube should see fewer muon neutrinos at energies around 25 GeV that reach IceCube after crossing the entire Earth,” explains Rolf Nahnhauer. “The reason for these missing muon neutrinos is that they oscillate into other types.” IceCube researchers selected Northern Hemisphere muon neutrino candidates with energies between a few GeV and around 50 GeV from data taken between May 2011 and April 2014. About 5200 events were found, much below the 7000 expected in the non-oscillations scenario.

    Neutrinos remain the most mysterious of the known elementary particles. Postulated by Austrian physicist Wolfgang Pauli in 1930, it took 25 years for their experimental detection. “Neutrinos are elusive,” says Olga Botner, ” and can travel through an enormous amount of material, even the whole Earth, without interacting.” Nevertheless, physicists have built more and more sophisticated instruments to reveal the mysteries of this very light particles. One of the surprising results was that the three different types of neutrinos, electron, muon and tau neutrinos, can change their identity, transforming from one type of neutrino to another. This phenomenon is known as neutrino oscillation. “Neutrino oscillations are only possible if neutrinos have a mass,” explains Nahnhauer. “On the other hand, massive neutrinos are not explained within the otherwise so successful Standard Model of particle physics.”

    Standard Model of Particle Physics. The diagram shows the elementary particles of the Standard Model (the Higgs boson, the three generations of quarks and leptons, and the gauge bosons), including their names, masses, spins, charges, chiralities, and interactions with the strong, weak and electromagnetic forces. It also depicts the crucial role of the Higgs boson in electroweak symmetry breaking, and shows how the properties of the various particles differ in the (high-energy) symmetric phase (top) and the (low-energy) broken-symmetry phase (bottom).

    The strength of the oscillation and the distances over which it develops depend on two parameters: the so-called mixing angle and the mass difference. The values of these parameters have been constrained by precise measurements of neutrinos from the sun, the atmosphere, nuclear reactors, and particle accelerators.

    The IceCube neutrino observatory at the South Pole has already demonstrated that it is a powerful tool to explore the universe by neutrinos, using the Antarctic ice sheet as its detection material. An array of more than 5000 optical sensors distributed in a cubic kilometer of the ice records the very rare collisions of neutrinos. And less than two years ago, IceCube physicists announced the discovery of the first high-energy neutrinos from the cosmos, acknowledged as “breakthrough of the year” by the journal Physics World.

    Now IceCube has proven that it can also deliver top particle physics results. The new measurement by the IceCube collaboration resulting in significantly improved constraints on the neutrino oscillation parameters has been accepted for publication by the scientific journal Physical Review D.

    Three years of IceCube data yielded a similar precision to that reached from about 15 years of Super-Kamiokande data. In contrast to the purified water in Super-Kamiokande’s 50-kiloton vessel, IceCube uses a natural target material, the glacier ice at the South Pole. IceCube’s 500 times larger observation volume produces larger event statistics in shorter times. “Both Super-Kamiokande and IceCube use the same ‘beam‘ which is atmospheric neutrinos, but at different energies. And we reach similar precision of the measurable oscillation parameters,” says Juan Pablo Yanez, postdoctoral researcher at DESY, who is the corresponding author of the paper. “The results now derived from IceCube data show errors still larger than, but already comparable to the most precise neutrino beam experiments MINOS and T2K. But as IceCube keeps taking data and improving the analyses we are hopeful to catch up soon.” adds Yanez.

    Currently the scientists are planning an upgrade of the IceCube detector called PINGU (Precision IceCube Next Generation Upgrade). A much higher density of optical modules in the whole central region will improve the sensitivity to several fundamental questions associated with neutrinos.

    “In particular we want to measure the so called neutrino mass hierarchy – whether there are two heavier neutrinos and one light one, or whether it is the other way around.” explains Rolf Nahnhauer. “This is important to understand how neutrinos obtain masses, but also has significant relevance on how the cosmos evolves. The current results provide an important experimental confirmation that our concepts work.“

    See the full article here.

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

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