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  • richardmitnick 3:57 pm on June 4, 2018 Permalink | Reply
    Tags: , FNAL MiniBooNE, , , ,   

    From physicsworld.com: “Evidence for sterile neutrinos claimed by Fermilab experiment” 

    physicsworld
    From physicsworld.com

    04 Jun 2018
    Edwin Cartlidge

    Physicists working on the Mini Booster Neutrino Experiment (MiniBooNE) at Fermilab in the US have released new results that they argue provide strong evidence for the existence of a new type of particle known as a sterile neutrino. The researchers say that their data are fully consistent with a previous hint of sterile neutrinos that emerged more than 20 years ago from the Liquid Scintillator Neutrino Detector (LSND) at the Los Alamos National Laboratory in New Mexico, although other groups have failed to reproduce the findings.

    FNAL/MiniBooNE

    Sterile neutrinos, if they exist, would be even more elusive than standard neutrinos, which themselves are chargeless and nearly massless. The Standard Model of particle physics tells us that neutrinos come in three flavours – electron, muon and tau – and that they “oscillate” from one flavour to another as they travel through space. But some extensions of the Standard Model predict that these known neutrinos can also oscillate into and out of sterile neutrinos, which might not interact at all with any other ordinary matter.

    MiniBooNE monitors the tiny flashes of light that are produced occasionally when electron neutrinos interact with atomic nuclei in about 800 tonnes of pure mineral oil contained in a spherical tank located underground on the Fermilab site near Chicago.

    MiniBooNE receptors

    Those neutrinos are generated after protons from the lab’s Booster accelerator are fired into a beryllium target to create muon neutrinos, which then oscillate to electron neutrinos as they travel several hundred metres through the Earth to the detector.

    Statistically speaking

    In a preprint uploaded recently to the arXiv server, the MiniBooNE collaboration reports having detected far more electron neutrinos than would be expected from purely Standard Model oscillations after collecting data for 15 years. According to collaboration member William Louis of Los Alamos, the measurement suggests that some of the muon neutrinos oscillate into sterile neutrinos that in turn transform into electron neutrinos. That interpretation, he says, is bolstered by the fact that the variation of electron-neutrino excess with neutrino energy – a parameter of neutrino oscillations – seen in MiniBooNE matches that recorded at Liquid Scintillator Neutrino Detector. He and his colleagues conclude that the combined excess from the two experiments has a statistical significance of 6.1σ, which is well above the 5σ that is normally considered a discovery in particle physics.

    Although MiniBooNE is quite similar to LSND – in using mineral oil to observe neutrinos from an accelerator-based source – and indeed has inherited personnel from the earlier project, its researchers are nevertheless confident that there are no common sources of error. “We think that is very unlikely,” says Louis. “The two experiments have very different energies and backgrounds, and therefore very different possible systematic errors”.

    Not a done deal

    However, the existence of sterile neutrinos is not yet a done deal. While some groups operating experiments that exploit neutrinos from nuclear reactors or radioactive sources have also gathered (somewhat weaker) evidence for the hypothetical particles, other groups have looked and found nothing. These include the IceCube collaboration, which operates a detector at the South Pole, and the now completed Main Injector Neutrino Oscillation Search (MINOS) at Fermilab.

    U Wisconsin ICECUBE neutrino detector at the South Pole

    U Wisconsin ICECUBE neutrino detector at the South Pole

    Lunar Icecube

    IceCube DeepCore annotated

    IceCube PINGU annotated


    DM-Ice II at IceCube annotated

    FNAL MINOS experiment

    FNAL Minos map

    FNAL MINOS near detector

    FNAL MINOS Far Detector in the Soudan Mine in northern Minnesota

    Indeed, some physicists outside the MiniBooNE collaboration have told Physics World that they remain unconvinced by the latest results.

    To try and settle the issue, numerous other dedicated experiments are either operating or under development. For their part, Louis and colleagues are currently setting up another three detectors at Fermilab – one of which is now running – to monitor the neutrino flux closer to the beryllium target than MiniBooNE and also further away. The idea, he says, is to show beyond doubt that the electron neutrino excess really is due to oscillations, given that the measured oscillation rate should vary with distance from the source as well as with energy. Results are expected “over the next three to five years,” he says.

    See the full article here .


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  • richardmitnick 2:32 pm on April 9, 2018 Permalink | Reply
    Tags: , FNAL MiniBooNE, Muon neutrinos,   

    From FNAL: “Neutrino experiment at Fermilab delivers an unprecedented measurement” 

    FNAL II photo

    FNAL Art Image
    FNAL Art Image by Angela Gonzales

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

    measurement

    April 6, 2018
    Kurt Riesselmann

    1
    This interior view of the MiniBooNE detector tank shows the array of photodetectors used to pick up the light particles that are created when a neutrino interacts with a nucleus inside the tank. Photo: Reidar Hahn

    FNAL/MiniBooNE

    MiniBooNE scientists demonstrate a new way to probe the nucleus with muon neutrinos.

    Tiny particles known as neutrinos are an excellent tool to study the inner workings of atomic nuclei. Unlike electrons or protons, neutrinos have no electric charge, and they interact with an atom’s core only via the weak nuclear force. This makes them a unique tool for probing the building blocks of matter. But the challenge is that neutrinos are hard to produce and detect, and it is very difficult to determine the energy that a neutrino has when it hits an atom.

    This week a group of scientists working on the MiniBooNE experiment at the Department of Energy’s Fermilab reported a breakthrough: They were able to identify exactly-known-energy muon neutrinos hitting the atoms at the heart of their particle detector. The result eliminates a major source of uncertainty when testing theoretical models of neutrino interactions and neutrino oscillations.

    “The issue of neutrino energy is so important,” said Joshua Spitz, Norman M. Leff assistant professor at the University of Michigan and co-leader of the team that made the discovery, along with Joseph Grange at Argonne National Laboratory. “It is extraordinarily rare to know the energy of a neutrino and how much energy it transfers to the target atom. For neutrino-based studies of nuclei, this is the first time it has been achieved.”

    To learn more about nuclei, physicists shoot particles at atoms and measure how they collide and scatter. If the energy of a particle is sufficiently large, a nucleus hit by the particle can break apart and reveal information about the subatomic forces that bind the nucleus together.

    But to get the most accurate measurements, scientists need to know the exact energy of the particle breaking up the atom. That, however, is almost never possible when doing experiments with neutrinos.

    Like other muon neutrino experiments, MiniBooNE uses a beam that comprises muon neutrinos with a range of energies. Since neutrinos have no electric charge, scientists have no “filter” that allows them to select neutrinos with a specific energy.

    MiniBooNE scientists, however, came up with a clever way to identify the energy of a subset of the muon neutrinos hitting their detector. They realized that their experiment receives some muon neutrinos that have the exact energy of 236 million electronvolts (MeV). These neutrinos stem from the decay of kaons at rest about 86 meters from the MiniBooNE detector emerging from the aluminum core of the particle absorber of the NuMI beamline, which was built for other experiments at Fermilab.

    Energetic kaons decay into muon neutrinos with a range of energies. The trick is to identify muon neutrinos that emerge from the decay of kaons at rest. Conservation of energy and momentum then require that all muon neutrinos emerging from the kaon-at-rest decay have to have exactly the energy of 236 MeV.

    “It is not often in neutrino physics that you know the energy of the incoming neutrino,” said MiniBooNE co-spokesperson Richard Van De Water of Los Alamos National Laboratory. “With the first observation by MiniBooNE of monoenergetic muon neutrinos from kaon decay, we can study the charged current interactions with a known probe that enable theorists to improve their cross section models. This is important work for the future short- and long-baseline neutrino programs at Fermilab.”

    This analysis was conducted with data collected from 2009 to 2011.

    “The result is notable,” said Rex Tayloe, co-spokesperson of the MiniBooNE collaboration and professor of physics at Indiana University Bloomington. “We were able to extract this result because of the well-understood MiniBooNE detector and our previous careful studies of neutrino interactions over 15 years of data collection.”

    Spitz and his colleagues already are working on the next monoenergetic neutrino result. A second neutrino detector located near MiniBooNE, called MicroBooNE, also receives muon neutrinos from the NuMI absorber, 102 meters away. Since MicroBooNE uses liquid-argon technology to record neutrino interactions, Spitz is optimistic that the MicroBooNE data will provide even more information.

    “MicroBooNE will provide more precise measurements of this known-energy neutrino,” he said. “The results will be extremely valuable for future neutrino oscillation experiments.”

    The MiniBooNE result was published in the April 6, 2018, issue of Physical Review Letters. This research was supported by the U.S. Department of Energy Office of Science.

    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.


    FNAL/MINERvA

    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

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    FNAL Holometer

     
  • richardmitnick 1:52 pm on May 3, 2016 Permalink | Reply
    Tags: , FNAL MiniBooNE,   

    From FNAL: “Preparing for the sterile neutrino search: Fermilab breaks ground on Short-Baseline Near Detector building” 

    FNAL II photo

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

    May 3, 2016
    Rashmi Shivni

    1
    Fermilab broke ground on the Short-Baseline Neutrino Detector building on April 27. From left: Josh Kenney, FESS; Steve Dixon, AD; David Schmitz, University of Chicago; Ting Miao, ND; Ornella Palamara, ND; Peter Wilson, ND; Catherine James, ND. Photo: Reidar Hahn

    FNAL Short-Baseline Near Detector
    FNAL Short-Baseline Near Detector

    On April 27, Fermilab broke ground on the building that will house the future Short-Baseline Near Detector.

    The particle detector, SBND, is one of three that, together, scientists will use to search for the sterile neutrino, a hypothesized particle whose existence, if confirmed, could not only help us better understand the types of neutrino we already know about, but also provide clues about how the universe formed.

    Members of the Fermilab Neutrino and Particle Physics divisions, working together with international collaborators, are currently refining the design of the detector itself. It will take about eight months to complete the SBND building.

    The three detectors make up the laboratory’s Short-Baseline Neutrino Program, which will use a powerful neutrino beam generated by the Fermilab accelerator complex. The beam will pass first through SBND and then through the MicroBooNE detector, which is already installed and taking data, having observed its first neutrino interactions in October. Finally, the beam will travel through ICARUS, the largest of the three detectors. ICARUS, which was used in a previous experiment at the Italian Gran Sasso laboratory, is currently at the CERN laboratory in Switzerland receiving upgrades before its big move to Fermilab in 2017.

    FNAL/Microboone
    FNAL/MicrobooNE

    FNAL/ICARUS
    FNAL/ICARUS

    INFN Gran Sasso ICARUS
    INFN Gran Sasso ICARUS, previous home of ICARUS

    “The entire Short-Baseline Neutrino Program is looking for oscillations, or the transformations, of muon neutrinos into electron neutrinos,” said Peter Wilson, SBN program coordinator. “Sterile neutrinos might have a role in this oscillation process.”

    The beam coming out of the accelerator comprises primarily muon neutrinos; the detectors will measure their transformation into electron neutrinos.

    All three detectors have specific functions in detecting the transformation. As the detector closest to the beam source, SBND will take an initial measurement of the beam’s composition – how much the beam contains each of the different neutrino types.

    “The intermediary and far detectors are used to search for sterile neutrinos in two different ways,” said Ornella Palamara, co-spokesperson for the SBND experiment. “Either there’s an appearance of an excess of electron neutrinos or there’s a disappearance of the number of muon neutrinos compared to the number we start with.”

    If there are more electron neutrinos than predicted, then muon neutrinos may have oscillated first into sterile neutrinos and then to electron neutrinos. If the data show a smaller number of muon neutrinos than predicted, the muon neutrinos may have transformed only into sterile neutrinos, which cannot be seen in the far detectors.

    Scientists first picked up on experimental hints of a sterile neutrino at Los Alamos National Laboratory’s LSND experiment in 1995. When the Fermilab experiment MiniBooNE followed up, scientists could not confirm the sterile neutrino’s existence, but neither could they rule it out.

    “That’s the power of this program,” Palamara said. “We’re building off previous measurements, but we have more sensitive tools to measure the neutrinos.”

    Part of the sensitivity of SBND lies in its liquid-argon time projection chamber, the active part of the detector, which will contain 112 tons of liquid argon. Neutrinos will interact with the nuclei of the argon atoms, and scientists on SBND will study the resulting particles to better understand the neutrinos that caused the interaction. Their findings will likely have application in future accelerator-based neutrino programs, such as the international Deep Underground Neutrino Experiment hosted by Fermilab.

    The Short-Baseline Neutrino Program will begin taking data in 2018.

    “The SBND groundbreaking is a noteworthy milestone, but it’s part of a much larger program,” Wilson said. “Many people are working on it, and everyone is excited to get the chance to understand new physics.”

    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
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  • richardmitnick 4:42 pm on August 12, 2015 Permalink | Reply
    Tags: , FNAL MiniBooNE, ,   

    From FNAL: “MicroBooNE sees first cosmic muons” 

    FNAL II photo

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

    Aug. 12, 2015
    Ali Sundermier

    1
    This image shows the first cosmic ray event recorded in the MicroBooNE TPC on Aug. 6. Image: MicroBooNE

    A school bus-sized detector packed with 170 tons of liquid argon has seen its first particle footprints.

    On Aug. 6, MicroBooNE , a liquid-argon time projection chamber, or LArTPC, recorded images of the tracks of cosmic muons, particles that shower down on Earth when cosmic rays collide with nuclei in our atmosphere.

    Temp 1
    MicroBooNE

    “This is the first detector of this size and scale we’ve ever launched in the U.S. for use in a neutrino beam, so it’s a very important milestone for the future of neutrino physics,” said Sam Zeller, co-spokesperson for the MicroBooNE collaboration.

    Picking up cosmic muons is just one brief stop during MicroBooNE’s expedition into particle physics. The centerpiece of the three detectors planned for Fermilab’s Short-Baseline Neutrino program, or SBN, MicroBooNE will pursue the much more elusive neutrino, taking data about this weakly interacting particle for about three years. When beam starts up in October, it will travel 470 meters and then traverse the liquid argon in MicroBooNE, where neutrino interactions will result in tracks that the detector can convert into precise three-dimensional images. Scientists will use these images to investigate anomalies seen in an earlier experiment called MiniBooNE, with the aim to determine whether the excess of low-energy events that MiniBooNE saw was due to a new source of background photons or if there could be additional types of neutrinos beyond the three established flavors.

    One of MicroBooNE’s goals is to measure how often a neutrino that interacts with an argon atom will produce certain types of particles. A second goal is to conduct R&D for future large-scale LArTPCs. MicroBooNE will carry signals up to two and a half meters across the detector, the longest drift ever for a LArTPC in a neutrino beam. This requires a very high voltage and very pure liquid argon. It is also the first time a detector will operate with its electronics submerged in liquid argon on such a large scale. All of these characteristics will be important for future experiments such as the Deep Underground Neutrino Experiment, or DUNE, which plans to use similar technology to probe neutrinos.

    “The entire particle physics community worldwide has identified neutrino physics as one of the key lines of research that could help us understand better how to go beyond what we know now,” said Matt Toups, run coordinator and co-commissioner for MicroBooNE with Fermilab Scientist Bruce Baller. “Those questions that are driving the field, we hope to answer with a very large LArTPC detector.”

    Another benefit of the experiment, Zeller said, is training the next generation of LArTPC experts for future programs and experiments. MicroBooNE is a collaborative effort of 25 institutions, with 55 students and postdocs working tirelessly to perfect the technology. Collaborators are keeping their eyes on the road toward the future of neutrino physics and liquid-argon technology.

    “It’s been a long haul,” said Bonnie Fleming, MicroBooNE co-spokesperson. “Eight and a half years ago liquid argon was a total underdog. I used to joke that no one would sit next to me at the lunch table. And it’s a world of difference now. The field has chosen liquid argon as its future technology, and all eyes are on us to see if our detector will work.”

    See the full article here.

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  • richardmitnick 12:45 pm on October 9, 2014 Permalink | Reply
    Tags: , FNAL MiniBooNE,   

    From FNAL: “Physics in a Nutshell – Neutrinos meet liquid argon” 


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

    Thursday, Oct. 9, 2014
    Tia Miceli

    Fermilab’s flagship effort is its neutrino program, which is ramping up to be the strongest in the world. This means creating the world’s best neutrino detectors. To that end, scientists at Fermilab are pursuing one hot technology that is lighting up neutrino physics, detection based on cryogenic liquid argon.

    tube
    Like neon, argon is used to make colorful lighted signs. Particle physicists are now putting argon to a far more exciting use: detecting neutrinos. Image: P Slawinski

    At first, argon seems to be a pretty boring element. As a noble gas, it does not react chemically. Making up one percent of our atmosphere, it is its third most common component, surpassed only by nitrogen and oxygen. But don’t let its mundane properties fool you. When we cool it down to extremely cold temperatures, it turns into a liquid with incredible properties for cutting-edge neutrino detectors.

    For particle physics, perhaps liquid argon’s most important feature is that it acts as both a target and detector for neutrinos, although it isn’t the only material that can be used this way. The Super-Kamiokande experiment in Japan used water stored in a deep-underground tank as large as Wilson Hall to detect neutrinos. Here at Fermilab, the MiniBooNE experiment used a giant sphere of oil that operated much the same way as Super-Kamiokande’s tank.

    sk
    Super-Kamiokande experiment

    mb
    The MiniBooNE experiment records a neutrino event, in this 2002 image from Fermilab. The ring of light, registered by some of more than one thousand light sensors inside the detector, indicates the collision of a muon neutrino with an atomic nuclei. Credit: Fermilab

    But with 40 protons and neutrons, liquid argon is denser than water or oil, so liquid-argon detectors see more neutrino collisions per unit volume than their oil- or water-based predecessors. That means faster measurements and consequently faster discoveries.

    Another advantage of liquid argon is that, when a neutrino interacts with it and subsequently generates charged particles, it produces two separate kinds of signals; oil- or water-based detectors produce only one. One type of signal, unique to liquid argon, results from its ability to record the charged particles’ trajectories.

    Charged particles are created in the liquid argon after a neutrino flies in and collides with an argon nucleus. The charged debris travels through the argon and easily knocks off electrons from the neighboring atoms along its path. The electronic traces in the liquid argon are pushed by an applied electric field toward an array of wires (similar to a guitar’s) on the side of the detector. The wires collect data on the particle trajectories, producing a signal.

    The second signal type is one shared with oil- and water-based detection: a flash of light. When a charged particle bumps into an argon atom’s electron, the electron transitions to a higher energy. As the electron transitions back to its original state, the excess energy is emitted as light.

    It turns out that argon is also relatively cheap. Companies liquefy air and heat it slowly. Since each of air’s components has a unique boiling temperature, they can be separated. The boiled-off argon is moved to a separate chamber where it is again condensed. The commercially available liquid argon that we buy is still not pure enough for our experiments, so once the liquid argon arrives at the lab, we filter out the remaining impurities by a factor of 10,000.

    Using a common and innocuous gas, Fermilab is establishing itself to be the world’s premier neutrino physics research center. Stay tuned to discover what secrets this technology will unlock!

    See the full article here.

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  • richardmitnick 10:43 am on June 4, 2014 Permalink | Reply
    Tags: , , FNAL MiniBooNE, , ,   

    From Symmetry: “MINOS result narrows field for sterile neutrinos” 

    Symmetry

    June 04, 2014
    Andre Salles

    If you’re searching for something that may not exist, and can pass right through matter if it does, then knowing where to look is essential.

    That’s why the search for so-called sterile neutrinos is a process of elimination. Experiments like Fermilab’s MiniBooNE and the Liquid Scintillator Neutrino Detector (LSND) at Los Alamos National Laboratory have published results consistent with the existence of these theoretical particles. But a new result from the long-running MINOS experiment announced this week severely limits the area in which they could be found and casts more doubt on whether they exist at all.

    no
    Photo by Reidar Hahn, Fermilab

    Scientists have observed three types or “flavors” of neutrinos—muon, electron and tau neutrinos—through their interactions with matter. If there are other types, as some scientists have theorized, they do not interact with matter, and the search for them has become one of the hottest and most contentious topics in neutrino physics. MINOS, located at Fermilab with a far detector in northern Minnesota, has been studying neutrinos since 2005, with an eye toward collecting data on neutrino oscillation over long distances.

    MINOS uses a beam of muon neutrinos generated at Fermilab. As that beam travels 500 miles through the earth to Minnesota, those muon neutrinos can change into other flavors.

    MINOS looks at two types of neutrino interactions: neutral current and charged current. Since MINOS can see the neutral current interactions of all three known flavors of neutrino, scientists can tell if fewer of those interactions occur than they should, which would be evidence that the muon neutrinos have changed into a particle that does not interact. In addition, through charged current interactions, MINOS looks specifically at muon neutrino disappearance, which allows for a much more precise measurement of neutrino energies, according to João Coelho of Tufts University.

    “Disappearance with an energy profile not described by the standard three-neutrino model would be evidence for the existence of an additional sterile neutrino,” Coelho says.

    The new MINOS result, announced today at the Neutrino 2014 conference in Boston, excludes a large and previously unexplored region for sterile neutrinos. To directly compare the new results with previous results from LSND and MiniBooNE, MINOS combined its data with previous measurements of electron antineutrinos from the Bugey nuclear reactor in France. The combined result, says Justin Evans of the University of Manchester, “provides a strong constraint on the existence of sterile neutrinos.”

    “The case for sterile neutrinos is still not closed,” Evans says, “but there is now a lot less space left for them to hide.”

    graph
    The vertical axis shows the possible mass regions for the sterile neutrinos. The horizontal axis shows how likely it is that a muon neutrino will turn into a sterile neutrino as it travels. The new MINOS result excludes everything to the right of the black line. The colored areas show limits by previous experiments. Courtesy of: MINOS collaboration

    See the full article here.

    Symmetry is a joint Fermilab/SLAC publication.



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  • richardmitnick 2:58 pm on February 7, 2014 Permalink | Reply
    Tags: , , , FNAL MiniBooNE   

    From Fermilab- “Frontier Science Result: MINERvA What happens in hydrocarbon stays in hydrocarbon (sometimes)” 


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

    Friday, Feb. 7, 2014
    Carrie McGivern, University of Pittsburgh

    When a neutrino enters the nucleus of an atom, it can interact with the protons and neutrons inside and impart enough energy to create completely new particles. Often a pion (a particle made of a quark and an antiquark) is produced. However, the nucleus is such a dense place that sometimes the pions never make it out of the atom!

    Figuring out how many pions are produced and how many exit the nucleus is very important in the field of neutrino physics because it determines how well the energy of the incoming neutrino can be measured. Experiments such as LBNE will measure how neutrinos oscillate as a function of neutrino energy, but they will need to understand what those pions are doing in order to get the neutrino energies right.

    Particle physicists have been measuring pions and constructing models of how they interact for a long time, but the neutrino interactions that produce these pions and what happens to them as they exit the nucleus is not nearly as well modeled. The interactions felt by the pions on their way out of the nucleus are called final-state interactions, and they are difficult to calculate because there are so many moving parts — all the protons and neutrons in the nucleus. We do have a few models, but it is important to verify them with experimental data from neutrino experiments. When the MiniBooNE measurement of pion production was first released, it was clear that the most complete models of what happens inside the nucleus were not describing the data. MINERvA now has a sample of several thousand events where a pion, proton and muon are produced when a neutrino interacts with a neutron or proton in the detector’s plastic scintillator, which is made of hydrocarbons (see top figure).

    graph
    This shows what an event in the MINERvA detector looks like when a neutrino comes in from the left and interacts with a proton in the detector, creating a pion that goes backwards, in addition to a proton and a muon.

    By studying the energy distribution of the pions that make it out of the nucleus, MINERvA can determine how big an effect the nucleus has on those pions. The better we understand (and then model) that effect, the better the whole field will be able to measure neutrino energies.

    See the full article here.

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  • richardmitnick 4:13 pm on December 11, 2013 Permalink | Reply
    Tags: , , FNAL MiniBooNE, , , ,   

    From Fermilab: “MicroBooNE, in 3-D” 


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

    Wednesday, Dec. 11, 2013
    Andre Salles

    Imagine your job is to analyze the data coming from Fermilab’s MicroBooNE experiment.

    It wouldn’t be an easy task. MicroBooNE has been designed specifically to follow up on the MiniBooNE experiment, which may have seen hints of a fourth type of neutrino, one that does not interact with matter in the same way as the three types we know about. The big clue to the possible existence of these particles is low-energy electrons.

    But that experiment could not adequately separate the production of electrons from the production of photons, which would not indicate a new particle. MicroBooNE’s detector, an 89-ton active volume liquid-argon time projection chamber, will be able to. To take advantage of this, every neutrino interaction in the chamber will have to be examined to determine if it created an electron or a photon.

    And there will be a lot of interactions to study — the MicroBooNE collaboration expects to see activity in their detector once every 20 seconds, including nearly 150 neutrino interactions each day.

    If all goes to plan, human operators won’t have to worry about any of that. When MicroBooNE switches on next summer, it will sport one of the most sophisticated 3-D reconstruction software programs ever designed for a neutrino experiment.

    According to Wesley Ketchum and Tingjun Yang, two postdocs leading the software development team at Fermilab, MicroBooNE’s computers will be able to accurately reconstruct neutrino interactions and automatically filter the ones that create electrons. The key to accomplishing this lies in the design of the time projection chamber.

    two
    Tingjun Yang (left) and Wesley Ketchum lead the effort to develop new 3-D reconstruction software for the MicroBooNE experiment. Here they stand inside the MicroBooNE time projection chamber. Photo: Reidar Hahn

    The MicroBooNE detector — the largest time projection chamber in the United States — will be filled with heavy liquid argon and placed in the path of the Booster’s neutrino beam. When neutrinos interact with the argon, they create charged particles that ionize the argon atoms. A high-voltage electric field will draw those ionization electrons toward three planes of wires, spaced three millimeters apart. As they pass through, each plane of wires will take a snapshot of the electrons. Taken together, the snapshots will form a full picture of the original particles.

    “Three planes of wires at different angles will provide a picture of the neutrino interaction in 3-D,” Ketchum said. “We only need two, but the third helps us get rid of ambiguity.”

    The software should be able to provide clear pictures of the data scientists are interested in studying.

    See the full article here [Sorry, the usually dependably archive link is not working. Go to the archive for today, Wednesday, Dec. 11, 2013]
    .

    Fermilab Campus

    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.


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  • richardmitnick 11:01 am on August 22, 2013 Permalink | Reply
    Tags: , , FNAL MiniBooNE, ,   

    From Fermilab: “Tracking particles with LArIAT” 

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

    Thursday, Aug. 22, 2013
    Laura Dattaro

    “A neutrino is a tricky thing: It rarely interacts with other particles, and it doesn’t leave a track as it enters a detector. But a relatively new technology, called a liquid-argon time projection chamber, is helping scientists to understand them. MicroBooNE, the second phase of the Booster Neutrino Experiment, is one example of a LArTPC, and in order to help it do its job, scientists are first building a test detector called LArIAT—essentially a mini MicroBooNE.

    micro
    Microboone Detector

    mini
    Miniboone

    LArIAT—Liquid-Argon TPC In A Test beam—is a small version of MicroBooNE, with a capacity for about three-quarters of a ton of liquid argon instead of MicroBooNE’s 170 tons. Its aim is to study particle tracks to better understand how different types of particles – in particular electrons and photons—interact in liquid argon, and how these interactions appear in the collected data.

    ‘Understanding what a proton track looks like in comparison to a pion track or a kaon track is one of the goals of LArIAT,’ said Jennifer Raaf, a spokesperson for the experiment.”

    See the full article here.

    Fermilab campus

    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.


    ScienceSprings is powered by MAINGEAR computers

     
  • richardmitnick 11:04 am on March 29, 2013 Permalink | Reply
    Tags: , , FNAL MiniBooNE,   

    From Fermilab- “Frontier Science Result: MiniBooNE Stealthier than a neutrino” 

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

    Friday, March 29, 2013
    Zarko Pavlovic

    “The search for sterile neutrinos has reached a new milestone. After collecting data for the past decade in both neutrino and antineutrino modes, the MiniBooNE experiment reports in a paper accepted for publication in Physical Review Letters an excess of events that suggests there may be additional neutrinos to the known three. MiniBooNE observed a combined excess of these events with 3.8 sigma significance.

    mast

    graph
    MiniBooNE observes excesses of 78.4 ±20.0 (stat) ±20.3 (syst) and 162.0 ±28.1 (stat) ±38.7 (syst) candidate electron neutrino events in antineutrino (top) and neutrino (bottom) modes, respectively. Here they are given as a function of reconstructed neutrino energy. No credit.

    It took 25 years to observe the electron neutrino after it was predicted to exist, so it is not surprising that it could take even longer to observe the proposed sterile partners of neutrinos. A sterile neutrino, unlike the neutrinos of the Standard Model, would not interact through the weak force. The existence of such neutrinos would be a sign of physics beyond the Standard Model.”

    See the full article here.

    Fermilab campus

    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.


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