1,721,365 research outputs found
Simulations of pion production in the Daedalus targets
Full text linkDAEDALUS, the Decay At-rest Experiment for DCP at a
Laboratory for Underground Science will look for evidence
of CP-violation in the neutrino sector, an ingredient in theories
that seek to explain the matter/antimatter asymmetry
in our universe. It will make a precision measurement of
the oscillations of muon antineutrinos to electron antineutrinos
using multiple neutrino sources created by low-cost
compact cyclotrons. The experiment utilizes decay-at-rest
neutrino beams produced by 800 MeV protons impinging
a beam target of graphite and copper. Two well established
Monte Carlo codes, MARS and GEANT4, have been used
to optimise the design and the performance of the target. A
study of the results obtained with these two codes is presented
in this paper
Viewpoint: Rethinking the Neutrino
No full textTo some, this may be the year of the dragon, but in neutrino physics, this is the year of θ[subscript 13]. Only one year ago, this supposedly “tiny” mixing angle, which describes how neutrinos oscillate from one mass state to another, was undetected, but the last twelve months have seen a flurry of results from experiments in Asia and Europe, culminating in the result from the Daya Bay Collaboration, now being reported in Physical Review Letters, that shows that θ[subscript 13] is not small after all [1]. A not-so-tiny mixing angle forces us to rethink theory, calling for new explanations for why quarks and leptons are so different. It also opens the door to new experiments, potentially allowing the discovery of CP violation—a difference between neutrinos and antineutrinos that may be related to the matter asymmetry of the early universe
Neutrino experiments and the Large Hadron Collider: friends across 14 orders of magnitude
No full textThis paper explores some of the questions that connect the Large Hadron Collider (LHC) and neutrino experiments. What is the origin of mass? What is the meaning of flavor? Is there direct evidence of new forces or particles? The neutrino program investigating these questions is large and diverse. The strategy here, to narrow the discussion, is to focus on relatively new ideas for experiments that may be less known within the LHC community
Neutrino physics with JUNO
Full text linkThe Jiangmen Underground Neutrino Observatory (JUNO), a 20 kton multi-purpose underground liquid scintillator detector, was proposed with the determination of the neutrino mass hierarchy (MH) as a primary physics goal. The excellent energy resolution and the large fiducial volume anticipated for the JUNO detector offer exciting opportunities for addressing many important topics in neutrino and astro-particle physics. In this document, we present the physics motivations and the anticipated performance of the JUNO detector for various proposed measurements. Following an introduction summarizing the current status and open issues in neutrino physics, we discuss how the detection of antineutrinos generated by a cluster of nuclear power plants allows the determination of the neutrino MH at a 3–4σ significance with six years of running of JUNO. The measurement of antineutrino spectrum with excellent energy resolution will also lead to the precise determination of the neutrino oscillation parameters sin² θ₁₂, Δm₂₁² and |Δm[subscript ee]²| to an accuracy of better than 1%, which will play a crucial role in the future unitarity test of the MNSP matrix. The JUNO detector is capable of observing not only antineutrinos from the power plants, but also neutrinos/antineutrinos from terrestrial and extra-terrestrial sources, including supernova burst neutrinos, diffuse supernova neutrino background, geoneutrinos, atmospheric neutrinos, and solar neutrinos. As a result of JUNO's large size, excellent energy resolution, and vertex reconstruction capability, interesting new data on these topics can be collected. For example, a neutrino burst from a typical core-collapse supernova at a distance of 10 kpc would lead to ~5000 inverse-beta-decay events and ~2000 all-flavor neutrino–proton ES events in JUNO, which are of crucial importance for understanding the mechanism of supernova explosion and for exploring novel phenomena such as collective neutrino oscillations. Detection of neutrinos from all past core-collapse supernova explosions in the visible universe with JUNO would further provide valuable information on the cosmic star-formation rate and the average core-collapse neutrino energy spectrum. Antineutrinos originating from the radioactive decay of uranium and thorium in the Earth can be detected in JUNO with a rate of ~400 events per year, significantly improving the statistics of existing geoneutrino event samples. Atmospheric neutrino events collected in JUNO can provide independent inputs for determining the MH and the octant of the θ₂₃ mixing angle. Detection of the 7Be and 8B solar neutrino events at JUNO would shed new light on the solar metallicity problem and examine the transition region between the vacuum and matter dominated neutrino oscillations. Regarding light sterile neutrino topics, sterile neutrinos with 10⁻⁵eV² < Δ m₄₁² < 10⁻²eV² and a sufficiently large mixing angle θ₁₄ could be identified through a precise measurement of the reactor antineutrino energy spectrum. Meanwhile, JUNO can also provide us excellent opportunities to test the eV-scale sterile neutrino hypothesis, using either the radioactive neutrino sources or a cyclotron-produced neutrino beam. The JUNO detector is also sensitive to several other beyondthe-standard-model physics. Examples include the search for proton decay via the p [arrow to] K⁺ + [bar ν] decay channel, search for neutrinos resulting from dark-matter annihilation in the Sun, search for violation of Lorentz invariance via the sidereal modulation of the reactor neutrino event rate, and search for the effects of non-standard interactions. The proposed construction of the JUNO detector will provide a unique facility to address many outstanding crucial questions in particle and astrophysics in a timely and cost-effective fashion. It holds the great potential for further advancing our quest to understanding the fundamental properties of neutrinos, one of the building blocks of our Universe
Limits on electron neutrino disappearance from the KARMEN and LSND νe-carbon cross section data
No full textThis paper presents a combined analysis of the KARMEN and LSND ν[subscript e]-carbon cross section measurements within the context of a search for ν[subscript e] disappearance at high Δm[superscript 2]. KARMEN and LSND were located at 17.7 m and 29.8 m, respectively, from the neutrino source, so, the consistency of the two measurements, as a function of antineutrino energy, sets strong limits on neutrino oscillations. Most of the allowed region from the ν[subscript e] disappearance analysis of the Gallium calibration data is excluded at >95% CL and the best-fit point is excluded at 3.6σ. Assuming CPT conservation, comparisons are also made to the oscillation analyses of reactor antineutrino data.National Science Foundation (U.S.
Multiple Cyclotron Method to Search for CP Violation in the Neutrino Sector
No full textNew low-cost, high-power proton cyclotrons open the opportunity for a novel precision search for CP violation in the light neutrino sector. The accelerators can produce decay-at-rest neutrino beams located at multiple distances from a Gd-doped ultralarge water Cherenkov detector in order to search for CP violation in ν̅ μ→ν̅ e oscillations at short baselines. This new type of search complements presently proposed experiments, providing measurements that could lead to a substantially better exploration of CP violation in the neutrino sector.National Science Foundation (U.S.
Electron antineutrino disappearance at KamLAND and JUNO as decisive tests of the short baseline [bar over ν][subscript μ] → [bar over v][subscript e] appearance anomaly
No full textThe IsoDAR antineutrino source, which produces a flux from [superscript 8]Li isotope decay at rest, when paired with the proposed Jiangmen Underground Neutrino Observatory detector, has unprecedented sensitivity to [bar over ν][subscript e] disappearance for oscillations at high Δm[superscript 2]. Assuming charge conjugation, parity transformation, and time reversal (CPT) invariance, the sensitive region for [bar over ν][subscript e] disappearance can be used to restrict the allowed parameter space of a [bar over ν][subscript μ] → [bar over ν][subscript e] appearance signal. The 5σ sensitivity of this experiment covers the entire [bar over ν][subscript μ] → [bar over ν][subscript e] allowed parameter space from a combined fit to short-baseline experiments. This represents a decisive test of the LSND neutrino experiment and MiniBooNE antineutrino appearance signals within all models that are CPT invariant. Running IsoDAR at KamLAND restricts a large part of the appearance signal region in a similar way.National Science Foundation (U.S.
Sterile Neutrinos: An Introduction to Experiments
Full text linkThis paper is written as one chapter in a collection of essays on neutrino physics for beginning graduate students. The text presents important experimental methods and issues for those interested in searches for sterile neutrinos. Other essays in the collection, written by other authors, will cover introduction to neutrinos in the Standard Model, a description of the theory, and discussion of details of detectors, thus these aspects are not covered here. However, beyond these points, this represents a self-contained tutorial on experimental studies of sterile neutrino oscillations, covering such issues as signals vs. limits, designing experiments, and performing and interpreting global fits to the oscillation data.National Science Foundation (U.S.) (Grant 1505855)National Science Foundation (U.S.) (Grant 1505858)National Science Foundation (U.S.) (Grant 1404209
Improved parametrization of K+ production in p-Be collisions at low energy using Feynman scaling
No full textThis paper describes an improved parametrization for proton-beryllium production of secondary K[superscript +] mesons for experiments with primary proton beams from 8.89 to 24 GeV/c. The parametrization is based on Feynman scaling in which the invariant cross section is described as a function of x[subscript F] and p[subscript T]. This method is theoretically motivated and provides a better description of the energy dependence of kaon production at low beam energies than other parametrizations such as the commonly used modified Sanford-Wang model. This Feynman scaling parametrization has been used for the simulation of the neutrino flux from the Booster Neutrino Beam at Fermilab and has been shown to agree with the neutrino interaction data from the SciBooNE experiment. This parametrization will also be useful for future neutrino experiments with low primary beam energies, such as those planned for the Project X accelerator.National Science Foundation (U.S.
Prospect/Refuge theory: An experimental approach
No full textViewed qualitatively, Jay Appleton's prospect/refuge theory is intuitively attractive. Viewed quantitatively, can it be substantiated and is it useful? This study aims to substantiate the theory. Prospect/refuge theory is presented in context with other landscape theories all of which are based on a long tradition of gardening practice. A review of gardening practice and theory is followed by a review of empirical aesthetics and the landscape. The main part of the study. is the set of experiments developed to test certain predictions of prospect/refuge theory using a variety of experimental methods. The results of these experiments give support to Appleton's hypotheses and open the way for future research in prospect/refuge theory
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