107 research outputs found
Atmospheric Tau Neutrinos in a Multi-kiloton Liquid Argon Detector
An ultra-large Liquid Argon Time Projection Chamber-based neutrino detector
will have the uncommon ability to detect atmospheric tau neutrino events. This
paper discusses the most promising modes for identifying charged current tau
neutrino interactions, and shows that, with simple kinematic cuts, ~30 tau
neutrinos can be isolated in a 100 kt*yr exposure, with greater than 4 sigma
significance. This sample is sufficient to perform flux-averaged total
cross-section and cross-section shape parameterization measurements -- the
first steps toward using tau neutrinos to search for physics beyond the
Standard Model.Comment: 14 pages, 11 figure
Annual Modulation of Cosmic Relic Neutrinos
The cosmic neutrino background (CvB), produced about one second after the Big
Bang, permeates the Universe today. New technological advancements make
neutrino capture on beta-decaying nuclei (NCB) a clear path forward towards the
detection of the CvB. We show that gravitational focusing by the Sun causes the
expected neutrino capture rate to modulate annually. The amplitude and phase of
the modulation depend on the phase-space distribution of the local neutrino
background, which is perturbed by structure formation. These results also apply
to searches for sterile neutrinos at NCB experiments. Gravitational focusing is
the only source of modulation for neutrino capture experiments, in contrast to
dark-matter direct-detection searches where the Earth's time-dependent velocity
relative to the Sun also plays a role.Comment: 6 pages, 2 figure
Precision muon reconstruction in Double Chooz
We describe a muon track reconstruction algorithm for the reactor anti-neutrino experiment Double Chooz. The Double Chooz detector consists of two optically isolated volumes of liquid scintillator viewed by PMTs, and an Outer Veto above these made of crossed scintillator strips. Muons are reconstructed by their Outer Veto hit positions along with timing
information from the other two detector volumes. All muons are fit under the hypothesis that they are through-going and ultrarelativistic. If the energy depositions suggest that the muon may have stopped, the reconstruction fits also for this hypothesis and chooses between the two via the relative goodness-of-fit. In the ideal case of a through-going
muon intersecting the center of the detector, the resolution is ∼40 mm in each transverse dimension. High quality muon reconstruction is an important tool for reducing the impact of the cosmogenic isotope background in Double Chooz.National Science Foundation (U.S.)United States. Department of Energ
Modeling quasielastic interactions of monoenergetic kaon decay-at-rest neutrinos
Monoenergetic muon neutrinos at 236 MeV are readily produced in intense
medium-energy proton facilities (2-3~GeV) when a positive kaon decays
at rest (KDAR; ). These neutrinos provide a
unique opportunity to both study the neutrino interaction and probe the nucleus
with a monoenergetic weak-interaction-only tool. We present cross section
calculations for quasielastic scattering of these 236~MeV neutrinos off
C and Ar, paying special attention to low-energy aspects of the
scattering process. Our model takes the description of the nucleus in a
mean-field (MF) approach as the starting point, where we solve Hartree-Fock
(HF) equations using a Skyrme type nucleon-nucleon interaction. Thereby, we
introduce long-range nuclear correlations by means of a continuum random phase
approximation (CRPA) framework where we solve the CRPA equations using a
Green's function method. The model successfully describes () data on
C and Ca in the kinematic region that overlaps with the KDAR
phase space. In addition to these results, we present future
prospects for precision KDAR cross section measurements and applications of our
calculations in current and future experiments that will utilize these
neutrinos
ArgoNeuT, a liquid argon time projection chamber in a low energy neutrino beam
ArgoNeuT (Argon Neutrino Test), a NSF/DOE project at Fermilab, is the first
LArTPC to go in a low energy neutrino beam and just the second LArTPC to go in
a neutrino beam ever. ArgoNeuT sits just upstream of the on-axis MINOS near
detector in the NuMI beamline, about 1 km from the target station and 100 m
underground. The detector features a 47X40X90 cm (169 L) active volume TPC with
a fully contained recirculation and purification system. Among other physics,
ArgoNeuT will measure the charged-current quasi-elastic (anti-) neutrino cross
section on argon at an energy of ~3 GeV.Comment: 3 pages, 2 figures, to appear in the proceedings of the 11th
International Conference on Topics in Astroparticle and Underground Physics
(TAUP 2009), Rome, Italy, 1-5 July 200
New Forces From Sources
Accelerator-based experiments reliant on charged pion and kaon decays to
produce muon-neutrino beams also deliver an associated powerful flux of muons.
Therefore, these experiments can additionally be sensitive to light new
particles that preferentially couple to muons and decay to visible final states
on macroscopic length scales. Such particles are produced through rare 3-body
meson decays in the decay pipe or via muon scattering in the beam dump, and
decay in a downstream detector. To demonstrate the potential of this search
strategy, we recast existing MiniBooNE and MicroBooNE studies of neutral pion
production in neutrino-induced neutral-current scattering () to place new leading limits on
light () muon-philic scalar particles that decay to diphotons through
loops of virtual muons. Our results exclude scalars of mass between 10 and 60
MeV in which this scenario resolves the muon anomaly. We also make
projections for the sensitivity of SBND to these models and provide a road map
for future neutrino experiments to perform dedicated searches for muon-philic
forces.Comment: 6 pages, 6 figure
Severe Constraints on New Physics Explanations of the MiniBooNE Excess
The MiniBooNE experiment has recently reported an anomalous 4.5
excess of electron-like events consistent with appearance from a
beam at short-baseline. Given the lack of corresponding
disappearance observations, required in the case of oscillations involving a
sterile flavor, there is strong motivation for alternative explanations of this
anomaly. We consider the possibility that the observed electron-like signal may
actually be due to hypothetical new particles,which do not involve new sources
of neutrino production or oscillations. We find that the electron-like event
energy and angular distributions in the full MiniBooNE data-set, including
neutrino mode, antineutrino mode, and beam dump mode, severely limit, and in
some cases rule out, new physics scenarios as an explanation for the observed
neutrino and antineutrino mode excesses. Specifically, scenarios in which the
new particle decays (visibly or semi-visibly) or scatters elastically in the
detector are strongly disfavored. Using generic kinematic arguments, this paper
extends the existing MiniBooNE results and interpretations to exhaustively
constrain previously unconsidered new physics signatures and emphasizes the
power of the MiniBooNE beam dump search to further constrain models for the
excess.Comment: 6 pages, 3 figure
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