301 research outputs found
Analysis of the Q^2-dependence of charged-current quasielastic processes in neutrino-nucleus interactions
We discuss the observed disagreement between the Q^2 distributions of
neutrino-nucleus quasielastic events, measured by a number of recent
experiments, and the predictions of Monte Carlo simulations based on the
relativistic Fermi gas model. The results of our analysis suggest that these
discrepancies are likely to be ascribable to both the breakdown of the impulse
approximation and the limitations of the Fermi gas description. Several issues
related to the extraction of the Q^2 distributions from the experimental data
are also discussed, and new kinematical variables, which would allow for an
improved analysis, are proposed.Comment: 8 pages, 8 figures, 1 tabl
The \gamma-ray production in neutral-current neutrino oxygen interaction in the energy range above 100 MeV
We calculate the cross section of the gamma-ray production from
neutral-current neutrino-oxygen quasi-elastic interaction, , or , in
which the residual nuclei (15N* or 15O*) lead to the gamma-ray emission with
gamma-ray energy >6 MeV at the branching ratio of 41%. Above 200 MeV, this
cross section dominates over that of gamma-ray production from the inelastic
reaction, . In the present calculation, spectral
function and the spectroscopic factors of
states are essential. The gamma-ray production is dominated by the deexcitation
of state of the residual nucleus
Numerical Implementation of lepton-nucleus interactions and its effect on neutrino oscillation analysis
We discuss the implementation of the nuclear model based on realistic nuclear
spectral functions in the GENIE neutrino interaction generator. Besides
improving on the Fermi gas description of the nuclear ground state, our scheme
involves a new prescription for selection, meant to efficiently enforce
energy momentum conservation. The results of our simulations, validated through
comparison to electron scattering data, have been obtained for a variety of
target nuclei, ranging from carbon to argon, and cover the kinematical region
in which quasi elastic scattering is the dominant reaction mechanism. We also
analyse the influence of the adopted nuclear model on the determination of
neutrino oscillation parameters.Comment: 19 pages, 35 figures, version accepted by Phys. Rev.
Estimate of the theoretical uncertainty of the cross sections for nucleon knockout in neutral-current neutrino-oxygen interactions
Free nucleons propagating in water are known to produce gamma rays, which
form a background to the searches for diffuse supernova neutrinos and sterile
neutrinos carried out with Cherenkov detectors. As a consequence, the process
of nucleon knockout induced by neutral-current quasielastic interactions of
atmospheric (anti)neutrinos with oxygen needs to be under control at the
quantitative level in the background simulations of the ongoing and future
experiments. In this paper, we provide a quantitative assessment of the
uncertainty associated with the theoretical description of the nuclear cross
sections, estimating it from the discrepancies between the predictions of
different models.Comment: 7 pages, 2 figure
Electron-hadron shower discrimination in a liquid argon time projection chamber
By exploiting structural differences between electromagnetic and hadronic showers in a multivariate analysis we present an efficient Electron-Hadron discrimination algorithm for liquid argon time projection chambers, validated using Geant4 simulated data
Underground Neutrino Detectors for Particle and Astroparticle Science: the Giant Liquid Argon Charge Imaging ExpeRiment (GLACIER)
The current focus of the CERN program is the Large Hadron Collider (LHC),
however, CERN is engaged in long baseline neutrino physics with the CNGS
project and supports T2K as recognized CERN RE13, and for good reasons: a
number of observed phenomena in high-energy physics and cosmology lack their
resolution within the Standard Model of particle physics; these puzzles include
the origin of neutrino masses, CP-violation in the leptonic sector, and baryon
asymmetry of the Universe. They will only partially be addressed at LHC. A
positive measurement of would certainly give a
tremendous boost to neutrino physics by opening the possibility to study CP
violation in the lepton sector and the determination of the neutrino mass
hierarchy with upgraded conventional super-beams. These experiments (so called
``Phase II'') require, in addition to an upgraded beam power, next generation
very massive neutrino detectors with excellent energy resolution and high
detection efficiency in a wide neutrino energy range, to cover 1st and 2nd
oscillation maxima, and excellent particle identification and
background suppression. Two generations of large water Cherenkov
detectors at Kamioka (Kamiokande and Super-Kamiokande) have been extremely
successful. And there are good reasons to consider a third generation water
Cherenkov detector with an order of magnitude larger mass than Super-Kamiokande
for both non-accelerator (proton decay, supernovae, ...) and accelerator-based
physics. On the other hand, a very massive underground liquid Argon detector of
about 100 kton could represent a credible alternative for the precision
measurements of ``Phase II'' and aim at significantly new results in neutrino
astroparticle and non-accelerator-based particle physics (e.g. proton decay).Comment: 31 pages, 14 figure
Precision measurement of the neutrino velocity with the ICARUS detector in the CNGS beam
During May 2012, the CERN-CNGS neutrino beam has been operated for two weeks
for a total of 1.8 10^17 pot in bunched mode, with a 3 ns narrow width proton
beam bunches, separated by 100 ns. This tightly bunched beam structure allows a
very accurate time of flight measurement of neutrinos from CERN to LNGS on an
event-by-event basis. Both the ICARUS-T600 PMT-DAQ and the CERN-LNGS timing
synchronization have been substantially improved for this campaign, taking
ad-vantage of additional independent GPS receivers, both at CERN and LNGS as
well as of the deployment of the "White Rabbit" protocol both at CERN and LNGS.
The ICARUS-T600 detector has collected 25 beam-associated events; the
corresponding time of flight has been accurately evaluated, using all different
time synchronization paths. The measured neutrino time of flight is compatible
with the arrival of all events with speed equivalent to the one of light: the
difference between the expected value based on the speed of light and the
measured value is tof_c - tof_nu = (0.10 \pm 0.67stat. \pm 2.39syst.) ns. This
result is in agreement with the value previously reported by the ICARUS
collaboration, tof_c - tof_nu = (0.3 \pm 4.9stat. \pm 9.0syst.) ns, but with
improved statistical and systematic errors.Comment: 21 pages, 13 figures, 1 tabl
Measurement of Through-Going Particle Momentum By Means Of Multiple Scattering With The ICARUS T600 TPC
The ICARUS collaboration has demonstrated, following the operation of a 600
ton (T600) detector at shallow depth, that the technique based on liquid Argon
TPCs is now mature. The study of rare events, not contemplated in the Standard
Model, can greatly benefit from the use of this kind of detectors. In
particular, a deeper understanding of atmospheric neutrino properties will be
obtained thanks to the unprecedented quality of the data ICARUS provides.
However if we concentrate on the T600 performance, most of the
charged current sample will be partially contained, due to the reduced
dimensions of the detector. In this article, we address the problem of how well
we can determine the kinematics of events having partially contained tracks.
The analysis of a large sample of atmospheric muons collected during the T600
test run demonstrate that, in case the recorded track is at least one meter
long, the muon momentum can be reconstructed by an algorithm that measures the
Multiple Coulomb Scattering along the particle's path. Moreover, we show that
momentum resolution can be improved by a factor two using an algorithm based on
the Kalman Filtering technique
First results on ProtoDUNE-SP liquid argon time projection chamber performance from a beam test at the CERN Neutrino Platform
The ProtoDUNE-SP detector is a single-phase liquid argon time projection chamber with an active volume of 7.2Ă 6.1Ă 7.0 m3. It is installed at the CERN Neutrino Platform in a specially-constructed beam that delivers charged pions, kaons, protons, muons and electrons with momenta in the range 0.3 GeV/c to 7 GeV/c. Beam line instrumentation provides accurate momentum measurements and particle identification. The ProtoDUNE-SP detector is a prototype for the first far detector module of the Deep Underground Neutrino Experiment, and it incorporates full-size components as designed for that module. This paper describes the beam line, the time projection chamber, the photon detectors, the cosmic-ray tagger, the signal processing and particle reconstruction. It presents the first results on ProtoDUNE-SP\u27s performance, including noise and gain measurements, dE/dx calibration for muons, protons, pions and electrons, drift electron lifetime measurements, and photon detector noise, signal sensitivity and time resolution measurements. The measured values meet or exceed the specifications for the DUNE far detector, in several cases by large margins. ProtoDUNE-SP\u27s successful operation starting in 2018 and its production of large samples of high-quality data demonstrate the effectiveness of the single-phase far detector design
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