We present a detailed description of a new hadronic multiparticle production model for use in neutrino interaction simulations. Its validity spans a wide invariant mass range starting from the pion ...production threshold. This model focuses on the low invariant mass region which is probed in few-GeV neutrino interactions and is of particular importance to neutrino oscillation experiments using accelerator and atmospheric fluxes. It exhibits reasonable agreement with a wide variety of experimental data. We also describe measurements that can be made in upcoming experiments that can improve modeling in areas where uncertainties are currently large.
We provide an overview of the status of Monte-Carlo event generators for high-energy particle physics. Guided by the experimental needs and requirements, we highlight areas of active development, and ...opportunities for future improvements. Particular emphasis is given to physics models and algorithms that are employed across a variety of experiments. These common themes in event generator development lead to a more comprehensive understanding of physics at the highest energies and intensities, and allow models to be tested against a wealth of data that have been accumulated over the past decades. A cohesive approach to event generator development will allow these models to be further improved and systematic uncertainties to be reduced, directly contributing to future experimental success. Event generators are part of a much larger ecosystem of computational tools. They typically involve a number of unknown model parameters that must be tuned to experimental data, while maintaining the integrity of the underlying physics models. Making both these data, and the analyses with which they have been obtained accessible to future users is an essential aspect of open science and data preservation. It ensures the consistency of physics models across a variety of experiments.
The DONUT experiment has analyzed 203 neutrino interactions recorded in nuclear emulsion targets. A decay search has found evidence of four tau neutrino interactions with an estimated background of ...0.34 events. This number is consistent with the Standard Model expectation.
Anomalies observed by different experiments, the most significant ones being the ∼3.8 sigma νe appearance in a ∼50 MeV νµ beam from muon decay at rest observed by the LSND experiment and the ∼3.8 ...sigma νe and ν ¯ e appearance in a ∼1 GeV neutrino beam from pion decay in flight observed by MiniBooNE, suggest the existence of sterile neutrinos. The Short Baseline Neutrino (SBN) program at Fermilab aims to perform a sensitive search for sterile neutrinos by performing analyses of νe appearance and νµ disappearance employing three Liquid Argon Time Projection Chambers (LAr-TPCs) at different baselines. The VALOR neutrino fitting group was established within the T2K experiment and has led numerous flagship T2K oscillation analyses, and provided sensitivity and detector optimisation studies for DUNE and Hyper-K. The neutrino oscillation framework developed by this group is able to perform fits of several samples and systematic parameters within different neutrino models and experiments. Thus, VALOR is an ideal environment for the neutrino oscillation fits using multiple LAr-TPC detectors with proper treatment of correlated systematic uncertainties necessary for the SBN analyses.
The T2K experiment presents new measurements of neutrino oscillation parameters using Formula omitted protons on target (POT) in (anti-)neutrino mode at the far detector (FD). Compared to the ...previous analysis, an additional Formula omitted POT neutrino data was collected at the FD. Significant improvements were made to the analysis methodology, with the near-detector analysis introducing new selections and using more than double the data. Additionally, this is the first T2K oscillation analysis to use NA61/SHINE data on a replica of the T2K target to tune the neutrino flux model, and the neutrino interaction model was improved to include new nuclear effects and calculations. Frequentist and Bayesian analyses are presented, including results on Formula omitted and the impact of priors on the Formula omitted measurement. Both analyses prefer the normal mass ordering and upper octant of Formula omitted with a nearly maximally CP-violating phase. Assuming the normal ordering and using the constraint on Formula omitted from reactors, Formula omitted using Feldman-Cousins corrected intervals, and Formula omitted using constant Formula omitted intervals. The CP-violating phase is constrained to Formula omitted using Feldman-Cousins corrected intervals, and Formula omitted is excluded at more than 90% confidence level. A Jarlskog invariant of zero is excluded at more than Formula omitted credible level using a flat prior in Formula omitted and just below Formula omitted using a flat prior in Formula omitted When the external constraint on Formula omitted is removed, Formula omitted in agreement with measurements from reactor experiments. These results are consistent with previous T2K analyses.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The T2K experiment reports updated measurements of neutrino and antineutrino oscillations using both appearance and disappearance channels. This result comes from an exposure of 14.9 (16.4) × 1020 ...protons on target in neutrino (antineutrino) mode. Significant improvements have been made to the neutrino interaction model and far detector reconstruction. An extensive set of simulated data studies have also been performed to quantify the effect interaction model uncertainties have on the T2K oscillation parameter sensitivity. T2K performs multiple oscillation analyses that present both frequentist and Bayesian intervals for the Pontecorvo-Maki-Nakagawa-Sakata parameters. For fits including a constraint on sin 2θ13 from reactor data and assuming normal mass ordering T2K measures sin 2θ23 = 0.53 +0.03 −0.04 and Δm232 = (2.45 ± 0.07) × 10−3 eV2 c−4. The Bayesian analyses show a weak preference for normal mass ordering (89% posterior probability) and the upper sin 2θ23 octant (80% posterior probability), with a uniform prior probability assumed in both cases. The T2K data exclude CP conservation in neutrino oscillations at the 2σ level.
The T2K experiment measures muon neutrino disappearance and electron neutrino appearance in accelerator-produced neutrino and antineutrino beams. With an exposure of 14.7(7.6)×1020 protons on target ...in the neutrino (antineutrino) mode, 89 νe candidates and seven anti-νe candidates are observed, while 67.5 and 9.0 are expected for δCP=0 and normal mass ordering. The obtained 2σ confidence interval for the CP-violating phase, δCP, does not include the CP-conserving cases (δCP=0, π). The best-fit values of other parameters are sin2θ23=0.526−0.036+0.032 and Δm322=2.463−0.070+0.071×10−3 eV2/c4.
The GENIE neutrino Monte Carlo generator Andreopoulos, C.; Bell, A.; Bhattacharya, D. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
02/2010, Letnik:
614, Številka:
1
Journal Article
Recenzirano
GENIE
1 is a new neutrino event generator for the experimental neutrino physics community. The goal of the project is to develop a ‘canonical’ neutrino interaction physics Monte Carlo whose validity ...extends to all nuclear targets and neutrino flavors from MeV to PeV energy scales. Currently, emphasis is on the few-GeV energy range, the challenging boundary between the non-perturbative and perturbative regimes, which is relevant for the current and near future long-baseline precision neutrino experiments using accelerator-made beams. The design of the package addresses many challenges unique to neutrino simulations and supports the full life-cycle of simulation and generator-related analysis tasks.
GENIE is a large-scale software system, consisting of
∼
120
000
lines of
C
++
code, featuring a modern object-oriented design and extensively validated physics content. The first official physics release of GENIE was made available in August 2007, and at the time of the writing of this article, the latest available version was v2.4.4.
Using a neutrino beam in which a
ν
τ
component was identified for the first time, the
ν
τ
magnetic moment was measured based on a search for an anomalous increase in the number of neutrino–electron ...interactions. One such event was observed when 2.3 were expected from background processes, giving an upper 90% confidence limit on
μ
ν
τ
of 3.9×10
−7
μ
B
.