Search results for "MiniBooNE"
showing 9 items of 49 documents
The nucleon axial mass and the MiniBooNE quasielastic neutrino-nucleus scattering problem
2011
The charged-current double differential neutrino cross section, measured by the MiniBooNE Collaboration, has been analyzed using a microscopical model that accounts for, among other nuclear effects, long range nuclear (RPA) correlations and multinucleon scattering. We find that MiniBooNE data are fully compatible with the world average of the nucleon axial mass in contrast with several previous analyses which have suggested an anomalously large value. We also discuss the reliability of the algorithm used to estimate the neutrino energy.
Minimal models with light sterile neutrinos
2011
We study the constraints imposed by neutrino oscillation experiments on the minimal extensions of the Standard Model (SM) with $n_R$ gauge singlet fermions ("right-handed neutrinos"), that can account for neutrino masses. We consider the most general coupling to SM fields of the new fields, in particular those that break lepton number and we do not assume any a priori hierarchy in the mass parameters. We proceed to analyze these models starting from the lowest level of complexity, defined by the number of extra fermionic degrees of freedom. The simplest choice that has enough free parameters in principle (i.e. two mass differences and two angles) to explain the confirmed solar and atmospher…
Sterile neutrino models and nonminimal cosmologies
2012
Cosmological measurements are affected by the energy density of massive neutrinos. We extend here a recent analysis of current cosmological data to nonminimal cosmologies. Several possible scenarios are examined: a constant $w\ensuremath{\ne}\ensuremath{-}1$ dark energy equation of state, a nonflat universe, a time-varying dark energy component and coupled dark matter-dark energy universes or modified gravity scenarios. When considering cosmological data only, ($3+2$) massive neutrino models with $\ensuremath{\sim}0.5\text{ }\text{ }\mathrm{eV}$ sterile species are allowed at 95% confidence level. This scenario has been shown to reconcile reactor, LSND and MiniBooNE positive signals with nu…
New determination of the N-Δ(1232) axial form factors from weak pion production and coherent pion production off nuclei at T2K and MiniBooNE energies…
2010
We re-evaluate our model predictions in Phys. Rev. D 79, 013002 (2009) for different observables in neutrino induced coherent pion production. This comes as a result of the new improved fit to old bubble chamber data of the dominant axial C_5^A nucleon-to-Delta form factor. We find an increase of 20%-30% in the values for the total cross sections. Uncertainties induced by the errors in the determination of C_5^A are computed. Our new results turn out to be compatible within about $1\sigma$ with the former ones. We also stress the existing tension between the recent experimental determination of the \sigma(CC coh \pi^+)}/\sigma(NC coh \pi^0)} $ ratio by the SciBooNE Collaboration and the the…
Neutrinos in Nuclear Physics: RPA, MEC, 2p2h (Pionic Modes of Excitation in Nuclei)
2016
This chapter is devoted to the study of weak interactions on nucleons and nuclei. I pay a special attention to the study of neutrino and antineutrino quasi-elastic reactions in nuclei , which are of the greatest importance for neutrino oscillation experiments, and crucial to achieve the precision goals required to make new discoveries, like the CP violation in the leptonic sector, possible. In particular, I discuss RPA correlations and 2p2h (multi-nucleon) effects on charged-current neutrino-nucleus reactions, and the influence of these nuclear effects on the recently measured MiniBooNE flux folded differential cross sections, and on the so-called nucleon axial mass puzzle. The modification…
Unexplained Excess of Electronlike Events from a 1-GeV Neutrino Beam
2009
The MiniBooNE Collaboration observes unexplained electronlike events in the reconstructed neutrino energy range from 200 to 475 MeV. With 6.46 x 10(20) protons on target, 544 electronlike events are observed in this energy range, compared to an expectation of 415.2 +/- 43.4 events, corresponding to an excess of 128.8 +/- 20.4 +/- 38.3 events. The shape of the excess in several kinematic variables is consistent with being due to either nu(e) and (nu) over bar (e) charged-current scattering or nu(mu) neutral-current scattering with a photon in the final state. No significant excess of events is observed in the reconstructed neutrino energy range from 475 to 1250 MeV, where 408 events are obse…
Neutrino flux prediction at MiniBooNE
2009
The booster neutrino experiment (MiniBooNE) searches for nu(mu)->nu(e) oscillations using the O(1 GeV) neutrino beam produced by the booster synchrotron at the Fermi National Accelerator Laboratory). The booster delivers protons with 8 GeV kinetic energy (8.89 GeV/c momentum) to a beryllium target, producing neutrinos from the decay of secondary particles in the beam line. We describe the Monte Carlo simulation methods used to estimate the flux of neutrinos from the beam line incident on the MiniBooNE detector for both polarities of the focusing horn. The simulation uses the Geant4 framework for propagating particles, accounting for electromagnetic processes and hadronic interactions in the…
Decaying sterile neutrinos and the short baseline oscillation anomalies
2019
The MiniBooNE experiment has observed a significant excess of electron neutrinos in a muon neutrino beam at source-detector distances too short to be compatible with standard neutrino oscillations. The most straightforward explanation for this signal in terms of oscillations between Standard Model neutrinos and a new, sterile, neutrino, is disfavored by null results from experiments looking for muon neutrino disappearance. Here, we discuss the possibility that MiniBooNE data are instead explained by a sterile neutrino that decays quickly back into active neutrinos plus a light boson. The flavor composition of the secondary neutrinos is determined by the sterile neutrino mixing angles, and w…
SOX : short distance neutrino oscillations with Borexino
2014
Abstract The Borexino detector has convincingly shown its outstanding performance in the in the sub-MeV regime through its unprecedented accomplishments in the solar and geo-neutrinos detection, which make it the ideal tool to unambiguously test the long-standing issue of the existence of a sterile neutrino, as suggested by several anomalies: the outputs of the LSND and Miniboone experiments, the results of the source calibration of the two Gallium solar ν experiments, and the recently hinted reactor anomaly. The SOX project will exploit two sources, based on chromium and cerium, which deployed under the experiment will emit two intense beams of ν e (Cr) and ν e ‾ (Ce). Interacting in the a…