828 research outputs found
Photon emission in neutral current interactions at the T2K experiment
We have applied a microscopic model for single photon emission in neutral current interactions on nucleons and nuclei to determine the number and distributions of such events at the Super-Kamiokande detector, for the flux and beam exposure of the T2K experiment in neutrino mode. These reactions represent an effectively irreducible background in electron-(anti) neutrino appearance measurements aimed at a precise measurement of mixing angle theta(13) and the CP violating phase. We have obtained a total number of photon events that is twice as large as the one from the NEUT event generator (version 5.1.4.2) used in the analysis of T2K data. Detailed comparisons of energy and angular distributions for the nu μand (nu) over bar μfluxes have also been performed
Weak Kaon Production off the Nucleon
The weak kaon production off the nucleon induced by neutrinos is studied at
the low and intermediate energies of interest for some ongoing and future
neutrino oscillation experiments. This process is also potentially important
for the analysis of proton decay experiments. We develop a microscopical model
based on the SU(3) chiral Lagrangians. The basic parameters of the model are
fpi, the pion decay constant, Cabibbo's angle, the proton and neutron magnetic
moments and the axial vector coupling constants for the baryons octet, D and F,
that are obtained from the analysis of the semileptonic decays of neutron and
hyperons. The studied mechanisms are the main source of kaon production for
neutrino energies up to 1.2 to 1.5 GeV for the various channels and the cross
sections are large enough to be amenable to be measured by experiments such as
Minerva and T2K
Antineutrino induced antikaon production off the nucleon
The charged current antikaon production off nucleons induced by antineutrinos
is studied at low and intermediate energies. We extend here our previous
calculation on kaon production induced by neutrinos. We have developed a
microscopic model that starts from the SU(3) chiral Lagrangians and includes
background terms and the resonant mechanisms associated to the lowest lying
resonance in the channel, namely, the Sigma*(1385). Our results could be of
interest for the background estimation of various neutrino oscillation
experiments like MiniBooNE and SuperK. They can also be helpful for the planned
antineutrino experiments like MINERvA, NOvA and T2K phase II and for beta-beam
experiments with antineutrino energies around 1 GeV.Comment: 15 pages and 6 figures. This version matches accepted version for
publication in Physical Review
Reheating after f(R) inflation
The reheating dynamics after the inflation induced by -corrected
model is considered. To avoid the complexity of solving the fourth order
equations, we analyze the inflationary and reheating dynamics in the Einstein
frame and its analytical solutions are derived. We also perform numerical
calculation including the backreaction from the particle creation and compare
the results with the analytical solutions. Based on the results, observational
constraints on the model are discussed.Comment: 16 pages, 11 figure
Search for Sc-K line emission from RX J0852.0--4622 Supernova remnant with Suzaku
We searched for evidence of line emission around 4keV from the northwestern
rim of the supernova remnant RX J0852.0-4622 using Suzaku XIS data. Several
papers have reported the detection of an emission line around 4.1keV from this
region of the sky. This line would arise from K-band fluorescence by Sc, the
immediate decay product of 44Ti. We performed spectral analysis for the entire
portion of the NW rim of the remnant within the XIS field of view, as well as
various regions corresponding to regions of published claims of line emission.
We found no line emission around 4.1keV anywhere, and are able to set a
restrictive upper limit to the X-ray flux: 1.1x10^-6 s^-1 cm^-2 for the entire
field. For every region, our flux upper limit falls below that of the
previously claimed detection. Therefore, we conclude that, to date, no definite
X-ray line feature from Sc-K emission has been detected in the NW rim of RX
J0852.0-4622. Our negative-detection supports the recent claim that RX
J0852-4622 is neither young (1700--4000 yr) nor nearby(~750 pc).Comment: Published in PAS
Final State Interactions Effects in Neutrino-Nucleus Interactions
Final State Interactions effects are discussed in the context of Monte Carlo
simulations of neutrino-nucleus interactions. A role of Formation Time is
explained and several models describing this effect are compared. Various
observables which are sensitive to FSI effects are reviewed including
pion-nucleus interaction and hadron yields in backward hemisphere. NuWro Monte
Carlo neutrino event generator is described and its ability to understand
neutral current production data in GeV neutrino flux
experiments is demonstrated.Comment: 13 pages, 16 figure
Testing whether muon neutrino flavor mixing is maximal
The small difference between the survival probabilities of muon neutrino and
antineutrino beams, traveling through earth matter in a long baseline
experiment such as MINOS, is shown to be an important measure of any possible
deviation from maximality in the flavor mixing of those states.Comment: Some revision has been made in the experimental discussions with two
new figures replacing the old ones and a clarification of the accuracy of the
perturbative result has been included. This version will be published in
Physical Review Letters. Title changed as asked by the editors of Physical
Review Letter
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