68 research outputs found
Extended Grimus-Stockinger theorem and inverse square law violation in quantum field theory
We study higher-order corrections to the Grimus-Stockinger theorem dealing
with the large-distance asymptotic behavior of the wave-packet modified
neutrino propagator within the framework of field-theoretical description of
the neutrino oscillation phenomenon. We discuss the possibility that these
corrections are responsible for breakdown of the classical inverse-square law
(ISL) at the macroscopic distances. In particular the ISL violation can be an
explanation of the well-known reactor antineutrino anomaly.Comment: 11 pages, no figures. Some additions are done and references are
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Extended Rein-Sehgal model for tau lepton production
The polarization density matrix formalism is employed to include the final
lepton mass and spin into the popular model by Rein and Sehgal for single pion
neutrinoproduction. We investigate the effect of the lepton mass on the
differential cross sections. The lepton polarization evaluated within the
extended RS model is compared against that follows from the single resonance
production model based upon the Rarita-Schwinger formalism with
phenomenological transition form factors.Comment: Contribution to the 3rd International Workshop on Neutrino-Nucleus
Interactions in the Few-GeV Region, 17-21 March, Gran Sasso (Italy
High-energy neutrino oscillations in absorbing matter
The impact of neutrino mixing, refraction and absorption on high-energy
neutrino propagation through a thick medium is studied using the MSW evolution
equation with complex indices of refraction. It is found that, owing to the
mixing with sterile neutrinos, the penetrability of active neutrinos may be
many orders of magnitude larger than it would be in the absence of mixing. The
effect is highly sensitive to changes in density and composition of the matter
background as well as to neutrino energy and mixing parameters. This may lead
to observational consequences in neutrino astrophysics.Comment: 20 pages, 4 figures, elsart preprint class. Final version accepted
for publication in PL
Lepton Polarization in Neutrino-Nucleon Interactions
We derive generic formulas for the polarization density matrix of leptons
produced in neutrino and antineutrino collisions and briefly consider some
important particular cases. Next we employ the general formalism in order to
include the final lepton mass and spin into the popular model by Rein and
Sehgal for single pion neutrinoproduction.Comment: Talk given at 10th International Workshop on High-Energy Spin Physics
(SPIN 03), Dubna, Russia, 16-20 Sep 2003. 12 pages; extended version, typos
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Atmospheric neutrino flux supported by recent muon experiments
We present a new one-dimensional calculation of low and intermediate energy
atmospheric muon and neutrino fluxes, using up-to-date data on primary cosmic
rays and hadronic interactions. We study several sources of uncertainties
relevant to our calculations. A comparison with the muon fluxes and charge
ratios measured in several modern balloon-borne experiments suggests that the
atmospheric neutrino flux is essentially lower than one used for the standard
analyses of the sub-GeV and multi-GeV neutrino induced events in underground
detectors.Comment: 23 pages, 7 figures, 2 tables. Typos corrected, figure layout
improved, references added. Final version accepted for publication in PL
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