698 research outputs found
Elastic Scattering of Neutrinos off Polarized Electrons
We calculate the cross sections for elastic nu_l + e -> nu_l + e and antinu_l
+ e -> antinu_l + e scattering (l=e, mu or tau) in the Born approximation and
with exactly fixed polarization states of target and final-state electrons,
discussing their sensitivity to the incident (anti)neutrino flavor. We suggest
investigation of the flavor composition of a (anti)neutrino beam by a
flux-independent analysis of the scattering of its constituents off polarized
electrons.Comment: 6 pages, 2 figure
W-propagator corrections to muon and tau leptonic decays
We derive the corrections induced by the W-boson propagator to the
differential rates of the leptonic decay of a polarized muon and tau lepton.
Results are presented both for decays inclusive of inner bremsstrahlung as well
as for radiative ones, when a photon emitted in the decay process is measured.
The numerical effect of these corrections is discussed. The definition of the
Fermi constant is briefly reviewed.Comment: 5 pages, no figures, accepted for publicatio
Radiative and leptonic decays at NLO
We present the differential rates and branching ratios of the radiative
decays , with or , and in the Standard Model at next-to-leading order. Radiative
corrections are computed taking into account the full depencence on the mass
of the final charged leptons, which is necessary for the correct
determination of the branching ratios. Only partial agreement is found with
previous calculations performed in the limit. Our results agree
with the measurements of the branching ratios and for a
minimum photon energy of 10 MeV in the and rest frames,
respectively. Babar's recent precise measurement of the branching ratio
, for the same photon energy
threshold, differs from our prediction by 3.5 standard deviations.Comment: 13 pages, 1 figure, results included as ancillary file
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