On the neutrino vector and axial vector charge radius

Enrico Nardi

doi:10.1063/1.1594325

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arXiv · hep-ph/0212266

On the neutrino vector and axial vector charge radius

Enrico Nardi

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Abstract

A Majorana neutrino is characterized by just one flavor diagonal electromagnetic form factor: the anapole moment, that in the static limit corresponds to the axial vector charge radius . As is the case for the vector charge radius of a Dirac neutrino, proving that this is a well defined physical quantity is non trivial. I will first describe briefly the origin of the long standing controversy about the physical or non physical nature of the neutrino charge radius. Then I will argue that, in contrast to Dirac neutrino electromagnetic form factors, for Majorana neutrinos cosmological and astrophysical arguments do not provide useful informations on , and therefore this quantity has to be studied by means of terrestrial experiment. Finally, I will discuss the constraints that can be derived on for the tau neutrino from a comprehensive analysis of the data on single photon production off Z-resonance, and I will conclude with a few comments on $ν_μ$ scattering data from the NuTeV, E734, CCFR and CHARM-II collaborations and on the limits implied for for the muon neutrino.

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Enrico Nardi. 2002-12-18. On the neutrino vector and axial vector charge radius. https://doi.org/10.1063/1.1594325

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