On the neutrino vector and axial vector charge radius

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 <r^2_A>. 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 <r^2_A>, and therefore this quantity has to be studied by means of terrestrial experiment. Finally, I will discuss the constraints that can be derived on <r^2_A> 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 ${\nu }_{\mu }$ scattering data from the NuTeV, E734, CCFR and CHARM-II collaborations and on the limits implied for <r^2_A> for the muon neutrino.

8 pages, 3 eps figures. Talk given in the X Mexican School of Particles and Fields, Playa del Carmen, Mexico, October 30 - November 6, 2002. Based in part on hep-ph/0210137 written in collaboration with M. Hirsch and D. A. Restrepo

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Cited by in corpus (4)

• Effects of physics beyond the standard model on the neutrino charge radius: an effective Lagrangian approach
• Impact of medium modification of the nucleon weak and electromagnetic form factors on the neutrino mean free path in dense matter
• Neutrino Electromagnetic Form Factors Effect on the Neutrino Cross Section in Dense Matter
• Effects of the neutrino electromagnetic form factors on the neutrino and antineutrino mean free paths in dense matter