2002/12/18 by Enrico Nardi · 1 citation
Physics and Astronomy · #Astrophysics and Cosmic Phenomena #Neutrino Physics Research #Particle physics theoretical and experimental studies #hep-ph
paper · pdf · doi:10.1063/1.1594325
published as AIP Conf.Proc. 670 (2003) 118-131 · 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
arxiv created 2002/12/18 · openalex publication_date 2003/01/01 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/29
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 〈rA2〉. As is the case for the vector charge radius of a Dirac neutrino, proving that this quantity 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 〈rA2〉. Therefore this quantity has to be studied by means of terrestrial experiment. Finally, I will discuss the constraints that can be derived on 〈rA2〉 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 νμ scattering data from the NuTeV, E734, CCFR and CHARM‐II collaborations and on the limits implied for 〈rA2〉 for the muon neutrino.