Sprecher
Beschreibung
The explosion of the type II supernova SN1987A provides a unique laboratory to constrain novel energy-loss mechanisms and possible extensions of the standard properties of neutrinos. Here we propose a detailed investigation on the production and emission of right-handed neutrinos νR via helicity-flip transitions mediated by a non-zero neutrino magnetic dipole moment μν within the extreme conditions of the proto-neutron star core. Since νR do not interact with Standard Model particles, these highly-energetic neutrinos escape the stellar interior, constituting a direct energy-loss channel that can significantly alter the cooling timescale of the supernova. Thus, consistency with the observed luminosity profile provides a first, constrained upper bound on the dipole magnetic moment. More restrictive bounds can be derived by investigating the fraction of r.h. neutrinos which undergo reconversion back into active l.h. neutrinos when propagating in the presence of the Galactic magnetic field. This process would result in a flux of high energy neutrinos that should have been observed in the underground detectors IMB and Kamiokande II during the SN1987A event. The absence of such 100 MeV-range events imposes the strongest constraint on the neutrino magnetic dipole moment.