Parity violation and its effects for neutrinos in astrophysical contexts have
been considered earlier in pioneering papers of Hawking and Vilenkin. But
because even the largest magnetic moments predicted by physics beyond the
Standard Model are some twelve orders of magnitude smaller than the Bohr
magneton, their implications for magnetic field generation and neutrino
oscillations are generally considered insignificant. Here we show that since in
astrophysical scenarios a huge number of neutrinos may be emitted, the
smallness of the magnetic moment, when coupled with parity violation, is
compensated by the sheer number of neutrinos. The merger of neutron stars would
leave behind a short pulse of electromagnetic synchrotron radiation even if the
neutrino jet in the merger points away from the neutrino detectors. We show
that the magnetic field can be as large as 10^6\,\mbox{Gauss} and comment on
the possibility of direct detection. Observation of such a pulse would lend
strong support for neutrino magnetic moments and resolve the missing neutrino
problem in neutron star mergers.Comment: 5 pages, version accepted for publication in Europhysics Letters
(EPL
