A. I. Rez

Constraining the neutrino magnetic moment with antineutrinos from the sun.

We discuss the impact of different solar neutrino data on the spin-flavor-precession (SFP) mechanism of neutrino conversion. We find that, although detailed solar rates and spectra allow the SFP solution as a subleading effect, the recent KamLAND constraint on the solar antineutrino flux places stronger constraints on this mechanism. Moreover, we show that for the case of random magnetic fields inside the Sun, one obtains a more stringent constraint on the neutrino magnetic moment down to the level of mu(nu)< or = few x 10(-12)mu(B), similar to bounds obtained from star cooling.

Enhanced solar antineutrino flux in random magnetic fields

We discuss the impact of the recent KamLAND constraint on the solar antineutrino flux on the analysis of solar neutrino data in the presence of Majorana neutrino transition magnetic moments and solar magnetic fields. We consider different stationary solar magnetic field models, both regular and random, highlighting the strong enhancement in the antineutrino production rates that characterize turbulent solar magnetic field models. Moreover, we show that for such magnetic fields inside the Sun, one can constrain the intrinsic neutrino magnetic moment down to the level of {mu}{sub {nu}} < or approx. fewx10{sup -12}{mu}{sub B} irrespective of details of the underlying turbulence model. This limit is more stringent than all current experimental sensitivities, and similar to the most stringent bounds obtained from stellar cooling. We also comment on the robustness of this limit and show that at most it might be weakened by 1 order of magnitude, under very unlikely circumstances.

Neutrino conversions in random magnetic fields and ν ̃ e from the Sun

The magnetic field in the convective zone of the Sun has a random small-scale component with the r.m.s. value substantially exceeding the strength of a regular large-scale field. For two Majorana neutrino flavors

Neutrino spin-flavor conversions and νe emission from the sun with random magnetic field

\times

Electron antineutrinos from the sun with random magnetic fields

two helicities in the presence of a neutrino transition magnetic moment and nonzero neutrino mixing we analyze the displacement of the allowed (

Neutrino conversions in random magnetic fields and

\Delta m^2- \sin^22\theta

\tilde{\nu}_e

)-parameter region reconciled for the SuperKamiokande(SK) and radiochemical (GALLEX, SAGE, Homestake) experiments in dependence on the r.m.s. magnetic field value

from the Sun

b

Neutrino conversions in random magnetic fields and electron anti-neutrino from the sun

, or more precisely, on a value

Why solar anti-neutrino data are very sensitive to Majorana neutrino magnetic moment?

\mu b