Joao Pulido

Resonance spin flavour precession and solar neutrinos

Abstract We examine the prospects for the resonance spin flavour precession as a solution to the solar neutrino problem. We study seven different realistic solar magnetic field profiles and, by numerically integrating the evolution equations, perform a fit of the event rates for the three types of solar neutrino experiments (Ga, Cl and SuperKamiokande) and a fit of the energy spectrum of the recoil electrons in SuperKamiokande. A χ 2 analysis shows that the quality of the rate fits is excellent for two of the field profiles and good for all others with χ 2 /d.o.f. always well below unity. Regarding the fits for the energy spectrum, their quality is better than that for the small mixing angle MSW solution of the solar neutrino problem, at the same level as that for the large mixing angle MSW solution but worse than that for the vacuum oscillations one. The experimental data on the spectrum are however largely uncertain especially in the high energy sector, so that it is too early yet to draw any clear conclusions on the likeliest type of particle physics solution to the solar neutrino problem.

Solar neutrino oscillations and bounds on neutrino magnetic moment and solar magnetic field

Abstract If the observed deficit of solar neutrinos is due to neutrino oscillations, neutrino conversions caused by the interaction of their transition magnetic moments with the solar magnetic field (spin-flavour precession) can still be present at a subdominant level. In that case, the combined action of neutrino oscillations and spin-flavour precession can lead to a small but observable flux of electron antineutrinos coming from the sun. Non-observation of these ν e s could set limits on neutrino transition moment μ and the strength and coordinate dependence of the solar magnetic field B ⊥ . The sensitivity of the ν e flux to the product μB ⊥ is the strongest in the case of the vacuum oscillation (VO) solution of the solar neutrino problem; in the case of the LOW solution, it is weaker, and it is the weakest for the LMA solution. For different solutions, different characteristics of the solar magnetic field B ⊥ ( r ) are probed: for the VO solution, the ν e flux is determined by the integral of B ⊥ ( r ) over the solar convective zone, for LMA it is determined by the magnitude of B ⊥ in the neutrino production region, and for LOW it depends on the competition between this magnitude and the derivative of B ⊥ ( r ) at the surface of the sun.

Quark–lepton complementarity with lepton and quark mixing data predict θ13 PMNS=(9+1 -2)°

The complementarity between the quark and lepton mixing matrices is shown to provide a robust prediction for the neutrino mixing angle

LMA and sterile neutrinos: a case for resonance spin flavour precession?

\theta_{13}^{PMNS}

SNO and the neutrino magnetic moment solution of the solar neutrino problem

. We obtain this prediction by first showing that the matrix

Probing neutrino magnetic moment and unparticle interactions with Borexino

V_M

Distinguishing magnetic moment from oscillation solutions of the solar neutrino problem with Borexino

, product of the CKM and PMNS mixing matrices, may have a zero (1,3) entry which is favored by experimental data. Hence models with bimaximal or tribimaximal forms of the correlation matrix

KamLAND, solar antineutrinos, and the solar magnetic field

V_M

Neutrino mass matrices with vanishing determinant

are quite possible. Any theoretical model with a vanishing (1,3) entry of

Low energy solar neutrinos and spin flavour precession

V_M