The MSW solution to the solar neutrino problem in the presence of random solar matter density perturbations

Abstract

We present the evolution equation describing MSW conversion, derived in the framework of the Schr\"odinger approach, in the presence of matter density fluctuations. Then we analyse the effect of such fluctuations in the MSW scenario as a solution to the solar neutrino problem. It is shown that the non-adiabatic MSW parameter region is rather stable (especially in $\delta m^2$) for matter density noise at the few percent level. We also discuss the possibility to probe solar matter density fluctuations at the future Borexino experiment.