Effects of non-standard neutrino interactions on MSW-LMA solution to the solar neutrino problem

We show that the non-standard neutrino interactions can play a role as subleading effect on the solar neutrino oscillations. We observe that very small flavor universality violations of order of 0.1-0.2 G(F) is sufficient to induce two phenomena: suppression of the v(e)-Earth regeneration and a shift of the resonance layer in the Sun. We obtain these phenomena even in the absence of any flavor changing interactions. We discuss their consequences and confront with a global analysis of solar + KamLAND results. We conclude that a new compatibility region in the Deltam(2) x tan(2)thetacircle dot, which we call very low large mixing angle region is found for Deltam(2) similar to 10(-5) eV(2) and tan(2)thetacircle dot = 0.45. (C) 2004 Elsevier B.V. All rights reserved.