Can massless neutrinos oscillate in presence of matter?

Abstract

In presence of matter the possibility of flavor oscillation of massless neutrino is explored. A comparison between vacuum oscillation and the matter induced oscillation of massless neutrinos is carried out to examine whether the flavor transition is possible in the framework of standard model if there is background matter. The Stodolsky type of equation describing the neutrino oscillation phenomenon as the motion of a spherical pendulum in flavor space is deduced. That pendular model is studied with zero vacuum oscillation frequency implying the zero neutrino mass evolved in the framework of standard model, but non-zero frequency arising due to the MSW effect. The implication of the non-zero term present in the Stodolsky equation at zero vacuum frequency is addressed properly.