Can massless neutrinos oscillate in presence of matter?

TL;DR

This paper investigates whether massless neutrinos can oscillate in matter within the standard model, analyzing the conditions and equations governing flavor transitions without neutrino mass.

Contribution

It introduces a Stodolsky-type equation for massless neutrino oscillation in matter and explores the possibility of flavor change without neutrino mass.

Findings

Massless neutrinos can exhibit flavor oscillations in matter due to the MSW effect.

The derived pendular model describes oscillations with zero vacuum frequency but non-zero matter-induced frequency.

Implications suggest flavor transitions are possible without neutrino mass in standard model conditions.

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.