Quantum Gravity Effects on Oscillation Parameters in a Four Flavor Framework

We consider the effects of Planck scale operators on four flavour neutrino mixings. Quantum gravity (Planck scale effects) leads to an effective SU(2)L × U(1) invariant dimension-5 Lagrangian involving, neutrino and Higgs fields. On symmetry breaking, this operator gives rise to correction to the neutrino masses and mixing.We investigate the effect of higher dimensional operators coming from Planck scale Physics on neutrino oscillation parameters in a four flavor framework. We find that most of the parameters are not altered by this effect but we get the interesting result that for certain values of the Majoranna phases, the 𝜃23 (the atmospheric neutrino mixing angle) goes significantly above 45 degrees. Hence these values of the Majoranna phases are disallowed by data.