EXTRINSIC CPT VIOLATION WITH STERILE NEUTRINO

In this work, the matter induced CPT violating effects in neutrino oscillations are quantified with the help of Neutrino Factory setup. Here this extrinsic CPT violation is checked for the disappearance channel (ߥ ఓ → ߥ ఓ). The information of extrinsic CPT violation will help us in investigating pure CPT violation. The profile of interior density of earth from which the neutrinos passes is considered as step function matter density profile (PREM) in the present work. In the considered (3+1) neutrino framework, extrinsic CPT violation is checked for baselines 1300 km – 7500 km for energy range 4 to 50 GeV. In order to check sterile contribution in the total extrinsic CPT violation, we have selected few observables which can disentangle the contributions arising due to the presence of sterile neutrino from those which arises due to the presence of three active neutrinos. In the presence of sterile neutrino these observables promote higher energies (more than 20 GeV) especially 15 GeV for long baseline experiments to probe pure(intrinsic) CPT violation because sterile contribution to extrinsic CPT violation becomes very less at these energies. To give a realistic estimate of extrinsic CPT violation, the product of sterile angles ߠ ଶସ and ߠ ଷସ is constrained in our analysis. We get ߠ ଶସ .ߠ ଷସ≳ 0.006 rad 2 with liquid argon detector and ߠ ଶସ .ߠ ଷସ≳ 0.007 rad 2 with magnetized iron detector at 90% C.L. for the