Checking T and CPT violation with sterile neutrino

Abstract

Post LSND results, sterile neutrinos have drawn attention and motivated the high energy physics, astronomy and cosmology to probe physics beyond the standard model considering minimal 3+1 (3 active and 1 sterile) to 3+N neutrino schemes. The analytical equations for neutrino conversion probabilities are developed in this work for 3+1 neutrino scheme. Here, we have tried to explore the possible signals of T and CPT violations with four flavor neutrino scheme at neutrino factory. Values of sterile parameters considered in this analysis are taken from two different types of neutrino experiments viz. long baseline experiments and reactor+atmospheric experiments. In this work golden and discovery channels are selected for the investigation of T violation. While observing T violation we stipulate that neutrino factory working at 50 GeV energy have the potential to observe the T violation signatures for the considered range of baselines(3000 km-7500 km). The ability of neutrino factory for constraining CPT violation is enhanced with increase in energy for normal neutrino mass hierarchy(NH). Neutrino factory with the exposure time of 500 kt-yr will be able to capture CPT violation with $ \delta c_{31}\geq 3.6\times10^{-23} $ GeV at 3$ \sigma $ level for NH and for IH with $ \delta c_{31}\geq 4\times10^{-23} $ GeV at 3$ \sigma $ level.