CPT Violation in Atmospheric Neutrino Oscillation: A Two Flavour Matter Effects

We have studied CPT Violation in atmospheric neutrino oscillation considering two flavour framework with matter effects. We analyze the atmospheric neutrino data within the simplest scheme of two neutrino oscillation. We consider as special case of matter density profile, which are relevant for neutrino oscillations. In particular, we compute to constrain a specific from of CPT violation in matter by upper bound, (|Delta _{31}^{m}-overline {Delta _{31}^{m}}<<4.80times 10^{-3}eV^{2}) and (|sin2theta _{13}^{m}-sin2bar {theta _{13}^{m}}|<0.685.) The dispersion relation for the CPT violation in neutrino oscillation in matter are discussed