Elementary Particle Interactions In A Background Magnetic Field
  The thesis deals with the effect of magnetic fields on elementary particle interactions, of which the neutrino is of prime concern. The initial part focuses on the quantum field theoretical description of scattering processes which involves charged particles, in presence of a background uniform magnetic field. A brief discussion on the charged particle propagators in an uniform background magnetic field using Schwinger's method is presented. A general analysis on neutrino self-energy in a background magnetic field (and in a magnetized medium) alongwith its effect on neutrino oscillation phenomenology, follows. The final part of the thesis deals with the topic of neutrino photon interactions in a background magnetic field and finds an expression of the effective electric charge of neutrinos in a magnetized medium. 
Kaushik Bhattacharya