Role of sterile neutrinos in oscillation probability
In the standard model of particle physics, there are three different generations with lepton doublets. Each doublet consists of a charged lepton and a neutral lepton. Charged leptons are of three different flavors - electron, muon and tau and neutral leptons are corresponding neutrinos of these three different flavors. Unlike the charged leptons, the neutrinos carry zero electric charge and have very little mass, only noticeably interacting with matter through the weak nuclear force. There are currently three known flavors of neutrino, the electron, muon, and tau, corresponding to the three generations of leptons. Now, recent experiments confirm neutrino oscillations, that is, neutrinos can oscillate between its different flavour eigen states. This indicates that atleast some of the neutrinos are massive. We can think of the flavor eigen states as the linear combinations of three mass eigen states ν1, ν2 , and ν3 . In the SeeSaw type-1 mechanism the three neutrinos get very light mass of the order of 0.1 eV in a natural way without considering very small Yukawa coupling associated with interaction of Higgs with neutrinos. In this project in the SeeSaw type-1 mechanism we consider one to three massive right-handed neutrinos and using the mass matrix from the SeeSaw type-1 mechanism, we are finding unitary mixing matrix which will give the mixing of the active and sterile neutrinos. With the help of mixing matrix we can find the oscillation probability of neutrinos. With the variation of heavy right handed neutrino mass we study the variations of oscillation probability of neutrinos from one flavor to other flavors. Also we like to study why active light neutrinos in spite of being massive, are found to be only left handed.
Keywords: right-handed neutrino, neutrino oscillation, mass mixing matrix