We analyze the geometric phase in the neutrino oscillation phenomenon, which follows the pion decay \pi+ --> \mu+ + \nu_{ \mu}. Its value \pi is consistent with the present-day global analysis of the Standard Model neutrino oscillation parameters, accounting for the nonzero value of \theta_13. The impact of the charge-parity (CP) violating phase \delta, the neutrino's nature, and the new physics is discussed.
Categories: hep-ph quant-ph