Proposal of a simple method to estimate neutrino oscillation probability and CP violation in matter

摘要

We study neutrino oscillation within the framework of three generations in matter. We propose a simple method to approximate the coefficients A, B and C which do not depend on the CP phase delta in the oscillation probability P(nu(e) --> nu(mu)) = A cos delta + B sin delta + C. An advantage of our method is that an approximate formula of the coefficients A, B and C in arbitrary matter without the usual first order perturbative calculations of the small parameter Deltam(21)(2)/Deltam(31)(2) or sintheta(13) can be derived. Furthermore, we show that all the approximate formulas for low, intermediate and high energy regions given by other authors in constant matter can be easily derived from our formula. It means that our formula is applicable over a wide energy region. (C) 2004 Elsevier B.V. All rights reserved.