Nonzero theta(13), CP Violation, and Broken mu - tau Symmetry

作者：Damanik Asan^*

来源：Chinese Journal of Physics, 2014, 52(5): 1439-1449.

DOI：10.6122/CJP.20140514

Recently, evidence for a nonzero and relatively large theta(13), as measured in the latest experiment, has a strong implication on the well-known neutrino mixing matrix and the existence of CP violation in the neutrino sector (J(CP) not equal 0). One of the well-known mixing matricies is the tribimaximal (TBM) neutrino mixing matrix that predicts the mixing angle theta(13) = 0 and J(CP) = 0. In order to accommodate a nonzero theta(13) and CP violation, we modified the TBM by introducing a simple perturbation matrix into the TBM matrix that can produce theta(13) = 7.89 degrees, which is in agreement with the current experimental results, and the Dirac phase (delta approximate to pi/2 and J(CP) approximate to 0.0222. The obtained neutrino mass matrix from the modified TBM with both nonzero theta(13) and delta is a complex neutrino mass matrix. If we impose mu - tau symmetry as a constraint into the neutrino mass matrix, one finds that the J(CP) = 0, which implies that CP violation cannot be accommodated in the mu - tau symmetry scheme. We break the mu - tau symmetry softly by introducing a small parameter x to perturb the neutrino mass matrix with the constraint that the trace of the perturbed neutrino mass matrix remains constant.

• 出版日期2014-10