Tuesday, March 20, 2012

1105.4460 (Y. H. Ahn et al.)

Towards a realistic tribimaximal-like neutrino mixing matrix    [PDF]

Y. H. Ahn, Hai-Yang Cheng, Sechul Oh
Motivated by the Qin-Ma (QM) parametrization for the quark mixing matrix in which the {\it CP}-odd phase is approximately maximal, we propose a simple {\it ansatz} for the charged lepton mixing matrix, namely, it has the QM-like parametrization, and assume the tribimaximal mixing (TBM) pattern for the neutrino mixing matrix. The deviation of the leptonic mixing matrix from the TBM one is then systematically studied. While the deviation of the solar and atmospheric neutrino mixing angles from the corresponding TBM values, i.e. $\sin^2\theta_{12}=1/3$ and $\sin^2\theta_{23}=1/2$, is fairly small, we find a nonvanishing reactor mixing angle given by $\sin\theta_{13}\approx \lambda/\sqrt{2}$ ($\lambda\approx 0.22$ being the Cabibbo angle) and a very large Dirac {\it CP}-odd phase. Specifically, we obtain $\theta_{13}\simeq 9.2^{\circ}$ and $\delta_{CP}\simeq {\cal O}(80^{\circ})$. Furthermore, we show that the leptonic \CP violation characterized by the Jarlskog invariant is $|J^{\ell}_{CP}|\simeq \lambda/6$, which could be tested in the future experiments such as the upcoming long baseline neutrino oscillation ones.
View original: http://arxiv.org/abs/1105.4460

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