Impacts of the observed theta_{13} on the running behaviors of Dirac and Majorana neutrino mixing angles and CP-violating phases

Abstract

The recent observation of the smallest neutrino mixing angle ${\theta }_{13}$ in the Daya Bay and RENO experiments motivates us to examine whether ${\theta }_{13}\simeq 9^{\circ }$ at the electroweak scale can be generated from ${\theta }_{13}=0^{\circ }$ at a superhigh-energy scale via the radiative corrections. We find that it is difficult but not impossible in the minimal supersymmetric standard model (MSSM), and a relatively large ${\theta }_{13}$ may have some nontrivial impacts on the running behaviors of the other two mixing angles and CP-violating phases. In particular, we demonstrate that the CP-violating phases play a crucial role in the evolution of the mixing angles by using the one-loop renormalization-group equations of the Dirac or Majorana neutrinos in the MSSM. We also take the "correlative" neutrino mixing pattern with ${\theta }_{12}\simeq 35.3^{\circ }$, ${\theta }_{23}=45^{\circ }$ and ${\theta }_{13}\simeq 9.7^{\circ }$ at a presumable flavor symmetry scale as an example to illustrate that the three mixing angles can receive comparably small radiative corrections and thus evolve to their best-fit values at the electroweak scale if the CP-violating phases are properly adjusted.

Comments: RevTeX 16 pages, 3 figures, 4 tables, more discussions added, references updated. Accepted for publication in Phys. Rev. D