The leptonic Dirac CP-violating phase from sum rules

14th International Conference on Topics in Astroparticle and Underground Physics

物理学;天文学

Girardi, I.^1 ; Petcov, S.T.^1,2,3 ; Titov, A.V.^1

SISSA/INFN, Via Bonomea 265, Trieste

34136, Italy^1

Kavli IPMU (WPI), University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa

277-8583, Japan^2

Institute of Nuclear Research and Nuclear Energy, Bulgarian Academy of Sciences, Sofia

1784, Bulgaria^3

关键词: Charged leptons;    Fundamental symmetries;    Likelihood functions;    Measured values;    Neutrino mass;    Neutrino mixing;    Neutrino oscillations;    Unitary matrix;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/718/6/062060/pdf
DOI  :  10.1088/1742-6596/718/6/062060

学科分类：天文学(综合)

来源: IOP

【 摘 要 】

In the reference 3-neutrino mixing scheme with three light massive neutrinos, CP-violating effects in neutrino oscillations can be caused by the Dirac CP-violating phase δ present in the unitary neutrino mixing matrix U. Using the fact that U = U†eUv, where Ueand Uvare unitary matrices arising from the diagonalisation, respectively, of the charged lepton and neutrino mass matrices, we consider in a systematic way forms of Ueand Uvallowing us to express δ as a function of the neutrino mixing angles present in U and the angles contained in Uv. After obtaining sum rules for cos δ, we consider several forms of Uvdictated by, or associated with, symmetries, such as tri-bimaximal, bimaximal, etc., for which the angles in Uvare fixed. For each of these forms and forms of Ueallowing to reproduce the measured values of the neutrino mixing angles, we construct the likelihood function for cos δ, using the prospective uncertainties in the determination of the mixing angles. Our results show that the measurement of δ along with improvement of the precision on the neutrino mixing angles can provide unique information about the possible existence of a new fundamental symmetry in the lepton sector.