Parallel Texture Structures with Cofactor Zeros in Lepton Sector

In this paper we investigate the parallel texture structures with cofactor zeros in the charged lepton and neutrino sectors. The textures can not be obtained from arbitrary leptonic matrices by making weak basis transformations, which therefore have physical meaning. The 15 parallel textures are grouped as 4 classes where each class has the same physical implications. It is founded that one of them is not phenomenological viable and another is equivalent to the texture zero structures extensively explored in previous literature. Thus we focus on the other two classes of parallel texture structures and study the their phenomenological implications. The constraints on the physical variables are obtained for each class, which are essential for the model selection and can be measured by future experiments. The model realization is illustrated in a radiated lepton mass model.Comment: 21 pages, 4 figures. An errors of calculation is corrected, phenomenology is partly change

Neutrino mass textures with one vanishing minor and two equal cofactors

In this paper, we carry out a numerical and systematic analysis of the neutrino mass textures, which contain one vanishing minor and an equality between two cofactors. Among 60 logically possible textures, only eight of them are excluded for both normal and inverted hierarchy by the current experimental data at 3\sigma level. We also demonstrate that the future long-baseline neutrino oscillation experiments, especially for the measurement of \theta 23 mixing angle, will play the important role in the model selection. The phenomenological implications from neutrinoless double beta decay and the cosmology observation are also examined. A discussion on the flavor symmetry realization of the textures is also given.Comment: 18 pages, 2 figure

Naturally Small Dirac Neutrino Mass with Intermediate SU(2)LSU(2)_{L} Multiplet Fields

If neutrinos are Dirac fermions, certain new physics beyond the standard model should exist to account for the smallness of neutrino mass. With two additional scalars and a heavy intermediate fermion, in this paper, we systematically study the general mechanism that can natrally generate the tiny Dirac neutrino mass at tree and in one-loop level. For tree level models, we focus on natural ones, in which the additional scalars develop small vacuum expectation values without fine-tuning. For one-loop level models, we explore those having dark matter candidates under $Z_2^D$ symmetry. In both cases, we concentrate on $SU(2)_L$ multiplet scalars no larger than quintuplet, and derive the complete sets of viable models. Phenomenologies, such as lepton flavor violation, leptogenesis, and LHC signatures are briefly discussed.Comment: 31 pages, 16 figure

The B−LB-L Scotogenic Models for Dirac Neutrino Masses

We construct the one-loop and two-loop scotogenic models for Dirac neutrino mass generation in the context of $U(1)_{B-L}$ extensions of standard model. It is indicated that the total number of intermediate fermion singlets is uniquely fixed by anomaly free condition and the new particles may have exotic $B-L$ charges so that the direct SM Yukawa mass term $\bar{\nu}_L\nu_R\overline{\phi^0}$ and the Majorana mass term $(m_N/2)\overline{\nu_R^C}\nu_R$ are naturally forbidden. After the spontaneous breaking of $U(1)_{B-L}$ symmetry, the discrete $Z_{2}$ or $Z_{3}$ symmetry appears as the residual symmetry and give rise to the stability of intermediated fields as DM candidate. Phenomenological aspects of lepton flavor violation, DM, leptogenesis and LHC signatures are discussed.Comment: 18 pages, 16 figure