We study the see-saw enhancement mechanism in presence of the right-handed phases of the Dirac neutrino mass matrix and the Majorana mass matrix. The enhancement condition given by S mirnov is modified. We point out that the see-saw enhancement could be obt ained due to the right-handed phases even if the Majorana matrix is proportional to the unit matrix. We show a realistic Dirac mass matrix ...

Consider the most general 3 x 3 Majorana neutrino mass matrix M. Motivated by present neutrino-oscillation data, much theoretical effort is directed at reducing it to a specific texture in terms of a small number of parameters. This procedure is often ad hoc. I propose instead that for any M one may choose, it should satisfy the condition UMU(T)=M, where U not equal 1 is a specific unitary matr...

The discrete subgroup ∆(27) of SU(3) has some interesting properties which may be useful for understanding charged-lepton and neutrino mass matrices. Assigning leptons to the 3 and 3̄ representations of ∆(27), a simple form of the Majorana neutrino mass matrix is obtained and compared to present data. Since the introduction of the discrete symmetry A4 [1, 2] for understanding the family structur...

With the recent experimental advance in our precise knowledge of the neutrino oscillation parameters, the correct form of the 3 × 3 neutrino mass matrix is now approximately known. I discuss how this may be obtained from symmetry principles, using as examples the finite groups A4 and Z4, predicting as a result three nearly degenerate Majorana neutrino masses in the 0.2 eV range. ——— Preprint ve...

A physical model which describes the CKM matrix is analyzed. The elements of such a matrix are field-strength renormalization factors. Each column gives the probability amplitude for the field operators of the coupled Lagrangian to create a one-particle eigenfunction of definite energy. The total conserved charge is the sum of the flavor charges which are not conserved separately. This work is ...

With the accumulation of many years of solar and atmospheric neutrino oscillation data, the approximate form of the 3 × 3 neutrino mixing matrix is now known. The theoretical challenge is to understand where this mixing matrix comes from. Recently, a remarkable fact was discovered that for a specific pattern of the neutrino mass matrix at a high scale, any flavor-changing radiative correction w...

We show that the bimaximal neutrino mixing pattern suggested by the solar and atmospheric neutrino data can be derived from the maximal, symmetric , four neutrino mixing in the limit that one of the neutrinos is made heavy. Imposing the constraints of no neutrinoless double beta decay and a 20% hot dark matter component of the universe leads to a three neutrino mass matrix recently suggested by...

With the accumulation of many years of solar and atmospheric neutrino oscillation data, the approximate form of the 3× 3 neutrino mixing matrix is now known. What is not known is the (presumably Majorana) neutrino mass matrix Mν itself. In this chapter, the approximate form of Mν is derived, leading to seven possible neutrino mass patterns: three have the normal hierarchy, two have the inverse ...

The standard model of leptons is extended to accommodate a discrete Z3 × Z2 family symmetry. After rotating the charged-lepton mass matrix to its diagonal form, the neutrino mass matrix reveals itself as very suitable for explaining atmospheric and solar neutrino oscillation data. A generic requirement of this approach is the appearance of three Higgs doublets at the electroweak scale, with obs...

On the basis of a seesaw-type mass matrix model for quarks and leptons, Mf ≃ mLM F mR, wheremL ∝ mR are universal for f = u, d, ν and e (up-quark-, down-quark-, neutrinoand charged lepton-sectors), and MF is given by MF = K(1 + 3bfX) (1 is a 3 × 3 unit matrix, X is a democratic-type matrix and bf is a complex parameter which depends on f , neutrino mass spectrum and mixings are discussed. The m...