#### Filter Results:

- Full text PDF available (197)

#### Publication Year

1992

2017

- This year (1)
- Last 5 years (7)
- Last 10 years (45)

#### Publication Type

#### Co-author

#### Journals and Conferences

#### Key Phrases

Learn More

- Ernest Ma
- 2008

A minimal extension of the Standard Model is proposed, where the observed lefthanded neutrinos obtain naturally small Majorana masses from a one-loop radiative seesaw mechanism. This model has two candidates (one bosonic and one fermionic) for the dark matter of the Universe. It has a very simple structure and should be verifiable in forthcoming experiments… (More)

- Ernest Ma, G. Rajasekaran
- 2001

The leptonic Higgs doublet model of neutrino masses is implemented with an A4 discrete symmetry (the even permutation of 4 objects or equivalently the symmetry of the tetrahedron) which has 4 irreducible representations: 1, 1, 1, and 3. The resulting spontaneous and soft breaking of A4 provides a realistic model of charged-lepton masses as well as a nearly… (More)

- Ernest Ma
- 1998

In the minimal standard electroweak gauge model, there is an effective dimensionfive operator which generates neutrino masses. I show that there are three tree-level realizations of this operator. One is the canonical seesaw mechanism with a righthanded neutrino. Another is having a heavy Higgs triplet as recently proposed. The third possibility is to have… (More)

- Ernest Ma
- 2006

I review some of the recent progress (up to September 2005) in applying nonAbelian discrete symmetries to the family structure of leptons, with particular emphasis on the tribimaximal mixing ansatz of Harrison, Perkins, and Scott. — Talk at Corfu2005 —

- Ernest Ma
- 2002

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… (More)

If the recently discovered anomalous events at HERA are due to a scalar leptoquark, then it is very likely to have weak isospin I = 1/2. In that case, present precision measurements of the oblique radiative parameters S and T provide strong constraints on the mass of the other component of this doublet. If the standard model is extended to include such a… (More)

- Ernest Ma, Utpal Sarkar
- 1998

A simple and economical extension of the minimal standard electroweak gauge model (without right-handed neutrinos) by the addition of two heavy Higgs scalar triplets would have two significant advantages. Naturally small Majorana neutrino masses would become possible, as well as leptogenesis in the early universe which gets converted at the electroweak… (More)

A heavy triplet of leptons (Σ,Σ,Σ)R per family is proposed as the possible anchor of a small seesaw neutrino mass. A new U(1) gauge symmetry is then also possible, and the associated gauge boson X may be discovered at or below the TeV scale. We discuss the phenomenology of this proposal, with and without possible constraints from the NuTeV and atomic parity… (More)

- Ernest Ma
- 2002

If the standard model of quark interactions is supplemented by a discrete A4 symmetry (which may be relevant for the lepton sector), the spontaneous breaking of the electroweak gauge symmetry allows arbitrary quark masses, but all mixing angles are predicted to be zero. A pattern of the explicit breaking of A4 is proposed, which results in a realistic… (More)

- Ernest Ma, Hideyuki Sawanaka, Morimitsu Tanimoto
- 2006

The successful A4 family symmetry for leptons is applied to quarks, motivated by the quark-lepton assignments of SU(5). Realistic quark masses and mixing angles are obtained, in good agreement with data. In particular, we find a strong correlation between |Vub| and the CP phase β, thus allowing for a decisive future test of this model. Since the original… (More)