Ernest Ma

Dark matter: The leptonic connection

Abstract Recent observations of high-energy positrons and electrons by the PAMELA and ATIC experiments may be an indication of the annihilation of dark matter into leptons and not quarks. This leptonic connection was foreseen already some years ago in two different models of radiative neutrino mass. We discuss here the generic interactions ( ν η 0 − l η + ) χ and l c ζ − χ c which allow this to happen, where χ and/or χ c are fermionic dark-matter candidates. We point out in particular the importance of χ χ → l + l − γ to both positron and gamma-ray signals within this framework.

Z3 dark matter and two-loop neutrino mass

Abstract Dark matter and neutrino mass are two of the most important issues to be understood in particle physics and astrophysics. Dark matter is universally assumed to be distinguished from ordinary matter by an odd–even parity, i.e. the discrete symmetry Z 2 , but that is not based on any fundamental principle. As an alternative and foil, a simple model of Z 3 dark matter is proposed and shown to be natural for understanding the smallness of neutrino mass as a two-loop radiative effect.

Radiative Scaling Neutrino Mass and Warm Dark Matter

Abstract A new and radical scenario of the simple 2006 model of radiative neutrino mass is proposed, where there is no seesaw mechanism, i.e. neutrino masses are not inversely proportional to some large mass scale, contrary to the prevalent theoretical thinking. The neutral singlet fermions in the loop have masses of order 10 keV, the lightest of which is absolutely stable and the others are very long-lived. All are components of warm dark matter, which is a possible new paradigm for explaining the structure of the Universe at all scales.

Lepton-number nonconservation in E6 superstring models

Abstract Lepton-number nonconservation is shown to be correlated with the mixing between the e, μ, τ, leptons and new heavy fermions of charge −1, as well as with the mixing between the d, s, b quarks and new heavy fermions of charge − 1 3 , all belonging to the 27 supermultiplets of E 6 as inspired by superstring theory. Various phenomenological implications are discussed.

Generalized lepton number and dark left-right gauge model

In a left-right gauge model of particle interactions, the left-handed fermion doublet

Dark vector-gauge-boson model

(ensuremath{nu},e{)}_{L}

Soft A4→Z3 symmetry breaking and cobimaximal neutrino mixing

is connected to its right-handed counterpart

TWO-BODY RADIATIVE GLUINO DECAYS

(n,e{)}_{R}

Gauge model of generation non-universality re-examined

through a scalar bidoublet so that

Sequential W and Z bosons

{e}_{L}