Hock-Seng Goh

Minimal SUSY SO(10), b–τ unification and large neutrino mixings

Abstract We show that the assumption of type II seesaw mechanism for small neutrino masses coupled with b – τ mass unification in a minimal SUSY SO (10) model leads not only to a natural understanding of large atmospheric mixing angle ( θ 23 ) among neutrinos, as recently noted, but also to large solar angle ( θ 12 ) and a small θ 13 ≡ U e 3 as required to fit observations. No additional symmetries are required to obtain large neutrino mixings. The proposed long baseline neutrino experiments will provide a crucial test of this model since it predicts U e 3 ≃0.16.

Minimal SUSY SO(10) model and predictions for neutrino mixings and leptonic CP violation

We discuss a minimal supersymmetric SO(10) model where

A Twin Higgs model from left-right symmetry

B\ensuremath{-}L

Phenomenology of The Left-Right Twin Higgs Model

symmetry is broken by a 126 dimensional Higgs boson multiplet which also contributes to fermion masses in conjunction with a 10 dimensional superfield. This minimal Higgs boson choice provides a partial unification of neutrino flavor structure with that of quarks and has been shown to predict all three neutrino mixing angles and the solar mass splitting in agreement with observations, provided one uses the type II seesaw formula for neutrino masses. In this paper we generalize this analysis to include arbitrary CP phases in couplings and vacuum expectation values. We find that (i) the predictions for neutrino mixings are similar with

SO(10) symmetry breaking and type II seesaw formula

{U}_{e3}\ensuremath{\simeq}0.18

The leptonic Higgs as a messenger of dark matter

as before and other parameters in a somewhat bigger range and (ii) that to first order in the quark mixing parameter

Proton decay in a minimal SUSY SO(10) model for neutrino mixings

\ensuremath{\lambda}

Lepton number violating signals of the top quark partners in the left-right twin Higgs model

(the Cabibbo angle), the leptonic mixing matrix is CP conserving. We also find that in the absence of any higher dimensional contributions to fermion masses, the CKM phase is different from that of the standard model implying that there must be new contributions to quark CP violation from the supersymmetry breaking sector. Inclusion of higher dimensional terms however allows the standard model CKM phase to be maintained.

Testing neutrino mass matrices with approximate Le–Lμ–Lτ symmetry

We present twin Higgs models based on the extension of the Standard Model to left-right symmetry that protect the weak scale against radiative corrections up to scales of order 5 TeV. In the ultraviolet the Higgs sector of these theories respects an approximate global symmetry, in addition to the discrete parity symmetry characteristic of left-right symmetric models. The Standard Model Higgs field emerges as the pseudo-Goldstone boson associated with the breaking of the global symmetry. The parity symmetry tightly constrains the form of radiative corrections to the Higgs potential, allowing natural electroweak breaking. The minimal model predicts a rich spectrum of exotic particles that will be accessible to upcoming experiments, and which are necessary for the cancellation of one-loop quadratic divergences. These include right-handed gauge bosons with masses not to exceed a few TeV and a pair of vector-like quarks with masses of order several hundred GeV.

R-axion detection at LHC

The twin Higgs mechanism was proposed recently to solve the little hierarchy problem. We study the implementation of the twin Higgs mechanism in left-right models. At the TeV scale, heavy quark and gauge bosons appear, with rich collider phenomenology. In addition, there are extra Higgs bosons, some of which couple to both the standard model fermion sector and the gauge sector, while others couple to the gauge bosons only. We present the particle spectrum and study the general features of the collider phenomenology of this class of model at the Large Hadron Collider.