Sudhanwa Patra

Signal of right-handed charged gauge bosons at the LHC?

We point out that the recent excess observed in searches for a right-handed gauge boson WR at CMS can be explained in a left-right symmetric model with D-parity violation. In a class of SO(10) models, in which D parity is broken at a high scale, the left-right gauge symmetry breaking scale is naturally small, and at a few TeV the gauge coupling constants satisfy gR≈0.6gL. Such models therefore predict a right-handed charged gauge boson WR in the TeV range with a suppressed gauge coupling as compared to the usually assumed manifest left-right symmetry case gR=gL. The recent CMS data show excess events which are consistent with the cross section predicted in the D-parity breaking model for 1.9TeV<MWR<2.4TeV. If the excess is confirmed, it would in general be a direct signal of new physics beyond the Standard Model at the LHC. A TeV scale WR would for example not only rule out SU(5) grand unified theory models. It would also imply B-L violation at the TeV scale, which would be the first evidence for baryon or lepton number violation in nature, and it has strong implications on the generation of neutrino masses and the baryon asymmetry in the Universe.

Reconciling the 2 TeV Excesses at the LHC in a Linear Seesaw Left-Right Model

We interpret the 2 TeV excesses at the LHC in a left-right symmetric model with Higgs doublets and spontaneous D-parity violation. The light neutrino masses are understood via a linear seesaw, suppressed by a high D-parity breaking scale, and the heavy neutrinos have a pseudo-Dirac character. In addition, with a suppressed right-handed gauge coupling gR/gL≈0.6 in an SO(10) embedding, we can thereby interpret the observed eejj excess at CMS. We show that it can be reconciled with the diboson and dijet excesses within a simplified scenario based on our model. Moreover, we find that the mixing between the light and heavy neutrinos can be potentially large, which would induce dominant nonstandard contributions to neutrinoless double beta decay via long-range λ and η neutrino exchange.

Implications of the diphoton excess on left–right models and gauge unification

The recent diphoton excess signal at an invariant mass of 750 GeV can be interpreted in the framework of left–right symmetric models with additional scalar singlets and vector-like fermions. We propose a minimal scenario for such a purpose. Extending the LRSM framework to include these new vector-like fermionic fields, on the other hand, results in interesting phenomenological implications for the LRSM fermion masses and mixing. Furthermore, existence of such vector-like fermions can also have interesting implications for baryogenesis and the dark matter sector. The introduction of a real bi-triplet scalar which contains a potential DM candidate will allow the gauge couplings to unify at ≈1017.7 GeV.

Minimal Left-Right Symmetric Dark Matter

We show that left-right symmetric models can easily accommodate stable TeV-scale dark matter particles without the need for an ad hoc stabilizing symmetry. The stability of a newly introduced multiplet either arises accidentally as in the minimal dark matter framework or comes courtesy of the remaining unbroken Z_{2} subgroup of B-L. Only one new parameter is introduced: the mass of the new multiplet. As minimal examples, we study left-right fermion triplets and quintuplets and show that they can form viable two-component dark matter. This approach is, in particular, valid for SU(2)×SU(2)×U(1) models that explain the recent diboson excess at ATLAS in terms of a new charged gauge boson of mass 2 TeV.

Double beta decay, lepton flavor violation, and collider signatures of left-right symmetric models with spontaneous D-parity breaking

We propose a class of left-right symmetric models (LRSMs) with spontaneous

Neutrinoless double-

D

\beta

-parity breaking, where

decay in TeV scale Left-Right symmetric models

SU(2{)}_{R}

Neutrino masses, dominant neutrinoless double beta decay, and observable lepton flavor violation in left-right models and SO(10) grand unification with low mass W R , Z R bosons

breaks at the TeV scale while discrete left-right symmetry breaks around

750 GeV diphoton excess at CERN LHC from a dark sector assisted scalar decay

1{0}^{9}\text{ }\text{ }\mathrm{GeV}