LHC probes of TeV-scale scalars in $\mathrm{SO}(10)$ grand unification

Abstract

We investigate the possibility of TeV-scale scalars as low energy remnants arising in the non-supersymmetric $\mathrm{SO}(10)$ grand unification framework where the field content is minimal. We consider a scenario where the $\mathrm{SO}(10)$ gauge symmetry is broken into the gauge symmetry of the Standard Model (SM) through multiple stages of symmetry breaking, and a colored and hypercharged scalar $\chi$ picks a TeV-scale mass in the process. The last stage of the symmetry breaking occurs at the TeV scale where the left-right symmetry, i.e. $\mathrm{SU}(2)_L\otimes \mathrm{SU}(2)_R\otimes \mathrm{U}(1)_{B-L}\otimes \mathrm{SU}(3)_C$, is broken into that of the SM by a singlet scalar field $\mathcal{S}$ of mass $M_{\mathcal{S}}\sim 1$ TeV, which is a component of an $\mathrm{SU}(2)_R$-triplet scalar field, acquiring a TeV-scale vacuum expectation value. For the LHC phenomenology, we consider a scenario where $\mathcal{S}$ is produced via gluon-gluon fusion through loop interactions with $\chi$ and also decays to a pair of SM gauge bosons through $\chi$ in the loop. We find that the parameter space is heavily constrained from the latest LHC data. We use a multivariate analysis to estimate the LHC discovery reach of $\mathcal{S}$ into the diphoton channel.