Explanation of the 95 GeV $\gamma\gamma$ and $b\bar{b}$ excesses in the Minimal Left-Right Symmetric Model

TL;DR

This paper explains the 95 GeV gamma-gamma and b-bbar excesses observed by CMS, ATLAS, and LEP using a scalar in the minimal left-right symmetric model, linking it to neutrino mass generation without extra scalars.

Contribution

It demonstrates that the minimal LRSM scalar responsible for neutrino seesaw can account for the observed excesses without additional scalar fields.

Findings

The scalar couples mainly to heavy right-handed particles, evading constraints.

Diphoton decay contributions come from mixing with the SM Higgs and heavy charged bosons.

Parameter space can be tested with future high-precision Higgs measurements.

Abstract

We propose a simple interpretation of the $\gamma\gamma$ excesses reported by both CMS and ATLAS groups at 95 GeV together with the LEP excess in the $Zb\bar{b}$ channel around the same mass in terms of a neutral scalar field in the minimal left-right symmetric model (LRSM). We point out that the scalar field which implements the seesaw mechanism for neutrino masses has all the right properties to explain these observations, without introducing any extra scalar fields. The key point is that this scalar particle is hardly constrained because it couples only to heavy right-handed particles. As a result, the diphoton decay mode receives contributions from both mixing with the Standard Model (SM) Higgs and the heavy charged bosons in the LRSM, depending on the $SU(2)_R\times U(1)_{B-L}$ symmetry breaking scale $v_R$. The complete allowed parameter space for explaining the 95 GeV excesses in this model can be probed with the high-precision measurements of the SM Higgs mixing with other scalars at the high-luminosity LHC and future Higgs factories.