Higgs Bosons at 95 and 125 GeV in the $U(1)_X$VLFM

TL;DR

This paper analyzes Higgs signal strengths at 95 and 125 GeV within a $U(1)_X$ extension of the Standard Model featuring vector-like fermions, aiming to explain observed excesses and match experimental data.

Contribution

It introduces a non-supersymmetric $U(1)_X$ model with scalar mixing and vector-like fermions that can simultaneously fit the 125 GeV Higgs and 95 GeV excesses.

Findings

The model reproduces the 125 GeV Higgs signal strengths.

It successfully explains the 95 GeV excess in diphoton and $bar{b}$ channels.

Parameter space analysis shows key roles for $g_X$, $g_{YX}$, $v_S$, $v_P$, and Yukawa couplings.

Abstract

We present a systematic analysis of the Higgs signal strengths at 125 GeV and 95 GeV in a non-supersymmetric $U(1)_X$ model with vector-like fermions ($U(1)_X$VLFM). This model extends the SM by introducing an additional $U(1)_X$ gauge symmetry, three right-handed neutrinos, two singlet Higgs fields ($\phi$ and $S$), and one generation of vector-like quarks and leptons. The scalar fields mix with each other in the neutral CP-even sector, leading to two Higgs-like states around 95 GeV and 125 GeV. A $\chi^2$ analysis is performed by combining the Higgs signal strength measurements at 125 GeV from ATLAS and CMS, including the $\gamma\gamma$, $WW^*$, $ZZ^*$, $b\bar{b}$, and $\tau\bar{\tau}$ channels, with the 95 GeV excesses observed in the diphoton and $b\bar{b}$ final states reported by CMS and LEP. Our results indicate that the $U(1)_X$VLFM can successfully reproduce the observed signal strengths of the 125 GeV Higgs while simultaneously explaining the 95 GeV excess. The parameters $g_X$, $g_{YX}$, $v_S$, $v_P$, and the new Yukawa couplings play a crucial role in achieving this consistency.