Indications for New Higgs Bosons

TL;DR

This paper reviews potential evidence for new Higgs bosons at around 95 GeV and 152 GeV, discussing their production mechanisms, possible models, and implications for Standard Model tensions.

Contribution

It identifies and analyzes experimental excesses suggesting new Higgs states and explores their theoretical implications and production channels.

Findings

Significant di-photon excesses at 95 GeV and 152 GeV.

The 152 GeV candidate may be produced via Drell-Yan processes involving an $SU(2)_L$ triplet.

The 152 GeV Higgs could explain tensions in top-quark distribution measurements.

Abstract

After the Higgs discovery, the question of whether particles beyond those of the Standard Model exist is more pressing than ever. In this context, the scalar sector is particularly promising, since it lies at the core of the internal problems of the Standard Model, while extensions of it allow us to resolve them and can provide explanations for Dark matter, non-zero neutrino masses, inflation etc. In these proceedings, we review the indications for new Higgs bosons at the electroweak scale with masses of $\approx$95 GeV and $\approx$152 GeV. These excesses are most significant in the di-photon channel but are supported by weaker-than-expected limits in other decay modes. While for the 95 GeV candidate the production mechanism is mostly unknown, the (hypothetical) 152 GeV Higgs is dominantly produced in association with leptons, $(b)$ jets and missing energy, pointing towards the Drell-Yan production of an $SU(2)_L$ triplet with $Y=0$. Interestingly, this model predicts $t\to H^\pm b$ with $H^\pm\to WZ$, which resembles the signature of $t\bar{t}Z$ production in the Standard Model and is in fact preferred by current data. Finally, we investigate the possibility that the significant tensions between the Standard Model predictions and the measurements in differential top-quark distributions are due to contamination from new physics involving both the 152 GeV and the 95 GeV scalar.