Exploring Higgs-Photon Production at the LHC

TL;DR

This paper investigates the potential for detecting new physics beyond the Standard Model through Higgs plus photon production at the LHC, using effective field theory and advanced analysis techniques to set constraints on new interactions.

Contribution

It introduces a detailed analysis of Higgs-photon production via dimension-6 operators in SMEFT, including novel kinematic observables and multivariate methods to enhance sensitivity at the LHC.

Findings

Constraints on Wilson coefficients from existing data.

Identification of kinematic variables to distinguish signal from background.

Projected sensitivity for 3σ discovery at the 14 TeV LHC with 3000 fb^{-1}

Abstract

We have investigated the signal for physics beyond the Standard Model via Higgs plus photon final state, hitherto unobserved at the LHC, in the framework of Standard Model Effective Field Theory. Using the relevant dimension-6 operators, we probe two distinct classes of interactions, based on the Lorentz structure of Higgs couplings to gauge bosons and fermions. To begin with, constraints on the Wilson coefficients of these operators have been derived from existing experimental data. We then focus on the hadronic decay of the Higgs boson to two bottom quarks in the boosted regime, leading to a high $p_T$ fat-jet recoiling against a hard photon. Following a CMS Run II search for a resonance decaying into a Higgs boson and a photon, a detailed signal and background analysis for this channel has been done and limits on the relevant Wilson coefficients have been obtained. By performing a cut-based analysis, we identify some kinematic observables that distinguish between signal and SM background. Minimum values of the Wilson coefficients that will yield $3\sigma$ signal significance at the 14 TeV run of the LHC with $3000 ~\rm fb^{-1}$ data, have been obtained. A multivariate analysis using a boosted decision tree and exploiting the jet substructure techniques further help to isolate the regions of phase space where the contribution of SMEFT driven signal is significantly enhanced. Finally, we briefly discuss the parameter dependencies and interpretations of the allowed values of the coefficients on a particularly interesting UV complete model namely, Minimal Supersymmetric Standard Model.