Search for new physics in high-mass diphoton events from proton-proton collisions at $\sqrt{s}$ = 13 TeV

TL;DR

This study searches for new physics signals in high-mass diphoton events at 13 TeV using CMS data, employing two background prediction methods, and sets the most stringent limits to date on certain extra-dimensional models.

Contribution

Introduces a dual-method approach for background estimation in high-mass diphoton searches and provides new constraints on extra-dimensional theories.

Findings

No significant excess observed in the data.

Sets the strongest limits to date on ADD extra dimensions.

Constrains heavy Higgs bosons and Randall-Sundrum gravitons.

Abstract

Results are presented from a search for new physics in high-mass diphoton events from proton-proton collisions at $\sqrt{s}$ = 13 TeV. The data set was collected in 2016-2018 with the CMS detector at the LHC and corresponds to an integrated luminosity of 138 fb$^{-1}$. Events with a diphoton invariant mass greater than 500 GeV are considered. Two different techniques are used to predict the standard model backgrounds: parametric fits to the smoothly-falling background and a first-principles calculation of the standard model diphoton spectrum at next-to-next-to-leading order in perturbative quantum chromodynamics calculations. The first technique is sensitive to resonant excesses while the second technique can identify broad differences in the invariant mass shape. The data are used to constrain the production of heavy Higgs bosons, Randall-Sundrum gravitons, the large extra dimensions model of Arkani-Hamed, Dimopoulos, and Dvali (ADD), and the continuum clockwork mechanism. No statistically significant excess is observed. The present results are the strongest limits to date on ADD extra dimensions and RS gravitons with a coupling parameter greater than 0.1.