Search for new resonances decaying to pairs of merged diphotons in proton-proton collisions at $\sqrt{s}$ = 13 TeV

TL;DR

This paper reports a search for new resonances in extended Higgs sectors decaying into pairs of merged diphotons using CMS data at 13 TeV, employing neural networks for event classification, but finds no evidence of such particles.

Contribution

Introduces a novel neural network-based method to classify merged diphoton events and sets the most sensitive limits to date on these resonances in this decay channel.

Findings

No evidence of new resonances was observed.

Upper limits on production cross sections were established.

The search is the most sensitive in this channel to date.

Abstract

A search is presented for an extended Higgs sector with two new particles, X and $\phi$, in the process X $\to$ $\phi\phi$ $\to$ $(\gamma\gamma)(\gamma\gamma)$. Novel neural networks classify events with diphotons that are merged and determine the diphoton masses. The search uses LHC proton-proton collision data at $\sqrt{s}$ = 13 TeV collected with the CMS detector, corresponding to an integrated luminosity of 138 fb$^{-1}$. No evidence of such resonances is seen. Upper limits are set on the production cross section for $m_X$ between 300 and 3000 GeV and $m_\phi / m_X$ between 0.5 and 2.5%, representing the most sensitive search in this channel.