Search for low-mass dilepton resonances in Higgs boson decays to four-lepton final states in proton–proton collisions at $$\sqrt{s}=13\,\text {TeV} $$ s = 13 TeV

Abstract

Abstract A search for low-mass dilepton resonances in Higgs boson decays is conducted in the four-lepton final state. The decay is assumed to proceed via a pair of beyond the standard model particles, or one such particle and a

$${\mathrm{Z}}$$

Z

boson. The search uses proton–proton collision data collected with the CMS detector at the CERN LHC, corresponding to an integrated luminosity of 137

$$\,\text {fb}^{-1}$$

fb

- 1

, at a center-of-mass energy

$$\sqrt{s} = 13\,\text {TeV} $$

s

= 13

TeV

. No significant deviation from the standard model expectation is observed. Upper limits at 95% confidence level are set on model-independent Higgs boson decay branching fractions. Additionally, limits on dark photon and axion-like particle production, based on two specific models, are reported.