Search for the exotic decay of the Higgs boson into two light pseudoscalars with four photons in the final state in proton-proton collisions at $\sqrt{s}$ = 13 TeV

A search for the exotic decay of the Higgs boson to a pair of light pseudoscalars,
each of which subsequently decays into a pair of photons, is presented. The search uses data
from proton-proton collisions at √
s = 13 TeV recorded with the CMS detector at the LHC
that corresponds to an integrated luminosity of 132 fb−1
. The analysis probes pseudoscalar
bosons with masses in the range 15–62 GeV, coming from the Higgs boson decay, which
leads to four well-isolated photons in the final state. No significant deviation from the
background-only hypothesis is observed. Upper limits are set on the product of the Higgs
boson production cross section and branching fraction into four photons. The observed
(expected) limits range from 0.80 (1.00) fb for a pseudoscalar boson mass of 15 GeV to 0.26
(0.24) fb for a mass of 62 GeV at 95% confidence level.