Search for the nonresonant and resonant production of a Higgs boson in association with an additional scalar boson in the $\gamma\gamma\tau\tau$ final state in proton-proton collisions at $\sqrt{s}$ = 13 TeV

TL;DR

This paper reports a search for scalar boson pairs in the gamma-gamma and tau-tau final state at 13 TeV, setting limits on production cross sections and constraining models like the NMSSM.

Contribution

It presents the first comprehensive search for both nonresonant and resonant scalar boson production in this final state at the LHC, with new upper limits and model constraints.

Findings

No significant signal observed in data.

Upper limits on Higgs pair production cross section are set at 930 fb.

Constraints on the NMSSM parameter space are improved.

Abstract

The results of a search for the production of two scalar bosons in final states with two photons and two tau leptons are presented. The search considers both nonresonant production of a Higgs boson pair, HH, and resonant production via a new boson X which decays either to HH or to H and a new scalar Y. The analysis uses up to 138 fb$^{-1}$ of proton-proton collision data, recorded between 2016 and 2018 by the CMS experiment at the LHC at a center-of-mass energy of 13 TeV. No evidence for signal is found in the data. For the nonresonant production, the observed (expected) upper limit at 95% confidence level (CL) on the HH production cross section is set at 930 (740) fb, corresponding to 33 (26) times the standard model prediction. At 95% CL, HH production is observed (expected) to be excluded for values of $\kappa_\lambda$ outside the range between $-$12 ($-$9.4) and 17 (15). Observed (expected) upper limits at 95% CL for the XHH cross section are found to be within 160 to 2200 (200 to 1800) fb, depending on the mass of X. In the X $\to$ Y($\gamma \gamma$)H($\tau\tau$) search, the observed (expected) upper limits on the product of the production cross section and decay branching fractions vary between 0.059$-$1.2 fb (0.087$-$0.68 fb). For the X $\to$ Y($\gamma \gamma$)H($\tau\tau$) search the observed (expected) upper limits on the product of the production cross section and Y $to$ $\gamma\gamma$ branching fraction vary between 0.69$-$15 fb (0.73$-$8.3 fb) in the low Y mass search, tightening constraints on the next-to-minimal supersymmetric standard model, and between 0.64$-$10 fb (0.70$-$7.6 fb) in the high Y mass search.