Search for Non-Resonant Higgs Boson Pair Production in Final States With Leptons, Taus, and Photons in <i>pp</I> Collisions at √<i>s</I>=13 Tev With the Atlas Detector

Abstract

A search is presented for non-resonant Higgs boson pair production, targeting the bbZZ, 4V (V = W or Z), VV tau tau, 4 tau, gamma gamma VV and gamma gamma tau tau decay channels. Events are categorised based on the multiplicity of light charged leptons (electrons or muons), hadronically decaying tau leptons, and photons. The search is based on a data sample of proton-proton collisions at root s = 13 TeV recorded with the ATLAS detector during Run 2 of the Large Hadron Collider, corresponding to an integrated luminosity of 140 fb(-1). No evidence of the signal is found and the observed (expected) upper limit on the cross-section for non-resonant Higgs boson pair production is determined to be 17 (11) times the Standard Model predicted cross-section at 95% confidence level under the background-only hypothesis. The observed (expected) constraints on the HHH coupling modifier, kappa(lambda), are determined to be -6.2 < kappa(lambda)< 11.6 (-4.5 < kappa(lambda)< 9.6) at 95% confidence level, assuming the Standard Model for the expected limits and that new physics would only affect kappa(lambda).