Search for Higgs boson and observation of Z boson through their decay into a charm quark-antiquark pair in boosted topologies in proton-proton collisions at SQUARE ROOTs=13 TeV

Abstract

A search for the standard model (SM) Higgs boson (H) produced with transverse momentum (p(T)) greater than 450 GeV and decaying to a charm quark-antiquark (c <overline>c) pair is presented. The search is performed using proton-proton collision data collected at root s =13 TeV by the CMS experiment at the LHC, corresponding to an integrated luminosity of 138 fb(-1). Boosted H -> c <overline>c decay products are reconstructed as a single large-radius jet and identified using a deep neural network charm tagging technique. The method is validated by measuring the Z -> c <overline>c decay process, which is observed in association with jets at high pT for the first time with a signal strength of 1.00 (+0.17) (-0.14) osystTHORN similar to 0.08(the) +/- 0.06 (stat), defined as the ratio of the observed process rate to the SM expectation. The observed (expected) upper limit on sigma(H)B(H -> c <overline>c) is set at 47 (39) times the SM prediction at 95% confidence level.