Measurement of the top quark Yukawa coupling from t¯t kinematic distributions in the dilepton final state in proton-proton collisions at √s = 13 TeV

Abstract

A measurement of the Higgs boson Yukawa coupling to the top quark is presented using proton-proton collision data at ffiffi s p ¼ 13 TeV, corresponding to an integrated luminosity of 137 fb−1, recorded with the CMS detector. The coupling strength with respect to the standard model value, Yt, is determined from kinematic distributions in t¯t final states containing ee, μμ, or eμ pairs. Variations of the Yukawa coupling strength lead to modified distributions for t¯t production. In particular, the distributions of the mass of the t¯t system and the rapidity difference of the top quark and antiquark are sensitive to the value of Yt. The measurement yields a best fit value of Yt ¼ 1.16þ0.24 −0.35 , bounding Yt < 1.54 at a 95% confidence level.