Search for the flavor-changing neutral current interactions of the top quark and the Higgs boson which decays into a pair of b quarks at $$ \sqrt{s}=13 $$ TeV

Abstract

Abstract A search for flavor-changing neutral currents (FCNC) in events with the top quark and the Higgs boson is presented. The Higgs boson decay to a pair of b quarks is considered. The data sample corresponds to an integrated luminosity of 35.9 fb−1 recorded by the CMS experiment at the LHC in proton-proton collisions at $$ \sqrt{s}=13 $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msqrt> <mml:mi>s</mml:mi> </mml:msqrt> <mml:mo>=</mml:mo> <mml:mn>13</mml:mn> </mml:math> TeV. Two channels are considered: single top quark FCNC production in association with the Higgs boson (pp → tH), and top quark pair production with FCNC decay of the top quark (t → qH). Final states with one isolated lepton and at least three reconstructed jets, among which at least two are associated with b quarks, are studied. No significant deviation is observed from the predicted background. Observed (expected) upper limits at 95% confidence level are set on the branching fractions of top quark decays, ℬ(t → uH) &lt; 0.47% (0.34%) and ℬ(t → cH) &lt; 0.47% (0.44%), assuming a single nonzero FCNC coupling.