Search for the Flavor-Changing Neutral Current Decay ${\rm t} \to {\rm qH}$ Where the Higgs Decays to $\rm b \overline b$ Pairs at $\sqrt{s} = 8$ TeV

A search for the flavor-changing neutral current Higgs (FCNH) process in top quark decays, ${\rm t}\to{\rm qH}$ ($\rm q = u, c$), is presented using a data sample corresponding to an integrated luminosity of 19.8 fb$^{-1}$ of proton-proton collisions at a center-of-mass energy of 8 TeV collected with the CMS detector at the LHC. The analysis is performed by tagging a top quark decaying into a bottom quark and a W boson, identified with a lepton and a neutrino, and searching for a $\rm b \overline b$ pair from the Higgs decay and a light quark in the event. No significant excess is observed over the background prediction. The branching fraction upper limits for ${\rm t} \to {\rm qH}$ are determined to be ${\cal B}({\rm t}\to{\rm cH})$ $<$ $1.16\%$ and ${\cal B}({\rm t}\to {\rm uH})$ $<$ $1.92\%$ at the $95\%$ confidence level, with expected limits of $0.89\%$ and $0.85\%$, respectively.