CMS-PAS-TOP-14-020

CMS-PAS-TOP-14-020
Search for the flavor-changing neutral current decay $\mathrm{ t \to qH}$ where the Higgs decays to $\mathrm{ b \overline b }$ pairs at $\sqrt{s} =$ 8 TeV
CMS Collaboration
November 2015

Abstract: A search for the flavor-changing neutral current Higgs (FCNH) process in top quark decays, $\mathrm{ t \to qH }$ ( $\mathrm{ q = u,\, c}$ ), 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 $\mathrm{ b \bar b }$ 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 $\mathrm{ t \to qH }$ are determined to be ${\cal B}( \mathrm{ t\to cH}) <$ 1.16% and ${\cal B}( \mathrm{ t \to uH} ) <$ 1.92% at the 95% confidence level, with expected limits of 0.89% and 0.85%, respectively.
Links: CDS record (PDF) ; inSPIRE record ; CADI line (restricted) ;

Summary	CMS Publications

Summary

This study searches for top quark flavor changing neutral current Higgs decays where the Higgs boson decays to bb and the W boson decays leptonically. The data used in this study correspond to an integrated luminosity of about 19.8 fb

$^{-1}$ at

$\sqrt{s} =$ 8 TeV collected by CMS in 2012. No significant excess of events over the SM background is observed.

$\mathcal{B}( \mathrm{ t \to cH })$ and

$\mathcal{B}( \mathrm{ t \to uH})$ branching fractions larger than 1.16% and 1.92% are excluded at the 95% confidence level. This is the first CMS result on

$\mathcal{B}( \mathrm{ t \to qH })$ using the

$\mathrm{ H \to bb}$ channel.