Search for Flavor Changing Neutral Current in Top Production and Decays

TL;DR

This paper reports on searches for flavor changing neutral currents in top quark production and decay using CMS data at 7 and 8 TeV, setting upper limits on various rare decay branching fractions.

Contribution

It presents the most recent upper limits on FCNC processes involving top quarks from CMS data at 7 and 8 TeV, covering multiple interaction channels.

Findings

Upper limits on $ ext{Br}(t o u ext{gamma})$ < 0.013%

Upper limits on $ ext{Br}(t o ug)$ < 0.036%

Upper limits on $ ext{Br}(t o uZ)$ < 0.05%

Abstract

Searches for flavor changing neutral currents in top production and decay using data collected by the Compact Muon Solenoid (CMS) experiment at $\sqrt{s}$ = 7 and 8 TeV are presented, corresponding to an integrated luminosity of around 5 fb$^{-1}$ and 20 fb$^{-1}$. FCNC searches are conducted to probe $tqZ$, $tq\gamma$, $tqH$, and $tgq$ interactions in various channels. By the time of the 38$^{th}$ ICHEP conference in 2016, the upper limits on $\mathcal{B}(t \to u\gamma)$ $<$ 0.013%, $\mathcal{B}(t \to ug)$ $<$ 0.036%, $\mathcal{B}(t \to uZ)$ $<$ 0.05% and $\mathcal{B}(t \to uH)$ $<$ 0.42% at the 95% confidence level had been obtained by the CMS collaboration.