Exclusion of an Exotic Top Quark with -4/3 Electric Charge Using Soft Lepton Tagging

Understand

We present a measurement of the electric charge of the top quark using $\ppbar$ collisions corresponding to an integrated luminosity of 2.7~fb$^{-1}$ at the CDF II detector.

• We reconstruct $\ttbar$ events in the lepton+jets final state and use kinematic information to determine which $b$-jet is associated with the leptonically- or hadronically-decaying $t$-quark.
• Soft lepton taggers are used to determine the $b$-jet flavor.
• Along with the charge of the $W$ boson decay lepton, this information permits the reconstruction of the top quark's electric charge.