Measurement of The Top Quark Electric Charge

In the Standard Model, the decay of the top quark: $t \to b W^+$ gives an electric charge of $2/3$ for the top quark. However the decay $t \to \bar{b}W^+$ does not violate any fundamental laws and it predicts a top quark charge of $4/3$. We provide a measurement of the electric charge of the top quark using $t \bar{t}$ events in the lepton + 4 jets final state using events 4~$fb^{-1}$ of D0 data.