Search for A Fourth Generation b' Quark in tW Final State at CMS in pp Collisions at sqrt(s) = 10 TeV

We present a feasibility study for the detection of a fourth generation $b^\prime$ quark pair production at $\sqrt{s} = 10$ TeV. If the mass of the $b^\prime$ quark is above the $m_t + m_W \approx$ 255~GeV/$c^2$ threshold, the decay $b^\prime \to tW$ is expected to be the dominant channel. By selecting same-sign dilepton and trilepton events, we estimate the sensitivity at LHC startup with the CMS detector. With a data set of 200 pb$^{-1}$, a $b^\prime \overline{b}{}^\prime \to t\overline{t} W^+W^-$ signal can be discovered with a significance of 3.7 standard deviations for $M(b^\prime)\sim$400 GeV/$c^2$. If no signal is observed in the data, a $b^\prime$ quark with a mass less than 485 GeV/$c^2$ can be excluded at the 95\% confidence level.