First Measurement of the $\lowercase{\ttbar}$ Differential Cross Section $\lowercase{d\sigma/d}M_{\lowercase{{t\overline{t}}}}$ in $\lowercase{\ppbar}$ Collisions at $\sqrt{\lowercase{s}}=1.96$ TeV

Abstract

We present a measurement of the $\ttbar$ differential cross section with respect to the $\ttbar$ invariant mass, dSigma/dMttbar, in $\ppbar$ collisions at $\sqrt{s}=1.96$ TeV using an integrated luminosity of $2.7\invfb$ collected by the CDF II experiment. The $\ttbar$ invariant mass spectrum is sensitive to a variety of exotic particles decaying into $\ttbar$ pairs. The result is consistent with the standard model expectation, as modeled by \texttt{PYTHIA} with \texttt{CTEQ5L} parton distribution functions.