Study of Charged-Current ep Interactions at Q2 > 200 GeV2 with the ZEUS Detector at HERA

Abstract

Deep inelastic charged--current reactions have been studied in $e^+p$ and $e^-p$ collisions at a center of mass energy of about $300\,\gev$ in the kinematic region $Q^2\greater200\,\gev^2$ and $x\greater0.006$ using the ZEUS detector at HERA. The integrated cross sections for $Q^2\greater200\,\gev^2$ are found to be $\sigep=30.3\,{}^{+5.5}_{\mns4.2}\,{}^{+1.6}_{\mns2.6}\,{\rm pb}$ and $\sigem=54.7\,{}^{+15.9}_{\mns\chax 9.8}\,{}^{+2.8}_{\mns3.4}\,{\rm pb}$. Differential cross sections have been measured as functions of the variables $x$, $y$ and $Q^2$. From the measured differential cross sections $dσ/dQ^2$, the $W$ boson mass is determined to be $M_W=79\,{}^{+8} _{-7}{}^{+4}_{-4}\,\gev$. Measured jet rates and transverse energy profiles agree with model predictions. A search for charged--current interactions with a large rapidity gap yielded one candidate event, corresponding to a cross section of $\sigep(Q^2\greater200\,\gev^2;η_{\rm max}<2.5)=0.8\,{}_{-0.7}^ {+1.8}\,\pm0.1\,{\rm pb}$.