Study of charged—currentep interactions atQ ²>200 GeV² with the ZEUS detector at HERA

Abstract

Deep inelastic charged-current reactions have been studied ine ⁺ p ande ⁻ p collisions at a center of mass energy of about 300GeV in the kinematic regionQ ²>200GeV² andx>0.006 using the ZEUS detector at HERA. The integrated cross sections forQ ²>200GeV² are found to be $\sigma _{e^ + p \to \bar \nu X} = 30.3_{ - 4.2 - 2.6}^{ + 5.5 + 1.6} pb$ and $\sigma _{e^ - p \to \nu X} = 54.7_{ - 9.8 - 3.4}^{ + 15.9 + 2.8} pb$. Differential cross sections have been measured as functions of the variablesx, y andQ ². From the measured differential cross sectionsdσ/dQ ², theW boson mass is determined to be $M_W = 79_{ - 7 - 4}^{ + 8 + 4} GeV$. 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 $\sigma _{e^ + p \to \bar \nu X} (Q^2 > 200 GeV^2 ; \eta _{\max }< 2.5) = 0.8_{ - 0.7}^{ + 1.8} \pm 0.1 pb$