Diffractive W and Z production at the Fermilab Tevatron

Abstract

We report on a measurement of the fraction of events with a W or Z boson which are produced diffractively in p̅ p collisions at √s=1.96 [square root of s = 1.96] TeV, using data from 0.6 fb-1 [fb superscript -1] of integrated luminosity collected with the CDF II detector equipped with a Roman-pot spectrometer that detects the p̅ from p̅ +p→p̅ +[X+W/Z]. We find that (1.00±0.11)% of Ws and (0.88±0.22)% of Zs are produced diffractively in a region of antiproton or proton fractional momentum loss ξ [xi] of 0.03<ξ<0.10 [0.03 < xi <0.10] and 4-momentum transferred squared t of -1<t<0 (GeV/c)2 [(GeV/c) superscript 2], where we account for the events in which the proton scatters diffractively while the antiproton dissociates, p̅ +p→[X+W/Z]+p, by doubling the measured proton dissociation fraction. We also report on searches for W and Z production in double Pomeron exchange, p+p̅ →p+[X+W/Z]+p̅ , and on exclusive Z production, p̅ +p→p̅ +Z+p. No signal is seen above background for these processes, and comparisons are made with expectations.