Search for exclusive Z boson production and observation of high mass ppbar->gammagamma->p+ll+pbar events in ppbar collisions at sqrt(s) = 1.96 TeV

Abstract

We present a search for exclusive Z boson production in proton-antiproton collisions at sqrt(s) = 1.96 TeV, using the CDF II detector at Fermilab. We observe no exclusive Z->ll candidates and place the first upper limit on the exclusive Z cross section in hadron collisions, sigma(exclu) < 0.96 pb at 95% confidence level. In addition, we observe eight candidate exclusive dilepton events from the quantum electrodynamic process ppbar->gammagamma->p+ll+pbar, and measure the cross section for M(ll) > 40 GeV/c2 and |eta(l)| < 4 to be sigma = 0.24^{+0.13}_{-0.10} pb, which is the first measurement for this mass range and is consistent with the standard model prediction.

Figures (2)

• Figure 1: (a) Exclusive photoproduction of a Z boson and (b) exclusive dilepton production via two-photon exchange at the Tevatron.
• Figure 2: (a) The dilepton invariant mass distribution, and (b) the distribution of $180^{\circ}$ minus the difference in the azimuthal lepton angles for the data and the lpair prediction with the geant detector simulation, scaled to account for acceptance and luminosity.