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

TL;DR

This paper searches for exclusive Z boson production in proton-antiproton collisions at 1.96 TeV, setting an upper limit on its cross section and measuring exclusive dilepton production consistent with the standard model.

Contribution

First upper limit on exclusive Z production cross section in hadron collisions and first measurement of exclusive dilepton production at high mass range.

Findings

No exclusive Z->ll candidates observed.

Upper limit on Z production cross section: < 0.96 pb.

Measured cross section for exclusive dilepton events: 0.24^{+0.13}_{-0.10} pb.

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.