Observation of Diffractive J/ψ Production at the Fermilab Tevatron

Authors

T. Affolder, Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, California
Kenneth A. Bloom, University of Nebraska-LincolnFollow
Collider Detector at Fermilab Collaboration

Date of this Version

12-10-2001

Comments

Published by American Physical Society. PPhys. Rev. Lett. 87, 241802 (2001). http://prl.aps.org. Copyright © 2001 American Physical Society. Permission to use.

Abstract

We report the first observation of diffractive J/ψ(→μ⁺μ^-) production in p̅p collisions at √s= 1.8 TeV. Diffractive events are identified by their rapidity gap signature. In a sample of events with two muons of transverse momentum p_{T,/sub> ^μ> 2 GeV/c within the pseudorapidity region |η| J/ψ production rates is found to be RJ/ψ=[1.45 ± 0.25]%. The ratio RJ/ψ(x) is presented as a function of x-Bjorken. By combining it with our previously measured corresponding ratio Rjj(x) for diffractive dijet production, we extract a value of 0.59 ± 0.15 for the gluon fraction of the diffractive structure function of the proton.}