We have observed the reactions p + p-bar --> p + X +
p-bar, with X being a centrally produced J/psi, psi(2S) or chi(c)0,
and gamma gamma --> mu+ mu-, in proton-antiproton collisions at
s**(1/2) ñ.96 TeV using the Run II Collider Detector at Fermilab.
The event signature requires two oppositely charged muons, each with
pseudorapi+dity |eta| < 0.6, with M_mu mu epsilon [3.0, 4.0] GeV/c2
and either no other particles, or one additional photon, detected.
The J/psi and the psi(2S) are prominent, on a continuum consistent with
the QED process gamma gamma --> mu+ mu-. Events with a J/psi and
an associated photon candidate are consistent with exclusive chi(c)0
production through double pomeron exchange. The exclusive vector
meson production is as expected for elastic photoproduction, gamma +
p -> J/psi(psi(2S)) + p, which is observed here for the first time
in hadron-hadron collisions. The cross section d sigma/dy|_y ð for p +
p-bar -> p + X + p-bar with x ÿ/psi, psi(2S) or chi(c)0 are 3.92 +/-
0.62 nb, 0.53 +/- 0.14 nb, and 76 +/- 14 nb, respectively. The cross
section for the continuum, with |eta(mu+/-)| < 0.6 M_mu mu epsilon
[3.0, 4.0] GeV/c2, is \int d sigma/dM.d_eta1.d_eta2 ò.7 +/- 0.5 pb,
consistent with QED prediction. We put an upper limit on the cross
section for oderon exchange in exclusive J/psi production: d sigma/dy|_y
ð(J/psi_OP) < 2.3 nb at 95% C.L.
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Updated: Tuesday, 2009 July 07 11:45:57 CDT automatically from input from carol picciolo