Exclusive chi_c at CDF

Angela Wyatt, University College London.
On behalf of the CDF collaboration.

Recently, there has been a lot of interest in the proposal that exclusive Higgs
production may prove to be an additional search channel for the Higgs boson at
 the LHC. While the cross section for this process is almost certainly too 
small to be observable at the Tevatron; it is possible to search for exclusive
 chi_c production.  This could be used to test predictions for exclusive Higgs 
production, although the chi_c production calculation can have large uncertainties.

Preliminary results are presented from a search for exclusive chi_c events at CDF.
The decay chain chi_c -> j/psi + photon -> mu^+ + mu^- + photon is used.  From an
 initial sample of di-muon events, double pomeron exchange events are selected. 
These are then used to search for "exclusive" events, defined to be events 
containing a j/psi or a j/psi + photon and nothing else OBSERVABLE in the CDF 
detector. Events compatible with being from exclusive chi_c are observed. However, 
the background from double pomeron exchange cannot yet be estimated and may be 
very large.  Hence, the j/psi + photon events are used to put an upper limit on
 exclusive chi_c production in the rapidity range |y| < 0.6.