Search for the eta(c)-prime (2 1(S)0) charmonium resonance.

We report on a search by Fermilab experiment E835 for the eta'(c) (2 S-1(0)) charmonium resonance in the process (p) over barp --> eta'(c)--> gamma gamma. No signal was observed and, based on 34 pb(-1) integrated luminosity, we determine the following upper limits (90% confidence level) to the product of the branching ratios for a resonance mass in the region 3575-3660 MeV/c(2): Br(eta'(c)-->(p) over barp) x Br(eta'(c)--> gamma gamma)< 12.0x10(-8) for <Gamma>= 5 MeV; <5.9x 10(-8) for <Gamma> =10 MeV; <4.8x 10(-8) for <Gamma> = 15 MeV. Combiing the present data with those of the predecessor experiment, E760, the upper limits become 8.0x10(-8), 5.0x10(-8), and 4.5x10(-8), respectively. In the restricted region 3589-3599 MeV/c(2), where a candidate was reported by the Crystal Ball experiment, we obtain the following limits from the combined E760-E835 experiments: Br(eta'(c)-->(p) over barp) x Br(eta'(c)--> gamma gamma)<5.6x10(-8) for <Gamma>=5 MeV; <3.7x10(-8) for <Gamma> = 8 MeV. A comparison of these with other experimental results is presented.