New measurements of the resonance parameters of the chi(c0)(1(3)P(0)) state of charmonium

The resonance parameters of the X-c0, the 1(3)P(0) state of charmonium, have been measured at the Fermilab Antiproton Accumulator in the reaction (p) over barp --> chi(c0) --> gammaJ/psi --> gamma(e(+)e(-)). A large data sample collected during the year 2000 run yields the results: M(chi(c0)) = 3415.4 +/- 0.4 +/- 0.2 MeV/c(2), Gamma(chi(c0)) = 9.8 +/- 1.0 +/- 0.1 MeV, B(chi(c0) --> (p) over barp) x B(chi(c0) --> gammaJ/psi) x B(J/psi --> (e(+)e(-))) = (1.61 +/- 0.11 +/- 0.08) x 10(-7). Taking B(chi(c0) --> gammaJ/psi) and B(J/psi --> e(+)e(-)) from the literature, we obtain B(chi(c0) --> (p) over barp) = (4.1 +/- 0.3(-0.9)(+1.6)) x 10(-4) and Gamma(chic) --> (p) over barp) = (4.0 +/- 0.4(-0.9)(+1.6)) keV. (C) 2002 Published by Elsevier Science B.V.