Study of the [chi][sub c0](1P[sub 0][number sign]3) State of Charmonium Formed in [bar p][number sign]p Annihilations

The resonance parameters of [chi][sub c0] , the 1P[sub 0]3 resonance of charmonium, have been measured at the Fermilab Antiproton Accumulator by means of the reaction [bar p]p[r arrow][chi][sub c0][r arrow][gamma]J/[psi][r arrow][gamma](e[sup +]e[sup [minus]]) . The results are M([chi][sub c0])=3417.4[sup +1.8][sub [minus]1.9][plus minus]0.2 MeV/c[sup 2] , [Gamma]([chi][sub c0])=16.6[sup +5.2][sub [minus]3.7][plus minus]0.1 MeV , and [Gamma]([chi][sub c0][r arrow][bar p] p)[times]B([chi][sub c0] [r arrow]J/[psi][gamma])[times]B(J/[psi][r arrow] e[sup +]e[sup [minus]])=2.89[sup +0.67][sub [minus]0 .53][plus minus]0.14 eV . Using known branching ratios we also obtain [Gamma]([chi][sub c0][r arrow][bar p] p)=8.0[sup +1.9+3.5][sub [minus]1.5[minus]1.9 ] keV . These results are discussed in relation to the other [chi][sub cJ] states and to theoretical predictions. [copyright] [ital 1999] [ital The American Physical Society ]