Experimental investigation of the two-photon widths of the chi(c0) and the chi(c2) mesons

Abstract

Using 12.7 fb(-1) of data collected with the CLEO detector at CESR, we observed two-photon production of the c (c) over bar states chi (c0) and chi (c2) in their decay to pi (+)pi (-)pi (+)pi (-). We measured Gamma (gamma gamma)(chi (c)) x B(chi (c) --> pi (+)pi (-)pi (+)pi (-)) to be 75 +/- 13(stat) +/-8(syst) eV for the chi (c0) and 6.4 =/- 1.8(stat) +/- 0.8(syst) eV for the chi (c2), implying Gamma (gamma gamma)(chi (c0)) = 3.76 +/- 0.65(stat) +/- 0.41(syst) +/- 1.69(br) keV and Gamma (gamma gamma)(chi (c2)) = 0.53 +/- 0.15(stat) +/-0.06(syst) +/-0.22(br) keV. Also, cancellation of dominant experimental and theoretical uncertainties permits a precise comparison of Gamma (gamma gamma)(chi (c0))/Gamma (gamma gamma)(chi (c2)), evaluated to be 7.4 +/- 2.4(stat) +/- 0.5(syst) +/-0.9(br), with QCD-based predictions.