摘要: The Crystal Ball NaI(T1) detector was used to study the photon spectra from the following inclusive charmonium decays: e exp + e exp - implies J/psi implies gamma + hadrons and e exp + e exp - implies psi' implies gamma + hadrons.... 展开 The Crystal Ball NaI(T1) detector was used to study the photon spectra from the following inclusive charmonium decays: e exp + e exp - implies J/psi implies gamma + hadrons and e exp + e exp - implies psi' implies gamma + hadrons. Data were collected at the Stanford Linear Accelerator Center's electron-positron colliding beam machine, SPEAR. The Crystal Ball detector consists of a highly segmented array of 732 NaI(T1) crystals (16 radiation lengths) covering approx. = 98% of 4 pi steradians, and is used to measure the photon energies, directions, and lateral shower distributions. This detector is excellently suited for studying the radiative transitions among the charmonium family of states: (1) from psi' to the triplet P states, chi(3415), chi (3510), chi(3550); (2) from psi' and J/psi to the singlet S state eta/sub c/(2984); and (3) from psi' to the radially excited singlet S state eta'/sub c/(3592). The analysis of 1.8 x 10 exp 6 psi' and 2.2 x 10 exp 6 J/psi decays yields the following spectrum of states: chi sub 0 (3418), chi sub 1 (3512), chi sub 2 (3558), eta/sub c/(2984), and eta'/sub c/(3592), each with a +-4 meV error on its mass. The branching ratios are measured to be: B(psi' implies gamma chi sub 0 sub 1 sub 2 ) = (9.9 +- 0.5 +- 0.8)%, (9.0 +- 0.5 +- 0.7)%, and (8.0 +- 0.5 +- 0.7)%, respectively; B(psi' implies gamma eta/sub c/) = 0.28 +- 0.06)% and B(J/psi implies gamma eta/sub c/) = 1.27 +- 0.36)%; and B(psi' implies gamma eta'/sub c/) = (0.5-1.2)% at the 90% confidence level. Values for the natural line widths are obtained: GAMMA(chi sub 0 sub 1 sub 2 ) = (13.5-20.4) MeV, < 3.8 MeV, (0.85-4.9) MeV, respectively (90% C.L.); GAMMA(eta/sub c/) = 11.5 +4.5/-4.0) MeV; and GAMMA(eta'/sub c/) < 7 MeV (90% C.L.). Cascade product branching ratios B(psi' implies gamma chi/sub J/).B(chi/sub J/ implies gamma J/psi) were measured for J = 1 and 2 to be: (2.56 +- 0.12 +- 0.20)% and (0.99 +- 0.10 +- 0.08)% respectively. No signal was seen for the J = 0 transition. (ERA citation 08:034753) 收起