ZHOU, HY , TSING HUA UNIV,DEPT PHYS,BEIJING 100084,PEOPLES R CHINA.
部门归属:
CORNELL UNIV,NEWMAN LAB NUCL STUDIES,ITHACA,NY 14853; CHINESE CTR ADV SCI & TECHNOL,WORLD LAB,BEIJING 100080,PEOPLES R CHINA; ACAD SINICA,INST THEORET PHYS,BEIJING 100080,PEOPLES R CHINA
英文摘要:
A systematic calculation of the coupled-channel effects in hadronic transitions in the ccBAR and bbBAR systems is given. The unitarized quark model based on the 3P0 quark-pair-creation mechanism is adopted as the coupled-channel model. The emitted pions can now be produced both from the conventional Okubo-Zweig-Iizuka- (OZI) forbidden process described by QCD multipole-gluon emissions and from the light-quark loop through an OZI-allowed process described by the quark-pair-creation model. There is interference between the two kinds of transition amplitudes. Taking the experimental values of GAMMA(psi' --> J/psi-pi-pi) and d-GAMMA(psi' --> J/psi-pi-pi)/dM(pi-pi) as inputs to determine the two unknown parameters in the theory, we predict the transition rates and M(pi-pi) distributions in the bbBAR system. The obtained rates for UPSILON' --> UPSILON-pi-pi, UPSILON" --> UPSILON-pi-pi, UPSILON" --> UPSILON'pi-pi and the distribution d-GAMMA(UPSILON' --> UPSILON-pi-pi)/dM(pi-pi) are in good agreement with the experiments. For d-GAMMA(UPSILON" --> UPSILON-pi-pi)/dM(pi-pi), the present theory does give a bigger low-M(pi-pi) distribution than the pure QCD multipole expansion does, but it is still too small to fit the CLEO data.
