Predictions of γ(4S)→h_b(1P,2P)π^+π^- transitions  

作　　者：Yun-Hua Chen 陈云华(School of Mathematics and Physics, University of Science and Technology Beijing)

机构地区：[1]School of Mathematics and Physics,University of Science and Technology Beijing,Beijing 100083,China

出　　处：《Chinese Physics C》2020年第2期42-50,共9页中国物理C（英文版）

基　　金：Supported in part by the Fundamental Research Funds for the Central Universities(FRF-BR-19-001A);the National Natural Science Foundation of China(11975028)

摘　　要：We study the contributions of intermediate bottomonium-like Zb states and the bottom meson loops in the heavy quark spin flip transitionsγ(4 S)→hb(1 P,2 P)π+π-.Depending on the constructive or destructive interferences between the Zb-exchange and the bottom meson loops mechanisms,we predict two possible branching ratios for each process:BRγ(4 S)→hb(1 P)π+π-≈(1.20.40.8×10^-6)or(0.5-0.20.5×10^-6),and BRγ(4 S)→(2 P)π+π-≈(7.1-1.1+1.7×10^-10)or(2.4-0.10.2×10^-10)).The contribution of the bottom meson loops is found to be considerably larger than that of the Zbexchange in the T(4 S)→hb(1 P)ππtransitions,while its decay rates are not comparable to those of heavy quark spin conservedγ(4 S)→γ(1 S,2 S)ππprocesses.We also predict the contribution of the charm meson loops in the branch fractions ofΨ(3 S,4 S)→hc(1 P)ππ.We study the contributions of intermediate bottomonium-like Zb states and the bottom meson loops in the heavy quark spin flip transitions γ（4 S）→hb（1 P,2 P）π+π-.Depending on the constructive or destructive interferences between the Zb-exchange and the bottom meson loops mechanisms,we predict two possible branching ratios for each process:BRγ（4 S）→hb（1 P）π+π-≈(1.20.40.8×10-6) or(0.5-0.20.5×10-6),and BRγ（4 S）→（2 P）π+π-≈(7.1-1.1+1.7×10-10)or(2.4-0.10.2×10（-10）).The contribution of the bottom meson loops is found to be considerably larger than that of the Zbexchange in the T（4 S）→hb（1 P）ππ transitions,while its decay rates are not comparable to those of heavy quark spin conserved γ（4 S）→γ（1 S,2 S）ππ processes.We also predict the contribution of the charm meson loops in the branch fractions of Ψ（3 S,4 S）→hc（1 P）ππ.

关 键 词：QUARKONIUM exotic states nonrelativistic effective field theory 

分 类 号：O641.1[理学—物理化学]