Semileptonic decays B→D^(*) lυ in the perturbative QCD factorization approach  

作　　者：Ying-Ying Fan Wen-Fei Wang Shan Cheng Zhen-Jun Xiao 

机构地区：[1]Department of Physics and Institute of Theoretical Physics,Nanjing Normal University

出　　处：《Chinese Science Bulletin》2014年第2期125-132,共8页

基　　金：supported by the National Natural Science Foundation of China(10975074 and 11235005)

摘　　要：In this paper,we study the B→D^(*) l-l -ι semileptonic decays and calculate the branching ratios B(B→D^(*) l-l -ι) and the ratios R(D^(*)) and R_D^( l,s) by employing the perturbative QCD(pQCD)factorization approach.We find that(a)for R(D)and R(D*)ratios,the pQCD predictions are R(D)=0.430-0.026?0.021,R(D*)=0.301±0.013 and agree well with BaBar’s measurements of ReD e?T T;(b)for the newly defined R_D^1 and R_D^s ratios,the pQCD predictions are R_D^l=0.450-0.051+0.064 and R_D^s=0.642-0.070+0.081,which may be more sensitive to the QCD dynamics of the considered semileptonic decays than R(D^(*)) and should be tested by experimental measurements.In this paper, we study the B → D（＊）l -v1 semileptonic decays and calculate the branching ratios/3（B →D（＊）l-vl） and the ratios R（D（＊）） and RDl by employing the perturbative QCD （pQCD） factorization approach. We find that （a） for R（D） and R（D＊） ratios, the pQCD predictions are R（D） = 0.430-0.026＋0.021, R（D＊） = 0.301 4- 0.013 and agree well with BaBar＇s measurements of R（D（＊））; （b） for the newly defined RDl and RDt ratios, the pQCD predictions are RDl =0.450-0.051＋0.064 and RDt 0.642-0.070＋0.081 which may be more sensitive to the QCD dynamics of the considered semileptonic decays than R（D（＊）） and should be tested by experimental measurements.

关 键 词：QCD因子化 微扰QCD 半轻子衰变 量子色动力学 实验测量 RDT 分支比 预言 

分 类 号：O572.243[理学—粒子物理与原子核物理]