在s^(1/2)=4.03GeV的e^+e^-湮没中D_s^+单标记的研究及D_s^+D_s^-对产生截面的测定

Measurement of Production Cross Section of D_s^+D_s^- in e^+e^- Annihilation at the Center-of-Mass Energy of s^(1/2)=4.03GeV'

利用北京正负电子对撞机 (BEPC)和北京谱仪 (BES) ,基于在质心系能量s=4.0 3GeV的e+ e-湮没中 ,D+ s 单标记的分析结果 ,测定了D+ s →K 0 K+ 和D+ s →K0 K+ 衰变的分支比。其结果Br(D+ s →K 0 K+ ) =(3.0 2± 0 .94±0 .91) % ,Br(D+ s →K0 K+ ) =(3.2 8± 1.2 2± 0 .94) %与世界平均值在误差范围内一致 .用π+ ,K 0 K+ ,K0 K+ 作为单标记 ,共观测到 94± 13个D+ s 事例 ,测得在e+ e-湮没中D+ s D-s 对产生的截面为σprodD+s D-s =45 1± 6 3± 118pb .

Measurement of the production cross section of the D + sD - s in e +e - annihilation at the Center of Mass Energy of s =4.03 GeV is reported in the paper. The cross section for the D + sD - s production has been measured using a data sample of 22.3 pb -1 collected with BES detector at BEPC e +e - collider. The D + s measons are reconstructed in the π +, K *0 K + and K 0 K + decay modes. A total number of 94±13 singly tagged D + s events is obtained from the three modes. This yelds the cross section value σ prod D + sD - s =(451±63±118)pb for D + sD - s production. Based on the numbers of singly tagged D + s events for each of the three decay modes,the decay branching fractions for D + s→ K *0 K + and K 0 K + have been determined to be (3.02±0.94±0.91)% and (3.28±1.22±0.94)%,respectively.