Direct measurements of the branching fractions for D0→K-e+ve< /sub> and D0→π-e+ve</ i> and determinations of the form factors fK+(0) and fπ+(0)

作者：Ablikim, M^*; Bai, JZ; Ban, Y; Bian, JG; Cai, X; Chang, JF; Chen, HF; Chen, HS; Chen, HX; Chen, JC; Chen, J; Chen, J; Chen, ML; Chen, YB; Chi, SP; Chu, YP; Cui, XZ; Dai, HL; Dai, YS; Deng, ZY; Dong, LY; Du, SX; Du, ZZ; Fang, J; Fang, SS; Fu, CD; Fu, HY; Gao, CS; Gao, YN; Gong, MY; Gong, WX; Gu, SD; Guo, YN; Guo, YQ; He, KL; He, M; He, X; Heng, YK; Hu, HM; Hu, T; Huang, L; Huang, XP; Ji, XB; Jia, QY; Jiang, CH; Jiang, XS; Jin, DP; Jin, S; Jin, Y; Lai, YF; Li, F; Li, G; Li, HH; Li, J

来源：Physics Letters B, 2004, 597(1): 39-46.

DOI：10.1016/j.physletb.2004.07.004

• DECAYS
• MESONS

The absolute branching fractions for the decays D-0 --> K(-)e(+)v(e) and D-0 --> pi(-)e(+)v(e) are determined using 7584 +/- 198 +/- 341 singly tagged (D) over bar (0) sample from the data collected around 3.773 GeV with the BES-II detector at the BEPC. In the system recoiling against the singly tagged (D) over bar (0) meson, 104.0 +/- 10.9 events for D-0 --> K(-)e(+)v(e) and 9.0 +/- 3.6 events for D-0 --> pi(-)e(+)v(e) decays are observed. Those yield the absolute branching fractions to be BF(D-0 --> K(-)e(+)v(e)) = (3.82 +/- 0.40 +/- 0.27) % and BF(D-0 --> pi(-)e(+)v(e)) = (0.33 +/- 0.13 +/- 0.03) %. The vector form factors are determined to be \f(+)(K) (0)\ = 0.78 +/- 0.04 +/- 0.03 and \f(+)(pi) (0)\ 0.73 +/- 0.14 +/- 0.06. The ratio of the two form factors is measured to be \f(+)(pi) (0)/f(+)(K) (0)\ = 0.93 +/- 0.19 +/- 0.07.

• 出版日期2004-9-2
• 单位南开大学; 武汉大学; 北京大学; 广西师范大学; 上海交通大学; 山东大学; 湖南大学; 辽宁大学; 中国高等科学技术中心; 浙江大学; 清华大学; 南京师范大学; 四川大学; 河南师范大学; 华中师范大学; 中国科学技术大学