Measurement of B -> D* Form Factors in the Semileptonic Decay B -> D* l nu.

Gill, M.

Technical Information Center Oak Ridge Tennessee

关键词: Form factors;    Decay;    Semileptonic decay;    Maximum-likelihood fit;    Momentum transfer;   

RP-ID  :  DE2004833017

学科分类：工程和技术（综合）

美国|英语

来源: National Technical Reports Library

【 摘 要 】

The authors present a preliminary measurement of R(sub 1), and R(sub 2), and (rho)(sup 2), which are the three parameters used to characterize the B (yields) D*(ell)(bar (nu))(sub e) form factors (A(sub 1), V, and A(sub 2)). They use 85 x 10(sup 6) B(bar B)-pairs accumulated on the (Upsilon)(4S) resonance at PEP-II. In this analysis they use the decay mode (bar B)(sup 0) (yields) D(sup +)*e(sup -)(bar (nu)) and its charge conjugate. The D*(sup +) is reconstructed in the channel D*(sup +) (yields) D(sup 0)(pi)(sup +) and the D(sup 0) in the channel D(sup 0) (yields) K(sup -)(pi)(sup +). They parameterize the form factors in terms of their ratios (determined by the parameters R(sub 1) and R(sub 2)) and the common slope (rho)(sup 2) in the variable w (a quantity related to the momentum transfer in the decay process). These parameters are determined via an unbinned maximum likelihood fit to the distributions in four kinematic variables (three decay angles and w). The results are R(sub 1) = 1.328 (+-) 0.055 (+-) 0.025 (+-) 0.025 and R(sub 2) = 0.920 (+-) 0.044 (+-) 0.020 (+-) 0.013 for the ratios and (rho)(sup 2) = 0.769 (+-) 0.l039 (+-) 0.019 (+-) 0.032 for the slope. The stated errors are the statistical uncertainty from the data, statistical uncertainty from the size of the Monte Carlo sample and the systematic uncertainty, respectively.