TY - JOUR

T1 - Improved QCD form factor constraints and Λb → Λcℓν̄

AU - Boyd, C. Glenn

AU - Lebed, Richard F.

N1 - Funding Information:
We would like to thank Ben Grinstein and Aneesh Manohar for valuable conversations, Vivek Sharma for a discussion of current experimental information, and especially Chris Quigg, who computed a number of Bc mass eigenvalues used in this paper. This work is supported in part by the Department of Energy under contract DOE-FG03-90ER40546.

PY - 1997/2/3

Y1 - 1997/2/3

N2 - We construct model-independent parametrizations of the individual QCD form factors relevant to Λb → Λcℓν̄ decays. These results follow from dispersion relations and analyticity, and incorporate an improvement in the technique that reduces the number of necessary parameters. To describe most form factors with 5-10% accuracy over the entire kinematic range, three parameters are necessary, one of which is its normalization at zero recoil. We also apply the improvement to meson decays, and find, using the heavy quark form factor normalization, that almost every B̄ → Dℓν̄ and B̄ → D* ℓν̄ form factor is well described by a single-variable parametrization. B̄ → πℓν requires a total of only three to five parameters, depending on the desired accuracy.

AB - We construct model-independent parametrizations of the individual QCD form factors relevant to Λb → Λcℓν̄ decays. These results follow from dispersion relations and analyticity, and incorporate an improvement in the technique that reduces the number of necessary parameters. To describe most form factors with 5-10% accuracy over the entire kinematic range, three parameters are necessary, one of which is its normalization at zero recoil. We also apply the improvement to meson decays, and find, using the heavy quark form factor normalization, that almost every B̄ → Dℓν̄ and B̄ → D* ℓν̄ form factor is well described by a single-variable parametrization. B̄ → πℓν requires a total of only three to five parameters, depending on the desired accuracy.

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U2 - 10.1016/s0550-3213(96)00614-1

DO - 10.1016/s0550-3213(96)00614-1

M3 - Article

AN - SCOPUS:0031550408

VL - 485

SP - 275

EP - 290

JO - Nuclear Physics B

JF - Nuclear Physics B

SN - 0550-3213

IS - 1-2

ER -