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arXiv 1202.4630hep-ph
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重夸克有效理论中半轻子重子衰变的形状因子

On the form factors of semileptonic baryon decays in Heavy Quark Effective Theory

Frederic Jugeau

摘要:

我们研究了LHCb上半轻子重子衰变Lambda_b到Lambda_c的非正向振幅的结果。我们得到了一个求和规则的次领先的弹性Isgur-Wise(IW)函数A(w),起源于O(1/mQ)的有效拉格朗日摄动的动力学部分。在求和规则中,只出现了中间态J^P=1/2+,它们对轴向矢量形状因子G1(w)的O(1/mQ)^2修正也有贡献,而G1(w)与零反冲w=1时的微分衰变率有关。这使我们能够得到一个用A(w)和主要弹性IW函数xi(w)的形状表示的修正-delta^(G1)_(1/mQ^2)的下界。另一个理论含义是A '(1)必须在xi(w)的斜率饱和其下限的极限中为零。因此,在重子的情况下,建立了主导IW函数和次主导IW函数A(w)之间的强关联。

英文摘要:

We study consequences of the non-forward amplitude for the semileptonic baryon decay Lambda_b into Lambda_c which will be measured in detail at LHCb. We obtain a sum rule for the subleading elastic Isgur-Wise (IW) function A(w) that originates from the kinetic part of the O(1/mQ) effective Lagrangian perturbation. In the sum rule appear only the intermediate states J^P=1/2+, the same that contribute to the O(1/mQ)^2 correction to the axial-vector form factor G1(w) involved in the differential decay rate at zero recoil w=1. This allows us to obtain a lower bound on the correction -delta^(G1)_(1/mQ^2) in terms of A(w) and the shape of the leading elastic IW function xi(w). Another theoretical implication is that A'(1) must vanish in the limit where the slope of the xi(w) saturates its lower bound. A strong correlation between the leading IW function and the subleading one A(w) is thus established in the case of the baryons.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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