کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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5493656 | 1526768 | 2017 | 6 صفحه PDF | دانلود رایگان |
I discuss the two-particle subleading power corrections in radiative leptonic Bâγâν decay at next-to-leading order in αs with the dispersion approach. Employing the method of regions, factorization of the Bâγâ form factors is demonstrated explicitly, at one loop, for a space-like hard-collinear photon. The two-particle soft (end-point) contribution is shown to be suppressed by one power of Î/mb, in the heavy quark limit, compared with the leading power contribution computed from QCD factorization. I further report the recent calculation on the three-particle subleading power contribution to the on-shell Bâγ form factors at tree level and demonstrate that the “soft” and the “hard” three-particle corrections are of the same power, in contrast to the two-particle counterparts, as already speculated from the rapidity divergence in the corresponding factorization formulae. Phenomenological implications of the subleading power contributions to the Bâγâν amplitude are also addressed in detail, focusing on the determination of the inverse moment of the leading-twist B-meson distribution amplitude.
Journal: Nuclear and Particle Physics Proceedings - Volumes 285â286, AprilâMay 2017, Pages 75-80