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arXiv · 1811.06461

Small-mass effects in heavy-to-light form factors

T. Engel·C. Gnendiger·A. Signer·Y. Ulrich
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Abstract

We present the heavy-to-light form factors with two different non-vanishing masses at next-to-next-to-leading order and study its expansion in the small mass. The leading term of this small-mass expansion leads to a factorized expression for the form factor. The presence of a second mass results in a new feature, in that the soft contribution develops a factorization anomaly. This cancels with the corresponding anomaly in the collinear contribution. With the generalized factorization presented here, it is possible to obtain the leading small-mass terms for processes with large masses, such as muon-electron scattering, from the corresponding massless amplitude and the soft contribution.

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T. Engel, C. Gnendiger, A. Signer, Y. Ulrich. 2018-11-15. Small-mass effects in heavy-to-light form factors. https://doi.org/10.1007/jhep02(2019)118

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