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arXiv · 1009.2776

Singular and Regular Gauges in Soft Collinear Effective Theory: The Introduction of the New Wilson Line T

Ahmad Idilbi·Ignazio Scimemi
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Abstract

Gauge invariance in soft-collinear effective theory (SCET) is discussed in regular (covariant) and singular (light-cone) gauges. It is argued that SCET, as it stands, is not capable to define in a gauge invariant way certain non-perturbative matrix elements that are an integral part of many factorization theorems. Those matrix elements involve two quark or gluon fields separated not only in light-cone direction but also in the transverse one. This observation limits the range of applicability of SCET. To remedy this we argue that one needs to introduce a new Wilson line as part of SCET formalism, that we call T. This Wilson line depends only on the transverse component of the gluon field. As such it is a new feature to the SCET formalism and it guarantees gauge invariance of the non-perturbative matrix elements in both classes of gauges.

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Ahmad Idilbi, Ignazio Scimemi. 2010-12-21. Singular and Regular Gauges in Soft Collinear Effective Theory: The Introduction of the New Wilson Line T. https://doi.org/10.1016/j.physletb.2010.11.060

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