Abstract
There has been a renewed interest in the description of dressed asymptotic states à la Faddeev-Kulish. In this regard, a worldline representation for asymptotic states dressed by radiation at subleading power in the soft expansion, known as the Generalized Wilson Line (GWL) in the literature, has been available for some time, and it recently found applications in the derivation of factorization theorems for scattering processes of phenomenological relevance. In this paper we revisit the derivation of the GWL in the light of the well-known supersymmetric wordline formalism for the relativistic spinning particle. In particular, we discuss the importance of wordline supersymmetry to understand the contribution of the soft background field to the asymptotic dynamics. We also provide a derivation of the GWL for the gluon case, which was not previously available in the literature, thus extending the exponentiation of next-to-soft gauge boson corrections to Yang-Mills theory. Finally, we comment about possible applications in the current research about asymptotic states in scattering amplitudes for gauge and gravity theories and their classical limit.
Highlights
A worldline representation for asymptotic states dressed by radiation at subleading power in the soft expansion, known as the Generalized Wilson Line (GWL) in the literature, has been available for some time, and it recently found applications in the derivation of factorization theorems for scattering processes of phenomenological relevance
The generalized Wilson line for a scalar particle has been already discussed in [28], it is useful to revisit the derivation in a different approach, i.e. starting from the constrained quantization of the relativistic particle, which is more standard in the worldline literature, highlighting the distinctive features that appear in the case of an asymptotic propagator dressed by soft radiation
The Generalized Wilson Line, originally proposed in [28] to extend the exponentiation of infrared radiation to next-to-leading power (NLP) and subsequently applied in [71, 72] to derive factorization theorems, is a powerful tool to describe asymptotic states dressed by soft radiation at subleading orders in the soft expansion
Summary
The generalized Wilson line for a scalar particle has been already discussed in [28], it is useful to revisit the derivation in a different approach, i.e. starting from the constrained quantization of the relativistic particle, which is more standard in the worldline literature, highlighting the distinctive features that appear in the case of an asymptotic propagator dressed by soft radiation. As depicted, in this case one typically considers a dressed propagator emitted from the hard function at a spacetime point xμi , which will be integrated over, to a final state of momentum pμf. For a generic dressed propagator, the charge QB0 does depend on xμ and the momentum pμ is not gauge invariant. This makes eq (2.13) more involved, so that it is more convenient to keep QB0 inside the integral over t. To see how to proceed, we consider a specific case for the background field B(x)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
