On the Sudakov form factor, and a factor of two
High Energy Physics - Phenomenology
2020-04-30 v4 High Energy Physics - Theory
Abstract
I answer a question that Roman Jackiw asked me, and I draw some lessons from the answer. The question is: why is the Sudakov form factor larger by a factor of two, if computed for off-shell fermions, in comparison to the on-shell case? The answer sheds some light on the interplay between infrared and collinear singularities -- and the importance of factors of two.
Cite
@article{arxiv.2001.04995,
title = {On the Sudakov form factor, and a factor of two},
author = {Stefano Forte},
journal= {arXiv preprint arXiv:2001.04995},
year = {2020}
}
Comments
19 pages, 2 figures. Contribution to the volume "Roman Jackiw -- 80th Birthday Festschrift". Note added with important extra references and some historical remarks; some typos corrected. Two more typos corrected and a note added. Final version, to be published in the Jackiw Festschrift volume