Journal Club

Seminar Room

If you want to propose a paper, you can contact Supratim Das Bakshi (sdb AT ugr.es)

Thursday 10th of February, 2022

Wilson Coefficients and Natural Zeros from the On-Shell Viewpoint

Luigi Delle Rose, Benedict von Harling, Alex Pomarol
We show how to simplify the calculation of the finite contributions from heavy particles to EFT Wilson coefficients by using on-shell methods. We apply the technique to the one-loop calculation of g-2 and H𝛾𝛾, showing how finite contributions can be obtained from the product of tree-level amplitudes. In certain cases, due to a parity symmetry of these amplitudes, the total contribution adds up to zero, as previously found in the literature. Our method allows to search for new natural zeros, as well as to obtain non-zero contributions in a straightforward way.
Comments: 17 pages, 5 figures
Subjects: High Energy Physics - Phenomenology (hep-ph); High Energy Physics - Theory (hep-th)
Cite as: arXiv:2201.10572 [hep-ph]
  (or arXiv:2201.10572v1 [hep-ph] for this version)

presented by Guilherme Guedes

 

Simple Rules for Evanescent Operators in One-Loop Basis Transformations

Jason Aebischer, Andrzej J. Buras, Jacky Kumar
Basis transformations often involve Fierz and other relations which are only valid in D=4 dimensions. In general D space-time dimensions however, evanescent operators have to be introduced, in order to preserve such identities. Such evanescent operators contribute to one-loop basis transformations as well as to two-loop renormalization group running. We present a simple procedure on how to systematically change basis at the one-loop level by obtaining shifts due to evanescent operators. As an example we apply this method to derive the one-loop basis transformation from the BMU basis useful for NLO QCD calculations, to the JMS basis used in the matching to the SMEFT.
Comments: 25 pages, 2 figures
Subjects: High Energy Physics - Phenomenology (hep-ph); High Energy Physics - Theory (hep-th)
Report number: AJB-22-1
Cite as: arXiv:2202.01225 [hep-ph]
  (or arXiv:2202.01225v1 [hep-ph] for this version)

presented by Javi Fuentes