Towards testing (g − 2) τ in e + e − → τ + τ −: radiative corrections and projections for Belle II

Abstract The arguably most promising avenue towards testing physics beyond the Standard Model in the anomalous magnetic moment of the τ proceeds via suitably constructed asymmetries in e + e − → τ + τ − in the presence of a polarized electron beam. Such a program, as could be realized at Belle II as...

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Bibliographic Details
Main Authors: Joël Gogniat, Martin Hoferichter, Yannick Ulrich
Format: Article
Language:English
Published: SpringerOpen 2025-07-01
Series:Journal of High Energy Physics
Subjects:
Online Access:https://doi.org/10.1007/JHEP07(2025)172
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Summary:Abstract The arguably most promising avenue towards testing physics beyond the Standard Model in the anomalous magnetic moment of the τ proceeds via suitably constructed asymmetries in e + e − → τ + τ − in the presence of a polarized electron beam. Such a program, as could be realized at Belle II assuming a polarization upgrade of the SuperKEKB e + e − collider, crucially relies on a careful consideration of radiative corrections. In this work, we present the complete one-loop result for the fully polarized e + e − → τ + τ − process and its implementation in the Monte-Carlo integrator McMule. As an application, we discuss projections relevant for measurements at Belle II, both with and without electron polarization, and outline the necessary steps for a generalization to next-to-next-to-leading order.
ISSN:1029-8479