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

2025/05/14 by Gogniat, Joël, Hoferichter, Martin, Ulrich, Yannick · 2 citations
#FOS: Physical sciences #High Energy Physics - Experiment (hep-ex) #High Energy Physics - Phenomenology (hep-ph) #Nuclear Theory (nucl-th)

paper · doi:10.48550/arxiv.2505.09678

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.

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• Models for the Electric Dipole Moment and Anomalous Magnetic Moment of the Tau Lepton
• Characterizing Dark Bosons at Chiral Belle

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