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Deriving experimental constraints on the scalar form factor in the second-class $τ\toηπν$ mode
by B. Moussallam
Submission summary
Authors (as registered SciPost users): | Bachir Moussallam |
Submission information | |
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Preprint Link: | https://arxiv.org/abs/2112.04429v1 (pdf) |
Date submitted: | 2021-12-09 14:50 |
Submitted by: | Moussallam, Bachir |
Submitted to: | SciPost Physics Proceedings |
Proceedings issue: | 16th International Workshop on Tau Lepton Physics (TAU2021) |
Ontological classification | |
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Academic field: | Physics |
Specialties: |
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Approach: | Theoretical |
Abstract
The rare second-class decay mode of the $\tau$ into $\eta\pi\nu$ could be observed for the first time at Belle II. It is important to try to derive a reliable evaluation of the branching fraction and of the energy distribution of this mode within the standard-model. Many predictions exist already in the literature which can differ by one to two orders of magnitude. Here, an approach based on a systematic use of the property of analyticity of form factors and scattering amplitudes in QCD is discussed. In particular, we will show that the scalar form factor in the $\tau$ decay can be related to photon-photon scattering and radiative $\phi$ decay amplitudes for which precise experimental measurements have been performed by the Belle and KLOE collaborations.
Current status:
Reports on this Submission
Report #1 by Swagato Banerjee (Referee 1) on 2024-11-29 (Invited Report)
Report
The branching fraction for the second class decay mode tau- -> pi- eta nu is studied using an approach based on a systematic use of the property of analyticity of form factors and scattering amplitudes in QCD. The scalar form factor in the τ decay can be related to photon-photon scattering and radiative φ decay amplitudes for which precise experimental measurements have been performed by the Belle and KLOE collaborations. The result are expectation of branching fractions at the 10^-6 level, which makes the search for this decay mode at the Belle II expreiment very challenging. However, these new measurements should be able to rule out some of the theoretical models.
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