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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.