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Latest Belle results on Tau decays
by Y. Jin; D. Epifanov; H. Aihara
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Submission summary
| Authors (as registered SciPost users): | Yifan Jin |
| Submission information | |
|---|---|
| Preprint Link: | scipost_201810_00006v1 (pdf) |
| Date submitted: | 2018-10-31 01:00 |
| Submitted by: | Jin, Yifan |
| Submitted to: | SciPost Physics Proceedings |
| Proceedings issue: | The 15th International Workshop on Tau Lepton Physics (TAU2018) |
| Ontological classification | |
|---|---|
| Academic field: | Physics |
| Specialties: |
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| Approach: | Experimental |
Abstract
We present preliminary results of a latest measurement at Belle, the branching fraction of rare tau decay, $\tau^- \rightarrow \pi^- \nu_{\tau} \ell^+ \ell^-$ ($\ell = e$ or $\mu$), using a 562 $\rm fb^{-1}$\ data set. The branching fraction of $\tau^- \rightarrow \pi^- e^+ e^- \nu_\tau$ is measured to be $\mathcal{B}(\tau^-\rightarrow \pi^- e^+ e^- \nu_\tau) = (2.11 \pm 0.19 \pm 0.30) \times 10^{-5}$, where the first uncertainty is statistical and the second is systematic. An upper limit is set on the branching fraction of $\tau^- \rightarrow \pi^- \mu^+ \mu^- \nu_\tau$, $\mathcal{B}(\tau^-\rightarrow \pi^- \mu^+ \mu^- \nu_\tau) < 1.06 \times 10^{-5}$, at 90\% CL.
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Reports on this Submission
Anonymous Report 1 on 2018-12-2 (Invited Report)
- Cite as: Anonymous, Report on arXiv:scipost_201810_00006v1, delivered 2018-12-02, doi: 10.21468/SciPost.Report.687
Report
The proceeding reports the preliminary result of the rare tau decay of $\tau^-\to\pi^-\nu_{\tau}l^+l^-$ from the Belle experiment. The $\pi^-\nu_{\tau}e^+e^-$ mode has been observed for the first time, the branching fraction is consistent with the Standard Model calculation, while the upper limit has been measured for the $\mu^+\mu^-$ mode. The measurements provide important information for the understanding of $\pi W\gamma^*$ vertex, as well as constrain to physics beyond Standard Model.
This proceeding is an important contribution to the field of tau physics and I recommend it for publication.
Requested changes
It would also be interest to show the central value of the branching fraction of
$\tau^{-}\to\pi^-\nu_{\tau}\mu^{+}\mu^{-}$, besides the upper limit.