# Test lepton flavor universality with (semi)leptonic $D$ decays at BESIII

### Submission summary

 As Contributors: Sifan Zhang Preprint link: scipost_201811_00017v1 Date accepted: 2019-01-17 Date submitted: 2018-11-14 01:00 Submitted by: Zhang, Sifan Submitted to: SciPost Physics Proceedings Proceedings issue: The 15th International Workshop on Tau Lepton Physics (Amsterdam, 2018-09) Academic field: Physics Specialties: High-Energy Physics - Experiment Approach: Experimental

### Abstract

Using 2.93~fb$^{-1}$ data taken at $\sqrt{s}=3.773$~GeV, 0.482~fb$^{-1}$ data taken at $\sqrt{s}=4.009$~GeV and 3.19~fb$^{-1}$ data taken at $\sqrt{s}=4.178$~GeV with the BESIII detector, precision measurements of the branching fractions of $D^0\to K^-\mu^+\nu_\mu$, $D^+\to\bar K^0\mu^+\nu_\mu$, $D^0\to\pi^-\mu^+\nu_\mu$, $D^+\to\pi^0\mu^+\nu_\mu$, $D^+\to\ell^+\nu_\ell$ and $D_s^+\to\ell^+\nu_\ell$ are performed. Combining the known branching fractions of $D\to\bar Ke^+\nu_e$, $D\to\pi e^+\nu_e$ and $D^+_s\to\tau^+\nu_\tau$, we have tested the lepton flavor universality with $D\to\bar K\ell^+\nu_\ell$, $D\to\pi\ell^+\nu_\ell$, $D^+\to\ell^+\nu_\ell$ and $D_{s}^+\to\ell^+\nu_\ell$ decays. We have also tested lepton flavor universality in different $q_{\ell\nu_\ell}^2$ intervals for $D\to\bar K\ell^+\nu_\ell$~($\ell=e$ or $\mu$). Besides, hadronic form factor $f_+^K(0)$, $D$ meson decay constant $f_{D_s^+}$ and $f_{D^+}$, and quark mixing matrix element $|V_{cs}|$ and $|V_{cd}|$ are also extracted with the most precise accuracies to date.

Published as SciPost Phys. Proc. 1, 016 (2019)

### Submission & Refereeing History

Submission scipost_201811_00017v1 on 14 November 2018

## Reports on this Submission

### Anonymous Report 1 on 2018-12-7 (Invited Report)

• Cite as: Anonymous, Report on arXiv:scipost_201811_00017v1, delivered 2018-12-07, doi: 10.21468/SciPost.Report.716

### Report

With one of the largest DDbar samples near threshold, BESIII has reported in these proceedings precision measurements on D meson decay constants, hadronic from factors, and the CKM matrix elements. These
measurements help to validate the theoretical calculations and test the unitarity of the CKM matrix. They have also reported their results on lepton flavor universality tests in semileptonic D decays. This analysis provides a chance to further test the Standard Model and understand the LFU anamolies in B-meson decays.

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