The 16th International Workshop on Tau Lepton Physics (TAU2021) (Virtual Edition)

Session

Session 2b: Test of fundamental symmetries with tau lepton

28 Sept 2021, 08:00

Virtual (Indiana University)

Conveners

Session 2b: Test of fundamental symmetries with tau lepton

• Sacha Davidson (Centre National de la Recherche Scientifique (FR))

Session 2b: Test of fundamental symmetries with tau lepton

• B. Lee Roberts (Boston University)

Session 2b: Test of fundamental symmetries with tau lepton

• Enrico Lunghi (Indiana University)

63. Search for charged lepton flavor violation at BESIII

Dayong Wang (Peking University)

28/09/2021, 08:00

Tau2021 Abstracts

Oral contribution

The charged Lepton Flavor Violation (cLFV) is highly suppressed in the Standard Model (SM) by the finite but tiny neutrino masses. Its branching fraction is calculated to be at a negligible level and so far none has been found in all the historical experiments, including searches in lepton ($\mu$,$\tau$) decays, pseudoscalar meson (K,$\pi$) decays, vector meson ($\varphi$,$J/\psi$,$\mathrm{{\rm Y}}$)...

118. Search for tau LFV/LNV decays at Belle

Kenta Uno

28/09/2021, 08:25

Oral contribution

We report the result of a search for \tau \to \ell \gamma (\ell = e, \mu) using the full data sample at Belle. Charged lepton flavor violation (CLFV) is forbidden in the Standard Model but possible in several new physics scenarios.
In many of these models, the radiative decays $\tau \to \ell \gamma$ are predicted to have a sizeable probability and are thus particularly interesting CLFV...

119. Measurement of the tau EDM at Belle

Kenji Inami (Nagoya university)

28/09/2021, 08:50

Tau2021 Abstracts

Oral contribution

We have measured the electric dipole moment (EDM) of the tau lepton using an 833 fb^-1 data sample collected with the Belle detector at the KEKB asymmetric-energy e^+e^- collider. Using an optimal observable method, we obtain the EDM result with O(10^-17) ecm uncertainty. The result is consistent with no EDM at the present level of experimental sensitivity and improves the sensitivity by about...

77. Probing charged lepton flavor violation with axion-like particles at Belle II

Yu-Heng Wu (National Tsing Hua University)

28/09/2021, 09:15

Tau2021 Abstracts

Oral contribution

We study charged lepton flavor violation associated with a light leptophilic axion-like particle (ALP), $X$, at the $B$-factory experiment Belle II.
We focus on production of the ALP in the tau decays $\tau \to Xl$ with $l=e,\mu$, followed by its decay via $X\to l^{-}{l}^{+}$.
The ALP can be either promptly decaying or long-lived.
We perform Monte-Carlo simulations, recasting a prompt search...

120. A next-generation rare pion decay experiment to study LFUV and CKM unitarity

David Hertzog

28/09/2021, 09:50

Oral contribution

I will briefly review the interesting collection of flavor anomalies that continue to accumulate from various experiment campaigns. What are they trying to tell us and, might there be connections? To add evidence to the experimental findings, a group of us is forming to develop a next-generation rare pion decay experiment. We aim to improve on the lepton flavor universality violation (LFUV)...

181. Search for Muon to Electron Conversion at J-PARC - COMET Experiment

MyeongJae Lee (Institute for Basic Science (Korea))

28/09/2021, 10:15

Tau2021 Abstracts

Oral contribution

COMET is an experiment at J-PARC, Japan, which will search for neutrinoless conversion of muons into electrons in the field of a nucleus (μ− + N → e− + N); a lepton flavor violating process. The experimental sensitivity goal for this process is order of 10^{−15} for Phase-I and 10^{−17} for Phase-II experiment, which is a factor of 100–10,000 improvements correspondingly over existing limits....

40. Status of the Mu2e experiment

Nam Tran (Boston University)

28/09/2021, 10:35

Tau2021 Abstracts

Oral contribution

The Mu2e experiment will measure the charged lepton flavor violating (CLFV), neutrino-less conversion of a negative muon into an electron in the field of a nucleus. The process has never been observed, but is predicted to occur in many Beyond the Standard Model scenarios at rates within the reach of the Mu2e experiment. The goal of the experiment is to improve the previous upper limit by four...

180. Muonic Force Behind Flavor Anomalies

Jure Zupan (University of Cincinnati)

28/09/2021, 11:10

Tau2021 Abstracts

Oral contribution

An economical theoretical framework for combined explanations of the flavor physics anomalies involving muons, (g-2)_mu, RK(*) and b->s mu mu supplements the Standard Model (SM) with a lepton-flavored U(1)_X gauge group where the auge boson has mass of O(0.1) GeV and a TeV-scale leptoquark. We explore the theory space of the chiral, anomaly-free U(1)_X gauge extensions and carry out a...

187. Lepton Flavour Violation searches and Lepton Universality tests at LHCb

Sara Celani (EPFL - Ecole Polytechnique Federale Lausanne (CH))

28/09/2021, 11:35

Oral contribution

30. Searches for violation of Lepton Flavor Universality at Belle II

Alberto Martini (DESY)

28/09/2021, 12:00

Tau2021 Abstracts

Oral contribution

Searches for the violation of lepton flavor universality (LFU) are critical precision tests of the standard model (SM) motivated by the growing number of anomalies reported in several measurements in the flavor sector (quarks and leptons) in the last decades. At the Belle II experiment, thanks to the large amount of tau-lepton pairs produced in electron-positron annihilation, it is possible to...