Workshop on Tau Physics at Belle II and STCF

Asia/Shanghai
Description

The tau lepton is sufficiently heavy to decay into both leptons and hadrons via the charged weak current. As a result, it provides a unique laboratory for studying electroweak interactions, hadronic dynamics, and possible signals of physics beyond the Standard Model (SM). Precision measurements of tau decays play an essential role in testing lepton universality, determining the CKM matrix element |Vus|, extracting the strong coupling constant αs, and searching for charged lepton flavor violation (CLFV). In addition, hadronic tau decays provide valuable input for studies of non-perturbative QCD and spectral functions.

Previous measurements by the BaBar and Belle experiments have significantly improved the precision of |Vus| and tests of lepton flavor universality, while also constraining parameter spaces of new physics models related to CLFV and dark matter scenarios. However, no substantial improvement in the determination of αs from hadronic tau decays has been achieved since the measurements performed during the LEP era. Furthermore, a 3σ discrepancy remains between the value of |Vus| extracted from inclusive strange hadronic tau decays and the value predicted by CKM unitarity. Future high-precision measurements will help clarify whether this discrepancy is caused by a statistical fluctuation or possibly by new physics.

The ongoing high-luminosity asymmetric e+e- collisions at the Υ(4S) resonance at Belle II provide an excellent opportunity to address these open questions. At the same time, the proposed Super Tau-Charm Facility (STCF) aims to provide an extremely clean experimental environment for tau and charm physics with very high luminosity near the tau-pair production threshold. The complementary capabilities of Belle II and STCF will enable a new generation of precision measurements in tau physics. In this context, organizing a workshop dedicated to tau physics is both timely and valuable. The meeting will bring together experimentalists and theorists to discuss recent developments, future experimental opportunities, and theoretical progress related to tau decays.


Topics to be Covered

  • Fundamentals of Tau Physics (Overview & Key properties)
  • Hadronic cross-sections at e+e- colliders and CVC tests.
  • Precision Measurements of Tau Decays and Spectral Functions
  • Determination of Standard Model parameters (|Vus|, αs).
  • Tests of CP symmetry, Lepton Flavor Universality, and Searches for New Physics in Tau Decays

Logistics & Fees

Local Organizing Committee (LOC) cordially invites you to attend this workshop in online or offline mode.

The conference fee can be paid at the registration desk upon arrival. Accommodation fees are not included in the registration fee and should be paid separately. Please note the following details regarding the event:

Item Details
Registration Fees

1. No registration fee for online participants

2. For offline participants, Faculty/Postdoc 1500 RMB/person, students 1000 RMB/person

3. If you bring a family member, the registration fee for the family member is 600 CNY. 

Accommodation

1. 450RMB/night of Holiday Inn Changchun High Tech Zone

2. 320RMB/night of Orange Hotel (Changchun Jida Nanxiao Qianjin Street Branch)


Conference WeChat Group

Please scan the QR code below to join the workshop WeChat group for the latest updates and discussions

Committees

Advisory Committee

Local Organizing Committee (LOC)

Vindhyawasini Prasad
Registration
Registration
Participants
    • Registration
    • Dinner
    • Tau Physics Overview
      Convener: Changzheng Yuan (IHEP)
      • 1
        Opening speech
      • 2
        Prospect of tau decays
        Speaker: Zhiqing Zhang (IJCLab, Orsay)
      • 3
        Quantum entanglement in tau sector
        Speaker: Chentao Bao (ZZU)
    • Group photo + Coffee break
    • CP symmetry, Michel parameters and EDM
      Convener: Alexander Bobrov (Russia)
      • 4
        CP symmetry in tau --> K pi nu decays
        Speaker: Xin-Qiang Li (Central China Normal University)
      • 5
        Michel parameters of tau at BelleII
        Speaker: Denis Epifanov (BINP)
      • 6
        Tau EDM
        Speaker: Yongcheng Wu (NNU)
    • Lunch
    • Tau to two mesons
      Convener: Manqi RUAN (IHEP)
      • 7
        Theoretical study of tau lepton decaying to two vectors or pseudoscalar mesons
        Speaker: Lianrong Dai (Huzhou Normal University)
      • 8
        Polarization study of two vector mesons in tau --> VV nu
        Speaker: Hiroyuki Umeeda
      • 9
        Tau decays into two mesons
        Speaker: Sergi Gonzalez-Solis (ICC, Barcelona Univ.)
    • Coffee break
    • Experimental status of tau decays
      Convener: Zhiqing Zhang (IJCLab, Orsay)
      • 10
        Tau physics at Belle II
        Speaker: Petar Rados (Nagoya University)
      • 11
        Measurements of Vus at Belle II
        Speaker: Michele Mantovano (DESY)
      • 12
        Searches in tau decays at Belle and Belle II
        Speaker: Dimitri Liventsev (KEK)
      • 13
        Tau physics status at BESIII
        Speaker: Jianyong Zhang (IHEP)
    • Banquet
    • Precision of hadronic tau decays
      Convener: Petar Rados (Nagoya University)
      • 14
        Quest for precision in hadronic cross-sections and CVC tests
        Speaker: Gabriel Lopez Castro (Mexico)
      • 15
        Radiative effects in hadronic tau decays
        Speaker: Denis Epifanov (BINP)
    • 10:00
      Coffee break
    • Hadronic tau decays
      Convener: Lianrong Dai (Huzhou Normal University)
      • 16
        Electromagnetic correction of hadronic tau decays and its implication for muon g-2
        Speaker: Prof. Zhi-Hui Guo (Hebei Normal University)
      • 17
        Measurement of the branching fractions of hadronic tau-lepton decays (tau -> hhh nu with h=pi,K) at Belle
        Speaker: Alexander Bobrov (Russia)
      • 18
        Hadronic tau decays at higher orders in QCD
        Speaker: Gauhar Abbas
    • 12:00
      Lunch
    • Tau physics in future colliders
      Conveners: Haiping Peng (University of Science and Technology of China), Haiping Peng (USTC)
      • 19
        Tau physics status at STCF
        Speaker: Mingyi Liu (USTC)
      • 20
        Tau Physics Feasibility Studies at CEPC
        Speakers: Manqi RUAN (IHEP), Manqi Ruan (IHEP)
      • 21
        Tau physics at FCC-ee
        Speaker: Alberto Lusiani (SNS and INFN, sezione di Pisa)
    • 15:30
      Coffee break
    • Tau properties
      Conveners: Xiaorong Zhou (USTC), Xiaorong Zhou (University of Science and Technology of China)
      • 22
        Precision measurement of tau properties
        Speaker: Fabian Becherer
      • 23
        True Tauonium
        Speaker: Dr Hua-Sheng Shao (LPTHE Paris)
      • 24
        Tau CLFV decays
        Speaker: Laura Zani (INFN)
      • 25
        Speaker
    • Dinner