Search for lepton-number- And baryon-number-violating tau decays at Belle

(Belle Collaboration)

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)


We search for lepton-number- and baryon-number-violating decays τ-→p¯e+e-, pe-e-, p¯e+μ-, p¯e-μ+, p¯μ+μ-, and pμ-μ- using 921 fb-1 of data, equivalent to (841±12)×106 τ+τ- events, recorded with the Belle detector at the KEKB asymmetric-energy e+e- collider. In the absence of a signal, 90% confidence-level upper limits are set on the branching fractions of these decays in the range (1.8-4.0)×10-8. We set the world's first limits on the first four channels and improve the existing limits by an order of magnitude for the last two channels.

Original languageEnglish
Article number111101
JournalPhysical Review D
Issue number11
Publication statusPublished - 2020 Dec 24

Bibliographical note

Funding Information:
We acknowledge fruitful discussions with and helpful suggestions from S. Mahapatra (Utkal University), E. Passemar (Indiana University), and P. S. Bhupal Dev (Washington University). We thank the KEKB group for excellent operation of the accelerator; the KEK cryogenics group for efficient solenoid operations; and the KEK computer group, the NII, and PNNL/EMSL for valuable computing and SINET5 network support. We acknowledge support from MEXT, JSPS and Nagoya’s TLPRC (Japan); ARC (Australia); FWF (Austria); NSFC and CCEPP (China); MSMT (Czechia); CZF, DFG, EXC153, and VS (Germany); DAE and DST (India); INFN (Italy); MOE, MSIP, NRF, RSRI, FLRFAS project, GSDC of KISTI and KREONET/GLORIAD (Korea); MNiSW and NCN (Poland); MSHE, Agreement 14.W03.31.0026 (Russia); University of Tabuk (Saudi Arabia); ARRS (Slovenia); IKERBASQUE (Spain); SNSF (Switzerland); MOE and MOST (Taiwan); and DOE and NSF (USA).

Publisher Copyright:
© 2020 authors. Published by the American Physical Society.

All Science Journal Classification (ASJC) codes

  • Nuclear and High Energy Physics


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