Abstract

The Crystal Ball detector at the Doris II storage ring at DESY was used to search for the exotic decay processes τ→e γ, τ→e π 0, and τ→e η. No signal was observed. We obtained the following 90% CL upper limits on the branching fractions: B( τ→e γ)<2.0×10 −4, B( τ→e π 0)<1.4×10 −4, B( τ→e η)<2.4×10 −4.

Highlights

  • The standard model of electroweak and strong interactions has been very succesful phenomenologically

  • One of the most unsatisfactory features is the large number of arbitrary parameters: quark and lepton masses, mixing angles, W mass, Weinberg angle, etc., none of which is predicted within the standard model

  • It is possible that upper limits on a branching ratio can yield information on the scale at which the new physics begins to play a significant role

Read more

Summary

15 September 1988

BESSET d, Ch. BIELERe, J.K. BIENLEINc, A. CAVALLI - SFORZAd,[2], R. Universitgit Wiirzburg ~4,D-8700 Wiirzburg, Germany b Harvard University 9, Cambridge, MA 02138, USA. Deutsches Elektronen Synchrotron DESY, D-2000 Hamburg, Fed. Rep. Germany d Princeton University ~, Princeton, NJ 08544, USA. L InstitutJ~r Experimentalphysik 8, Universitiit Hamburg, D-2000 Hamburg, Fed. Rep. Germany r INFNand University of Florence, 1-50100Florence, Italy. Universitiit Erlangen-Niirnberg 7, D-8520 Erlangen, Germany J University of Nijmegen and NIKHEF ~o,NL-6525 ED Nijmegen, The Netherlands k Cracow Institute of Nuclear Physics, PL-30055 Cracow, Poland. The Crystal Ball detector at the Doris II storage ring at DESY was used to search for the exotic decay processes x ~ , x-~en°, and x--,er[1].

Introduction
Data sample and detector
Analysis
Event selection
Results
Discussion

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.