Chronology of Milestone Events in Particle Physics - PERL 1977F
Chronology of Milestone Events in Particle Physics

  Nobel prize to M. Perl awarded in 1995 "for the discovery of the lepton''. Co-winner F. Reines "for the detection of the neutrino''  

PERL 1977F

Perl, M.L. et al.
Properties of the Proposed Charged Lepton
Phys. Lett. 70B (1977) 487;

Abstracts
The anomalous e and 2-prong x events produced in e+e annihilation are used to determine the properties of the proposed charged lepton. We find the mass is 1.90 0.10 GeV/c2; the mass of the associated neutrino, , is less than 0.6 GeV/c2 with 95% confidence; V-A coupling is favored over V+A coupling for the - current and the leptonic branching ratios are 0.186 0.010 0.028 from the e events and 0.175 0.027 0.030 from the x events where the first error is statistical and the second is systematic.

Accelerator SLAC-SPEAR Detectors SMAG

Related references
More (earlier) information appears in
M. L. Perl et al., Phys. Lett. 63B (1976) 466;
M. L. Perl et al., Phys. Rev. Lett. 35 (1975) 1489;

Reactions
  e+ e e+ (neutrals) 3.8-7.8 GeV (Ecm) pt, cs
  e+ e + e (neutrals) 3.8-7.8 GeV (Ecm) pt, cs
  e+ e X 3.8-7.8 GeV (Ecm) cs
  e+ e + X 3.8-7.8 GeV (Ecm) cs

Particles studied
  + mass, w, qn, ex, pw
  mass, w, qn, ex, pw
  ex, mass

Record comments
Firm establishment of the lepton properties.
    
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