Measurement of Gamma(K(mu3)) / Gamma(K(e3)) ratio using stopped positive kaons

Collaboration
Jun, 2001

Citations per year

2001200620112016202101234
Abstract: (Elsevier)
The ratio of the K + → π 0 μ + ν ( K μ 3 + ) and K + → π 0 e + ν ( K e 3 + ) decay widths, Γ ( K μ 3 )/ Γ ( K e 3 ), has been measured with stopped positive kaons. K μ 3 + and K e 3 + samples containing 2.4×10 4 and 4.0×10 4 events, respectively, were analyzed. The Γ ( K μ 3 )/ Γ ( K e 3 ) ratio was obtained to be 0.671±0.007(stat.)±0.008(syst.) calculating the detector acceptance by a Monte Carlo simulation. The coefficient of the q 2 dependent term of the f 0 form factor was also determined to be λ 0 =0.019±0.005(stat.)±0.004(syst.) with the assumption of μ – e universality in K l 3 + decay. The agreement of our result with the λ 0 value obtained from K μ 3 + Dalitz plot analyses supports the validity of the μ – e universality.
Note:
  • 12 pages, 6 figures
  • K+: semileptonic decay
  • at rest
  • K+: branching ratio
  • decay: form factor
  • momentum transfer dependence
  • universality: (muon electron)
  • Dalitz plot
  • magnetic spectrometer: experimental results
  • KEK PS
  • K+ --> pi0 muon+ neutrino/mu