Measurement of Γ(K3)/Γ(K3) ratio using stopped positive kaons

Abstract

The ratio of the K + → π 0 µ + ν (K + µ3 ) and K + → π 0 e + ν (K + e3 ) decay widths, Γ(K µ3 )/Γ(K e3 ), has been measured with stopped positive kaons. K + µ3 and K + e3 samples containing 2.4×10 4 and 4.0×10 4 events, respectively, were analyzed. The Γ(K µ3 )/Γ(K e3 ) 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 + l3 decay. The agreement of our result with the λ 0 value obtained from K + µ3 Dalitz plot analyses supports the validity of the µ-e universality.

Measurements of charged kaon semileptonic decay branching fractions K±→π0μ±ν and K±→π0e±ν and their ratio

“…R Ke3/K2π and R Kµ3/K2π results compared to the corresponding PDG value[2]. R Kµ3/Ke3 results compared to KEK-246 results[17], the corresponding PDG value of 2006[2] and to the predictions assuming µ − e universality, Eq. (6), with the λ + and λ 0 values given for K ± in the PDG of 2006[2].…”

Measurement of direct photon emission in K+→π+π0γ decay using stopped positive kaons

“…The experimental apparatus was based on the E246 experiment searching for Tviolating transverse muon polarization in K + → π 0 µ + ν (K µ3 ) decay [11]. Besides the T -violation search, spectroscopic studies for K + → π 0 e + ν (K e3 ), K µ3 , and K π3 decays have been carried out using the same detector system [12,13,14]. A schematic cross sectional view of the detector is shown in Fig.…”

New limit on T-violating parameters in kaon decays

“…The difference in the number of hits between these two counters is an asymmetry representing the transverse polarization P T of interest. 1 The matrix element (1.1) doesn't include explicitly any exotic terms, since our recent study of K + → π 0 e + ν (K + e3 ) decays shows that, first, scalar fS and tensor fT form factors are consistent with zero [2] and, second, there is no deviation from µ-e universality [3].…”