Measurement of theKμ3+Decay Parameters

A sample of K+ mesons stopped in the CERN 1.1-m3 heavy-liquid bubble chamber has been used to study the Dalitz-plot density and the μ+ polarization in Kμ3+ decay and to measure the Kμ3+ and Ke3+ branching ratios. All three analyses are described in detail, and they are used, separately and combined, to study the form of the strangeness-changing, semileptonic weak interaction. This is found to be consistent with a coupling of vector currents and to be invariant under time reversal. The vector form factors are studied with a wide range of assumptions as to their possible four-momentum (q2) dependence, and the results of all three measurements are in agreement. If λ+ is fixed at 0.029 (the average value from Ke3+ experiments) and if ξ is assumed to be independent of q2, then the result is ξ=-0.65±0.13. Assuming that f+(q2) and ξ(q2) are both linear functions of q2, a three-parameter fit gives λ+=0.060±0.019, ξ(0)=-1.0±0.5, and ξ(5.1mπ2)=-0.97±0.20. © 1971 The American Physical Society.SCOPUS: ar.jinfo:eu-repo/semantics/publishe