Measurement of structure-dependent K+ --> &mgr;(+)nu(&mgr;)gamma decay

S Adler; MS Atiya; IH Chiang; MV Diwan; JS Frank; JS Haggerty; SH Kettell; TF Kycia; KK Li; LS Littenberg; A Sambamurti; A Stevens; RC Strand; C Witzig; TK Komatsubara; M Kuriki; N Muramatsu; S Sugimoto; T Inagaki; S Kabe; M Kobayashi; Y Kuno; T Sato; T Shinkawa; Y Yoshimura; Y Kishi

doi:10.1103/PhysRevLett.85.2256

Measurement of structure-dependent K+ --> &mgr;(+)nu(&mgr;)gamma decay

Phys Rev Lett. 2000 Sep 11;85(11):2256-9. doi: 10.1103/PhysRevLett.85.2256.

Authors

Affiliation

¹ Brookhaven National Laboratory, Upton, New York 11973, USA.

PMID: 10977985
DOI: 10.1103/PhysRevLett.85.2256

Abstract

We report the first measurement of a structure-dependent component in the decay K+-->&mgr;(+)nu(&mgr;)gamma. Using the kinematic region where the muon kinetic energy is greater than 137 MeV and the photon energy is greater than 90 MeV, we find that the absolute value of the sum of the vector and axial-vector form factors is |F(V)+F(A)| = 0.165+/-0.007+/-0.011. This corresponds to a branching ratio of B(SD+) = (1.33+/-0.12+/-0.18)x10(-5). We also set the limit -0. 04<F(V)-F(A)<0.24 at 90% C.L.