An experimental investigation of the radiative structure decay K+ → e+υγ

Radiative semileptonic kaon decays

“…In these kinematical regions, background from K + → e + ν e π 0 is absent because E max e (K e3 ) = 228 MeV. The combined result of both experiments is 4 [11] Γ…”

“…The form factor A (V ) is related to the matrix element of the axial (vector) current in (3.4). In Appendix B we display the general decomposition of A µν , V µν for q 2 = 0 and provide also the link with the notation used by the PDG [10] and in [11,12].…”

“…The PDG uses data from two experiments [11,15], both of which have been sensitive mainly to the SD + term in (3.16). In [15], 56 events with E γ > 100 MeV, E e + > 236 MeV and θ e + γ > 120 • have been identified, whereas the later experiment [11] has collected 51 events with E γ > 48 MeV, E e + > 235 MeV, and θ e + γ > 140 • . In these kinematical regions, background from K + → e + ν e π 0 is absent because E max e (K e3 ) = 228 MeV.…”

“…has been obtained from a sample of electrons with energies 220 MeV ≤ E e ≤ 230 MeV [11]. Using (3.21,3.22), the result (3.28) leads to…”

Precise measurement of Γ(K→e ν(γ))/Γ(K→μ ν(γ)) and study of K→e ν γ

“…Interference among the two processes is negligible [5]. The DE contribution to the total width is approximately equal to that of IB [5] but is presently known with a 15% fractional accuracy [6].…”