Results on kaon physics from OKA setup at U-70

Abstract

Some recent results from OKA setup are presented. First, the decay K+ →π0e+υ(Ke3) is studied. About 3.15M events are selected for the analysis. The linear and quadratic slopes for the decay formfactor f+(t) are measured: . For the exotic scalar and tensor interactions we get: FS/f+(0) = (−0.44±0.7±0.24) × 10−2; FT/f+(0) = (0.16±2±1.3) × 10−2. Several alternative parametrizations are tried: the Pole fit parameter is found to be MV = 890 ± 3.7 MeV; the parameter of the Dispersive parametrization is measured to be Λ+ = (24.72 ± 0.23) × 10−3. Second, the results of a search for heavy neutrino in the Kμ2 decay are shown. The upper limits on the mixing parameter of the heavy neutrino with the muon neutrino |UμH|2 are obtained. Typically, |UμH|2 ≤ 10−6 for the region 225 ≤ mH ≤ 375 MeV. Third, a new study of the radiative Kμ3 decay are presented. The number of signal events is ∼ 580 which is 4 times larger than in previous measurements. which should be compared with 4.7 × 10−4 from the theory. An estimate of the T-odd asymmetry gives Aξ = (−0.19±0.05±0.09). A space asymmetry over , where is the angle between photon and muon momenta in the kaon rest frame is measured to be A(cosθ*) = 0.6±0.05±0.1.