High statistic measurement of the K- ->pi0 e- nu decay form-factors
/ Authors
O.P.Yushchenko, S.A.Akimenko, G.I.Britvich, K.V.Datsko, A.P.Filin, A.V.Inyakin, A.S.Konstantinov, V.F.Konstantinov, I.Y.Korolkov, V.A.Khmelnikov
and 13 more authors
V.M.Leontiev, V.P.Novikov, V.F.Obraztsov, V.A.Polyakov, V.I.Romanovsky, V.M.Ronjin, V.I.Shelikhov, N.E.Smirnov, O.G.Tchikilev, V.A.Uvarov, V.N.Bolotov, S.V.Laptev, A.Yu.Polyarush
/ Abstract
The decay K − → π 0 e − ν is studied using in-flight decays detected with the ”ISTRA+” spectrometer. About 920K events are collected for the analysis. The λ + slope parameter of the decay form-factor f + ( t ) in the linear approximation (average slope) is measured: λ lin+ = 0 . 02774 ± 0 . 00047(stat) ± 0 . 00032(syst). The quadratic contribution to the form-factor was estimated to be λ ′ + = 0 . 00084 ± 0 . 00027(stat) ± 0 . 00031(syst). The linear slope, which has a meaning of df + ( t ) /dt | t =0 for this fit, is λ + = 0 . 02324 ± 0 . 00152(stat) ± 0 . 00032(syst). The limits on possible tensor and scalar couplings are derived: f T /f + (0) = − 0 . 012 ± 0 . 021(stat)