Extraction of Kaon Formfactors from K^- -> mu^- nu_mu gamma Decay at ISTRA+ Setup
hep-ex
/ Authors
The ISTRA+ Collaboration, :, V. A. Duk, V. N. Bolotov, A. A. Khudyakov, V. A. Lebedev, A. I. Makarov, V. P. Novikov, A. Yu. Polyarush, S. A. Akimenko
and 11 more authors
G. I. Britvich, A. P. Filin, A. V. Inyakin, I. Ya. Korolkov, V. M. Leontiev, V. F. Obraztsov, V. A. Polyakov, V. I. Romanovsky, O. G. Tchikilev, V. A. Uvarov, O. P. Yushchenko
/ Abstract
The radiative decay K->mu nu gamma has been studied at ISTRA+ setup in a new kinematical region. About 22K events of K^- -> mu^- nu_mu gamma have been observed. The sign and value of Fv-Fa have been measured for the first time. The result is Fv-Fa=0.21(4)(4).