Experimental study of direct photon emission in K/it− → π−π0γ decay using ISTRA+ detector
/ Authors
V. Uvarov, S. Akimenko, V. Bolotov, G. Britvich, K. Datsko, V. A. Duk, A. Filin, A. Inyakin, V. Khmelnikov, A. Konstantinov
and 14 more authors
V. Konstantinov, I. Korolkov, S. Laptev, V. Leontiev, V. Novikov, V. Obraztsov, V. Polyakov, A. Polyarush, V. Romanovsky, V. Ronjin, V. Shelikhov, N. Smirnov, O. Tchikilev, O. Yushchenko
/ Abstract
The branching ratio in the charged-pion-kinetic-energy region of 55 to 90 MeV for the direct photon emission in the K− → π−π0γ decay has been measured using in-flight decays detected with the ISTRA+ setup operating in the 25-GeV/c negative secondary beam of the U-70 PS. The value Br(DE)=[0.37±0.39(stat.)±0.10(syst.)]×10−5 obtained from the analysis of 930 completely reconstructed events is consistent with the average value of two stopped-kaon experiments, but it differs by 2.5 standard deviations from the average value of three in-flight-kaon experiments. The result is also compared with recent theoretical predictions.
Journal: Physics of Atomic Nuclei