Experimental study of direct photon emission in K/it{sup -} {sup {yields}} {pi}{sup -}{pi}{sup 0}{gamma} decay using ISTRA+ detector

• Published in: Physics of atomic nuclei Vol. 69; no. 1
• Main Authors: Uvarov, V. A., Akimenko, S. A., Bolotov, V. N., Britvich, G. I., Datsko, K. V., Duk, V. A., Filin, A. P., Inyakin, A. V., Khmelnikov, V. A., Konstantinov, A. S., Konstantinov, V. F., Korolkov, I. Ya, Laptev, S. V., Leontiev, V. M., Novikov, V. P., Obraztsov, V. F., Polyakov, V. A., Polyarush, A. Yu, Romanovsky, V. I., Ronjin, V. M.
• Format: Journal Article
• Language: English
• Published: United States 15.01.2006
• Subjects: BRANCHING RATIO; FORECASTING; GAMMA RADIATION; GEV RANGE 10-100; KAONS MINUS; KINETIC ENERGY; MEV RANGE 10-100; PARTICLE DECAY; PHOTON EMISSION; PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; PIONS MINUS; PIONS NEUTRAL; SECONDARY BEAMS
• DOI: 10.1134/S1063778806010042
• ISSN: 1063-7788

The branching ratio in the charged-pion-kinetic-energy region of 55 to 90 MeV for the direct photon emission in the K{sup -} {sup {yields}} {pi}{sup -}{pi}{sup 0}{gamma} 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.)]x10{sup -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.