Search for the forbidden decays eta -->3gamma and eta-->pi^0gamma and the rare decay eta -->pi^0pi^0 gamma gamma (CROSBI ID 116810)
Prilog u časopisu | izvorni znanstveni rad | međunarodna recenzija
Podaci o odgovornosti
Nefkens, B.M.K. ; Prakhov, S. ; Allgower, C.E. ; Bekrenev, V. ; Briscoe, W.J. ; Clajus, M. ; Comfort, J.R. ; Craig, K. ; Grosnick, D. ; G.M. ; Isenhower, D. ; Knecht, N. ; Koetke, D. ; Koulbardis, A. ; Kozlenko, N. ; Kruglov, S. ; Lolos, G. ; Lopatin, I. ; Manley, D.M. ; Manweiler, R. ; Marusic, A. ; McDonald, S. ; Olmsted, J. ; Papandreou, Z. ; Peaslee, D. ; Phaisangittisakul, N. ; Price, J.W. ; Ramirez, A.F. ; Sadler, M. ; Shafi, A. ; Spinka, H. ; Stanislaus, T.D.S. ; Starostin, A. ; Staudenmaier, H.M. ; Supek, Ivan ; Tippens, W.B.
engleski
Search for the forbidden decays eta -->3gamma and eta-->pi^0gamma and the rare decay eta -->pi^0pi^0 gamma gamma
A new upper limit is presented for the branching ratio (BR) of eta -->3 gamma. This decay is not allowed by charge-conjugation invariance. We have determined that BR(eta -->3gamma)<4x10^-5. We also obtained BR(eta-->Pi^0 gamma-->3gamma)<9x10^-5 ; this decay mode is absolutely forbidden, as it violates conservation of angular momentum. Finally, we have established that BR(eta-->pi^0pi^0 gamma gamma)<1.2x10^-3 in a restricted diphoton-energy region. All three upper limits are at the 90% confidence level. They were obtained by using the Crystal Ball multiphoton spectrometer at the AGS and are based on the analysis of 28 million eta mesons produced in the pi^-p-->eta n reaction close to threshold.
decays; pseudoscalar meson
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