TY  - SER
AU  - Augustyniak,W.
AU  - Bardan,W.
AU  - Bashkanov,M.
AU  - Bergmann,F.S.
AU  - Berłowski,M.
AU  - Bondar,A.
AU  - Büscher,M.
AU  - Calén,H.
AU  - Ciepał,I.
AU  - Clement,H.
AU  - Czerwiński,E.
AU  - Demmich,K.
AU  - Engels,R.
AU  - Erven,A.
AU  - Skorodko,T.
AU  - Adlarson,P.
TI  - Search for C violation in the decay η→π0e+e−with WASA-at-COSY
KW  - фотоны
KW  - бозоны
KW  - распад
KW  - мезоны
KW  - детекторы
KW  - статьи в журналах
N1  - Библиогр.: 24 назв
N2  - We report on the investigation of the rare decay $eta
ightarrowpi^0+ ext{e}^++ ext{e}^-$ which is of interest to study both $C$ violation in the electromagnetic interaction and to search for contributions from physics beyond the Standard Model, since the allowed decay via a two-photon intermediate state is strongly suppressed. The experiment has been performed using the WASA-at-COSY installation, located at the COSY accelerator of the Forschungszentrum J"ulich, Germany. In total $3 imes10^7$ events of the reaction $ ext{p}+ ext{d}
 ightarrow{^3 ext{He}}+eta$ have been recorded at an excess energy of $Q = 59.8, extrm{MeV}$. Based on this data set the $C$ parity violating decay $eta
 ightarrowpi^0+gamma^*
 ightarrowpi^0+ extrm{e}^++ extrm{e}^-$ via a single-photon intermediate state has been searched for, resulting in new upper limits of $Gammaleft(eta
 ightarrowpi^0+ extrm{e}^++ extrm{e}^-
 ight)/ Gammaleft(eta
 ightarrowpi^++pi^-+pi^0
 ight) < 3.28 imes10^{-5}$ and $Gammaleft(eta
 ightarrowpi^0+ extrm{e}^++ extrm{e}^-
 ight)/ Gammaleft(eta
 ightarrow extrm{all}
 ight) < 7.5 imes10^{-6} ( extrm{CL} = 90,%)$, respectively
UR  - http://vital.lib.tsu.ru/vital/access/manager/Repository/vtls:000788132
ER  -