학술논문
Pentaquark $\Theta^+$ search at HERMES
Document Type
Working Paper
Author
The HERMES Collaboration; Akopov, N.; Akopov, Z.; Augustyniak, W.; Avakian, R.; Avetissian, A.; Avetisyan, E.; Belostotski, S.; Blok, H. P.; Borissov, A.; Bowles, J.; Bryzgalov, V.; Burns, J.; Capitani, G. P.; Cisbani, E.; Ciullo, G.; Contalbrigo, M.; Dalpiaz, P. F.; Deconinck, W.; De Leo, R.; De Sanctis, E.; Di Nezza, P.; Elbakian, G.; Etzelmüller, E.; Fabbri, R.; Fantoni, A.; Felawka, L.; Frullani, S.; Gabbert, D.; García, J. Garay; Garibaldi, F.; Gavrilov, G.; Giordano, F.; Gliske, S.; Hartig, M.; Hasch, D.; Holler, Y.; Hristova, I.; Imazu, Y.; Ivanilov, A.; Jackson, H. E.; Joosten, S.; Kaiser, R.; Karyan, G.; Keri, T.; Kinney, E.; Kisselev, A.; Kozlov, V.; Kravchenko, P.; Krivokhijine, V. G.; Lagamba, L.; Lapikás, L.; Lehmann, I.; Ruiz, A. López; Lorenzon, W.; Lu, X.; Ma, B. -Q.; Mahon, D.; Manaenkov, S. I.; Mao, Y.; Marianski, B.; de la Ossa, A. Martinez; Marukyan, H.; Miller, C. A.; Miyachi, Y.; Movsisyan, A.; Murray, M.; Nappi, E.; Nass, A.; Negodaev, M.; Nowak, W. -D.; Pappalardo, L. L.; Perez-Benito, R.; Petrosyan, A.; Reimer, P. E.; Reolon, A. R.; Riedl, C.; Rith, K.; Rosner, G.; Rostomyan, A.; Rubin, J.; Ryckbosch, D.; Salomatin, Y.; Schnell, G.; Schüler, K. P.; Seitz, B.; Shibata, T. -A.; Stancari, M.; Steijger, J. J. M.; Taroian, S.; Terkulov, A.; Truty, R.; Trzcinski, A.; Tytgat, M.; Van Haarlem, Y.; Van Hulse, C.; Veretennikov, D.; Vikhrov, V.; Vilardi, I.; Wang, S.; Yaschenko, S.; Ye, H.; Ye, Z.; Yen, S.; Zihlmann, B.; Zupranski, P.
Source
Phys. Rev. D 91, 057101 (2015)
Subject
Language
Abstract
The earlier search at HERMES for narrow baryon states excited in quasi-real photoproduction, decaying through the channel $pK_S^0\rightarrow p\pi^+\pi^-$, has been extended with improved decay-particle reconstruction, more advanced particle identification, and increased event samples. The structure observed earlier at an invariant mass of 1528 MeV shifts to 1522 MeV and the statistical significance drops to about 2$\sigma$ for data taken with a deuterium target. The number of events above background is $68_{-31}^{+98}\text{(stat)}\pm13\text{(sys)}$. No such structure is observed in the hydrogen data set.