Search for a narrow baryonic state decaying to pK^0_S and pbarK^0_S in deep inelastic scattering at HERA

Abramowicz, H.; Abt, I.; Adamczyk, L.; Adamus, M.; Antonelli, S.; Aushev, V.; Behnke, O.; Behrens, U.; Bertolin, A.; Bhadra, S.; Bloch, I.; Boos, E. G.; Brock, I.; Brook, N. H.; Brugnera, R.; Bruni, A.; Bussey, P. J.; Caldwell, A.; Capua, M.; Catterall, C. D.; Chwastowski, J.; Ciborowski, J.; Ciesielski, R.; Cooper-Sarkar, A. M.; Corradi, M.; Dementiev, R. K.; Devenish, R. C. E.; Dusini, S.; Foster, B.; Gach, G.; Gallo, E.; Garfagnini, A.; Geiser, A.; Gizhko, A.; Gladilin, L. K.; Golubkov, Y.; Grzelak, G.; Guzik, M.; Gwenlan, C.; Hain, W.; Hlushchenko, O.; Hochman, D.; Hori, R.; Ibrahim, Z. A.; Iga, Y.; Ishitsuka, M.; Januschek, F.; Jomhari, N. Z.; Kadenko, I.; Kananov, S.; Karshon, U.; Kaur, P.; Kisielewska, D.; Klanner, R.; Klein, U.; Korzhavina, I. A.; Kotanski, A.; Kotz, U.; Kovalchuk, N.; Kowalski, H.; Krupa, B.; Kuprash, O.; Kuze, M.; Levchenko, B. B.; Levy, A.; Limentani, S.; Lisovyi, M.; Lobodzinska, E.; Lohr, B.; Lohrmann, E.; Longhin, A.; Lontkovskyi, D.; Lukina, O.; Makarenko, I.; Malka, J.; Mastroberardino, A.; Mohamad Idris, F.; Mohammad Nasir, N.; Myronenko, V.; Nagano, K.; Nobe, T.; Nowak, R. J.; Onishchuk, Y.; Paul, E.; Perlanski, W.; Pokrovskiy, N. S.; Polini, A.; Przybycien, M.; Roloff, P.; Ruspa, M.; Saxon, D. H.; Schioppa, M.; Schneekloth, U.; Schorner-Sadenius, T.; Shcheglova, L. M.; Shevchenko, R.; Shkola, O.; Shyrma, Y.; Singh, I.; Skillicorn, I. O.; Slominski, W.; Solano, A.; Stanco, L.; Stefaniuk, N.; Stern, A.; Stopa, P.; Sztuk-Dambietz, J.; Tassi, E.; Tokushuku, K.; Tomaszewska, J.; Tsurugai, T.; Turcato, M.; Turkot, O.; Tymieniecka, T.; Verbytskyi, A.; Wan Abdullah, W. A. T.; Wichmann, K.; Wing, M.; Yamada, S.; Yamazaki, Y.; Zakharchuk, N.; Zarnecki, A. F.; Zawiejski, L.; Zenaiev, O.; Zhautykov, B. O.; Zotkin, D. S.

doi:10.1016/j.physletb.2016.06.001

A search for a narrow baryonic state in the pK^0_S and pbarK^0_S system has been performed in ep collisions at HERA with the ZEUS detector using an integrated luminosity of 358 pb-1 taken in 2003-2007. The search was performed with deep inelastic scattering events at an ep centre-of-mass energy of 318 GeV for exchanged photon virtuality, Q2, between 20 and 100 GeV2. Contrary to evidence presented for such a state around 1.52 GeV in a previous ZEUS analysis using a sample of 121 pb-1 taken in 1996-2000, no resonance peak was found in the p(p)K^0_S invariant-mass distribution in the range 1.45-1.7 GeV. Upper limits on the production cross section are set.