Search for a narrow baryonic state decaying to pK 0 S and pK 0 S in deep inelastic scattering

Article history: Received 7 April 2016 Received in revised form 27 May 2016 Accepted 1 June 2016 Available online xxxx Editor: L. Rolandi A search for a narrow baryonic state in the pK 0 S and pK 0 S system has been performed in ep collisions at HERA with the ZEUS detector using an integrated luminosity of 358 pb 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, Q , between 20 and 100 GeV. Contrary to evidence presented for such a state around 1.52 GeV in a previous ZEUS analysis using a sample of 121 pb 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.  2016 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). Funded by SCOAP. E-mail address: m.wing@ucl.ac.uk (M. Wing). 1 Supported by the Italian National Institute for Nuclear Physics (INFN). 2 Supported by the German Federal Ministry for Education and Research (BMBF), under contract No. 05 H09PDF. 3 Supported by HIR grant UM.C/625/1/HIR/149 and UMRG grants RU0062013RU006-2013, RP012A-13AFR and RP012B-13AFR from Universiti Malaya, and ERGS grant ER004-2012A from the Ministry of Education, Malaysia. 4 Supported by the National Science Centre under contract No. DEC-2012/06/ M/ST2/00428. 5 Supported by the Science and Technology Facilities Council, UK. 6 Supported by the German Federal Ministry for Education and Research (BMBF), under contract No. 05h09GUF, and the SFB 676 of the Deutsche Forschungsgemeinschaft (DFG). 7 Supported by the Japanese Ministry of Education, Culture, Sports, Science and Technology (MEXT) and its grants for Scientific Research. 8 Supported by RF Presidential grant No. 3042.2014.2 for the Leading Scientific Schools. 9 Supported by the Israel Science Foundation. 10 Supported by the Natural Sciences and Engineering Research Council of Canada (NSERC). 11 Now at INFN Roma, Italy. 12 Now at Sant Longowal Institute of Engineering and Technology, Longowal, Punjab, India. 13 Now at Sri Guru Granth Sahib World University, Fatehgarh Sahib, India. 14 Also at Agensi Nuklear Malaysia, 43000 Kajang, Bangi, Malaysia. 15 Partially supported by the Polish National Science Centre projects DEC-2011/01/ B/ST2/03643 and DEC-2011/03/B/ST2/00220. 16 Now at Rockefeller University, New York, NY 10065, USA. 17 Now at European X-ray Free-Electron Laser facility GmbH, Hamburg, Germany. 18 Now at University of Liverpool, United Kingdom. 19 Now at Tel Aviv University, Isreal. 20 Now at Physikalisches Institut, Universität Heidelberg, Germany. 21 Supported by the Alexander von Humboldt Foundation. 22 Now at CERN, Geneva, Switzerland. 23 Alexander von Humboldt Professor; also at DESY and University of Oxford. 24 Also at DESY. 25 Also at University of Tokyo, Japan. 26 Now at Kobe University, Japan. 27 Member of National Technical University of Ukraine, Kyiv Polytechnic Institute, Kyiv, Ukraine. 28 Now at DESY CMS group. 29 Now at DESY ATLAS group. 30 Now at LNF, Frascati, Italy. 31 Also at Max Planck Institute for Physics, Munich, Germany, External Scientific Member.