Eur. Phys. J. C (2007) 52: 507-514
https://doi.org/10.1140/epjc/s10052-007-0407-3

Regular Article - Experimental Physics

Search for baryonic resonances decaying to Ξπ in deep-inelastic scattering at HERA

¹ I. Physikalisches Institut der RWTH, Aachen, Germany
² Vinca Institute of Nuclear Sciences, Belgrade, Serbia
³ School of Physics and Astronomy, University of Birmingham, Birmingham, UK
⁴ Inter-University Institute for High Energies ULB-VUB,, Universiteit Antwerpen, Antwerpen, Brussels, Belgium
⁵ Rutherford Appleton Laboratory, Chilton, Didcot, UK
⁶ Institute for Nuclear Physics, Cracow, Poland
⁷ Institut für Physik, Universität Dortmund, Dortmund, Germany
⁸ Joint Institute for Nuclear Research, Dubna, Russia
⁹ CEA, DSM/DAPNIA, CE-Saclay, Gif-sur-Yvette, France
¹⁰ DESY, Hamburg, Germany
¹¹ Institut für Experimentalphysik, Universität Hamburg, Hamburg, Germany
¹² Max-Planck-Institut für Kernphysik, Heidelberg, Germany
¹³ Physikalisches Institut, Universität Heidelberg, Philosophenweg 12, 69120, Heidelberg, Germany
¹⁴ Kirchhoff-Institut für Physik, Universität Heidelberg, Heidelberg, Germany
¹⁵ Institute of Experimental Physics, Slovak Academy of Sciences, Košice, Slovak Republic
¹⁶ Department of Physics, University of Lancaster, Lancaster, UK
¹⁷ Department of Physics, University of Liverpool, Liverpool, UK
¹⁸ Queen Mary and Westfield College, London, UK
¹⁹ Physics Department, University of Lund, Lund, Sweden
²⁰ CPPM, CNRS/IN2P3 - Univ. Mediterranee, Marseille, France
²¹ Departamento de Fisica Aplicada, CINVESTAV, Mérida, Yucatán, Mexico
²² Departamento de Fisica, CINVESTAV, Mérida, Yucatán, Mexico
²³ Institute for Theoretical and Experimental Physics, Moscow, Russia
²⁴ Lebedev Physical Institute, Moscow, Russia
²⁵ Max-Planck-Institut für Physik, München, Germany
²⁶ LAL, Université de Paris-Sud 11, IN2P3-CNRS, Orsay, France
²⁷ LLR, Ecole Polytechnique, IN2P3-CNRS, Palaiseau, France
²⁸ LPNHE, Universités Paris VI and VII, IN2P3-CNRS, Paris, France
²⁹ Faculty of Science, University of Montenegro, Podgorica, Montenegro
³⁰ Institute of Physics, Academy of Sciences of the Czech Republic, Praha, Czech Republic
³¹ Faculty of Mathematics and Physics, Charles University, Praha, Czech Republic
³² Dipartimento di Fisica Università di Roma Tre and INFN Roma 3, Roma, Italy
³³ Institute for Nuclear Research and Nuclear Energy, Sofia, Bulgaria
³⁴ Institute of Physics and Technology of the Mongolian Academy of Sciences, Ulaanbaatar, Mongolia
³⁵ Paul Scherrer Institut, Villigen, Switzerland
³⁶ Fachbereich C, Universität Wuppertal, Wuppertal, Germany
³⁷ Yerevan Physics Institute, Yerevan, Armenia
³⁸ DESY, Zeuthen, Germany
³⁹ Institut für Teilchenphysik, ETH, Zürich, Switzerland
⁴⁰ Physik-Institut der Universität Zürich, Zürich, Switzerland
⁴¹ Physics Department, National Technical University, Zografou Campus, 15773, Athens, Greece
⁴² Rechenzentrum, Universität Wuppertal, Wuppertal, Germany
⁴³ University of P.J. Šafárik, Košice, Slovak Republic
⁴⁴ CERN, Geneva, Switzerland
⁴⁵ Max-Planck-Institut für Physik, München, Germany
⁴⁶ Comenius University, Bratislava, Slovak Republic
⁴⁷ DESY and University Hamburg, Helmholtz Humboldt Research Award, Hamburg, Germany
⁴⁸ National Institute for Physics and Nuclear Engineering, Magurele, Bucharest, Romania

^* e-mail: obehnke@mail.desy.de

Received: 3 July 2007
Published online: 28 September 2007

Abstract

A search for narrow baryonic resonances decaying into Ξ^-π^- or Ξ^-π⁺ and their antiparticles is carried out with the H1 detector using deep inelastic scattering events at HERA in the range of negative photon four-momentum transfer squared 2 < Q² < 100 GeV². No signal is observed for a new baryonic state in the mass range 1600–2300 MeV in either the doubly charged or the neutral decay channels. The known Ξ(1530)⁰ is observed through its decay mode into Ξ^-π⁺. Upper limits are given on the ratio of the production rates of new baryonic states, such as the hypothetical pentaquark states Ξ^– _5q or Ξ⁰ _5q, relative to the Ξ(1530)⁰ baryon state.