Strangeness production at low Q 2 in deep-inelastic ep scattering at HERA

F. D. Aaron; C. Alexa; V. Andreev; B. Antunovic; S. Aplin; A. Asmone; A. Astvatsatourov; A. Bacchetta; S. Backovic; A. Baghdasaryan; E. Barrelet; W. Bartel; M. Beckingham; K. Begzsuren; O. Behnke; A. Belousov; N. Berger; J. C. Bizot; M.-O. Boenig; V. Boudry; I. Bozovic-Jelisavcic; J. Bracinik; G. Brandt; M. Brinkmann; V. Brisson; D. Bruncko; A. Bunyatyan; G. Buschhorn; L. Bystritskaya; A. J. Campbell; K. B. Cantun Avila; F. Cassol-Brunner; K. Cerny; V. Cerny; V. Chekelian; A. Cholewa; J. G. Contreras; J. A. Coughlan; G. Cozzika; J. Cvach; J. B. Dainton; K. Daum; M. Deák; Y. de Boer; B. Delcourt; M. Del Degan; J. Delvax; A. De Roeck; E. A. De Wolf; C. Diaconu; V. Dodonov; A. Dossanov; A. Dubak; G. Eckerlin; V. Efremenko; S. Egli; R. Eichler; A. Eliseev; E. Elsen; S. Essenov; A. Falkiewicz; P. J. W. Faulkner; L. Favart; A. Fedotov; R. Felst; J. Feltesse; J. Ferencei; M. Fleischer; A. Fomenko; E. Gabathuler; J. Gayler; S. Ghazaryan; A. Glazov; I. Glushkov; L. Goerlich; M. Goettlich; N. Gogitidze; M. Gouzevitch; C. Grab; T. Greenshaw; B. R. Grell; G. Grindhammer; S. Habib; D. Haidt; M. Hansson; C. Helebrant; R. C. W. Henderson; E. Hennekemper; H. Henschel; G. Herrera; M. Hildebrandt; K. H. Hiller; D. Hoffmann; R. Horisberger; A. Hovhannisyan; T. Hreus; M. Jacquet; M. E. Janssen; X. Janssen; V. Jemanov; L. Jönsson; A. W. Jung; H. Jung; M. Kapichine; J. Katzy; I. R. Kenyon; C. Kiesling; M. Klein; C. Kleinwort; T. Klimkovich; T. Kluge; A. Knutsson; R. Kogler; V. Korbel; P. Kostka; M. Kraemer; K. Krastev; J. Kretzschmar; A. Kropivnitskaya; K. Krüger; K. Kutak; M. P. J. Landon; W. Lange; G. Laštovička-Medin; P. Laycock; A. Lebedev; G. Leibenguth; V. Lendermann; S. Levonian; G. Li; K. Lipka; A. Liptaj; B. List; J. List; N. Loktionova; R. Lopez-Fernandez; V. Lubimov; A.-I. Lucaci-Timoce; L. Lytkin; A. Makankine; E. Malinovski; P. Marage; Ll. Marti; H.-U. Martyn; S. J. Maxfield; A. Mehta; K. Meier; A. B. Meyer; H. Meyer; H. Meyer; J. Meyer; V. Michels; S. Mikocki; I. Milcewicz-Mika; F. Moreau; A. Morozov; J. V. Morris; M. U. Mozer; M. Mudrinic; K. Müller; P. Murín; K. Nankov; B. Naroska; Th. Naumann; P. R. Newman; C. Niebuhr; A. Nikiforov; G. Nowak; K. Nowak; M. Nozicka; B. Olivier; J. E. Olsson; S. Osman; D. Ozerov; V. Palichik; I. Panagoulias; M. Pandurovic; Th. Papadopoulou; C. Pascaud; G. D. Patel; O. Pejchal; H. Peng; E. Perez; A. Petrukhin; I. Picuric; S. Piec; D. Pitzl; R. Plačakytė; R. Polifka; B. Povh; T. Preda; V. Radescu; A. J. Rahmat; N. Raicevic; A. Raspiareza; T. Ravdandorj; P. Reimer; E. Rizvi; P. Robmann; B. Roland; R. Roosen; A. Rostovtsev; M. Rotaru; J. E. Ruiz Tabasco; Z. Rurikova; S. Rusakov; D. Salek; F. Salvaire; D. P. C. Sankey; M. Sauter; E. Sauvan; S. Schmidt; S. Schmitt; C. Schmitz; L. Schoeffel; A. Schöning; H.-C. Schultz-Coulon; F. Sefkow; R. N. Shaw-West; I. Sheviakov; L. N. Shtarkov; S. Shushkevich; T. Sloan; I. Smiljanic; P. Smirnov; Y. Soloviev; P. Sopicki; D. South; V. Spaskov; A. Specka; Z. Staykova; M. Steder; B. Stella; U. Straumann; D. Sunar; T. Sykora; V. Tchoulakov; G. Thompson; P. D. Thompson; T. Toll; F. Tomasz; T. H. Tran; D. Traynor; T. N. Trinh; P. Truöl; I. Tsakov; B. Tseepeldorj; I. Tsurin; J. Turnau; E. Tzamariudaki; K. Urban; A. Valkárová; C. Vallée; P. Van Mechelen; A. Vargas Trevino; Y. Vazdik; S. Vinokurova; V. Volchinski; D. Wegener; M. Wessels; Ch. Wissing; E. Wünsch; V. Yeganov; J. Žáček; J. Zálešák; Z. Zhang; A. Zhelezov; A. Zhokin; Y. C. Zhu; T. Zimmermann; H. Zohrabyan; F. Zomer

doi:10.1140/epjc/s10052-009-0995-1

2024 Impact factor 4.8

Particles and Fields

Open Access

Eur. Phys. J. C (2009) 61: 185-205
https://doi.org/10.1140/epjc/s10052-009-0995-1

Regular Article - Experimental Physics

Strangeness production at low Q ² in deep-inelastic ep scattering at HERA

H1 Collaboration
F. D. Aaron⁶, C. Alexa⁶, V. Andreev²⁶, B. Antunovic¹², S. Aplin¹², A. Asmone³⁴, A. Astvatsatourov⁴^,5, A. Bacchetta¹², S. Backovic³¹, A. Baghdasaryan³⁹, E. Barrelet³⁰, W. Bartel¹², M. Beckingham¹², K. Begzsuren³⁶, O. Behnke¹⁵, A. Belousov²⁶, N. Berger⁴¹, J. C. Bizot²⁸, M.-O. Boenig⁹, V. Boudry²⁹, I. Bozovic-Jelisavcic², J. Bracinik³, G. Brandt¹², M. Brinkmann¹², V. Brisson²⁸, D. Bruncko¹⁷, A. Bunyatyan¹⁴^,39, G. Buschhorn²⁷, L. Bystritskaya²⁵, A. J. Campbell¹², K. B. Cantun Avila²³, F. Cassol-Brunner²², K. Cerny³³, V. Cerny¹⁷, V. Chekelian²⁷, A. Cholewa¹², J. G. Contreras²³, J. A. Coughlan⁷, G. Cozzika¹¹, J. Cvach³², J. B. Dainton¹⁹, K. Daum³⁸, M. Deák¹², Y. de Boer¹², B. Delcourt²⁸, M. Del Degan⁴¹, J. Delvax⁴^,5, A. De Roeck¹², E. A. De Wolf⁴^,5, C. Diaconu²², V. Dodonov¹⁴, A. Dossanov²⁷, A. Dubak³¹, G. Eckerlin¹², V. Efremenko²⁵, S. Egli³⁷, R. Eichler⁴¹, A. Eliseev²⁶, E. Elsen¹², S. Essenov²⁵, A. Falkiewicz⁸, P. J. W. Faulkner³, L. Favart⁴^,5, A. Fedotov²⁵, R. Felst¹², J. Feltesse¹¹, J. Ferencei¹⁷, M. Fleischer¹², A. Fomenko²⁶, E. Gabathuler¹⁹, J. Gayler¹², S. Ghazaryan³⁹, A. Glazov¹², I. Glushkov⁴⁰, L. Goerlich⁸, M. Goettlich¹³, N. Gogitidze²⁶, M. Gouzevitch²⁹, C. Grab⁴¹, T. Greenshaw¹⁹, B. R. Grell¹², G. Grindhammer²⁷, S. Habib¹³, D. Haidt¹², M. Hansson²¹, C. Helebrant¹², R. C. W. Henderson¹⁸, E. Hennekemper¹⁶, H. Henschel⁴⁰, G. Herrera²⁴, M. Hildebrandt³⁷, K. H. Hiller⁴⁰, D. Hoffmann²², R. Horisberger³⁷, A. Hovhannisyan³⁹, T. Hreus⁴^,5, M. Jacquet²⁸, M. E. Janssen¹², X. Janssen⁴^,5, V. Jemanov¹³, L. Jönsson²¹, A. W. Jung¹⁶, H. Jung¹², M. Kapichine¹⁰, J. Katzy¹², I. R. Kenyon³, C. Kiesling²⁷, M. Klein¹⁹, C. Kleinwort¹², T. Klimkovich¹², T. Kluge¹⁹, A. Knutsson¹², R. Kogler²⁷, V. Korbel¹², P. Kostka⁴⁰, M. Kraemer¹², K. Krastev¹², J. Kretzschmar¹⁹, A. Kropivnitskaya²⁵, K. Krüger¹⁶, K. Kutak¹², M. P. J. Landon²⁰, W. Lange⁴⁰, G. Laštovička-Medin³¹, P. Laycock¹⁹, A. Lebedev²⁶, G. Leibenguth⁴¹, V. Lendermann¹⁶, S. Levonian¹², G. Li²⁸, K. Lipka¹³, A. Liptaj²⁷, B. List¹³, J. List¹², N. Loktionova²⁶, R. Lopez-Fernandez²⁴, V. Lubimov²⁵, A.-I. Lucaci-Timoce¹², L. Lytkin¹⁴, A. Makankine¹⁰, E. Malinovski²⁶, P. Marage⁴^,5, Ll. Marti¹², H.-U. Martyn¹, S. J. Maxfield¹⁹, A. Mehta¹⁹, K. Meier¹⁶, A. B. Meyer¹², H. Meyer¹², H. Meyer³⁸, J. Meyer¹², V. Michels¹², S. Mikocki⁸, I. Milcewicz-Mika⁸, F. Moreau²⁹, A. Morozov¹⁰, J. V. Morris⁷, M. U. Mozer⁴^,5, M. Mudrinic², K. Müller⁴², P. Murín¹⁷, K. Nankov³⁵, B. Naroska¹³, Th. Naumann⁴⁰, P. R. Newman³, C. Niebuhr¹², A. Nikiforov¹², G. Nowak⁸, K. Nowak⁴², M. Nozicka¹², B. Olivier²⁷, J. E. Olsson¹², S. Osman²¹, D. Ozerov²⁵, V. Palichik¹⁰, I. Panagoulias¹², M. Pandurovic², Th. Papadopoulou¹², C. Pascaud²⁸, G. D. Patel¹⁹, O. Pejchal³³, H. Peng¹², E. Perez¹¹, A. Petrukhin²⁵, I. Picuric³¹, S. Piec⁴⁰, D. Pitzl¹², R. Plačakytė¹², R. Polifka³³, B. Povh¹⁴, T. Preda⁶, V. Radescu¹², A. J. Rahmat¹⁹, N. Raicevic³¹, A. Raspiareza²⁷, T. Ravdandorj³⁶, P. Reimer³², E. Rizvi²⁰, P. Robmann⁴², B. Roland⁴^,5, R. Roosen⁴^,5, A. Rostovtsev²⁵, M. Rotaru⁶, J. E. Ruiz Tabasco²³, Z. Rurikova¹², S. Rusakov²⁶, D. Salek³³, F. Salvaire¹², D. P. C. Sankey⁷, M. Sauter⁴¹, E. Sauvan²², S. Schmidt¹², S. Schmitt¹², C. Schmitz⁴², L. Schoeffel¹¹, A. Schöning¹²^,42^*, H.-C. Schultz-Coulon¹⁶, F. Sefkow¹², R. N. Shaw-West³, I. Sheviakov²⁶, L. N. Shtarkov²⁶, S. Shushkevich²⁷, T. Sloan¹⁸, I. Smiljanic², P. Smirnov²⁶, Y. Soloviev²⁶, P. Sopicki⁸, D. South⁹, V. Spaskov¹⁰, A. Specka²⁹, Z. Staykova¹², M. Steder¹², B. Stella³⁴, U. Straumann⁴², D. Sunar⁴^,5, T. Sykora⁴^,5, V. Tchoulakov¹⁰, G. Thompson²⁰, P. D. Thompson³, T. Toll¹², F. Tomasz¹⁷, T. H. Tran²⁸, D. Traynor²⁰, T. N. Trinh²², P. Truöl⁴², I. Tsakov³⁵, B. Tseepeldorj³⁶, I. Tsurin⁴⁰, J. Turnau⁸, E. Tzamariudaki²⁷, K. Urban¹⁶, A. Valkárová³³, C. Vallée²², P. Van Mechelen⁴^,5, A. Vargas Trevino¹², Y. Vazdik²⁶, S. Vinokurova¹², V. Volchinski³⁹, D. Wegener⁹, M. Wessels¹², Ch. Wissing¹², E. Wünsch¹², V. Yeganov³⁹, J. Žáček³³, J. Zálešák³², Z. Zhang²⁸, A. Zhelezov²⁵, A. Zhokin²⁵, Y. C. Zhu¹², T. Zimmermann⁴¹, H. Zohrabyan³⁹ and F. Zomer²⁸

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, Brussels, Belgium
⁵ Universiteit Antwerpen, Antwerpen, Belgium
⁶ National Institute for Physics and Nuclear Engineering (NIPNE), Bucharest, Romania
⁷ Rutherford Appleton Laboratory, Chilton, Didcot, UK
⁸ Institute for Nuclear Physics, Cracow, Poland
⁹ Institut für Physik, TU Dortmund, Dortmund, Germany
¹⁰ Joint Institute for Nuclear Research, Dubna, Russia
¹¹ CEA, DSM/Irfu, CE-Saclay, Gif-sur-Yvette, France
¹² DESY, Hamburg, Germany
¹³ Institut für Experimentalphysik, Universität Hamburg, Hamburg, Germany
¹⁴ Max-Planck-Institut für Kernphysik, Heidelberg, Germany
¹⁵ Physikalisches Institut, Universität Heidelberg, Heidelberg, Germany
¹⁶ Kirchhoff-Institut für Physik, Universität Heidelberg, Heidelberg, Germany
¹⁷ Institute of Experimental Physics, Slovak Academy of Sciences, Košice, Slovak Republic
¹⁸ Department of Physics, University of Lancaster, Lancaster, UK
¹⁹ Department of Physics, University of Liverpool, Liverpool, UK
²⁰ Queen Mary and Westfield College, London, UK
²¹ Physics Department, University of Lund, Lund, Sweden
²² CPPM, CNRS/IN2P3—Univ. Mediterranee, Marseille, France
²³ Departamento de Fisica Aplicada, CINVESTAV, Mérida, Yucatán, Mexico
²⁴ Departamento de Fisica, CINVESTAV, México, Mexico
²⁵ Institute for Theoretical and Experimental Physics, Moscow, Russia
²⁶ Lebedev Physical Institute, Moscow, Russia
²⁷ Max-Planck-Institut für Physik, München, Germany
²⁸ LAL, Univ Paris-Sud, CNRS/IN2P3, Orsay, France
²⁹ LLR, Ecole Polytechnique, IN2P3-CNRS, Palaiseau, France
³⁰ LPNHE, Universités Paris VI and VII, IN2P3-CNRS, Paris, France
³¹ Faculty of Science, University of Montenegro, Podgorica, Montenegro
³² Institute of Physics, Academy of Sciences of the Czech Republic, Praha, Czech Republic
³³ Faculty of Mathematics and Physics, Charles University, Praha, Czech Republic
³⁴ Dipartimento di Fisica Università di Roma Tre and INFN Roma 3, Roma, Italy
³⁵ Institute for Nuclear Research and Nuclear Energy, Sofia, Bulgaria
³⁶ Institute of Physics and Technology of the Mongolian Academy of Sciences, Ulaanbaatar, Mongolia
³⁷ Paul Scherrer Institut, Villigen, Switzerland
³⁸ Fachbereich C, Universität Wuppertal, Wuppertal, Germany
³⁹ Yerevan Physics Institute, Yerevan, Armenia
⁴⁰ DESY, Zeuthen, Germany
⁴¹ Institut für Teilchenphysik, ETH, Zürich, Switzerland
⁴² Physik-Institut der Universität Zürich, Zürich, Switzerland

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

Received: 22 October 2008
Revised: 16 December 2008
Published online: 8 April 2009

Abstract

The production of neutral strange hadrons is investigated using deep-inelastic scattering events measured with the H1 detector at HERA. The measurements are made in the phase space defined by the negative four-momentum transfer squared of the photon 2<Q ²<100 GeV² and the inelasticity 0.1<y<0.6. The K _s ⁰ and $\varLambda(\bar{\varLambda})$ production cross sections and their ratios are determined. K _s ⁰ production is compared to the production of charged particles in the same region of phase space. The Λ– $\bar{\varLambda}$ asymmetry is also measured and found to be consistent with zero. Predictions of leading order Monte Carlo programs are compared to the data.

© Springer-Verlag , 2009

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