Exclusive meson photoproduction with a leading neutron at HERA

V. Andreev; A. Baghdasaryan; K. Begzsuren; A. Belousov; A. Bolz; V. Boudry; G. Brandt; V. Brisson; D. Britzger; A. Buniatyan; A. Bylinkin; L. Bystritskaya; A. J. Campbell; K. B. Cantun Avila; K. Cerny; V. Chekelian; J. G. Contreras; J. Cvach; J. B. Dainton; K. Daum; C. Diaconu; M. Dobre; V. Dodonov; G. Eckerlin; S. Egli; E. Elsen; L. Favart; A. Fedotov; J. Feltesse; J. Ferencei; M. Fleischer; A. Fomenko; E. Gabathuler; J. Gayler; S. Ghazaryan; L. Goerlich; N. Gogitidze; M. Gouzevitch; C. Grab; A. Grebenyuk; T. Greenshaw; G. Grindhammer; D. Haidt; R. C. W. Henderson; J. Hladkỳ; D. Hoffmann; R. Horisberger; T. Hreus; F. Huber; M. Jacquet; X. Janssen; H. Jung; M. Kapichine; C. Kiesling; M. Klein; C. Kleinwort; R. Kogler; P. Kostka; J. Kretzschmar; K. Krüger; M. P. J. Landon; W. Lange; P. Laycock; A. Lebedev; S. Levonian; K. Lipka; B. List; J. List; B. Lobodzinski; E. Malinovski; H.-U. Martyn; S. J. Maxfield; A. Mehta; A. B. Meyer; H. Meyer; J. Meyer; S. Mikocki; A. Morozov; K. Müller; Th. Naumann; P. R. Newman; C. Niebuhr; G. Nowak; J. E. Olsson; D. Ozerov; C. Pascaud; G. D. Patel; E. Perez; A. Petrukhin; I. Picuric; H. Pirumov; D. Pitzl; R. Plačakytė; B. Pokorny; R. Polifka; B. Povh; V. Radescu; N. Raicevic; T. Ravdandorj; P. Reimer; E. Rizvi; P. Robmann; R. Roosen; A. Rostovtsev; M. Rotaru; S. Rusakov; D. Šálek; D. P. C. Sankey; M. Sauter; E. Sauvan; S. Schmitt; L. Schoeffel; A. Schöning; F. Sefkow; S. Shushkevich; Y. Soloviev; P. Sopicki; D. South; V. Spaskov; A. Specka; M. Steder; B. Stella; U. Straumann; T. Sykora; P. D. Thompson; D. Traynor; P. Truöl; I. Tsakov; B. Tseepeldorj; J. Turnau; A. Valkárová; C. Vallée; P. Van Mechelen; Y. Vazdik; D. Wegener; E. Wünsch; J. Žáček; Z. Zhang; R. Žlebčík; H. Zohrabyan; F. Zomer

doi:10.1140/epjc/s10052-015-3863-1

2021 Impact factor 4.991

Particles and Fields

Open Access

Eur. Phys. J. C (2016) 76: 41
https://doi.org/10.1140/epjc/s10052-015-3863-1

Regular Article - Experimental Physics

H1 Collaboration

V. Andreev²¹, A. Baghdasaryan³³, K. Begzsuren³⁰, A. Belousov²¹, A. Bolz¹², V. Boudry²⁴, G. Brandt⁴⁴, V. Brisson²³, D. Britzger¹⁰, A. Buniatyan², A. Bylinkin²⁰^,41, L. Bystritskaya²⁰, A. J. Campbell¹⁰, K. B. Cantun Avila¹⁹, K. Cerny²⁷, V. Chekelian²², J. G. Contreras¹⁹, J. Cvach²⁶, J. B. Dainton¹⁶, K. Daum³²^,37, C. Diaconu¹⁸, M. Dobre⁴, V. Dodonov¹⁰, G. Eckerlin¹⁰, S. Egli³¹, E. Elsen¹⁰, L. Favart³, A. Fedotov²⁰, J. Feltesse⁹, J. Ferencei¹⁴, M. Fleischer¹⁰, A. Fomenko²¹, E. Gabathuler¹⁶, J. Gayler¹⁰, S. Ghazaryan¹⁰, L. Goerlich⁶, N. Gogitidze²¹, M. Gouzevitch³⁸, C. Grab³⁵, A. Grebenyuk³, T. Greenshaw¹⁶, G. Grindhammer²², D. Haidt¹⁰, R. C. W. Henderson¹⁵, J. Hladkỳ²⁶, D. Hoffmann¹⁸, R. Horisberger³¹, T. Hreus³, F. Huber¹², M. Jacquet²³, X. Janssen³, H. Jung³^,10, M. Kapichine⁸, C. Kiesling²², M. Klein¹⁶, C. Kleinwort¹⁰, R. Kogler¹¹, P. Kostka¹⁶, J. Kretzschmar¹⁶, K. Krüger¹⁰, M. P. J. Landon¹⁷, W. Lange³⁴, P. Laycock¹⁶, A. Lebedev²¹, S. Levonian¹⁰, K. Lipka¹⁰, B. List¹⁰, J. List¹⁰, B. Lobodzinski²², E. Malinovski²¹, H.-U. Martyn¹, S. J. Maxfield¹⁶, A. Mehta¹⁶, A. B. Meyer¹⁰, H. Meyer³², J. Meyer¹⁰, S. Mikocki⁶, A. Morozov⁸, K. Müller³⁶, Th. Naumann³⁴, P. R. Newman², C. Niebuhr¹⁰, G. Nowak⁶, J. E. Olsson¹⁰, D. Ozerov¹⁰, C. Pascaud²³, G. D. Patel¹⁶, E. Perez³⁹, A. Petrukhin³⁸, I. Picuric²⁵, H. Pirumov¹⁰, D. Pitzl¹⁰, R. Plačakytė¹⁰, B. Pokorny²⁷, R. Polifka²⁷^,42, B. Povh¹³, V. Radescu¹², N. Raicevic²⁵, T. Ravdandorj³⁰, P. Reimer²⁶, E. Rizvi¹⁷, P. Robmann³⁶, R. Roosen³, A. Rostovtsev⁴⁵, M. Rotaru⁴, S. Rusakov²¹, D. Šálek²⁷, D. P. C. Sankey⁵, M. Sauter¹², E. Sauvan¹⁸^,43, S. Schmitt¹⁰^*, L. Schoeffel⁹, A. Schöning¹², F. Sefkow¹⁰, S. Shushkevich¹⁰, Y. Soloviev¹⁰^,21, P. Sopicki⁶, D. South¹⁰, V. Spaskov⁸, A. Specka²⁴, M. Steder¹⁰, B. Stella²⁸, U. Straumann³⁶, T. Sykora³^,27, P. D. Thompson², D. Traynor¹⁷, P. Truöl³⁶, I. Tsakov²⁹, B. Tseepeldorj³⁰^,40, J. Turnau⁶, A. Valkárová²⁷, C. Vallée¹⁸, P. Van Mechelen³, Y. Vazdik²¹, D. Wegener⁷, E. Wünsch¹⁰, J. Žáček²⁷, Z. Zhang²³, R. Žlebčík²⁷, H. Zohrabyan³³ and F. Zomer²³

¹ I. Physikalisches Institut der RWTH, Aachen, Germany
² School of Physics and Astronomy, University of Birmingham, Birmingham, UK
³ Inter-University Institute for High Energies ULB-VUB, Brussels and Universiteit Antwerpen, Antwerp, Belgium
⁴ Horia Hulubei National Institute for R&D in Physics and Nuclear Engineering (IFIN-HH), Bucharest, Romania
⁵ STFC, Rutherford Appleton Laboratory, Didcot, Oxfordshire, UK
⁶ Institute of Nuclear Physics Polish Academy of Sciences, 31342, Kraków, Poland
⁷ Institut für Physik, TU Dortmund, Dortmund, Germany
⁸ Joint Institute for Nuclear Research, Dubna, Russia
⁹ Irfu/SPP, CE Saclay, Gif-sur-Yvette Cedex, France
¹⁰ DESY, Hamburg, Germany
¹¹ Institut für Experimentalphysik, Universität Hamburg, Hamburg, Germany
¹² Physikalisches Institut, Universität Heidelberg, Heidelberg, Germany
¹³ Max-Planck-Institut für Kernphysik, Heidelberg, Germany
¹⁴ Institute of Experimental Physics, Slovak Academy of Sciences, Košice, Slovak Republic
¹⁵ Department of Physics, University of Lancaster, Lancaster, UK
¹⁶ Department of Physics, University of Liverpool, Liverpool, UK
¹⁷ School of Physics and Astronomy, Queen Mary, University of London, London, UK
¹⁸ Aix Marseille Université, CNRS/IN2P3, CPPM UMR 7346, 13288, Marseille, France
¹⁹ Departamento de Fisica Aplicada, CINVESTAV, Mérida, Yucatán, Mexico
²⁰ Institute for Theoretical and Experimental Physics, Moscow, Russia
²¹ Lebedev Physical Institute, Moscow, Russia
²² Max-Planck-Institut für Physik, Munich, Germany
²³ LAL, Université Paris-Sud, CNRS/IN2P3, Orsay, France
²⁴ LLR, Ecole Polytechnique, CNRS/IN2P3, Palaiseau, France
²⁵ Faculty of Science, University of Montenegro, Podgorica, Montenegro
²⁶ Institute of Physics, Academy of Sciences of the Czech Republic, Prague, Czech Republic
²⁷ Faculty of Mathematics and Physics, Charles University, Prague, Czech Republic
²⁸ Dipartimento di Fisica, Università di Roma Tre and INFN Roma 3, Rome, Italy
²⁹ Institute for Nuclear Research and Nuclear Energy, Sofia, Bulgaria
³⁰ Institute of Physics and Technology of the Mongolian Academy of Sciences, Ulaanbaatar, Mongolia
³¹ Paul Scherrer Institut, Villigen, Switzerland
³² Fachbereich C, Universität Wuppertal, Wuppertal, Germany
³³ Yerevan Physics Institute, Yerevan, Armenia
³⁴ DESY, Zeuthen, Germany
³⁵ Institut für Teilchenphysik, ETH, Zurich, Switzerland
³⁶ Physik-Institut der Universität Zürich, Zurich, Switzerland
³⁷ Rechenzentrum, Universität Wuppertal, Wuppertal, Germany
³⁸ IPNL, Université Claude Bernard Lyon 1, CNRS/IN2P3, Villeurbanne, France
³⁹ CERN, Geneva, Switzerland
⁴⁰ Ulaanbaatar University, Ulaanbaatar, Mongolia
⁴¹ Moscow Institute of Physics and Technology, Moscow, Russia
⁴² Department of Physics, University of Toronto, Toronto, ON, M5S 1A7, Canada
⁴³ LAPP, Université de Savoie, CNRS/IN2P3, Annecy-le-Vieux, France
⁴⁴ II. Physikalisches Institut, Universität Göttingen, Göttingen, Germany
⁴⁵ Institute for Information Transmission Problems RAS, Moscow, Russia

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

Received: 14 August 2015
Accepted: 22 December 2015
Published online: 23 January 2016

Abstract

A first measurement is presented of exclusive photoproduction of mesons associated with leading neutrons at HERA. The data were taken with the H1 detector in the years 2006 and 2007 at a centre-of-mass energy of GeV and correspond to an integrated luminosity of 1.16 pb. The mesons with transverse momenta GeV are reconstructed from their decays to charged pions, while leading neutrons carrying a large fraction of the incoming proton momentum, , are detected in the Forward Neutron Calorimeter. The phase space of the measurement is defined by the photon virtuality GeV, the total energy of the photon–proton system GeV and the polar angle of the leading neutron mrad. The cross section of the reaction is measured as a function of several variables. The data are interpreted in terms of a double peripheral process, involving pion exchange at the proton vertex followed by elastic photoproduction of a meson on the virtual pion. In the framework of one-pion-exchange dominance the elastic cross section of photon-pion scattering, , is extracted. The value of this cross section indicates significant absorptive corrections for the exclusive reaction .