https://doi.org/10.1140/epjc/s10052-010-1369-4
Regular Article - Experimental Physics
Measurement of leading neutron production 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, 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 IPN, Mexico City, Mexico
25
Institute for Theoretical and Experimental Physics, Moscow, Russia
26
Lebedev Physical Institute, Moscow, Russia
27
Max-Planck-Institut für Physik, Munich, Germany
28
LAL, University Paris-Sud, CNRS/IN2P3, Orsay, France
29
LLR, Ecole Polytechnique, CNRS/IN2P3, Palaiseau, France
30
LPNHE, Universités Paris VI and VII, CNRS/IN2P3, 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, Rome, Italy
35
Institute for Nuclear Research and Nuclear Energy, Sofia, Bulgaria
36
Institute of Physics and Technology, 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, Universität Zürich, Zürich, Switzerland
* e-mail: kruegerk@mail.desy.de
Received:
4
January
2010
Revised:
14
May
2010
Published online:
16
July
2010
The production of leading neutrons, where the neutron carries a large fraction x
L
of the incoming proton’s longitudinal momentum, is studied in deep-inelastic positron-proton scattering at HERA. The data were taken with the H1 detector in the years 2006 and 2007 and correspond to an integrated luminosity of 122 pb−1. The semi-inclusive cross section is measured in the phase space defined by the photon virtuality 6<Q
2<100 GeV2, Bjorken scaling variable 1.5⋅10−4<x<3⋅10−2, longitudinal momentum fraction 0.32<x
L
<0.95 and neutron transverse momentum p
T
<0.2 GeV. The leading neutron structure function, 
, and the fraction of deep-inelastic scattering events containing a leading neutron are studied as a function of Q
2, x and x
L
. Assuming that the pion exchange mechanism dominates leading neutron production, the data provide constraints on the shape of the pion structure function.
© Springer-Verlag / Società Italiana di Fisica, 2010
