Journal article
Leading neutron production in e(+)p collisions at HERA
Nuclear physics. B, Vol.637(1-3), pp.3-56
08/19/2002
DOI: 10.1016/S0550-3213(02)00439-X
Abstract
The production of neutrons carrying at least 20% of the proton beam energy (x(L) > 0.2) in e(+) p collisions has been studied with the ZEUS detector at HERA for a wide range of Q(2), the photon virtuality, from photoproduction to deep inelastic scattering. The neutron-tagged cross section, ep --> e(1) Xn, is measured relative to the inclusive cross section, ep --> e(1)X, thereby reducing the systematic uncertainties. For x(L) > 0.3, the rate of neutrons in photoproduction is about half of that measured in hadroproduction, which constitutes a clear breaking of factorisation. There is about a 20% rise in the neutron rate between photoproduction and deep inelastic scattering, which may be attributed to absorptive rescattering in the gammap system. For 0.64. < x(L) < 0.82, the rate of neutrons is almost independent of the Bjorken scaling variable x and Q(2). However, at lower and higher x(L) values, there is a clear but weak dependence on these variables, thus demonstrating the breaking of limiting fragmentation. The neutron-tagged structure function, F-2(LN(3)) (x, Q(2), x(L)), rises at low values of x in a way similar to that of the inclusive F-2(x, Q(2)) of the proton. The total gammapi cross section and the structure function of the pion, F-2(pi) (x(pi), Q(2)) where x(pi) = x/(1 - x(L)), have been determined using a one-pion-exchange model, up to uncertainties in the normalisation due to the poorly understood pion flux. At fixed Q(2), F-2(pi) has approximately the same x dependence as F-2 of the proton. (C) 2002 Published by Elsevier Science B.V.
Details
- Title: Subtitle
- Leading neutron production in e(+)p collisions at HERA
- Creators
- ZEUS CollaborationJ Repond (Contributor)
- Resource Type
- Journal article
- Publication Details
- Nuclear physics. B, Vol.637(1-3), pp.3-56
- DOI
- 10.1016/S0550-3213(02)00439-X
- ISSN
- 0550-3213
- eISSN
- 1873-1562
- Publisher
- Elsevier
- Number of pages
- 54
- Language
- English
- Date published
- 08/19/2002
- Academic Unit
- Physics and Astronomy
- Record Identifier
- 9984627203502771
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