Leading neutron production in e⁺p collisions at HERA

Chekanov, S. et al. (2002) Leading neutron production in e⁺p collisions at HERA. Nuclear Physics B, B637(1-3), 3 -56. (doi: 10.1016/S0550-3213(02)00439-X)

Abstract

The production of neutrons carrying at least 20% of the proton beam energy (x/sub L/ gt 0.2) in e/sup +/ p collisions has been studied with the ZEUS detector at HERA for a wide range of Q/sup 2/, the photon virtuality, from photoproduction to deep inelastic scattering. The neutron-tagged cross section, ep to e' Xn, is measured relative to the inclusive cross section, ep to e' X, thereby reducing the systematic uncertainties. For x/sub L/ gt 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 gamma p system. For 0.64 lt x/sub L/ lt 0.82, the rate of neutrons is almost independent of the Bjorken scaling variable x and Q/sup 2/. However, at lower and higher x/sub 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/sub 2//sup LN(3)/ (x,Q/sup 2/,x/sub L/), rises at low values of x in a way similar to that of the inclusive F/sub 2/(x, Q/sup 2/) of the proton. The total gamma pi cross section and the structure function of the pion, F/sub 2//sup pi / (x/sub pi /, Q/sup 2/) where x/sub pi / = x/(1 - x/sub 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/sup 2/, F/sub 2//sup pi / has approximately the same x dependence as F/sub 2/ of the proton.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Ferrando, Dr James and Saxon, Professor David and Collins-Tooth, Dr Christopher and Bussey, Dr Peter and Doyle, Professor Anthony and Skillicorn, Professor Ian
• Authors: Chekanov, S., Krakauer, D., Magill, S., Musgrave, B., Pellegrino, A., Repond, J., Yoshida, R., Mattingly, M.C.K., Antonioli, P., Bari, G., Basile, M., Bellagamba, L., Boscherini, D., Bruni, A., Bruni, G., Cara Romeo, G., Cifarelli, L., Cindolo, F., Contin, A., Corradi, M., de Pasquale, S., Giusti, P., Iacobucci, G., Levi, G., Margotti, A., Nania, R., Palmonari, F., Pesci, A., Sartorelli, G., Zichichi, A., Aghuzumtsyan, G., Bartsch, D., Brock, I., Crittenden, J., Goers, S., Hartmann, H., Hilger, E., Irrgang, P., Jakob, H.P., Kappes, A., Katz, U.F., Kerger, R., Kind, O., Paul, E., Rautenberg, J., Renner, R., Schnurbusch, H., Stifutkin, A., Tandler, J., Voss, K.C., Weber, A., Bailey, D.S., Brook, N.H., Cole, J.E., Foster, B., Heath, G.P., Heath, H.F., Robins, S., Rodrigues, E., Scott, J., Tapper, R.J., Wing, M., Capua, M., Mastroberardino, A., Schioppa, M., Susinno, G., Kim, J.Y., Kim, Y.K., Lee, J.H., Lim, I.T., Pac, M.Y., Caldwell, A., Helbich, M., Liu, X., Mellado, B., Paganis, S., Schmidke, W.B., Sciulli, F., Chwastowski, J., Eskreys, A., Figiel, J., Olkiewicz, K., Przybycien, M.B., Stopa, P., Zawiejski, L., Bednarek, B., Grabowska-Bold, I., Jelen, K., Kisielewska, D., Kowal, A.M., Kowal, M., Kowalski, T., Mindur, B., Przybycien, M., Rulikowska-Zarebska, E., Suszycki, L., Szuba, D., Szuba, J., Kotanski, A., Slominski, W., Bauerdick, L.A.T., Behrens, U., Borras, K., Chiochia, V., Dannheim, D., Derrick, M., Drews, G., Fourletova, J., Fox-Murphy, A., Fricke, U., Geiser, A., Goebel, F., Gottlicher, P., Gutsche, O., Haas, T., Hain, W., Hartner, G.F., Hillert, S., Kotz, U., Kowalski, H., Labes, H., Lelas, D., Lohr, B., Mankel, R., Martinez, M., Moritz, M., Notz, D., Pellmann, I.A., Petrucci, M.C., Polini, A., Schneekloth, U., Selonke, F., Surrow, B., Wessoleck, H., Wichmann, R., Wolf, G., Youngman, C., Zeuner, W., Lopez-Duran Viani, A., Meyer, A., Schlenstedt, S., Barbagli, G., Gallo, E., Genta, C., Pelfer, P.G., Bamberger, A., Benen, A., Coppola, N., Markun, P., Raach, H., Wolfle, S., Bell, M., Bussey, P.J., Doyle, A.T., Glasman, C., Hanlon, S., Lee, S.W., Lupi, A., McCance, G.J., Saxon, D.H., Skillicorn, I.O., Gialas, I., Bodmann, B., Carli, T., Holm, U., Klimek, K., Krumnack, N., Lohrmann, E., Milite, M., Salehi, H., Stonjek, S., Wick, K., Ziegler, A., Ziegler, A., Collins-Tooth, C., Foudas, C., Goncalo, R., Long, K.R., Metlica, F., Miller, D.B., Tapper, A.D., Walker, D.B., Cloth, P., Filges, D., Kuze, M., Nagano, K., Tokushuku, K., Yamada, S., Yamazaki, Y., Barakbaev, A.N., Boos, E.G., Pokrovskiy, N.S., Zhautykov, B.O., Lim, H., Son, D., Barreiro, F., Gonzalez, O., Labarga, L., del Peso, J., Redondo, I., Terron, J., Vazquez, M., Barbi, M., Bertolin, A., Corriveau, F., Ochs, A., Padhi, S., Stairs, D.G., St Laurent, M., Tsurugai, T., Antonov, A., Bashkirov, V., Danilov, P., Dolgoshein, B.A., Gladkov, D., Sosnovtsev, V., Suchkov, S., Dementiev, R.K., Ermolov, P.F., Golubkov, Y., Katkov, I.I., Khein, L.A., Korzhavina, I.A., Kuzmin, V.A., Levchenko, B.B., Lukina, O.Y., Proskuryakov, A.S., Shcheglova, L.M., Vlasov, N.N., Zotkin, S.A., Bokel, C., Engelen, J., Grijpink, S., Koffeman, E., Kooijman, P., Maddox, E., Schagen, S., Tassi, E., Tiecke, H., Tuning, N., Velthuis, J.J., Wiggers, L., de, W., Brummer, N., Bylsma, B., Durkin, L.S., Gilmore, J., Ginsburg, C.M., Kim, C.L., Ling, T.Y., Boogert, S., Cooper-Sarkar, A.M., Devenish, R.C.E., Ferrando, J., and Grzelak, G.
• Subjects: Q Science > QC Physics
• College/School: College of Science and Engineering > School of Physics and Astronomy
• Journal Name: Nuclear Physics B
• ISSN: 0550-3213