Measurement of inclusive prompt photon photoproduction at HERA

• Published in: Physics letters. B 2000-01, Vol.472 (1), p.175-188
• Main Authors: Krakauer, D., Pellegrino, A., Anselmo, F., Bari, G., Boscherini, D., Bruni, G., Cara Romeo, G., Contin, A., Coppola, N., Corradi, M., Giusti, P., Amelung, C., Brock, I., Deffner, R., Jakob, H.-P., Paul, E., Voss, K.Ch, Brook, N.H., Heath, G.P., Mastroberardino, A., Lee, J.H., Lim, I.T., Liu, W., Sampson, S., Sciulli, F., Chwastowski, J., Jeleń, K., Przybycień, M., Suszycki, L., Fricke, U., Hasell, D., Hebbel, K., Martı́nez, M., Monteiro, T., Rohde, M., Youngman, C., Coldewey, C., Straub, P.B., Barbagli, G., Maccarrone, G., Votano, L., Eisenhardt, S., Macdonald, N., Sinclair, L.E., Skillicorn, I.O., Waugh, R., Meyer-Larsen, A., Gialas, I., Gladilin, L.K., Kçira, D., Lohrmann, E., Zetsche, F., Goncalo, R., Long, K.R., Tapper, A.D., Filges, D., Kuze, M., Nagano, K., An, S.H., Lee, S.B., Park, S.K., Redondo, I., Corriveau, F., Stairs, D.G., Golubkov, Yu.A., Khein, L.A., Kooijman, P., Tiecke, H., Vossebeld, J., Durkin, L.S., Ling, T.Y., Sutton, M.R., Bertolin, A., Brugnera, R., Dondana, S., Dosselli, U., Morandin, M., Voci, C., Sadrozinski, H.F.-W., Dagan, S., Kananov, S., Kreisel, A., Hamatsu, R., Cartiglia, N., Maselli, S., Peroni, C., Staiano, A., Bailey, D.C., Galea, R., Levman, G.M., Catterall, C.D., Heaphy, E.A., Ciborowski, J., Grzelak, G., Wróblewski, A.K., Żarnecki, A.F., Reeder, D.D., Smith, W.H., Cole, J.E., Khakzad, M.
• Format: Article
• Language: English
• Subjects: CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; CROSS SECTIONS; ENERGY RANGE; LUMINOSITY; PHOTONS; PHOTOPRODUCTION; PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; QUANTUM CHROMODYNAMICS; TRANSVERSE ENERGY
• ISSN: 0370-2693; 1873-2445
• DOI: 10.1016/S0370-2693(99)01450-1

First inclusive measurements of isolated prompt photons in photoproduction at the HERA ep collider have been made with the ZEUS detector, using an integrated luminosity of 38.4 pb −1. Cross sections are given as a function of the pseudorapidity and the transverse energy ( η γ , E T γ ) of the photon, for E T γ >5 GeV in the γp centre-of-mass energy range 134–285 GeV. Comparisons are made with predictions from Monte Carlo models having leading-logarithm parton showers, and with next-to-leading-order QCD calculations, using currently available parameterisations of the photon structure. For forward η γ (proton direction) good agreement is found, but in the rear direction all predictions fall below the data.