Further studies of isolated photon production with a jet in deep inelastic scattering at HERA

Abramowicz, H.; Abt, I.; Adamczyk, L.; Adamus, M.; Aggarwal, R.; Antonelli, S.; Aushev, V.; Aushev, Y.; Behnke, O.; Behrens, U.; Bertolin, A.; Bloch, I.; Brock, I.; Brook, N. H.; Brugnera, R.; Bruni, A.; Bussey, P. J.; Caldwell, A.; Capua, M.; Catterall, C. D.; Chwastowski, J.; Ciborowski, J.; Ciesielski, R.; Cooper-Sarkar, A. M.; Corradi, M.; Dementiev, R. K.; Devenish, R. C. E.; Dusini, S.; Foster, B.; Gach, G.; Gallo, E.; Garfagnini, A.; Geiser, A.; Gizhko, A.; Gladilin, L. K.; Golubkov, Y. A.; Grzelak, G.; Guzik, M.; Gwenlan, C.; Hlushchenko, O.; Hochman, D.; Hori, R.; Ibrahim, Z. A.; Iga, Y.; Ishitsuka, M.; Jomhari, N. Z.; Kadenko, I.; Kananov, S.; Karshon, U.; Kaur, P.; Kisielewska, D.; Klanner, R.; Klein, U.; Korzhavina, I. A.; Kotanski, A.; Kovalchuk, N.; Kowalski, H.; Krupa, B.; Kuprash, O.; Kuze, M.; Levchenko, B. B.; Levy, A.; Lisovyi, M.; Lobodzinska, E.; Lohr, B.; Lohrmann, E.; Longhin, A.; Lukina, O. Y.; Malka, J.; Mastroberardino, A.; Idris, F. M.; Nasir, N. M.; Myronenko, V.; Nagano, K.; Onishchuk, Y.; Paul, E.; Perlanski, W.; Pokrovskiy, N. S.; Polini, A.; Przybycien, M.; Ruspa, M.; Saxon, D. H.; Schioppa, M.; Schneekloth, U.; Schorner-Sadenius, T.; Shcheglova, L. M.; Shkola, O.; Shyrma, Y.; Skillicorn, I. O.; Slominski, W.; Solano, A.; Stanco, L.; Stefaniuk, N.; Stern, A.; Stopa, P.; Sztuk-Dambietz, J.; Tassi, E.; Tokushuku, K.; Tomaszewska, J.; Tsurugai, T.; Turcato, M.; Turkot, O.; Tymieniecka, T.; Verbytskyi, A.; Abdullah, W. A. T. W.; Wichmann, K.; Wing, M.; Yamada, S.; Yamazaki, Y.; Zarnecki, A. F.; Zawiejski, L.; Zenaiev, O.; Zhautykov, B. O.

doi:10.1007/JHEP01(2018)032

Isolated photons with high transverse energy have been studied in deep inelastic ep scattering with the ZEUS detector at HERA, using an integrated luminosity of 326 pb−1 in the range of exchanged-photon virtuality 10-350 GeV^2. Outgoing isolated photons with transverse energy 4 < ET_γ < 15 GeV and pseudorapidity − 0.7 < η_γ < 0.9 were measured with accompanying jets having transverse energy and pseudorapidity 2.5 < ET_jet < 35 GeV and −1.5 < η_jet < 1.8, respectively. Differential cross sections are presented for the following variables: the fraction of the incoming photon energy and momentum that is transferred to the outgoing photon and the leading jet; the fraction of the incoming proton energy transferred to the photon and leading jet; the differences in azimuthal angle and pseudorapidity between the outgoing photon and the leading jet and between the outgoing photon and the scattered electron. Comparisons are made with theoretical predictions: a leading-logarithm Monte Carlo simulation, a next-to-leading-order QCD prediction, and a prediction using the kT-factorisation approach.