Measurement of isolated photon production in deep-inelastic scattering at HERA

• Published in: The European physical journal. C, Particles and fields Vol. 54; no. 3; pp. 371 - 387
• Main Authors: Alexa, C., Andreev, V., Asmone, A., Baranov, P., Baudrand, S., Belousov, A., Bizot, J.C., Boenig, M.-O., Boudry, V., Bozovic-Jelisavcic, I., Brinkmann, M., Cassol-Brunner, F., Chekelian, V., Delvax, J., De Wolf, E.A., Dodonov, V., Dubak, A., Eisele, F., Felst, R., Finke, L., Ginzburgskaya, S., Glushkov, I., Goerlich, L., Greenshaw, T., Grell, B.R., Habib, S., Haidt, D., Helebrant, C., Hreus, T., Jacquet, M., Jemanov, V., Jönsson, L., Jung, A.W., Katzy, J., Kenyon, I.R., Klein, M., Kleinwort, C., Korbel, V., Krüger, K., Laštovička-Medin, G., Laycock, P., Levonian, S., Li, G., Lipka, K., List, B., Loktionova, N., Makankine, A., Marti, L., Martisikova, M., Martyn, H.-U., Maxfield, S.J., Mehta, A., Meier, K., Meyer, A.B., Meyer, H., Morozov, A., Morris, J.V., Müller, K., Naumann, T., Newman, P.R., Palichik, V., Papadopoulou, T., Patel, G.D., Peng, H., Perez, E., Perez-Astudillo, D., Pitzl, D., Plačakytė, R., Raicevic, N., Reimer, P., Risler, C., Rizvi, E., Salek, D., Sauter, M., Sauvan, E., Schmidt, S., Schmitt, S., Schultz-Coulon, H.-C., Sheviakov, I., Sloan, T., Smiljanic, I., Straumann, U., Sunar, D., Tchoulakov, V., Thompson, G., Tomasz, F., Trinh, T.N., Urban, K., Vinokurova, S., Weber, G., Wegener, D., Werner, C., Wissing, C., Zálešák, J., Zhang, Z., Zhelezov, A., Zhokin, A., Zhu, Y.C., Zomer, F.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 2008; Springer Nature B.V; Springer Verlag (Germany)
• Subjects: Astronomy; Astrophysics and Cosmology; Computer simulation; Cross-sections; Elementary Particles; Fysik; Hadrons; Heavy Ions; High Energy Physics - Experiment; Inelastic scattering; Luminosity; Measurement Science and Instrumentation; Momentum transfer; Natural Sciences; Naturvetenskap; Nuclear Energy; Nuclear Physics; Photons; Physical Sciences; Physics; Physics and Astronomy; Quantum Field Theories; Quantum Field Theory; Regular Article - Experimental Physics; String Theory; Subatomic Physics; Subatomär fysik; Photon Candidate; Leading Order Calculation; Monte Carlo; Leading Order; Monte Carlo Prediction
• ISSN: 1434-6044; 1434-6052
• DOI: 10.1140/epjc/s10052-008-0541-6

The production of isolated photons in deep-inelastic scattering ep→eγX is measured with the H1 detector at HERA. The measurement is performed in the kinematic range of negative four-momentum transfer squared 4<Q 2 <150 GeV 2 and a mass of the hadronic system W X >50 GeV. The analysis is based on a total integrated luminosity of 227 pb -1 . The production cross section of isolated photons with a transverse energy in the range 3<E T γ <10 GeV and pseudorapidity range -1.2<η γ <1.8 is measured as a function of E T γ , η γ and Q 2 . Isolated photon cross sections are also measured for events with no jets or at least one hadronic jet. The measurements are compared with predictions from Monte Carlo generators modelling the photon radiation from the quark and the electron lines, as well as with calculations at leading and next to leading order in the strong coupling. The predictions significantly underestimate the measured cross sections.