Measurement of isolated photon production in hadronic Z decays

• Published in: Physics letters. B 1991-08, Vol.264 (3), p.476-486
• Main Authors: Deschizeaux, B., Gaitan, V., Farilla, A., Nuzzo, S., Ranieri, A., Raso, G., Ruggieri, F., Hu, H., Lin, J., Wang, T., Lehraus, I., Lusiani, A., Marchioro, A., Miquel, R., Nash, J., Ranjard, F., Rothberg, J., St.Denis, R., Wasserbaech, S., Witzeling, W., Bardadin-Otwinowska, M., El Fellous, R., Falvard, A., Henrard, P., Jousset, J., Montret, J.-C., Stimpfl, G., Efthymiopoulos, I., Blondel, A., Bonneaud, G., Rosowsky, A., Candlin, D.J., Veitch, E., Corden, M., Georgiopoulos, C., Ikeda, M., Sawyer, L., Campana, P., Felici, G., Laurelli, P., Nicoletti, G., Picchi, P., Halley, A.W., ten Have, I., Raine, C., Hepp, V., Wunsch, M., Belk, A.T., Beuselinck, R., Greene, A.M., Hassard, J.F., Patton, S.J., Keemer, N.R., Renk, B., Albanese, J.-P., Courvoisier, D., Etienne, F., Papalexiou, S., Qian, Z., Cowan, G., Dietl, H., Pan, Y., Schwarz, A.S., Janot, P., Kim, D.W., Lefrançois, J., Veillet, J.-J., Videau, I., Abbaneo, D., Bagliesi, G., Fidecaro, F., Focardi, E., Ligabue, F., Moneta, L., Tecchini, R., Carter, J.M., Salmon, D.P., Thompson, J.C., Bloch-Devaux, B., Klopfenstein, C., Perez, P., Perrier, F., Rander, J., Schwindling, J., Booth, C.N., Carney, R., Dinsdale, M., Dogru, M., Martin, J., Thompson, L.F., Barberio, E., Mirabito, L., Giannini, G., Rolandi, L., Bellantoni, L., Cinabro, D., Gao, Y.S., Pan, Y.B., Wear, J.A., Zobernig, G.
• Format: Article
• Language: English
• Subjects: High Energy Physics - Experiment; Physics
• ISSN: 0370-2693; 1873-2445
• DOI: 10.1016/0370-2693(91)90380-9

The production of high energy isolated photons in hadronic Z decays is measured with the ALEPH detector at LEP using a sample of 180 000 hadronic events. Such photons are mainly radiated by quarks, thus giving direct insights into the early parton showering mechanism. The observed rate is compared with a QCD calculation of final state radiation from quarks.