Soft photons inside hadronic jets converted in front of the DELPHI main tracker (TPC) in events of qq disintegrations of the Z(0) were studied in the kinematic range 0.2 < E-y < I GeV and transverse momentum with respect to the closest jet direction P-T < 80 MeV/c. A clear excess of photons in the experimental data as compared to the Monte Carlo predictions is observed. This excess (uncorrected for the photon detection efficiency) is (1.17 +/- 0.06 +/- 0.27) x 10(-3) gamma/jet in the specified kinematic region, while the expected level of the inner hadronic bremsstrahlung (which is not included in the Monte Carlo) is (0.340 +/- 0.001 +/- 0.038) X 10(-3) gamma/jet. The ratio of the excess to the predicted bremsstrahlung rate is then (3.4 +/- 0.2 +/- 0.8), which is similar in strength to the anomalous soft photon signal observed in fixed target experiments with hadronic beams.
Evidence for an excess of soft photons in hadronic decays of Z(0) / J. Abdallah, P. Abreu, W. Adam, P. Adzic, T. Albrecht, T. Alderweireld, R. ALEMANY FERNANDEZ, T. Allmendinger, P.P. Allport, U. Amaldi, N. Amapane, S. Amato, E. Anashkin, A. Andreazza, S. Andringa, N. Anjos, P. Antilogus, W.D. Apel, Y. Arnoud, S. Ask, B. Asman, J.E. Augustin, A. Augustinus, P. Baillon, A. Ballestrero, P. Bambade, R. Barbier, D. Bardin, G.J. Barker, A. Baroncelli, M. Battaglia, M. Baubillier, K.H. Becks, M. Begalli, A. Behrmann, E. BEN HAIM, N. Benekos, A. Benvenuti, C. Berat, M. Berggren, L. Berntzon, D. Bertrand, M. Besancon, N. Besson, D. Bloch, M. Blom, M. Bluj, M. Bonesini, M. Boonekamp, P.S.L. Booth, G. Borisov, O. Botner, B. Bouquet, T.J.V. Bowcock, I. Boyko, M. Bracko, R. Brenner, E. Brodet, P. Bruckman, J.M. Brunet, B. Buschbeck, P. Buschmann, M. Calvi, T. Camporesi, V. Canale, F. Carena, N. Castro, F. Cavallo, M. Chapkin, P. Charpentier, P. Checchia, R. Chierici, P. Chliapnikov, J. Chudoba, S.U. Chung, K. Cieslik, P. Collins, R. Contri, G. Cosme, F. Cossutti, M.J. Costa, D. Crennell, J. Cuevas, J. D'Hondt, J. Dalmau, T. DA SILVA, W. DA SILVA, G. DELLA RICCA, A. DE ANGELIS, W. DE BOER, C. DE CLERCQ, B. DE LOTTO, N. DE MARIA, A. DE MIN, L. DE PAULA, L. DI CIACCIO, A. DI SIMONE, K. Doroba, J. Drees, G. Eigen, T. Ekelof, M. Ellert, M. Elsing, M.C.E. Santo, G. Fanourakis, D. Fassouliotis, M. Feindt, J. Fernandez, A. Ferrer, F. Ferro, U. Flagmeyer, H. Foeth, E. Fokitis, F. FULDA QUENZER, J. Fuster, M. Gandelman, C. Garcia, P. Gavillet, E. Gazis, R. Gokieli, B. Golob, G. GOMEZ CEBALLOS, P. Goncalves, E. Graziani, G. Grosdidier, K. Crzelak, J. Guy, C. Haag, A. Hallgren, K. Hamacher, K. Hamilton, S. Haug, F. Hauler, V. Hedberg, M. Hennecke, H. Herr, J. Hoffman, S.O. Holmgren, P.J. Holt, M.A. Houlden, K. Hultqvist, J.N. Jackson, G. Jarlskog, P. Jarry, D. Jeans, E.K. Johansson, P.D. Johansson, P. Jonsson, C. Joram, L. Jungermann, F. Kapusta, S. Katsanevas, E. Katsoufis, G. Kernel, B.P. Kersevan, U. Kerzel, B.T. King, N.J. Kjaer, P. Kluit, P. Kokkinias, C. Kourkoumelis, O. Kouznetsov, Z. Krumstein, M. Kucharczyk, J. Lamsa, G. Leder, F. Ledroit, L. Leinonen, R. Leitner, J. Lemonne, V. Lepeltier, T. Lesiak, W. Liebig, D. Liko, A. Lipniacka, J.H. Lopes, J.M. Lopez, D. Loukas, P. Lutz, L. Lyons, J. Macnaughton, A. Malek, S. Maltezos, F. Mandl, J. Marco, R. Marco, B. Marechal, M. Margoni, J.C. Marin, C. Mariotti, A. Markou, C. MARTINEZ RIVERO, J. Masik, N. Mastroyiannopoulos, F. Matorras, C. Matteuzzi, F. Mazzucato, M. Mazzucato, R. MC NULTY, C. Meroni, E. Migliore, W. Mitaroff, U. Mjoernmark, T. Moa, M. Moch, K. Moenig, R. Monge, J. Montenegro, D. Moraes, S. Moreno, P. Morettini, U. Mueller, K. Muenich, M. Mulders, L. Mundim, W. Murray, B. Muryn, G. Myatt, T. Myklebust, M. Nassiakou, F. Navarria, K. Nawrocki, R. Nicolaidou, M. Nikolenko, A. OBLAKOWSKA MUCHA, V. Obraztsov, A. Olshevski, A. Onofre, O. Orava, K. Osterberg, A. Ouraou, A. Oyanguren, M. Paganoni, S. Paiano, J.P. Palacios, H. Palka, T.D. Papadopoulou, L. Pape, C. Parkes, F. Parodi, U. Parzefall, A. Passeri, O. Passon, L. Peralta, V. Perepelitsa, A. Perrotta, A. Petrolini, J. Piedra, L. Pieri, F. Pierre, M. Pimenta, E. Piotto, T. Podobnik, V. Poireau, M.E. Pol, G. Polok, V. Pozdniakov, N. Pukhaeva, A. Pullia, J. Rames, A. Read, P. Rebecchi, J. Rehn, D. Reid, R. Reinhardt, P. Renton, F. Richard, J. Ridky, M. Rivero, D. Rodriguez, A. Romero, P. Ronchese, P. Roudeau, T. Rovelli, V. RUHLMANN KLEIDER, D. Ryabtchikov, A. Sadovsky, L. Salmi, J. Salt, C. Sander, A. SAVOY NAVARRO, U. Schwickerath, A. Segar, R. Sekulin, M. Siebel, A. Sisakian, G. Smadja, O. Smirnova, A. Sokolov, A. Sopczak, R. Sosnowski, T. Spassov, M. Stanitzki, A. Stocchi, J. Strauss, B. Stugu, M. Szczekowski, M. Szeptycka, T. Szumlak, T. Tabarelli, A.C. Taffard, F. Tegenfeldt, J. Timmermans, L. Tkatchev, M. Tobin, S. Todorovova, B. Tome, A. Tonazzo, P. Tortosa, P. Travnicek, D. Treille, G. Tristram, M. Trochimczuk, C. Troncon, M.L. Turluer, I.A. Tyapkin, P. Tyapkin, S. Tzamarias, V. Uvarov, G. Valenti, P. VAN DAM, J. VAN ELDIK, N. VAN REMORTEL, I. VAN VULPEN, G. Vegni, F. Veloso, W. Venus, P. Verdier, V. Verzi, D. Vilanova, L. Vitale, V. Vrba, H. Wahlen, A.J. Washbrook, C. Weiser, D. Wicke, J. Wickens, G. Wilkinson, M. Winter, M. Witek, O. Yushchenko, A. Zalewska, P. Zalewski, D. Zavrtanik, V. Zhuravlov, N.I. Zimin, A. Zintchenko, M. Zupan. - In: THE EUROPEAN PHYSICAL JOURNAL. C, PARTICLES AND FIELDS. - ISSN 1434-6044. - 47:2(2006), pp. 273-294. [10.1140/epjc/s2006-02568-8]
Evidence for an excess of soft photons in hadronic decays of Z(0)
A. Andreazza;C. Meroni;G. Vegni;
2006
Abstract
Soft photons inside hadronic jets converted in front of the DELPHI main tracker (TPC) in events of qq disintegrations of the Z(0) were studied in the kinematic range 0.2 < E-y < I GeV and transverse momentum with respect to the closest jet direction P-T < 80 MeV/c. A clear excess of photons in the experimental data as compared to the Monte Carlo predictions is observed. This excess (uncorrected for the photon detection efficiency) is (1.17 +/- 0.06 +/- 0.27) x 10(-3) gamma/jet in the specified kinematic region, while the expected level of the inner hadronic bremsstrahlung (which is not included in the Monte Carlo) is (0.340 +/- 0.001 +/- 0.038) X 10(-3) gamma/jet. The ratio of the excess to the predicted bremsstrahlung rate is then (3.4 +/- 0.2 +/- 0.8), which is similar in strength to the anomalous soft photon signal observed in fixed target experiments with hadronic beams.File | Dimensione | Formato | |
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