In the reaction e+e- -> WW -> (q_1 qbar_2)(q_3 qbar_4) the usual hadronization models treat the colour singlets q_1 qbar_2 and q_3 qbar_4 coming from two W bosons independently. However, since the final state partons may coexist in space and time, cross-talk between the two evolving hadronic systems may be possible during fragmentation through soft gluon exchange. This effect is known as Colour Reconnection. In this article the results of the investigation of Colour Reconnection effects in fully hadronic decays of W pairs in DELPHI at LEP are presented. Two complementary analyses were performed, studying the particle flow between jets and W mass estimators, with negligible correlation between them, and the results were combined and compared to models. In the framework of the SK-I model, the value for its kappa parameter most compatible with the data was found to be: kappa_{SK-I} = 2.2^{+2.5}_{-1.3} corresponding to the probability of reconnection P_{reco} to be in the range 0.31 < P_{reco} < 0.68 at 68% confidence level with its best value at 0.52.

Investigation of colour reconnection in WW events with the DELPHI detector at LEP-2 / J. Abdallah, P. Abreu, W. Adam, P. Adzic, T. Albrecht, 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. Espirito 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.H. Gavillet, E. Gazis, R. Gokieli, B. Golob, G. Gomez Ceballos, P. Goncalves, E. Graziani, G. Grosdidier, K. Grzelak, 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, 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. Mcnulty, 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, R. 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, 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. - 51:2(2007 May 05), pp. 249-269. [10.1140/epjc/s10052-007-0304-9]

Investigation of colour reconnection in WW events with the DELPHI detector at LEP-2

A. Andreazza;C. Meroni;G. Vegni;
2007

Abstract

In the reaction e+e- -> WW -> (q_1 qbar_2)(q_3 qbar_4) the usual hadronization models treat the colour singlets q_1 qbar_2 and q_3 qbar_4 coming from two W bosons independently. However, since the final state partons may coexist in space and time, cross-talk between the two evolving hadronic systems may be possible during fragmentation through soft gluon exchange. This effect is known as Colour Reconnection. In this article the results of the investigation of Colour Reconnection effects in fully hadronic decays of W pairs in DELPHI at LEP are presented. Two complementary analyses were performed, studying the particle flow between jets and W mass estimators, with negligible correlation between them, and the results were combined and compared to models. In the framework of the SK-I model, the value for its kappa parameter most compatible with the data was found to be: kappa_{SK-I} = 2.2^{+2.5}_{-1.3} corresponding to the probability of reconnection P_{reco} to be in the range 0.31 < P_{reco} < 0.68 at 68% confidence level with its best value at 0.52.
Physics ; elementary particle physics ; LEP ; standard model
Settore FIS/04 - Fisica Nucleare e Subnucleare
5-mag-2007
Article (author)
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/38549
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