Measurement of the triple gluon vertex from double quark tagged 4-jet events

Measurement of the triple gluon vertex from double quark tagged 4-jet events

The 4-jet events collected by the DELPHI experiment at LEP1 in 1992, 1993 and 1994 are analysed to determine the contribution of the triple-gluon vertex. Two of the four jets are tagged as jets from b- or c-quarks using lifetime and lepton transverse momentum information. The 4-jet contributions fro...

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Veröffentlicht in:Physics letters. B 1997-11, Vol.414 (3), p.401-418
Hauptverfasser: Abreu, P., Allport, P.P., Almehed, S., Apel, W-D., Arnoud, Y., Barbi, M., Barring, O., Bates, M.J., Baubillier, M., Belokopytov, Yu, Benvenuti, A.C., Bertini, D., Bianchi, F., Bizouard, M-A., Bonesini, M., Boonekamp, M., Booth, P.S.L., Boudinov, E., Bouquet, B., Brenke, T., Brenner, R.A., Carena, F., Caso, C., Chen, M., Colomer, M., Cosme, G., Czellar, S., Dalmagne, B., Damgaard, G., Delpierre, P., De Angelis, A., Doroba, K., Dris, M., Durand, J-D., Elsing, M., Fichet, S., Foeth, H., Galloni, A., Geryukov, L., Gorn, L., Graziani, E., Guy, J., Hernandez, J.J., Heuser, J.-M., Holthuizen, D., Jackson, J.N., Jonsson, P., Karafasoulis, K., Karvelas, E., Khokhlov, Yu, Khovanski, N.N., Knoblauch, D., Kokkinias, P., Kronkvist, I., Lanceri, L., Loerstad, B., Lopez, J.M., Maio, A., Mc Pherson, G., Migliore, E., Mulders, M., Navarria, F.L., Neumeister, N., Papageorgiou, K., Pernegger, H., Petrolini, A., Piana, G., Podobrin, O., Polok, G., Pukhaeva, N., Radojicic, D., Redaelli, N.G., Renton, P.B., Romero, A., Rosenberg, E.I., Rovelli, T., Ruhlmann-Kleider, V., Schwickerath, U., Schyns, M.A.E., Sedykh, Y., Smith, G.R., Spassov, T., Stocchi, A., Szeptycka, M., Tkatchev, L.G., Tsirou, A., Turluer, M-L., Tyapkin, I.A., Ullaland, O., Van Lysebetten, A., Vegni, G., Venus, W., Vilanova, D., Vitale, L., Wahlen, H., Wielers, M., Yip, K., Zach, F., Zimin, N.I., Zucchelli, G.C.
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Sprache:eng
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Zusammenfassung:The 4-jet events collected by the DELPHI experiment at LEP1 in 1992, 1993 and 1994 are analysed to determine the contribution of the triple-gluon vertex. Two of the four jets are tagged as jets from b- or c-quarks using lifetime and lepton transverse momentum information. The 4-jet contributions from double-gluon bremsstrahlung, the triple-gluon vertex, and secondary quark-antiquark pair production then yield significantly different two-dimensional distributions in the generalized Nachtmann Reiter angle versus the opening angle of the two secondary jets. These distributions are used to fit C A C F , the ratio of the coupling strength of the triple-gluon vertex to that of gluon bremsstrahlung, and N C N A , the ratio of the number of quark colours to the number of gluons, giving C A C F = 2.51 ± 0.28 and N C N A = 0.38 ± 0.10 in agreement with the values expected from QCD: C A C F = 9 4 = 2.25 and N C N A = 3 8 = 0.375 .
ISSN:0370-2693
1873-2445
DOI:10.1016/S0370-2693(97)01192-1