6533b853fe1ef96bd12adc19
RESEARCH PRODUCT
Measurement of the triple-gluon vertex from 4-JET events at LEP
Delphi CollaborationPaul AllenJ. T. M. ChrinMaría Victoria Castillo GiménezEduardo Cortina GilAntonio Ferrer SoriaJuan A. Fuster VerdúM. D. M. De Fez LasoJuan José Gómez CadenasCarmen García GarcíaJuan José Hernández ReyEmilio Higón RodríguezCarlos Lacasta LlácerJosé Julio Lozano BahiloSalvador Martí GarcíaJosé Salt CairolsJuan Antonio Valls FerrerJuan Zúñiga Románsubject
High Energy Physics::LatticeHigh Energy Physics::PhenomenologyHigh Energy Physics::ExperimentFísica nucleardescription
From the combined data of 1990 and 1991 of the DELPHI experiment at LEP, 13057 4-jet events are obtained and used for determining the contribution of the triple-gluon vertex. The relevant variables are the generalized Nachtmann Reiter angle theta(NR)* and the opening angle of the two least energetic jets. A fit to their two-dimensional distribution yields C(A)/C(F)=2.12+/-0.35 and N(C)/N(A)=0.46+/-0.19, where C(A)/C(F) is the ratio of the coupling strength of the triple-gluon vertex to that of gluon bremsstrahlung from quarks, and N(C)/N(A), the ratio of the number of quark colours to the number of gluons. This constitutes a convincing model-independent proof of the existence of the triple-gluon vertex, since its contribution is directly proportional to C(A)/C(F). The results are in agreement with the values expected from QCD: C(A)/C(F)=2.25, and N(C)/N(A)=3/8.
year | journal | country | edition | language |
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1993-01-01 |