MEASUREMENT OF THE TRIPLE-GLUON VERTEX FROM 4-JET EVENTS AT LEP

MEASUREMENT OF THE TRIPLE-GLUON VERTEX FROM 4-JET EVENTS AT LEP

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 θNR* and the opening angle of the two least energetic jets....

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Bibliographic Details
Main Authors: Abreu, P, Adam, W, Adye, T, Agasi, E, Aleksan, R, Alekseev, G, Algeri, A, Allen, P, Almehed, S, Alsvaag, S, Amaldi, U, Andreazza, A, Antilogus, P, Apel, W, Apsimon, R, Arnoud, Y, Asman, B, Augustin, J, Augustinus, A, Baillon, P, Bambade, P, Barao, F, Barate, R, Barbiellini, G, Bardin, D
Format: Journal article
Language:English
Published: 1993
Description
Summary: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 θNR* and the opening angle of the two least energetic jets. A fit to their two-dimensional distribution yields {Mathematical expression} where CA/CF is the ratio of the coupling strength of the triple-gluon vertex to that of gluon bremsstrahlung from quarks, and NC/NA, 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 CA/CF. The results are in agreement with the values expected from QCD:CA/CF=2.25, and NC/NA=3/8. © 1993 Springer-Verlag.

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