An upper limit for Br( Z0 → ggg) from symmetric 3-jet Z0 hadronic decays

• Published in: Physics letters. B 1996-12, Vol.389 (2), p.405-415
• Main Authors: Abreu, P., Allport, P.P., Almehed, S., Apel, W-D., Barbi, M., Baroncelli, A., Bartl, W., Bates, M.J., Baubillier, M., Baudot, J., Belokopytov, Yu, Bertini, D., Bertrand, D., Bianchi, F., Bizouard, M-A., Booth, P.S.L., Brenner, R.A., Bruckman, P., Carena, F., Cattai, A., Chochula, P., Collins, P., Contri, R., Cuevas Maestro, J., Dahm, J., Dalmagne, B., Da Silva, W., Deghorain, A., De Brabandere, S., De Min, A., De Paula, L., Dijkstra, H., Di Diodato, A., Edsall, D., Elsing, M., Firestone, A., Fulda-Quenzer, F., Gazis, E.N., Gele, D., Gerber, J-P., Golob, B., Gopal, G., Gouz, Yu, Grefrath, A., Gunther, M., Herr, H., Holthuizen, D., Hultqvist, K., Jacobsson, R., Jean-Marie, B., Johansson, E.K., Jonsson, P., Kaiser, M., Kapusta, F., Karvelas, E., Khomenko, B.A., King, B., Kostioukhine, V., Krupinski, W., Lepeltier, V., Libby, J., Liko, D., Mandl, F., Marco, R., Masik, J., Matorras, F., Matteuzzi, C., Mc Cubbin, M., Murray, W.J., Negri, P., Nielsen, B.S., Nomerotski, A., Oberschulte-Beckmann, W., Olshevski, A.G., Paganini, P., Paganoni, M., Pol, M.E., Rebecchi, P., Romero, A., Sanchez, J., Schimmelpfennig, M., Serbelloni, L., Skaali, T.B., Stevenson, K., Szczekowski, M., Todorov, T., Transtromer, G., Trischuk, W., Tristram, G., Van Eldik, J., Van Lysebetten, A., Vegni, G., Vincent, P., Vrba, V., Wahlen, H., Winter, M., Woschnagg, K., Zach, F., Zalewski, P., Zito, M.
• Format: Article
• Language: English
• ISSN: 0370-2693; 1873-2445
• DOI: 10.1016/S0370-2693(96)01450-5

An upper limit for BR( Z 0 → 3 g) is obtained from a correlation method, which distinguishes statistically between quark and gluon jets by using the difference in their charged particle multiplicity distributions. From the sample of threefold symmetric three-jet events collected by the DELPHI experiment at LEP during 1991–1994, the 95% confidence level upper limit is deduced to be: BR( Z 0 → 3 g) ≤ 1.6 × 10 −2 for the JADE and BR( Z 0 → 3 g) ≤ 1.5 × 10 −2 for the DURHAM jet-finder.