| Contributors: |
Abreu, P; Adam, W; Adye, T; Adzic, P; Ajinenko, I; Albrecht, Z; Alderweireld, T; Alekseev, Gd; Alemany, R; Allmendinger, T; Allport, Pp; Almehed, S; Amaldi, U; Amapane, N; Amato, S; Anassontzis, Eg; Andersson, P; Andreazza, A; Andringa, S; Antilogus, P; Apel, Wd; Arnoud, Y; Asman, B; Augustin, Je; Augustinus, A; Baillon, P; Ballestrero, A; Bambade, P; Barao, F; Barbiellini, G; Barbier, R; Bardin, Dy; Barker, G; Baroncelli, A; Battaglia, M; Baubillier, M; Becks, Kh; Begalli, M; Behrmann, A; Beilliere, P; Belokopytov, Y; Benekos, Nc; Benvenuti, Ac; Berat, C; Berggren, M; Berntzon, L; Bertrand, D; Besancon, M; Bilenky, M; Bizouard, Ma; Bloch, D; Blom, Hm; Bonesini, M; Boonekamp, M; Booth, Psl; Borisov, G; Bosio, C; Botner, O; Boudinov, E; Bouquet, B; Bourdarios, C; Bowcock, Tjv; Boyko, I; Bozovic, I; Bozzo, M; Bracko, M; Branchini, P; Brenner, Ra; Bruckman, P; Brunet, Jm; Bugge, L; Buran, T; Buschmann, P; Cabrera, S; Caccia, M; Calvi, M; Camporesi, T; Canale, V; Carena, F; Carroll, L; Caso, C; Gimenez, Mvc; Cattai, A; Cavallo, Fr; Charpentier, P; Checchia, P; Chelkov, Ga; Chierici, R; Chliapnikov, P; Chochula, P; Chorowicz, V; Chudoba, J; Cieslik, K; Collins, P; Contri, R; Cortina, E; Cosme, G; Cossutti, F; Costa, M; Crawley, Hb |
| Description: |
Measurements of on-shell ZZ production are described, using data collected by DELPHI in 1997 and 1998, at centre-of-mass energies roots = 182.6 GeV and 188.6 GeV, respectively. Results obtained in each of the final states q (q) over barq (q) over bar, mu (+)mu (-) q (q) over bar e(+)e(-)q (q) over bar, nuq (q) over bar, l(+)l(-)l(+)l(-), and nul(+)l(-) are presented. The measured cross-sections for on-shell ZZ production via the tree-level doubly-resonant graphs (NC02) are: sigma (NC02) (182.6 GeV) = 0.38 +/- 0.18 (stat) +/- 0.04 (syst) pb, sigma (NC02) (188.6 GeV) = 0.60+/-0.13 (stat) +/- 0.07 (syst) pb. They are consistent with the Standard Model expectations of 0.25 and 0.65 pb at each energy. (C) 2001 Published by Elsevier Science B.V. RI Ragazzi, Stefano/D-2463-2009; Gonzalez Caballero, Isidro/E-7354-2010; Krammer, Manfred/A-6508-2010; Muresan, Raluca-Anca/C-3725-2011; Katsanevas, Stavros/A-4297-2011; Ruiz, Alberto/E-4473-2011; Andreazza, Attilio/E-5642-2011; Marti-Garcia, Salvador/F-3085-2011; Verzi, Valerio/B-1149-2012; branchini, paolo/A-4857-2011; Shellard, Ronald/G-4825-2012; Petrolini, Alessandro/H-3782-2011; Fruhwirth, Rudolf/H-2529-2012; Monge, Maria Roberta/G-9127-2012 |