Author/Authors :
R. Barate، نويسنده , , D. Buskulic، نويسنده , , D. Decamp، نويسنده , , P. Ghez، نويسنده , , C. Goy، نويسنده , , J.-P. Lees، نويسنده , , A. Lucotte، نويسنده , , M.-N. Minard، نويسنده , , Nief، Francois نويسنده , , B. Pietrzyk، نويسنده , , M.P. Casado، نويسنده , , M. Chmeissani، نويسنده , , P. Comas، نويسنده , , J.M. Crespo، نويسنده , , M. Delfino، نويسنده , , E. Fernandez، نويسنده , , M. Fernandez-Bosman، نويسنده , , Ll. Garrido، نويسنده , , A. Juste، نويسنده , , M. Martinez، نويسنده , , et al.، نويسنده ,
Abstract :
In June 1996, the LEP centre-of-mass energy was raised to 161 GeV. Pair production of W bosons in e+e− collisions was observed for the first time by the LEP experiments. An integrated luminosity of 11 pb−1 was recorded in the ALEPH detector, in which WW candidate events were observed. In 6 events both Ws decay leptonically. In 16 events, one W decays leptonically, the other into hadrons. In the channel where both Ws decay into hadrons, a signal was separated from the large background by means of several multi-variate analyses. The W pair cross-section is measured to be σWW = 4.23 ± 0.73 (stat.) ± 0.19 (syst.) pb. From this cross-section, the W mass is derived within the framework of the Standard Model: mW = 80.14 ± 0.34 (stat.) ± 0.09 (syst.) ± 0.03 (LEP energy) GeV/c2
