Measurement of W-pair cross sections in $e^+ e^-$ interactions at $\sqrt{s}$ = 172 GeV and W decay branching fractions

• Published in: Physics letters. B 1997-06, Vol.407, p.419-431
• Main Authors: Acciarri, M., Adriani, O., Aguilar-Benitez, M., Ahlen, S., Alcaraz, J., Alemanni, G., Allaby, J., Aloisio, A., Alverson, G., Alviggi, M G., Ambrosi, G., Anderhub, H., Andreev, V P., Angelescu, T., Anselmo, F., Arefiev, A., Azemoon, T., Aziz, T., Bagnaia, P., Baksay, L., Banerjee, S., Banerjee, Sw, Banicz, K., Barczyk, A., Barillere, R., Barone, L., Bartalini, P., Baschirotto, A., Basile, M., Battiston, R., Bay, A., Becattini, F., Becker, U., Behner, F., Berdugo, J., Berges, P., Bertucci, B., Betev, B L., Bhattacharya, S., Biasini, M., Biland, A., Bilei, G M., Blaising, J J., Blyth, S C., Bobbink, G J., Bock, R., Bohm, A., Boldizsar, L., Borgia, B., Bourilkov, D., Bourquin, M., Braccini, S., Branson, J G., Brigljevic, V., Brock, I C., Buffini, A., Buijs, A., Burger, J D., Burger, W J., Busenitz, J., Button, A., Cai, X D., Campanelli, M., Capell, M., Cara Romeo, G., Carlino, G., Cartacci, a M., Casaus, J., Castellini, G., Cavallari, F., Cavallo, N., Cecchi, C., Cerrada, M., Cesaroni, F., Chamizo, M., Chang, y H., Chaturvedi, U K., Chekanov, S V., Chemarin, M., Chen, A., Chen, G., Chen, G M., Chen, H F., Chen, H S., Chereau, X., Chiefari, G., Chien, C Y., Cifarelli, L., Cindolo, F., Civinini, C., Clare, I., Clare, R., Cohn, H O., Coignet, G., Colijn, a P., Commichau, V., Costantini, S., Cotorobai, F., de La Cruz, B., Csilling, A.
• Format: Article
• Language: English
• Subjects: High Energy Physics - Experiment; Physics
• ISSN: 0370-2693
• DOI: 10.1016/S0370-2693(97)00802-2

We report on the measurement of W-boson pair-production with the L3 detector at LEP at an average centre-of-mass energy of 172.13~GeV. In a data sample corresponding to a total luminosity of 10.25~pb$^{-1}$ we select 110 four-fermion events with pairs of hadronic jets or leptons with high invariant masses. Branching fractions of W decays into different fermion-antifermion pairs are determined with and without the assumption of charged-current lepton universality. The branching fraction for hadronic W decays is measured to be: $ B(\mathrm{W\rightarrow hadrons}) = 64.2^{+3.7}_{-3.8}~(stat.) \pm 0.5~(syst.)~\%$. Combining all final states the total cross section for W-pair production is measured to be: $\sigma_{\mathrm{WW}} = 12.27^{+1.41}_{-1.32}~(stat.)\pm0.23~(syst.)$~pb. The results are in good agreement with the Standard Model.