Charge asymmetry and weak interaction effects in e +e −→ μ+μ− and e +e −→ τ+τ

• Published in: Physics letters. B Vol. 110; no. 2; pp. 173 - 180
• Main Authors: Brandelik, R., Braunschweig, W., Gather, K., Kirschfink, F.J., Lübelsmeyer, K., Martyn, H.-U., Peise, G., Rimkus, J., Sander, H.G., Schmitz, D., Trines, D., Wallraff, W., Boerner, H., Fischer, H.M., Hartmann, H., Hilger, E., Hillen, W., Knop, G., Köpke, L., Kolanoski, H., Löhr, B., Wedemeyer, R., Wermes, N., Wollstadt, M., Burkhardt, H., Cooper, S., Heyland, D., Hultschig, H., Joos, P., Koch, W., Kötz, U., Kowalski, H., Ladage, A., Lüke, D., Lynch, H.L., Mättig, P., Mess, K.H., Notz, D., Pyrlik, J., Quarrie, D.R., Riethmüller, R., Shapira, A., Söding, P., Wolf, G., Fohrmann, R., Holder, M., Krasemann, H.L., Leu, P., Pandoulas, D., Poelz, G., Römer, O., Schmüser, P., Wiik, B.H., Al-Agil, I., Beuselinck, R., Binnie, D.M., Campbell, A.J., Dornan, P.J., Garbutt, D.A., Jones, T.D., Jones, W.G., Lloyd, S.L., Sedgbeer, J.K., Stern, R.A., Yarker, S., Bell, K.W., Bowler, M.G., Brock, I.C., Cashmore, R.J., Carnegie, R., Devenish, R., Grossmann, P., Illingworth, J., Ogg, M., Salmon, G.L., Thomas, J., Wyatt, T.R., Youngman, C., Foster, B., Hart, J.C., Harvey, J., Proudfoot, J., Saxon, D.H., Woodworth, P.L., Duchovni, E., Eisenberg, Y., Karshon, U., Mikenberg, G., Revel, D., Ronat, E., Barklow, T., Freeman, J., Meyer, T., Rudolph, G., Wicklund, E., Wu, Sau Lan, Zobernig, G.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.03.1982
• ISSN: 0370-2693; 1873-2445
• DOI: 10.1016/0370-2693(82)91029-2

We have measured, at an average centre-of-mass energy of 34.22 GeV a forward-backward charge asymmetry in the reaction e +e −→ μ + μ − of value −0.161 ± 0.032. This demonstrates the existence of an axial vector neutral current with coupling strength of g e a g μ a=0.53 ± 0.10. We have also obtained a limit on the vector coupling strength of g e v g μ v<0.12. The Weinberg angle is found to be sin 2 θ W=0.29 +0.09 −0.11. From the reaction e +e −→ τ + τ − we have found g e a g τ a<0.34, g e v g τ v<0.55.