The three different helicity states of W(+/-) bosons, produced in the reaction e(+)e(-) --> W(+)W(-) --> lvq (q) over bar are studied using leptonic and hadronic W decays at root s = 183 GeV and 189 GeV. The W polarisation is also measured as a function of the scattering angle between the W(-) and the direction of the e(-) beam. The analysis demonstrates that W bosons are produced with all three helicities, the longitudinal and the two transverse states. Combining the results from the two center-of-mass energies and with leptonic and hadronic W decays, the fraction of longitudinally polarised W(+/-) bosons is measured to be 0.261 +/- 0.016(syst.) +/- 0.016(syst.) in agreement with the expectation from the Standard Model. (C) 2000 Elsevier Science B.V. All rights reserved.

Direct observation of longitudinally polarised W +/- bosons / Acciarri, M., Achard, P., Adriani, O., AGUILAR BENITEZ, M., Alcaraz, J., Alemanni, G., Allaby, J., Aloisio, A., Alviggi, M.g., Ambrosi, G., Anderhub, H., Andreev, V.p., Angelescu, T., Anselmo, F., Arefiev, A., Azemoon, T., Aziz, T., Bagnaia, P., Baksay, L., Balandras, A., et al.. - In: PHYSICS LETTERS. SECTION B. - ISSN 0370-2693. - 474:(2000), pp. 194-204. [10.1016/S0370-2693(99)01489-6]

Direct observation of longitudinally polarised W +/- bosons

BAGNAIA, Paolo;BARONE, Luciano Maria;FACCINI, Riccardo;FERRONI, Fernando;GENTILE, Simonetta;GIAGU, Stefano;LUCI, Claudio;ORGANTINI, Giovanni;PARAMATTI, Riccardo;
2000

Abstract

The three different helicity states of W(+/-) bosons, produced in the reaction e(+)e(-) --> W(+)W(-) --> lvq (q) over bar are studied using leptonic and hadronic W decays at root s = 183 GeV and 189 GeV. The W polarisation is also measured as a function of the scattering angle between the W(-) and the direction of the e(-) beam. The analysis demonstrates that W bosons are produced with all three helicities, the longitudinal and the two transverse states. Combining the results from the two center-of-mass energies and with leptonic and hadronic W decays, the fraction of longitudinally polarised W(+/-) bosons is measured to be 0.261 +/- 0.016(syst.) +/- 0.016(syst.) in agreement with the expectation from the Standard Model. (C) 2000 Elsevier Science B.V. All rights reserved.
2000
01 Pubblicazione su rivista::01a Articolo in rivista
Direct observation of longitudinally polarised W +/- bosons / Acciarri, M., Achard, P., Adriani, O., AGUILAR BENITEZ, M., Alcaraz, J., Alemanni, G., Allaby, J., Aloisio, A., Alviggi, M.g., Ambrosi, G., Anderhub, H., Andreev, V.p., Angelescu, T., Anselmo, F., Arefiev, A., Azemoon, T., Aziz, T., Bagnaia, P., Baksay, L., Balandras, A., et al.. - In: PHYSICS LETTERS. SECTION B. - ISSN 0370-2693. - 474:(2000), pp. 194-204. [10.1016/S0370-2693(99)01489-6]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11573/248620
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