We have measured the cross section for e +e -→hadrons over the center of mass energy range of the Z 0 peak, from 88.22 to 95.03 GeV. We determine the Z 0 mass M z=91.164±0.013(experiment)±0.030(LEP) GeV. Within the framework of the standard model we determine the invisible width, Γ invisible=0.502±0.018 GeV, and the number of light neutrino species, N v=3.01±0.11. We exclude the existence of a supersymmetric scalar neutrino having a mass less than 31.4 GeV, at the 95% confidence level. We performed a model independent combined fit to the e +e -→hadrons and e +e -→μ +μ - data to determine total width, leptonic width and hadronic width of the Z 0.
A precision measurement of the number of neutrino species / A. O., Aguilar Benitez; Alviggi, Mariagrazia; Aloisio, Alberto; Chiefari, Giovanni; Napolitano, Marco; Merola, Leonardo; Paternoster, Giovanni; Patricelli, Sergio; Sciacca, Crisostomo. - In: PHYSICS LETTERS. SECTION B. - ISSN 0370-2693. - STAMPA. - 249:(1990), pp. 341-352.
A precision measurement of the number of neutrino species
ALVIGGI, MARIAGRAZIA;ALOISIO, ALBERTO;CHIEFARI, GIOVANNI;NAPOLITANO, MARCO;MEROLA, LEONARDO;PATERNOSTER, GIOVANNI;PATRICELLI, SERGIO;SCIACCA, CRISOSTOMO
1990
Abstract
We have measured the cross section for e +e -→hadrons over the center of mass energy range of the Z 0 peak, from 88.22 to 95.03 GeV. We determine the Z 0 mass M z=91.164±0.013(experiment)±0.030(LEP) GeV. Within the framework of the standard model we determine the invisible width, Γ invisible=0.502±0.018 GeV, and the number of light neutrino species, N v=3.01±0.11. We exclude the existence of a supersymmetric scalar neutrino having a mass less than 31.4 GeV, at the 95% confidence level. We performed a model independent combined fit to the e +e -→hadrons and e +e -→μ +μ - data to determine total width, leptonic width and hadronic width of the Z 0.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
