We have measured the cross-section of the production of single photon events in e+e- collisions near the Z0 resonance. For an integrated luminosity of 9.6 pb-1, we have observed 202 single photon candidates with energy between 0.9 and 3.5 GeV in the polar angular region between 45-degrees and 135-degrees. Assuming that the only stable weakly interacting particles are light neutrinos with standard model couplings, we determine the number of light neutrino species to be N(nu) = 3.14 +/- 0.24 (stat.) +/- 0.12 (syst.). This corresponds to an invisible Z0 width of GAMMA(inv) = 524 +/- 40 +/- 20 MeV.
Determination of the Number of Light Neutrino Species
SANTOCCHIA, Attilio;FIANDRINI, Emanuele;PAULUZZI, Michele
1992
Abstract
We have measured the cross-section of the production of single photon events in e+e- collisions near the Z0 resonance. For an integrated luminosity of 9.6 pb-1, we have observed 202 single photon candidates with energy between 0.9 and 3.5 GeV in the polar angular region between 45-degrees and 135-degrees. Assuming that the only stable weakly interacting particles are light neutrinos with standard model couplings, we determine the number of light neutrino species to be N(nu) = 3.14 +/- 0.24 (stat.) +/- 0.12 (syst.). This corresponds to an invisible Z0 width of GAMMA(inv) = 524 +/- 40 +/- 20 MeV.File in questo prodotto:
Non ci sono file associati a questo prodotto.
I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
