Determination of the number of light neutrino species
We have measured the cross-section of the production of single photon events in e + e- collisions near the Z ° 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 ° and 135 °. A...
Guardado en:
| Autores principales: | , |
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| Formato: | Articulo |
| Lenguaje: | Inglés |
| Publicado: |
1992
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| Materias: | |
| Acceso en línea: | http://sedici.unlp.edu.ar/handle/10915/73124 |
| Aporte de: |
| Sumario: | We have measured the cross-section of the production of single photon events in e + e- collisions near the Z ° 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 ° and 135 °. 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 Nv = 3.14 + 0.24 (stat.)4-0.12 (syst.). This corresponds to an invisible Z ° width of Finv = 524 + 40 4- 20 MeV. |
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