Formation of the η<sub>c</sub> in two-photon collisions at LEP
The two-photon width Γ<sub>γγ</sub> of the η<sub>c</sub> meson has been measured with the L3 detector at LEP. The η<sub>c</sub> is studied in the decay modes π+π−π+π−, π+π−K+K−, K0sK±π∓, K+K−π0, π+π−η, π+π−η′, and ρ+ρ− using an integrated luminosity of 140 pb<s...
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| Autores principales: | , |
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| Formato: | Articulo |
| Lenguaje: | Inglés |
| Publicado: |
1999
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| Materias: | |
| Acceso en línea: | http://sedici.unlp.edu.ar/handle/10915/79983 |
| Aporte de: |
| Sumario: | The two-photon width Γ<sub>γγ</sub> of the η<sub>c</sub> meson has been measured with the L3 detector at LEP. The η<sub>c</sub> is studied in the decay modes π+π−π+π−, π+π−K+K−, K0sK±π∓, K+K−π0, π+π−η, π+π−η′, and ρ+ρ− using an integrated luminosity of 140 pb<sup>−1</sup> at √<math><mtext>s</mtext><mtext>≃91</mtext></math> GeV and of 52 pb<sup>−1</sup> at √s ≃ 183 GeV. The result is Γ<sub>γγ</sub> (η<sub>c</sub>)=6.9±1.7 stat ± 0.8 sys ± 2.0(BR) keV. The Q<sup>2</sup> dependence of the η<sub>c</sub> cross section is studied for Q<sup>2</sup> < 9 GeV2. It is found to be better described by a Vector Meson Dominance model form factor with a J-pole than with a ρ-pole. In addition, a signal of 29±11 events is observed at the χ<sub>c0</sub> mass. Upper limits for the two-photon widths of the χ<sub>c0</sub>, χ<sub>c2</sub>, and η<sub>′c</sub> are also given. |
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