Formation of the ηc in two-photon collisions at LEP

Acciarri, M. ; Achard, P. ; Adriani, O. ; Aguilar-Benitezx, M. ; Gurtu, A. ; et., al (1999) Formation of the ηc in two-photon collisions at LEP Physics Letters B, 461 (1-2). pp. 155-166. ISSN 0370-2693

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The two-photon width Γγγ of the ηc meson has been measured with the L3 detector at LEP. The ηc is studied in the decay modes π+ππ+π, π+πK+K, K0sK±π, K+K-π0, π+πη, π+πη', and ρ+ρ using an integrated luminosity of 140 pb−1 at √s ≃ 91 GeV and of 52 pb−1 at √s ≃ 183 GeV. The result is Γγγηc = 6.9±1.7 stat±0.8 sys±2.0(BR) keV. The Q2 dependence of the ηc cross section is studied for Q2−9 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 χc0 mass. Upper limits for the two-photon widths of the χc0, χc2, and ηc; are also given.

Item Type:Article
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ID Code:83551
Deposited On:21 Feb 2012 12:51
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