Study ofηformation in photon-photon collisions
H. Aihara · Physical review. D. Particles, fields, gravitation, and cosmology/Physical review. D. Particles and fields · 1986
The two-photon production of the \ensuremath{\eta} meson has been observed, and a value has been determined for the two-photon \ensuremath{\eta} decay width by a measurement of the cross section \ensuremath{\sigma}(${e}^{+}$${e}^{\mathrm{\ensuremath{-}}}$\ensuremath{\rightarrow}${e}^{+}$${e}^{\mathrm{\ensuremath{-}}}$\ensuremath{\eta}) where \ensuremath{\eta}\ensuremath{\rightarrow}\ensuremath{\gamma}\ensuremath{\gamma}. The measurement was made with the TPC/Two-Gamma facility at the SLAC ${e}^{+}$${e}^{\mathrm{\ensuremath{-}}}$ collider PEP, with an accumulated data sample of 64.5 ${\mathrm{pb}}^{\mathrm{\ensuremath{-}}1}$. The \ensuremath{\eta}\ensuremath{\rightarrow}\ensuremath{\gamma}\ensuremath{\gamma} events were both triggered and detected by the pole-tip calorimeter. The measured two-photon \ensuremath{\eta} decay width is ${\ensuremath{\Gamma}}_{\ensuremath{\eta}\ensuremath{\rightarrow}\ensuremath{\gamma}\ensuremath{\gamma}}$=0.64\ifmmode\pm\else\textpm\fi{}0.14 (statistical) \ifmmode\pm\else\textpm\fi{}0.13 (systematic) keV, in agreement with earlier similarly determined values.