Central Exclusive Production (CEP) is a unique process at hadron machines in which particles are produced via colourless propagators. LHCb have measured the cross-sections for the CEP of vector mesons, $J/\psi,\psi(2S),\Upsilon(1S),\Upsilon(2S)$ and $\Upsilon(3S)$, which are photo-produced. In the double pomeron exchange process, preliminary measurements have been made of $\chi_{ c0},\chi_{ c1}, \chi_{ c2}$ meson production while the first observations of the CEP of pairs of charmonia, $J/\psi J/\psi$ and $J/\psi \psi(2S)$, have been made and limits obtained on the pair production of other charmonia.
Categories: hep-ex