Observation of $J/Ï$ pair production in pp collisions at $\sqrt{s}=7 TeV$
arXiv:1109.0963 · doi:10.1016/j.physletb.2011.12.015
Abstract
The production of $J/Ï$ pairs in proton-proton collisions at a centre-of-mass energy of 7 TeV has been observed using an integrated luminosity of $37.5 pb^{-1}$ collected with the LHCb detector. The production cross-section for pairs with both \jpsi in the rapidity range $2<y^{J/Ï}<4.5$ and transverse momentum $p_{T}^{J/Ï}<10 GeV/c$ is $$ Ï^{J/ÏJ/Ï} = 5.1\pm1.0\pm1.1 nb,$$ where the first uncertainty is statistical and the second systematic.
10 pages, 3 figures