Observation of $J/\psi$ pair production in pp collisions at $\sqrt{s}=7 TeV$

TL;DR

This paper reports the first observation of $J/$ pair production in proton-proton collisions at 7 TeV, measuring the production cross-section using data from the LHCb detector.

Contribution

It presents the first measurement of $J/$ pair production cross-section at 7 TeV in proton-proton collisions.

Findings

Measured cross-section: 5.1 ± 1.0 ± 1.1 nb

Observation of $J/$ pairs at LHCb

Data collected with 37.5 pb^{-1} luminosity

Abstract

The production of $J/\psi$ 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 $2<y^{J/\psi}<4.5$ and transverse momentum $p_{T}^{J/\psi}<10 GeV/c$ is $$ \sigma^{J/\psi J/\psi} = 5.1\pm1.0\pm1.1 nb,$$ where the first uncertainty is statistical and the second systematic.