Speaker
Matthieu Lenhardt
(Laboratoire de physique subatomique et des technologies associee)
Description
Recently, it has been argued that high-multiplicity pp collisions could lead to the formation of high energy density matter as in heavy ions collisions [1]. Indeed, the charged particle multiplicity reached in pp collisions at the LHC [2] is similar to the one measured in semi-peripheral Cu-Cu collisions at \sqrt{s_{NN}} = 200 GeV [3].
We will present the dependence on charged particle multiplicity of the single-muon and J/\psi \rightarrow \mu^{+}\mu{-} yields in pp collisions at \sqrt{s} = 7 TeV. The number of reconstructed tracklets (\eta<1.6) in the silicon pixel detector are exploited to measure the charged particle density at mid-rapidity. Single-muons (p_{T}>4 GeV/c) from heavy flavoured hadron decays and inclusive J/\psi (p_{T}>0) yields have been measured with the muon spectrometer (2.5<\eta<4.0). J/\psi yields at multiplicities five times the average pp multiplicity will be presented.
[1] K. Werner et al. arXiv:1010.0400v1, and K. Werner et al., Phys. Rev. Lett. 106, 122004 (2011)
[2] ALICE Collaboration, EPJC: Vol. 68 (2010) 345
[3] PHOBOS Collaboration, Phys. Rev. C 83, 024913 (2011)
Author
Matthieu Lenhardt
(Laboratoire de physique subatomique et des technologies associee)