Correlations and ridge in $p$Pb collisions in the LHCb Experiment

The LHCb experiment, besides its main programme concerning flavour physics performs also very well as a general purpose forward detector, covering the pseudo-rapidity range from 2.0 to 5.0. Exploiting the experiment’s unique geometry, the LHCb collaboration is pursuing a rich programme of forward QCD measurements. In particular two-particle angular correlations are studied in proton-lead collisions at a nucleon-nucleon centre-of-mass energy of √SNN = 5 TeV, with data collected by the LHCb detector at the LHC in 2013. The analysis is based on data recorded in two opposing beam configurations, in which either the direction of the proton or that of the lead remnants is analysed. This is the first measurement of a long-range correlation on the near side in proton-lead collisions in the forward region. It extends previous observations in the central region.