Long-range multiplicity correlations in proton-proton collisions
The forward-backward long-range multiplicity correlations in proton-proton collisions are investigated in the model with two independent sources of particles: one left- and one right-moving wounded nucleon. A good agreement with the UA5 collaboration proton-antiproton data at the c.m. energy of 200 GeV is observed. For comparison the model with only one source of particles is also discussed.
Monte Carlo Glauber wounded nucleon model with meson cloud
We study the effect of the nucleon meson cloud on predictions of the Monte Carlo Glauber wounded nucleon model for AA, pA, and pp collisions. From the analysis of the data on the charged multiplicity density in AA collisions we find that the meson–baryon Fock component reduces the required fraction of binary collisions by a factor of ~2 for Au + Au collisions at √s = 0.2 TeV and ~1.5 for Pb + Pb collisions at √s = 2.76 TeV. For central AA collisions, the meson cloud can increase the multiplicity density by ~16–18%. We give predictions for the midrapidity charged multiplicity density in Pb + Pb collisions at √s = 5.02 TeV for the future LHC run 2. We find that the meson cloud has a weak effect on the centrality dependence of the ellipticity ϵ2 in AA collisions. For collisions of the deformed uranium nuclei at √s = 0.2 TeV, we find that the meson cloud may improve somewhat agreement with the data on the dependence of the elliptic flow on the charged multiplicity for very small centralities defined via the ZDCs signals. We find that the meson cloud may lead to a noticeable reduction of ϵ2 and the size of the fireball in pA and pp collisions.
On the forward–backward correlations in a two-stage scenario
Abstract It is demonstrated that in a two-stage scenario with elementary Poissonian emitters of particles (colour strings) arbitrarily distributed in their number and average multiplicities, the forward–backward correlations are completely determined by the final distribution of forward particles. The observed linear form of the correlations then necessarily requires this distribution to have a negative binomial form. For emitters with a negative binomial distribution in the produced particles distributed so as to give the final distribution also of the negative binomial form, the forward–backward correlations have an essentially non-linear form which disagrees with the experimental data.