Pseudorapidity distributions of charged particles as a function of mid and forward rapidity mutiplicities in pp collisions at $\sqrt{s}$ = 5.02, 7 and 13 TeV

The multiplicity dependence of the pseudorapidity density of charged particles in proton-proton (pp) collisions at centre-of-mass energies $\sqrt{s}$ = 5.02, 7 and 13 TeV measured by ALICE is reported. The analysis relies on track segments measured in the midrapidity range ($|\eta| <~ 1.5$). Results are presented for inelastic events having at least one charged particle produced in the pseudorapidity interval $|\eta|<~1$ ($\mathrm{INEL}_{>0}$). The multiplicity dependence of the pseudorapidy density of charged particles is measured with mid and forward rapidity multiplicity estimators, the latter being less affected by autocorrelations. A detailed comparison with predictions from the PYTHIA 8 and EPOS LHC event generators is also presented. Both generators provide a good description of the data.

 

Accepted by: EPJC
e-Print: arXiv:2009.09434 | PDF | inSPIRE
CERN-EP-2020-170

Figure 2

Charged-particle pseudorapidity density (upper panels) and the same scaled by $1/\left(\dndeta\right)_\mathrm{incl.}$ (lower panels) for the 0--0.01 to 70--100\% multiplicity classes measured with the forward multiplicity estimator ($-3.7

Figure 3

Charged-particle pseudorapidity density (upper panels) and the same scaled by $1/\left(\dndeta\right)_\mathrm{incl.}$ (lower panels) for the 0--1 to 70--100\% multiplicity classes measured with the midrapidity multiplicity estimator ($-2

Figure 4

The panels in the first and third row show the normalised pseudorapidity density distributions of charged particles in ppcollisions at \s~=~5.02, 7 and \unit[13]{TeV} compared with different models for the 0--1\% and 70--100\% multiplicity classes by the forward rapidity multiplicity estimator, respectively. The panels in the second and fourth row report the corresponding model/data ratio. Note that the multiplicity classes of the models correspond to \multcc, which is slightly different from the \multc\ of the ALICE data.

Figure 5

The panels in the first and third row show the normalised pseudorapidity density distributions of charged particles in ppcollisions at \s~=~5.02, 7 and \unit[13]{TeV} compared with different models for the 0--1\% and 70--100\% multiplicity classes by the midrapidity multiplicity estimator, respectively. The panels in the second and fourth row report the corresponding model/data ratio. The multiplicity classes of the models correspond to \multcc, which is slightly different from the \multc\ of the ALICE data.

Figure 6

Energy dependence of \avdndeta\ (upper) and \avdndeta\ scaled by the inclusive \dndeta\ (lower) for the multiplicity classes by the forward multiplicity estimator in pp collisions. Lines show fits with a power-law function. Corresponding bands indicate one standard deviation of the fit. Exponents and corresponding uncertainties of the fit are listed in the legend.