Measurement of D-meson production versus multiplicity in p-Pb collisions at s N N = 5.02 $$ \sqrt{{\mathrm{s}}_{\mathrm{NN}}}=5.02 $$ TeV

Abstract

Abstract:The measurement of prompt D-meson production as a function of multiplicity in p-Pb collisions at √ s NN = 5.02 TeV with the ALICE detector at the LHC is reported. D 0 , D + and D * + mesons are reconstructed via their hadronic decay channels in the centre-of-mass rapidity range −0.96 < y cms < 0.04 and transverse momentum interval 1 < p T < 24 GeV/c. The multiplicity dependence of D-meson production is examined by either comparing yields in p-Pb collisions in different event classes, selected based on the multiplicity of produced particles or zero-degree energy, with those in pp collisions, scaled by the number of binary nucleon-nucleon collisions (nuclear modification factor); as well as by evaluating the per-event yields in p-Pb collisions in different multiplicity intervals normalised to the multiplicity-integrated ones (relative yields). The nuclear modification factors for D 0 , D + and D * + are consistent with one another. The D-meson nuclear modification factors as a function of the zero-degree energy are consistent with unity within uncertainties in the measured p T regions and event classes. The relative D-meson yields, calculated in various p T intervals, increase as a function of the charged-particle multiplicity. The results are compared with the equivalent pp measurements at √ s = 7 TeV as well as with EPOS 3 calculations.

Study of prompt D 0 meson production in pPb collisions at s N N = 5 $$ \sqrt{s_{\mathrm{N}\;\mathrm{N}}}=5 $$ TeV

“…Recently, CNM effects were measured in pPb collisions at the LHC for quarkonium and heavy flavour production [22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39]. The ALICE experiment studied D meson productions in pPb collisions [25,27,31] at √ s NN = 5 TeV in the region −0.96 < y * < 0.04, where y * is the rapidity of the D meson defined in the centre-of-mass system of the colliding nucleons. Their results suggest that the suppression observed in PbPb collisions is due to hot nuclear matter effects, i.e.…”

Open heavy-flavour measurements in pp and p–Pb collisions with ALICE at the LHC

“…Figure 2 shows the average self-normalised D meson yield as a function of the self-normalised charged particle multiplicity, for pp collisions at √ s = 7 TeV [14] and p-Pb collisions at √ s NN = 5.02 TeV [15]. A faster than linear increase is seen for both collision systems, which is compared with (GeV) s models for pp collisions on the right of figure 2.…”

“…The data qualitatively agree with models including parton saturation and interaction between colour strings in the percolation model [16], and multiparton interactions via the PYTHIA8 [17] and EPOS [18] event generators. The measurement in p-Pb collisions has also been compared with predictions from EPOS which can be found in [15]. It is interesting to note that switching viscous hydrodynamic effects on for EPOS gives a better description of the steepness of the measured data in both pp and p-Pb collisions, suggesting collective effects could play a role in particle production at high multiplicity.…”

“…It is interesting to note that switching viscous hydrodynamic effects on for EPOS gives a better description of the steepness of the measured data in both pp and p-Pb collisions, suggesting collective effects could play a role in particle production at high multiplicity. Left: Average self-normalised D meson yields as a function of the self-normalised charged particle multiplicity at mid-rapidity for 2 < p T < 4 GeV/c in pp and p-Pb collisions [15]. The uncertainty on the B feed-down fraction is drawn on the bottom panel.…”

“…[29]). Figure 5 shows the Q pPb measured in p-Pb collisions at √ s NN = 5.02 TeV [15] where the centrality is estimated using the energy deposited in the Zero Degree Neutron Calorimeter (ZNA) by slow nucleons produced in the collision by nuclear deexcitation processes, or knocked out by wounded nucleons. This centrality estimator does not rely on a multiplicity measurement and thus is expected to generate the least bias.…”