The measurement of prompt D-meson production as a function of multiplicity in p-Pb collisions at $\sqrt{s_{\rm NN}}=5.02$ 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 $-0.96< y_{\mathrm{cms}}<0.04$ and transverse momentum interval $1<p_{\rm T}<24$ 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 $p_{\rm T}$ regions and event classes. The relative D-meson yields, calculated in various $p_{\rm T}$ intervals, increase as a function of the charged-particle multiplicity. The results are compared with the equivalent pp measurements at $\sqrt{s}=7$ TeV as well as with EPOS~3 calculations.
Average $Q_{\rm pPb}$ of D$^{0}$, D$^{+}$ and D*$^{+}$ mesons for the sum of particles and antiparticles in several multiplicity and PT(D) intervals for p-Pb collisions at $\sqrt{s_{NN}}$ = 5.02 TeV as a function of the multiplicity at central rapidity evaluated with the ZNA estimator. The values are reported together with their uncertainties, which are quoted as statistical followed by systematic uncertainties. Normalisation uncertainty is not quoted and amounts to $\pm 0.07$, $\pm 0.05$, $\pm 0.07$ and $\pm 0.08$ for the 0-20%, 20-40%, 40-60% and 60-100% intervals, respectively.
Average $Q_{\rm pPb}$ of D$^{0}$, D$^{+}$ and D*$^{+}$ mesons for the sum of particles and antiparticles in several multiplicity and PT(D) intervals for p-Pb collisions at $\sqrt{s_{NN}}$ = 5.02 TeV as a function of the multiplicity at central rapidity evaluated with the CL1 estimator. The values are reported together with their uncertainties, which are quoted as statistical followed by systematic uncertainties. Normalisation uncertainty is not quoted and amounts to $\pm 0.05$, $\pm 0.05$, $\pm 0.07$ and $\pm 0.23$ for the 0-20%, 20-40%, 40-60% and 60-100% intervals, respectively.
Average $Q_{\rm pPb}$ of D$^{0}$, D$^{+}$ and D*$^{+}$ mesons for the sum of particles and antiparticles in several multiplicity and PT(D) intervals for p-Pb collisions at $\sqrt{s_{NN}}$ = 5.02 TeV as a function of the multiplicity at central rapidity evaluated with the V0A estimator. The values are reported together with their uncertainties, which are quoted as statistical followed by systematic uncertainties. Normalisation uncertainty is not quoted and amounts to $\pm 0.05$, $\pm 0.05$, $\pm 0.06$ and $\pm 0.22$ for the 0-20%, 20-40%, 40-60% and 60-100% intervals, respectively.
The transverse momentum ($p_{\mathrm T}$) distribution of primary charged particles is measured in minimum bias (non-single-diffractive) p-Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV with the ALICE detector at the LHC. The $p_{\mathrm T}$ spectra measured near central rapidity in the range $0.5<p_{\mathrm T}<20$ GeV/$c$ exhibit a weak pseudorapidity dependence. The nuclear modification factor $R_{\mathrm{pPb}}$ is consistent with unity for $p_{\mathrm T}$ above 2 GeV/$c$. This measurement indicates that the strong suppression of hadron production at high $p_{\mathrm T}$ observed in Pb-Pb collisions at the LHC is not due to an initial-state effect. The measurement is compared to theoretical calculations.
Normalized differential primary charged particle yield.
pp INEL cross section scaled by nuclear overlap.
Nuclear Modification Factor R_pPb in the central region.
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