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A bstract The cross section for coherent photonuclear production of J/ ψ is presented as a function of the electromagnetic dissociation (EMD) of Pb. The measurement is performed with the ALICE detector in ultra-peripheral Pb-Pb collisions at a centre-of-mass energy per nucleon pair of s NN = 5.02 TeV. Cross sections are presented in five different J/ ψ rapidity ranges within | y | < 4, with the J/ ψ reconstructed via its dilepton decay channels. In some events the J/ ψ is not accompanied by EMD, while other events do produce neutrons from EMD at beam rapidities either in one or the other beam direction, or in both. The cross sections in a given rapidity range and for different configurations of neutrons from EMD allow for the extraction of the energy dependence of this process in the range 17 < W γ Pb , n < 920 GeV, where W γ Pb , n is the centre-of-mass energy per nucleon of the γ Pb system. This range corresponds to a Bjorken- x interval spanning about three orders of magnitude: 1.1 × 10 − 5 < x < 3.3 × 10 − 2 . In addition to the ultra-peripheral and photonuclear cross sections, the nuclear suppression factor is obtained. These measurements point to a strong depletion of the gluon distribution in Pb nuclei over a broad, previously unexplored, energy range. These results, together with previous ALICE measurements, provide unprecedented information to probe quantum chromodynamics at high energies.

A bstract Systematic studies of charge-dependent two- and three-particle correlations in Pb-Pb collisions at s NN = 2.76 and 5.02 TeV used to probe the Chiral Magnetic Effect (CME) are presented. These measurements are performed for charged particles in the pseudorapidity ( η ) and transverse momentum ( p T ) ranges | η | < 0 . 8 and 0 . 2 < p T < 5 GeV/ c . A significant charge-dependent signal that becomes more pronounced for peripheral collisions is reported for the CME-sensitive correlators γ 1, 1  = 〈cos( φ α  +  φ β  − 2Ψ 2 )〉 and γ 1, − 3  = 〈cos( φ α  − 3 φ β  + 2Ψ 2 )〉. The results are used to estimate the contribution of background effects, associated with local charge conservation coupled to anisotropic flow modulations, to measurements of the CME. A blast-wave parametrisation that incorporates local charge conservation tuned to reproduce the centrality dependent background effects is not able to fully describe the measured γ 1 , 1 . Finally, the charge and centrality dependence of mixed-harmonics three-particle correlations, of the form γ 1, 2  = 〈cos( φ α  + 2 φ β  − 3Ψ 3 )〉, which are insensitive to the CME signal, verify again that background contributions dominate the measurement of γ 1 , 1 .

A bstract Measurement of Z-boson production in p-Pb collisions at s NN = 8 . 16 TeV and Pb-Pb collisions at s NN = 5 . 02 TeV is reported. It is performed in the dimuon decay channel, through the detection of muons with pseudorapidity − 4 < η μ < − 2 . 5 and transverse momentum p T μ > 20 GeV/ c in the laboratory frame. The invariant yield and nuclear modification factor are measured for opposite-sign dimuons with invariant mass 60 < m μμ < 120 GeV/ c 2 and rapidity 2 . 5 < y cms μμ < 4. They are presented as a function of rapidity and, for the Pb-Pb collisions, of centrality as well. The results are compared with theoretical calculations, both with and without nuclear modifications to the Parton Distribution Functions (PDFs). In p-Pb collisions the center-of-mass frame is boosted with respect to the laboratory frame, and the measurements cover the backward ( − 4 . 46 < y cms μμ < − 2 . 96) and forward (2 . 03 < y cms μμ < 3 . 53) rapidity regions. For the p-Pb collisions, the results are consistent within experimental and theoretical uncertainties with calculations that include both free-nucleon and nuclear-modified PDFs. For the Pb-Pb collisions, a 3 . 4 σ deviation is seen in the integrated yield between the data and calculations based on the free-nucleon PDFs, while good agreement is found once nuclear modifications are considered.

A bstract The fractions of non-prompt (i.e. originating from beauty-hadron decays) D 0 and D + mesons with respect to the inclusive yield are measured as a function of the charged-particle multiplicity in proton-proton collisions at a centre-of-mass energy of s = 13 TeV with the ALICE detector at the LHC. The results are reported in intervals of transverse momentum ( p T ) and integrated in the range 1 < p T < 24 GeV/ c . The fraction of non-prompt D 0 and D + mesons is found to increase slightly as a function of p T in all the measured multiplicity intervals, while no significant dependence on the charged-particle multiplicity is observed. In order to investigate the production and hadronisation mechanisms of charm and beauty quarks, the results are compared to PYTHIA 8 as well as EPOS 3 and EPOS 4 Monte Carlo simulations, and to calculations based on the colour glass condensate including three-pomeron fusion.

A bstract Inclusive J /ψ yields and average transverse momenta in p-Pb collisions at a center-of-mass energy per nucleon pair s NN = 8 . 16 TeV are measured as a function of the charged-particle pseudorapidity density with ALICE. The J /ψ mesons are reconstructed at forward (2 . 03 < y cms < 3 . 53) and backward ( − 4 . 46 < y cms < − 2 . 96) center-of-mass rapidity in their dimuon decay channel while the charged-particle pseudorapidity density is measured around midrapidity. The J /ψ yields at forward and backward rapidity normalized to their respective average values increase with the normalized charged-particle pseudorapidity density, the former showing a weaker increase than the latter. The normalized average transverse momenta at forward and backward rapidity manifest a steady increase from low to high charged-particle pseudorapidity density with a saturation beyond the average value.

The production yields of the Σ(1385) ± and Ξ(1530) 0 resonances are measured in pp collisions at$$ \\sqrt{s} $$s = 13 TeV with ALICE. The measurements are performed as a function of the charged-particle multiplicity ⟨d N ch / d η ⟩, which is related to the energy density produced in the collision. The results include transverse momentum ( p T ) distributions, p T -integrated yields, mean transverse momenta of Σ(1385) ± and Ξ(1530) 0 , as well as ratios of the p T -integrated resonance yields relative to yields of other hadron species. The Σ(1385) ± /π ± and Ξ(1530) 0 /π ± yield ratios are consistent with the trend of the enhancement of strangeness production from low to high multiplicity pp collisions, which was previously observed for strange and multi-strange baryons. The yield ratio between the measured resonances and the long-lived baryons with the same strangeness content exhibits a hint of a mild increasing trend at low multiplicity, despite too large uncertainties to exclude the flat behaviour. The results are compared with predictions from models such as EPOS-LHC and PYTHIA 8 with Rope shoving. The latter provides the best description of the multiplicity dependence of the Σ(1385) ± and Ξ(1530) 0 production in pp collisions at$$ \\sqrt{s} $$s = 13 TeV.

The production of strange hadrons ($$ {\\textrm{K}}_{\\textrm{S}}^0 $$K S 0 , Λ, Ξ ± , and Ω ± ), baryon-to-meson ratios (Λ /$$ {\\textrm{K}}_{\\textrm{S}}^0 $$K S 0 , Ξ /$$ {\\textrm{K}}_{\\textrm{S}}^0 $$K S 0 , and Ω /$$ {\\textrm{K}}_{\\textrm{S}}^0 $$K S 0 ), and baryon-to-baryon ratios (Ξ / Λ, Ω / Λ, and Ω / Ξ) associated with jets and the underlying event were measured as a function of transverse momentum ( p T ) in pp collisions at$$ \\sqrt{s} $$s = 13 TeV and p Pb collisions at$$ \\sqrt{s_{\\textrm{NN}}} $$s NN = 5 . 02 TeV with the ALICE detector at the LHC. The inclusive production of the same particle species and the corresponding ratios are also reported. The production of multi-strange hadrons, Ξ ± and Ω ± , and their associated particle ratios in jets and in the underlying event are measured for the first time. In both pp and p–Pb collisions, the baryon-to-meson and baryon-to-baryon yield ratios measured in jets differ from the inclusive particle production for low and intermediate hadron p T (0.6–6 GeV/ c ). Ratios measured in the underlying event are in turn similar to those measured for inclusive particle production. In pp collisions, the particle production in jets is compared with P ythia 8 predictions with three colour-reconnection implementation modes. None of them fully reproduces the data in the measured hadron p T region. The maximum deviation is observed for Ξ ± and Ω ± which reaches a factor of about six. The event multiplicity dependence is further investigated in p−Pb collisions. In contrast to what is observed in the underlying event, there is no significant event-multiplicity dependence for particle production in jets. The presented measurements provide novel constraints on hadronisation and its Monte Carlo description. In particular, they demonstrate that the fragmentation of jets alone is insufficient to describe the strange and multi-strange particle production in hadronic collisions at LHC energies.

The elliptic flow$$(v_2)$$( v 2 ) of$${\\textrm{D}}^{0}$$D 0 mesons from beauty-hadron decays (non-prompt$${\\textrm{D}}^{0})$$D 0 ) was measured in midcentral (30–50%) Pb–Pb collisions at a centre-of-mass energy per nucleon pair$$\\sqrt{s_{\\textrm{NN}}} = 5.02$$s NN = 5.02  TeV with the ALICE detector at the LHC. The$${\\textrm{D}}^{0}$$D 0 mesons were reconstructed at midrapidity$$(|y|<0.8)$$( | y | < 0.8 ) from their hadronic decay$$\\mathrm {D^0 \\rightarrow K^-\\uppi ^+}$$D 0 → K - π + , in the transverse momentum interval$$2< p_{\\textrm{T}} < 12$$2 < p T < 12  GeV/ c . The result indicates a positive$$v_2$$v 2 for non-prompt$${{\\textrm{D}}^{0}}$$D 0 mesons with a significance of 2.7$$\\sigma $$σ . The non-prompt$${{\\textrm{D}}^{0}}$$D 0 -meson$$v_2$$v 2 is lower than that of prompt non-strange D mesons with 3.2$$\\sigma $$σ significance in$$2< p_\\textrm{T} < 8~\\textrm{GeV}/c$$2 < p T < 8 GeV / c , and compatible with the$$v_2$$v 2 of beauty-decay electrons. Theoretical calculations of beauty-quark transport in a hydrodynamically expanding medium describe the measurement within uncertainties.

The measurement of the production of charm jets, identified by the presence of a D 0 meson in the jet constituents, is presented in proton–proton collisions at centre-of-mass energies of$$ \\sqrt{s} $$s = 5.02 and 13 TeV with the ALICE detector at the CERN LHC. The D 0 mesons were reconstructed from their hadronic decay D 0 → K − π + and the respective charge conjugate. Jets were reconstructed from D 0 -meson candidates and charged particles using the anti- k T algorithm, in the jet transverse momentum range 5 < p T , chjet < 50 GeV/ c , pseudorapidity | η jet | < 0 . 9 − R , and with the jet resolution parameters R = 0 . 2 , 0 . 4 , 0 . 6. The distribution of the jet momentum fraction carried by a D 0 meson along the jet axis$$ \\left({z}_{\\Big\\Vert}^{\\textrm{ch}}\\right) $$z ‖ ch was measured in the range 0 . 4 <$$ {z}_{\\Big\\Vert}^{\\textrm{ch}} $$z ‖ ch < 1 . 0 in four ranges of the jet transverse momentum. Comparisons of results for different collision energies and jet resolution parameters are also presented. The measurements are compared to predictions from Monte Carlo event generators based on leading-order and next-to-leading-order perturbative quantum chromodynamics calculations. A generally good description of the main features of the data is obtained in spite of a few discrepancies at low p T , chjet . Measurements were also done for R = 0 . 3 at$$ \\sqrt{s} $$s = 5 . 02 and are shown along with their comparisons to theoretical predictions in an appendix to this paper.

The azimuthal ($$\\Delta \\varphi $$Δ φ ) correlation distributions between heavy-flavor decay electrons and associated charged particles are measured in pp and p–Pb collisions at$$\\sqrt{s_{\\mathrm{{NN}}} = 5.02$$s NN = 5.02 TeV. Results are reported for electrons with transverse momentum$$4

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