Measurements of charged-particle production in pp, p$-$Pb, and Pb$-$Pb collisions in the toward, away, and transverse regions with the ALICE detector are discussed. These regions are defined event-by-event relative to the azimuthal direction of the charged trigger particle, which is the reconstructed particle with the largest transverse momentum ($p_{\mathrm{T}}^{\rm trig}$) in the range $8<p_{\mathrm{T}}^{\rm trig}<15$ GeV$/c$. The toward and away regions contain the primary and recoil jets, respectively; both regions are accompanied by the underlying event (UE). In contrast, the transverse region perpendicular to the direction of the trigger particle is dominated by the so-called UE dynamics, and includes also contributions from initial- and final-state radiation. The relative transverse activity classifier, $R_{\mathrm{T}}=N_{\mathrm{ch}}^{\mathrm{T}}/\langle N_{\mathrm{ch}}^{\mathrm{T}}\rangle$, is used to group events according to their UE activity, where $N_{\mathrm{ch}}^{\mathrm{T}}$ is the charged-particle multiplicity per event in the transverse region and $\langle N_{\mathrm{ch}}^{\mathrm{T}}\rangle$ is the mean value over the whole analysed sample. The energy dependence of the $R_{\mathrm{T}}$ distributions in pp collisions at $\sqrt{s}=2.76$, 5.02, 7, and 13 TeV is reported, exploring the Koba-Nielsen-Olesen (KNO) scaling properties of the multiplicity distributions. The first measurements of charged-particle $p_{\rm T}$ spectra as a function of $R_{\mathrm{T}}$ in the three azimuthal regions in pp, p$-$Pb, and Pb$-$Pb collisions at $\sqrt{s_{\rm NN}}=5.02$ TeV are also reported. Data are compared with predictions obtained from the event generators PYTHIA 8 and EPOS LHC. This set of measurements is expected to contribute to the understanding of the origin of collective-like effects in small collision systems (pp and p$-$Pb).

Measurements of the charge-dependent two-particle angular correlation function in proton-lead (pPb) collisions at a nucleon-nucleon center-of-mass energy of $\sqrt{s_\mathrm{NN}}$ = 8.16 TeV and lead-lead (PbPb) collisions at$\sqrt{s_\mathrm{NN}}$ = 5.02 TeV are reported. The pPb and PbPb datasets correspond to integrated luminosities of 186\nbinv and 0.607 nb$^{-1}$, respectively, and were collected using the CMS detector at the CERN LHC. The charge-dependent correlations are characterized by balance functions of same- and opposite-sign particle pairs. The balance functions, which contain information about the creation time of charged particle pairs and the development of collectivity, are studied as functions of relative pseudorapidity ($\Delta \eta$) and relative azimuthal angle ($\Delta \phi$), for various multiplicity and transverse momentum ($p_\mathrm{T}$) intervals. A multiplicity dependence of the balance function is observed in $\Delta \eta$ and $\Delta \phi$ for both systems. The width of the balance functions decreases towards high-multiplicity collisions in the momentum region $\lt$2 GeV, for pPb and PbPb results. No multiplicity dependence is observed at higher transverse momentum. The data are compared with HYDJET, HIJING and AMPT generator predictions, none of which capture completely the multiplicity dependence seen in the data.

The correlations between different moments of two flow amplitudes, extracted with the recently developed asymmetric cumulants, are measured in Pb$-$Pb collisions at $\sqrt{s_{\rm NN}} = 5.02$ TeV recorded by the ALICE detector at the CERN Large Hadron Collider. The magnitudes of the measured observables show a dependence on the different moments as well as on the collision centrality, indicating the presence of non-linear response in all even moments up to the eighth. Furthermore, the higher-order asymmetric cumulants show different signatures than the symmetric and lower-order asymmetric cumulants. Comparisons with state-of-the-art event generators using two different parametrizations obtained from Bayesian optimization show differences between data and simulations in many of the studied observables, indicating a need for further tuning of the models behind those event generators. These results provide new and independent constraints on the initial conditions and transport properties of the system created in heavy-ion collisions.

The production of $\pi^\pm$, ${\rm K}^\pm$, and $(\overline{\rm p})$p is measured in pp collisions at $\sqrt{s}=13$ TeV in different topological regions. Particle transverse momentum ($p_{\rm T}$) spectra are measured in the ``toward'', ``transverse'', and ``away'' angular regions defined with respect to the direction of the leading particle in the event. While the toward and away regions contain the fragmentation products of the near-side and away-side jets, respectively, the transverse region is dominated by particles from the Underlying Event (UE). The relative transverse activity classifier, $R_{\rm T}=N_{\rm T}/\langle N_{\rm T}\rangle$, is used to group events according to their UE activity, where $N_{\rm T}$ is the measured charged-particle multiplicity per event in the transverse region and $\langle N_{\rm T}\rangle$ is the mean value over all the analysed events. The first measurements of identified particle $p_{\rm T}$ spectra as a function of $R_{\rm T}$ in the three topological regions are reported. The yield of high transverse momentum particles relative to the $R_{\rm T}$-integrated measurement decreases with increasing $R_{\rm T}$ in both the toward and away regions, indicating that the softer UE dominates particle production as $R_{\rm T}$ increases and validating that $R_{\rm T}$ can be used to control the magnitude of the UE. Conversely, the spectral shapes in the transverse region harden significantly with increasing $R_{\rm T}$. This hardening follows a mass ordering, being more significant for heavier particles. The $p_{\rm T}$-differential particle ratios $({\rm p+\overline{p}})/(\pi^+ +\pi^-)$ and $({\rm K^+ +K^-})/(\pi^+ +\pi^-)$ in the low UE limit $(R_{\rm T}\rightarrow 0)$ approach expectations from Monte Carlo generators such as PYTHIA 8 with Monash 2013 tune and EPOS LHC, where the jet-fragmentation models have been tuned to reproduce ${\rm e^+ e^-}$ results.

Measurements of (anti)proton, (anti)deuteron, and (anti)$^3$He production in the rapidity range $-1<y< 0$ as a function of the transverse momentum and event multiplicity in p-Pb collisions at a center-of-mass energy per nucleon-nucleon pair $\sqrt{s_{\rm NN}} = 8.16$ TeV are presented. The coalescence parameters $B_2$ and $B_3$, measured as a function of the transverse momentum per nucleon and of the mean charged-particle multiplicity density, confirm a smooth evolution from low to high multiplicity across different collision systems and energies. The ratios between (anti)deuteron and (anti)$^3$He yields and those of (anti)protons are also reported as a function of the mean charged-particle multiplicity density. A comparison with the predictions of the statistical hadronization and coalescence models for different collision systems and center-of-mass energies favors the coalescence description for the deuteron-to-proton yield ratio with respect to the canonical statistical model.

This paper presents measurements of charged-hadron spectra obtained in $pp$, $p$+Pb, and Pb+Pb collisions at $\sqrt{s}$ or $\sqrt{s_{_\text{NN}}}=5.02$ TeV, and in Xe+Xe collisions at $\sqrt{s_{_\text{NN}}}=5.44$ TeV. The data recorded by the ATLAS detector at the LHC have total integrated luminosities of 25 pb${}^{-1}$, 28 nb${}^{-1}$, 0.50 nb${}^{-1}$, and 3 $\mu$b${}^{-1}$, respectively. The nuclear modification factors $R_{p\text{Pb}}$ and $R_\text{AA}$ are obtained by comparing the spectra in heavy-ion and $pp$ collisions in a wide range of charged-particle transverse momenta and pseudorapidity. The nuclear modification factor $R_{p\text{Pb}}$ shows a moderate enhancement above unity with a maximum at $p_{\mathrm{T}} \approx 3$ GeV; the enhancement is stronger in the Pb-going direction. The nuclear modification factors in both Pb+Pb and Xe+Xe collisions feature a significant, centrality-dependent suppression. They show a similar distinct $p_{\mathrm{T}}$-dependence with a local maximum at $p_{\mathrm{T}} \approx 2$ GeV and a local minimum at $p_{\mathrm{T}} \approx 7$ GeV. This dependence is more distinguishable in more central collisions. No significant $|\eta|$-dependence is found. A comprehensive comparison with several theoretical predictions is also provided. They typically describe $R_\text{AA}$ better in central collisions and in the $p_{\mathrm{T}}$ range from about 10 to 100 GeV.

This article reports measurements of the angle between differently defined jet axes in pp collisions at $\sqrt{s} = 5.02$ TeV carried out by the ALICE Collaboration. Charged particles at midrapidity are clustered into jets with resolution parameters $R=0.2$ and 0.4. The jet axis, before and after Soft Drop grooming, is compared to the jet axis from the Winner-Takes-All (WTA) recombination scheme. The angle between these axes, $\Delta R_{\mathrm{axis}}$, probes a wide phase space of the jet formation and evolution, ranging from the initial high-momentum-transfer scattering to the hadronization process. The $\Delta R_{\mathrm{axis}}$ observable is presented for $20 < {p_{\mathrm{T}}^{\mathrm{ch\; jet}}}< 100$ GeV/$c$, and compared to predictions from the PYTHIA 8 and Herwig 7 event generators. The distributions can also be calculated analytically with a leading hadronization correction related to the non-perturbative component of the Collins$-$Soper$-$Sterman (CSS) evolution kernel. Comparisons to analytical predictions at next-to-leading-logarithmic accuracy with leading hadronization correction implemented from experimental extractions of the CSS kernel in Drell$-$Yan measurements are presented. The analytical predictions describe the measured data within 20% in the perturbative regime, with surprising agreement in the non-perturbative regime as well. These results are compatible with the universality of the CSS kernel in the context of jet substructure.

We report the measurement of $K^{*0}$ meson at midrapidity ($|y|<$ 1.0) in Au+Au collisions at $\sqrt{s_{\rm NN}}$~=~7.7, 11.5, 14.5, 19.6, 27 and 39 GeV collected by the STAR experiment during the RHIC beam energy scan (BES) program. The transverse momentum spectra, yield, and average transverse momentum of $K^{*0}$ are presented as functions of collision centrality and beam energy. The $K^{*0}/K$ yield ratios are presented for different collision centrality intervals and beam energies. The $K^{*0}/K$ ratio in heavy-ion collisions are observed to be smaller than that in small system collisions (e+e and p+p). The $K^{*0}/K$ ratio follows a similar centrality dependence to that observed in previous RHIC and LHC measurements. The data favor the scenario of the dominance of hadronic re-scattering over regeneration for $K^{*0}$ production in the hadronic phase of the medium.

We report the triton ($t$) production in mid-rapidity ($|y| <$ 0.5) Au+Au collisions at $\sqrt{s_\mathrm{NN}}$= 7.7--200 GeV measured by the STAR experiment from the first phase of the beam energy scan at the Relativistic Heavy Ion Collider (RHIC). The nuclear compound yield ratio ($\mathrm{N}_t \times \mathrm{N}_p/\mathrm{N}_d^2$), which is predicted to be sensitive to the fluctuation of local neutron density, is observed to decrease monotonically with increasing charged-particle multiplicity ($dN_{ch}/d\eta$) and follows a scaling behavior. The $dN_{ch}/d\eta$ dependence of the yield ratio is compared to calculations from coalescence and thermal models. Enhancements in the yield ratios relative to the coalescence baseline are observed in the 0%-10% most central collisions at 19.6 and 27 GeV, with a significance of 2.3$\sigma$ and 3.4$\sigma$, respectively, giving a combined significance of 4.1$\sigma$. The enhancements are not observed in peripheral collisions or model calculations without critical fluctuation, and decreases with a smaller $p_{T}$ acceptance. The physics implications of these results on the QCD phase structure and the production mechanism of light nuclei in heavy-ion collisions are discussed.

The first measurements of elliptic flow of $\pi^\pm$, ${\rm K}^\pm$, p+$\overline{\rm p}$, ${\rm K_{S}^0}$, $\Lambda$+$\overline{\Lambda}$, $\phi$, $\Xi^-$+$\Xi^+$, and $\Omega^-$+$\Omega^+$ using multiparticle cumulants in Pb$-$Pb collisions at $\sqrt{s_{\rm NN}}$ = 5.02 TeV are presented. Results obtained with two- ($v_2\{2\}$) and four-particle cumulants ($v_2\{4\}$) are shown as a function of transverse momentum, $p_{\rm T}$, for various collision centrality intervals. Combining the data for both $v_2\{2\}$ and $v_2\{4\}$ also allows us to report the first measurements of the mean elliptic flow, elliptic flow fluctuations, and relative elliptic flow fluctuations for various hadron species. These observables probe the event-by-event eccentricity fluctuations in the initial state and the contributions from the dynamic evolution of the expanding quark-gluon plasma. The characteristic features observed in previous $p_{\rm T}$-differential anisotropic flow measurements for identified hadrons with two-particle correlations, namely the mass ordering at low $p_{\rm T}$ and the approximate scaling with the number of constituent quarks at intermediate $p_{\rm T}$, are similarly present in the four-particle correlations and the combinations of $v_2\{2\}$ and $v_2\{4\}$. In addition, a particle species dependence of flow fluctuations is observed that could indicate a significant contribution from final state hadronic interactions. The comparison between experimental measurements and CoLBT model calculations, which combine the various physics processes of hydrodynamics, quark coalescence, and jet fragmentation, illustrates their importance over a wide $p_{\rm T}$ range.

Azimuthal anisotropy of produced particles is one of the most important observables used to access the collective properties of the expanding medium created in relativistic heavy-ion collisions. In this paper, we present second ($v_{2}$) and third ($v_{3}$) order azimuthal anisotropies of $K_{S}^{0}$, $\phi$, $\Lambda$, $\Xi$ and $\Omega$ at mid-rapidity ($|y|<$1) in Au+Au collisions at $\sqrt{s_{\text{NN}}}$ = 54.4 GeV measured by the STAR detector. The $v_{2}$ and $v_{3}$ are measured as a function of transverse momentum and centrality. Their energy dependence is also studied. $v_{3}$ is found to be more sensitive to the change in the center-of-mass energy than $v_{2}$. Scaling by constituent quark number is found to hold for $v_{2}$ within 10%. This observation could be evidence for the development of partonic collectivity in 54.4 GeV Au+Au collisions. Differences in $v_{2}$ and $v_{3}$ between baryons and anti-baryons are presented, and ratios of $v_{3}$/$v_{2}^{3/2}$ are studied and motivated by hydrodynamical calculations. The ratio of $v_{2}$ of $\phi$ mesons to that of anti-protons ($v_{2}(\phi)/v_{2}(\bar{p})$) shows centrality dependence at low transverse momentum, presumably resulting from the larger effects from hadronic interactions on anti-proton $v_{2}$.

The correlations between flow harmonics $v_n$ for $n=2$, 3 and 4 and mean transverse momentum $[p_\mathrm{T}]$ in $^{129}$Xe+$^{129}$Xe and $^{208}$Pb+$^{208}$Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.44$ TeV and 5.02 TeV, respectively, are measured using charged particles with the ATLAS detector. The correlations are sensitive to the shape and size of the initial geometry, nuclear deformation, and initial momentum anisotropy. The effects from non-flow and centrality fluctuations are minimized, respectively, via a subevent cumulant method and event activity selection based on particle production in the very forward rapidity. The results show strong dependences on centrality, harmonic number $n$, $p_{\mathrm{T}}$ and pseudorapidity range. Current models describe qualitatively the overall centrality- and system-dependent trends but fail to quantitatively reproduce all the data. In the central collisions, where models generally show good agreement, the $v_2$-$[p_\mathrm{T}]$ correlations are sensitive to the triaxiality of the quadruple deformation. The comparison of model to the Pb+Pb and Xe+Xe data suggests that the $^{129}$Xe nucleus is a highly deformed triaxial ellipsoid that is neither a prolate nor an oblate shape. This provides strong evidence for a triaxial deformation of $^{129}$Xe nucleus using high-energy heavy-ion collision.

The transverse-momentum ($p_{\rm T}$) spectra of ${\rm K}^*(892)^0$ and $\phi(1020)$ measured with the ALICE detector up to $p_{\rm T}$ = 16 GeV/$c$ in the rapidity range $-1.2 < y < 0.3$, in p-Pb collisions at the center-of-mass energy per nucleon-nucleon collision $\sqrt{s_{\rm NN}}$ = 5.02 TeV are presented as a function of charged particle multiplicity and rapidity. The measured $p_{\rm T}$ distributions show a dependence on both multiplicity and rapidity at low $p_{\rm T}$ whereas no significant dependence is observed at high $p_{\rm T}$. A rapidity dependence is observed in the $p_{\rm T}$-integrated yield (d$N$/d$y$), whereas the mean transverse momentum ($\left< p_{\rm T} \right>$) shows a flat behavior as a function of rapidity. The rapidity asymmetry ($Y_{\rm asym}$) at low $p_{\rm T}$ ( < 5 GeV/$c$) is more significant for higher multiplicity classes. At high $p_{\rm T}$, no significant rapidity asymmetry is observed in any of the multiplicity classes. Both ${\rm K}^*(892)^0$ and $\phi(1020)$ show similar $Y_{\rm asym}$. The nuclear modification factor ($Q_{\rm CP}$) as a function of $p_{\rm T}$ shows a Cronin-like enhancement at intermediate $p_{\rm T}$, which is more prominent at higher rapidities (Pb-going direction) and in higher multiplicity classes. At high $p_{\rm T}$ (> 5 GeV/$c$), the $Q_{\rm CP}$ values are greater than unity and no significant rapidity dependence is observed.

Production cross sections of $\Upsilon$(1S), $\Upsilon$(2S), and $\Upsilon$(3S) states decaying into $\mu^+\mu^-$ in proton-lead (pPb) collisions are reported using data collected by the CMS experiment at $\sqrt{s_\mathrm{NN}} =$ 5.02 TeV. A comparison is made with corresponding cross sections obtained with pp data measured at the same collision energy and scaled by the Pb nucleus mass number. The nuclear modification factor for $\Upsilon$(1S) is found to be $R_\mathrm{pPb}(\Upsilon(1S))$ = 0.806 $\pm$ 0.024 (stat) $\pm$ 0.059 (syst). Similar results for the excited states indicate a sequential suppression pattern, such that $R_\mathrm{pPb}(\Upsilon(1S))$$\gt$$R_\mathrm{pPb}(\Upsilon(2S))$$\gt$$R_\mathrm{pPb}(\Upsilon(3S))$. The suppression is much less pronounced in pPb than in PbPb collisions, and independent of transverse momentum $p_\mathrm{T}^\Upsilon$ and center-of-mass rapidity $y_\mathrm{CM}^\Upsilon$ of the individual $\Upsilon$ state in the studied range $p_\mathrm{T}^\Upsilon$$\lt$ 30 GeV$/c$ and $\vert y_\mathrm{CM}^\Upsilon\vert$$\lt$ 1.93. Models that incorporate sequential suppression of bottomonia in pPb collisions are in better agreement with the data than those which only assume initial-state modifications.

Angular correlations of heavy-flavour and charged particles in high-energy proton-proton collisions are sensitive to the production mechanisms of heavy quarks and to their fragmentation as well as hadronisation processes. The measurement of the azimuthal-correlation function of prompt D mesons with charged particles in proton-proton collisions at a centre-of-mass energy of $\sqrt{s} = 13$ TeV with the ALICE detector is reported, considering D$^{0}$, D$^{+}$, and D$^{*+}$ mesons in the transverse-momentum interval $3 < p_{\rm T} < 36$ GeV/$c$ at midrapidity ($|y| < 0.5$), and charged particles with $p_{\rm T} > 0.3$ GeV/$c$ and pseudorapidity $|\eta| < 0.8$. This measurement has an improved precision and provides an extended transverse-momentum coverage compared to previous ALICE measurements at lower energies. The study is also performed as a function of the charged-particle multiplicity, showing no modifications of the correlation function with multiplicity within uncertainties. The properties and the transverse-momentum evolution of the near- and away-side correlation peaks are studied and compared with predictions from various Monte Carlo event generators. Among those considered, PYTHIA8 and POWHEG+PYTHIA8 provide the best description of the measured observables. The obtained results can provide guidance on tuning the generators.

The production of $\mathrm{K}^{*}(\mathrm{892})^{0}$ and $\mathrm{\phi(1020)}$ resonances has been measured in p-Pb collisions at $\sqrt{s_{\rm NN}}$ = 8.16 TeV using the ALICE detector. Resonances are reconstructed via their hadronic decay channels in the rapidity interval $-$0.5 $<$$y$$<$ 0 and the transverse momentum spectra are measured for various multiplicity classes up to $p_{\rm T}$ = 20 GeV/$c$ for $\mathrm{K}^{*}(\mathrm{892})^{0}$ and $p_{\rm T}$ = 16 GeV/$c$ for $\mathrm{\phi(1020)}$. The $p_{\rm T}$ -integrated yields and mean transverse momenta are reported and compared with previous results in pp, p-Pb and Pb-Pb collisions. The $x_{\mathrm{T}}$ scaling for $\mathrm{K}^{*}(\mathrm{892})^{0}$ and $\mathrm{\phi(1020)}$ resonance production is newly tested in p-Pb collisions and found to hold in the high-$p_{\rm T}$ region at LHC energies. The nuclear modification factors ($R_{\rm pPb}$) as a function of $p_{\rm T}$ for $\mathrm{K}^{*0}$ and $\mathrm{\phi}$ at $\sqrt{s_{NN}}$ = 8.16 TeV are presented along with the new $R_{\rm pPb}$ measurements of $\mathrm{K}^{*0}$, $\mathrm{\phi}$ , $\Xi$, and $\Omega$ at $\sqrt{s_{\rm NN}}$ = 5.02 TeV. At intermediate $p_{\rm T}$ (2-8 GeV/$c$), $R_{\rm pPb}$ of $\Xi$, $\Omega$ show a Cronin-like enhancement, while $\mathrm{K}^{*0}$ and $\mathrm{\phi}$ show no or little nuclear modification. At high $p_{\rm T}$ ($>$ 8 GeV/$c$), the $R_{\rm pPb}$ values of all hadrons are consistent with unity within uncertainties. The $R_{\rm pPb}$ of $\mathrm{K}^{*}(\mathrm{892})^{0}$ and $\mathrm{\phi(1020)}$ at $\sqrt{s_{\rm NN}}$ = 8.16 and 5.02 TeV show no significant energy dependence.

The chiral magnetic effect (CME) is predicted to occur as a consequence of a local violation of $\cal P$ and $\cal CP$ symmetries of the strong interaction amidst a strong electro-magnetic field generated in relativistic heavy-ion collisions. Experimental manifestation of the CME involves a separation of positively and negatively charged hadrons along the direction of the magnetic field. Previous measurements of the CME-sensitive charge-separation observables remain inconclusive because of large background contributions. In order to better control the influence of signal and backgrounds, the STAR Collaboration performed a blind analysis of a large data sample of approximately 3.8 billion isobar collisions of $^{96}_{44}$Ru+$^{96}_{44}$Ru and $^{96}_{40}$Zr+$^{96}_{40}$Zr at $\sqrt{s_{\rm NN}}=200$ GeV. Prior to the blind analysis, the CME signatures are predefined as a significant excess of the CME-sensitive observables in Ru+Ru collisions over those in Zr+Zr collisions, owing to a larger magnetic field in the former. A precision down to 0.4% is achieved, as anticipated, in the relative magnitudes of the pertinent observables between the two isobar systems. Observed differences in the multiplicity and flow harmonics at the matching centrality indicate that the magnitude of the CME background is different between the two species. No CME signature that satisfies the predefined criteria has been observed in isobar collisions in this blind analysis.

The jet angularities are a class of jet substructure observables which characterize the angular and momentum distribution of particles within jets. These observables are sensitive to momentum scales ranging from perturbative hard scatterings to nonperturbative fragmentation into final-state hadrons. We report measurements of several groomed and ungroomed jet angularities in pp collisions at $\sqrt{s}=5.02$ TeV with the ALICE detector. Jets are reconstructed using charged particle tracks at midrapidity ($|\eta| < 0.9$). The anti-$k_{\rm T}$ algorithm is used with jet resolution parameters $R=0.2$ and $R=0.4$ for several transverse momentum $p_{\rm T}^{\text{ch jet}}$ intervals in the 20$-$100 GeV/$c$ range. Using the jet grooming algorithm Soft Drop, the sensitivity to softer, wide-angle processes, as well as the underlying event, can be reduced in a way which is well-controlled in theoretical calculations. We report the ungroomed jet angularities, $\lambda_{\alpha}$, and groomed jet angularities, $\lambda_{\alpha\text{,g}}$, to investigate the interplay between perturbative and nonperturbative effects at low jet momenta. Various angular exponent parameters $\alpha = 1$, 1.5, 2, and 3 are used to systematically vary the sensitivity of the observable to collinear and soft radiation. Results are compared to analytical predictions at next-to-leading-logarithmic accuracy, which provide a generally good description of the data in the perturbative regime but exhibit discrepancies in the nonperturbative regime. Moreover, these measurements serve as a baseline for future ones in heavy-ion collisions by providing new insight into the interplay between perturbative and nonperturbative effects in the angular and momentum substructure of jets. They supply crucial guidance on the selection of jet resolution parameter, jet transverse momentum, and angular scaling variable for jet quenching studies.

Measurements of elliptic ($v_2$) and triangular ($v_3$) flow coefficients of $\pi^{\pm}$, K$^{\pm}$, p+$\rm \overline{p}$, K$^0_{\rm S}$, and $\Lambda + \overline{\Lambda}$ obtained with the scalar product method in Xe-Xe collisions at $\sqrt{s_{\rm NN}}$ = 5.44 TeV are presented. The results are obtained in the rapidity range $\left | y \right |<0.5$ and reported as a function of transverse momentum, $p_{\rm T}$, for several collision centrality classes. The flow coefficients exhibit a particle mass dependence for $p_{\rm T}<3$ GeV/$c$, while a grouping according to particle type (i.e., meson and baryon) is found at intermediate transverse momenta (3< $p_{\rm T}$ <8 GeV/$c$). The magnitude of the baryon $v_{2}$ is larger than that of mesons up to $p_{\rm T}$ = 6 GeV/$c$. The centrality dependence of the shape evolution of the $p_{\rm T}$-differential $v_2$ is studied for the various hadron species. The $v_2$ coefficients of $\pi^{\pm}$, K$^{\pm}$, and p+$\rm \overline{p}$ are reproduced by MUSIC hydrodynamic calculations coupled to a hadronic cascade model (UrQMD) for $p_{\rm T} <1$ GeV/$c$. A comparison with $v_{\rm n}$ measurements in the corresponding centrality intervals in Pb-Pb collisions at $\sqrt{s_{\rm NN}}$ = 5.02 TeV yields an enhanced $v_2$ in central collisions and diminished value in semicentral collisions.

The production of K$^{*}(892)^{0}$ and $\phi(1020)$ mesons in proton-proton (pp) and lead-lead (Pb-Pb) collisions at $\sqrt{s_\mathrm{NN}} = 5.02$ TeV has been measured using the ALICE detector at the Large Hadron Collider (LHC). The transverse momentum ($p_{\mathrm{T}}$) distributions of K$^{*}(892)^{0}$ and $\phi(1020)$ mesons have been measured at midrapidity $(|y|<0.5)$ up to $p_{\mathrm{T}} = 20$ GeV$/c$ in inelastic pp collisions and for several Pb-Pb collision centralities. The collision centrality and collision energy dependence of the average transverse momenta agree with the radial flow scenario observed with stable hadrons, showing that the effect is stronger for more central collisions and higher collision energies. The $\mathrm{K^{*0}/K}$ ratio is found to be suppressed in Pb-Pb collisions relative to pp collisions: this indicates a loss of the measured K$^{*}(892)^{0}$ signal due to rescattering of its decay products in the hadronic phase. In contrast, for the longer-lived $\phi(1020)$ mesons, no such suppression is observed. The nuclear modification factors ($R_{\rm AA}$) of K$^{*}(892)^{0}$ and $\phi(1020)$ mesons are calculated using pp reference spectra at the same collision energy. In central Pb-Pb collisions for $p_{\rm T} > 8$ GeV$/c$, the $R_{\rm AA}$ values of K$^{*}(892)^{0}$ and $\phi(1020)$ are below unity and observed to be similar to those of pions, kaons, and (anti)protons. The $R_{\rm AA}$ values at high $p_{\mathrm T}$ ($>$~8 GeV$/c$) for K$^{*}(892)^{0}$ and $\phi(1020)$ mesons are in agreement within uncertainties for $\sqrt{s_\mathrm{NN}} = 5.02$ and 2.76 TeV.

The spectra measurements of charged hadrons produced in the shower of a parton originating in the same hard scattering with a leptonically decaying Z boson, are reported in lead-lead (PbPb) and proton-proton (pp) collisions at a nucleon-nucleon center-of-mass energy of 5.02 TeV. Both PbPb and pp data sets are recorded by the CMS experiment at the LHC, and correspond to an integrated luminosity of 1.7 nb$^{-1}$ and 320 pb$^{-1}$, respectively. Hadronic collision data with one reconstructed Z boson candidate with the transverse momentum $p_\mathrm{T}$$\gt$ 30 GeV/$c$ are analyzed. The Z boson constrains the initial energy and direction of the associated parton. In heavy ion events, azimuthal angular distributions of charged hadrons with respect to the direction of a Z boson are sensitive to modifications of the in-medium parton shower and medium response. Compared to reference data from pp interactions, the results for central PbPb collisions indicate a modification of the angular correlations. The measurements of the fragmentation functions and $p_\mathrm{T}$ spectra of charged particles in Z boson events, which are sensitive to medium modifications of the parton shower longitudinal structure, are also reported. Significant modifications in central PbPb events compared to pp reference data are also found for these observables.

Differential cross sections for the Drell-Yan process, including Z boson production, using the dimuon decay channel are measured in proton-lead (pPb) collisions at a nucleon-nucleon centre-of-mass energy of 8.16 TeV. A data sample recorded with the CMS detector at the LHC is used, corresponding to an integrated luminosity of 173 nb$^{-1}$. The differential cross section as a function of the dimuon mass is measured in the range 15-600 GeV, for the first time in proton-nucleus collisions. It is also reported as a function of dimuon rapidity over the mass ranges 15-60 GeV and 60-120 GeV, and ratios for the p-going over the Pb-going beam directions are built. In both mass ranges, the differential cross sections as functions of the dimuon transverse momentum $p_\mathrm{T}$ and of a geometric variable $\phi^*$ are measured, where $\phi^*$ highly correlates with $p_\mathrm{T}$ but is determined with higher precision. In the Z mass region, the rapidity dependence of the data indicate a modification of the distribution of partons within a lead nucleus as compared to the proton case. The data are more precise than predictions based upon current models of parton distributions.

Modifications to the distribution of charged particles with respect to high transverse momentum ($p_\mathrm{T}$) jets passing through a quark-gluon plasma are explored using the CMS detector. Back-to-back dijets are analyzed in lead-lead and proton-proton collisions at $\sqrt{s_\mathrm{NN}} =$ 5.02 TeV via correlations of charged particles in bins of relative pseudorapidity and angular distance from the leading and subleading jet axes. In comparing the lead-lead and proton-proton collision results, modifications to the charged-particle relative distance distribution and to the momentum distributions around the jet axis are found to depend on the dijet momentum balance $x_j$, which is the ratio between the subleading and leading jet $p_\mathrm{T}$. For events with $x_j$$\approx$ 1, these modifications are observed for both the leading and subleading jets. However, while subleading jets show significant modifications for events with a larger dijet momentum imbalance, much smaller modifications are found for the leading jets in these events.

The first measurement of the production of pions, kaons, (anti-)protons and $\phi$ mesons at midrapidity in Xe-Xe collisions at $\sqrt{s_{\rm NN}} = 5.44$ TeV is presented. Transverse momentum ($p_{\rm T}$) spectra and $p_{\rm T}$-integrated yields are extracted in several centrality intervals bridging from p-Pb to mid-central Pb-Pb collisions in terms of final-state multiplicity. The study of Xe-Xe and Pb-Pb collisions allows systems at similar charged-particle multiplicities but with different initial geometrical eccentricities to be investigated. A detailed comparison of the spectral shapes in the two systems reveals an opposite behaviour for radial and elliptic flow. In particular, this study shows that the radial flow does not depend on the colliding system when compared at similar charged-particle multiplicity. In terms of hadron chemistry, the previously observed smooth evolution of particle ratios with multiplicity from small to large collision systems is also found to hold in Xe-Xe. In addition, our results confirm that two remarkable features of particle production at LHC energies are also valid in the collision of medium-sized nuclei: the lower proton-to-pion ratio with respect to the thermal model expectations and the increase of the $\phi$-to-pion ratio with increasing final-state multiplicity.

The NA61/SHINE experiment at the CERN Super Proton Synchrotron (SPS) studies the onset of deconfinement in hadron matter by a scan of particle production in collisions of nuclei with various sizes at a set of energies covering the SPS energy range. This paper presents results on inclusive double-differential spectra, transverse momentum and rapidity distributions and mean multiplicities of $\pi^\pm$, $K^\pm$, $p$ and $\bar{p}$ produced in the 20$\%$ most $central$$^7$Be+$^9$Be collisions at beam momenta of 19$A$, 30$A$, 40$A$, 75$A$ and 150$A$ GeV/$c$. The energy dependence of the $K^\pm$/$\pi^\pm$ ratios as well as of inverse slope parameters of the $K^\pm$ transverse mass distributions are close to those found in inelastic $p$+$p$ reactions. The new results are compared to the world data on $p$+$p$ and Pb+Pb collisions as well as to predictions of the EPOS, UrQMD, AMPT, PHSD and SMASH models.

The inclusive production of the J/$\psi$ and $\psi$(2S) charmonium states is studied as a function of centrality in p-Pb collisions at a centre-of-mass energy per nucleon pair $\sqrt{s_{\rm NN}} = 8.16$ TeV at the LHC. The measurement is performed in the dimuon decay channel with the ALICE apparatus in the centre-of-mass rapidity intervals $-4.46 < y_{\rm cms} < -2.96$ (Pb-going direction) and $2.03 < y_{\rm cms} < 3.53$ (p-going direction), down to zero transverse momentum ($p_{\rm T}$). The J/$\psi$ and $\psi$(2S) production cross sections are evaluated as a function of the collision centrality, estimated through the energy deposited in the zero degree calorimeter located in the Pb-going direction. The $p_{\rm T}$-differential J/$\psi$ production cross section is measured at backward and forward rapidity for several centrality classes, together with the corresponding average $\langle p_{\rm T} \rangle$ and $\langle p^{2}_{\rm T} \rangle$ values. The nuclear effects affecting the production of both charmonium states are studied using the nuclear modification factor. In the p-going direction, a suppression of the production of both charmonium states is observed, which seems to increase from peripheral to central collisions. In the Pb-going direction, however, the centrality dependence is different for the two states: the nuclear modification factor of the J/$\psi$ increases from below unity in peripheral collisions to above unity in central collisions, while for the $\psi$(2S) it stays below or consistent with unity for all centralities with no significant centrality dependence. The results are compared with measurements in p-Pb collisions at $\sqrt{s_{\rm NN}} = 5.02$ TeV and no significant dependence on the energy of the collision is observed. Finally, the results are compared with theoretical models implementing various nuclear matter effects.

The STAR Collaboration at the Relativistic Heavy Ion Collider reports the first measurement of inclusive jet production in peripheral and central Au+Au collisions at $\sqrt{s_{NN}}$=200 GeV. Jets are reconstructed with the anti-k$_{T}$ algorithm using charged tracks with pseudorapidity $|\eta|<1.0$ and transverse momentum $0.2<p_{T,jet}^{ch}<30$ GeV/$c$, with jet resolution parameter $R$=0.2, 0.3, and 0.4. The large background yield uncorrelated with the jet signal is observed to be dominated by statistical phase space, consistent with a previous coincidence measurement. This background is suppressed by requiring a high-transverse-momentum (high-$p_T$) leading hadron in accepted jet candidates. The bias imposed by this requirement is assessed, and the $p_T$ region in which the bias is small is identified. Inclusive charged-particle jet distributions are reported in peripheral and central Au+Au collisions for $5<p_{T,jet}^{ch}<25$ GeV/$c$ and $5<p_{T,jet}^{ch}<30$ GeV/$c$, respectively. The charged-particle jet inclusive yield is suppressed for central Au+Au collisions, compared to both the peripheral Au+Au yield from this measurement and to the $pp$ yield calculated using the PYTHIA event generator. The magnitude of the suppression is consistent with that of inclusive hadron production at high $p_T$, and that of semi-inclusive recoil jet yield when expressed in terms of energy loss due to medium-induced energy transport. Comparison of inclusive charged-particle jet yields for different values of $R$ exhibits no significant evidence for medium-induced broadening of the transverse jet profile for $R<0.4$ in central Au+Au collisions. The measured distributions are consistent with theoretical model calculations that incorporate jet quenching.

The PHENIX experiment at the Relativistic Heavy Ion Collider measured $\pi^0$ and $\eta$ mesons at midrapidity in U$+$U collisions at $\sqrt{s_{_{NN}}}=192$ GeV in a wide transverse momentum range. Measurements were performed in the $\pi^0(\eta)\rightarrow\gamma\gamma$ decay modes. A strong suppression of $\pi^0$ and $\eta$ meson production at high transverse momentum was observed in central U$+$U collisions relative to binary scaled $p$$+$$p$ results. Yields of $\pi^0$ and $\eta$ mesons measured in U$+$U collisions show similar suppression pattern to the ones measured in Au$+$Au collisions at $\sqrt{s_{_{NN}}}=200$ GeV for similar numbers of participant nucleons. The $\eta$/$\pi^0$ ratios do not show dependence on centrality or transverse momentum, and are consistent with previously measured values in hadron-hadron, hadron-nucleus, nucleus-nucleus, and $e^+e^-$ collisions.

The production of $\pi^{\pm}$, $\rm{K}^{\pm}$, $\rm{K}^{0}_{S}$, $\rm{K}^{*}(892)^{0}$, $\rm{p}$, $\phi(1020)$, $\Lambda$, $\Xi^{-}$, $\Omega^{-}$, and their antiparticles was measured in inelastic proton-proton (pp) collisions at a center-of-mass energy of $\sqrt{s}$ = 13 TeV at midrapidity ($|y|<0.5$) as a function of transverse momentum ($p_{\rm{T}}$) using the ALICE detector at the CERN LHC. Furthermore, the single-particle $p_{\rm{T}}$ distributions of $\rm{K}^{0}_{S}$, $\Lambda$, and $\overline{\Lambda}$ in inelastic pp collisions at $\sqrt{s}$ = 7 TeV are reported here for the first time. The $p_{\rm{T}}$ distributions are studied at midrapidity within the transverse momentum range $0\leq p_{\rm{T}}\leq20$ GeV/$c$, depending on the particle species. The $p_{\rm{T}}$ spectra, integrated yields, and particle yield ratios are discussed as a function of collision energy and compared with measurements at lower $\sqrt{s}$ and with results from various general-purpose QCD-inspired Monte Carlo models. A hardening of the spectra at high $p_{\rm{T}}$ with increasing collision energy is observed, which is similar for all particle species under study. The transverse mass and $x_{\rm{T}}\equiv2p_{\rm{T}}/\sqrt{s}$ scaling properties of hadron production are also studied. As the collision energy increases from $\sqrt{s}$ = 7 to 13 TeV, the yields of non- and single-strange hadrons normalized to the pion yields remain approximately constant as a function of $\sqrt{s}$, while ratios for multi-strange hadrons indicate enhancements. The $p_{\rm{T}}$-differential cross sections of $\pi^{\pm}$, $\rm{K}^{\pm}$ and $\rm{p}$ ($\overline{\rm{p}}$) are compared with next-to-leading order perturbative QCD calculations, which are found to overestimate the cross sections for $\pi^{\pm}$ and $\rm{p}$ ($\overline{\rm{p}}$) at high $p_{\rm{T}}$.

This paper presents the measurements of $\pi^{\pm}$, $\rm{K}^{\pm}$, $\rm{p}$ and $\bar{\rm{p}}$ transverse momentum ($p_{\rm{T}}$) spectra as a function of charged-particle multiplicity density in proton-proton (pp) collisions at $\sqrt{s}$ = 13 TeV with the ALICE detector at the LHC. Such study allows us to isolate the center-of-mass energy dependence of light-flavour particle production. The measurements reported here cover a $p_{\rm{T}}$ range from 0.1 GeV/$c$ to 20 GeV/$c$ and are done in the rapidity interval $|y|<0.5$. The $p_{\rm{T}}$-differential particle ratios exhibit an evolution with multiplicity, similar to that observed in pp collisions at $\sqrt{s}$ = 7 TeV, which is qualitatively described by some of the hydrodynamical and pQCD-inspired models discussed in this paper. Furthermore, the $p_{\rm{T}}$-integrated hadron-to-pion yield ratios measured in pp collisions at two different center-of-mass energies are consistent when compared at similar multiplicities. This also extends to strange and multistrange hadrons, suggesting that, at LHC energies, particle hadrochemistry scales with particle multiplicity the same way under different collision energies and colliding systems.

The measurement of the azimuthal-correlation function of prompt D mesons with charged particles in pp collisions at $\sqrt{s}$ = 5.02 TeV and p-Pb collisions at $\sqrt{s_{\rm NN}}$ = 5.02 TeV with the ALICE detector at the LHC is reported. The D$^{\rm 0}$, D$^{\rm +}$, and D$^{\rm *+}$ mesons, together with their charge conjugates, were reconstructed at midrapidity in the transverse momentum interval 3 < $p_{\rm T}$ < 24 GeV/c and correlated with charged particles having $p_{\rm T}$ > 0.3 GeV/c and pseudorapidity $|\eta| <$ 0.8. The properties of the correlation peaks appearing in the near- and away-side regions (for $\Delta \varphi \approx$ 0 and $\Delta \varphi \approx \pi$, respectively) were extracted via a fit to the azimuthal correlation functions. The shape of the correlation functions and the near- and away-side peak features are found to be consistent in pp and p-Pb collisions, showing no modifications due to nuclear effects within uncertainties. The results are compared with predictions from Monte Carlo simulations performed with the PYTHIA, POWHEG+PYTHIA, HERWIG, and EPOS 3 event generators.

Measurements of identified hadrons as a function of the charged-particle multiplicity in pp collisions enable a search for the onset of collective effects in small collision systems. With such measurements, it is possible to study the mechanisms that determine the shapes of hadron transverse momentum ($p_{\rm{T}}$) spectra, to search for possible modifications of the yields of short-lived hadronic resonances due to scattering effects in the hadron-gas phase, and to investigate different explanations for the multiplicity evolution of strangeness production provided by phenomenological models. In this paper, these topics are addressed through measurements of the $\rm{K}^{*}(892)^{0}$ and $\phi(1020)$ mesons at midrapidity in pp collisions at $\sqrt{s}$ = 13 TeV as a function of the charged-particle multiplicity. The results include the $p_{\rm{T}}$ spectra, $p_{\rm{T}}$-integrated yields, mean transverse momenta, and the ratios of the yields of these resonances to those of longer-lived hadrons. Comparisons with results from other collision systems and energies, as well as predictions from phenomenological models, are also discussed.

Charmonium is a valuable probe in heavy-ion collisions to study the properties of the quark gluon plasma, and is also an interesting probe in small collision systems to study cold nuclear matter effects, which are also present in large collision systems. With the recent observations of collective behavior of produced particles in small system collisions, measurements of the modification of charmonium in small systems have become increasingly relevant. We present the results of J/ψ measurements at forward and backward rapidity in various small collision systems, p+p, p+Al, p+Au and 3He+Au, at √sNN =200 GeV. The results are presented in the form of the observable RAB, the nuclear modification factor, a measure of the ratio of the J/ψ invariant yield compared to the scaled yield in p+p collisions. We examine the rapidity, transverse momentum, and collision centrality dependence of nuclear effects on J/ψ production with different projectile sizes p and 3He, and different target sizes Al and Au. The modification is found to be strongly dependent on the target size, but to be very similar for p+Au and 3He+Au. However, for 0%–20% central collisions at backward rapidity, the modification for 3He+Au is found to be smaller than that for p+Au, with a mean fit to the ratio of 0.89±0.03(stat)±0.08(syst), possibly indicating final state effects due to the larger projectile size.

The Quark Gluon Plasma (QGP) produced in ultra relativistic heavy-ion collisions at the Large Hadron Collider (LHC) can be studied by measuring the modifications of jets formed by hard scattered partons which interact with the medium. We studied these modifications via angular correlations of jets with charged hadrons for jets with momenta 20 < $p_{\rm{T}}^{\rm{jet}}$ < 40 GeV/$c$ as a function of the associated particle momentum. The reaction plane fit (RPF) method is used in this analysis to remove the flow modulated background. The analysis of angular correlations for different orientations of the jet relative to the second order event plane allows for the study of the path length dependence of medium modifications to jets. We present the dependence of azimuthal angular correlations of charged hadrons with respect to the angle of the axis of a reconstructed jet relative to the event plane in Pb-Pb collisions at $\sqrt{s_{\rm{NN}}}$ = 2.76 TeV. The dependence of particle yields associated with jets on the angle of the jet with respect to the event plane is presented. Correlations at different angles relative to the event plane are compared through ratios and differences of the yield. No dependence of the results on the angle of the jet with respect to the event plane is observed within uncertainties, which is consistent with no significant path length dependence of the medium modifications for this observable.

The first evidence of spin alignment of vector mesons ($K^{*0}$ and $\phi$) in heavy-ion collisions at the Large Hadron Collider (LHC) is reported. The spin density matrix element $\rho_{00}$ is measured at midrapidity ($|y| <$ 0.5) in Pb-Pb collisions at a center-of-mass energy ($\sqrt{s_{\rm NN}}$) of 2.76 TeV with the ALICE detector. $\rho_{00}$ values are found to be less than 1/3 (1/3 implies no spin alignment) at low transverse momentum ($p_{\rm T} <$ 2 GeV/$c$) for $K^{*0}$ and $\phi$ at a level of 3$\sigma$ and 2$\sigma$, respectively. No significant spin alignment is observed for the $K^0_S$ meson (spin = 0) in Pb-Pb collisions and for the vector mesons in $pp$ collisions. The measured spin alignment is unexpectedly large but qualitatively consistent with the expectation from models which attribute it to a polarization of quarks in the presence of angular momentum in heavy-ion collisions and a subsequent hadronization by the process of recombination.

The azimuthal anisotropy of charged particles produced in $\sqrt{s_{\mathrm{NN}}}=8.16$ TeV $p$+Pb collisions is measured with the ATLAS detector at the LHC. The data correspond to an integrated luminosity of $165$ $\mathrm{nb}^{-1}$ that was collected in 2016. Azimuthal anisotropy coefficients, elliptic $v_2$ and triangular $v_3$, extracted using two-particle correlations with a non-flow template fit procedure, are presented as a function of particle transverse momentum ($p_\mathrm{T}$) between $0.5$ and $50$ GeV. The $v_2$ results are also reported as a function of centrality in three different particle $p_\mathrm{T}$ intervals. The results are reported from minimum-bias events and jet-triggered events, where two jet $p_\mathrm{T}$ thresholds are used. The anisotropies for particles with $p_\mathrm{T}$ less than about $2$ GeV are consistent with hydrodynamic flow expectations, while the significant non-zero anisotropies for $p_\mathrm{T}$ in the range $9$-$50$ GeV are not explained within current theoretical frameworks. In the $p_\mathrm{T}$ range $2$-$9$ GeV, the anisotropies are larger in minimum-bias than in jet-triggered events. Possible origins of these effects, such as the changing admixture of particles from hard scattering and the underlying event, are discussed.

Anisotropies in the initial energy density distribution of the quark-gluon plasma created in high energy heavy ion collisions lead to anisotropies in the azimuthal distributions of the final-state particles known as collective flow. Fourier harmonic decomposition is used to quantify these anisotropies. The higher-order harmonics can be induced by the same order anisotropies (linear response) or by the combined influence of several lower order anisotropies (nonlinear response) in the initial state. The mixed higher-order anisotropic flow and nonlinear response coefficients of charged particles are measured as functions of transverse momentum and centrality in PbPb collisions at nucleon-nucleon center-of-mass energies $\sqrt{s_\mathrm{NN}} =$ 2.76 and 5.02 TeV with the CMS detector. The results are compared with viscous hydrodynamic calculations using several different initial conditions, as well as microscopic transport model calculations. None of the models provides a simultaneous description of the mixed higher-order flow harmonics and nonlinear response coefficients.

This article reports measurements of the $p_{\rm{T}}$-differential inclusive jet cross-section in pp collisions at $\sqrt{s}$ = 5.02 TeV and the $p_{\rm{T}}$-differential inclusive jet yield in Pb-Pb 0-10% central collisions at $\sqrt{s_{\rm{NN}}}$ = 5.02 TeV. Jets were reconstructed at mid-rapidity with the ALICE tracking detectors and electromagnetic calorimeter using the anti-$k_{\rm{T}}$ algorithm. For pp collisions, we report jet cross-sections for jet resolution parameters $R=0.1-0.6$ over the range $20<p_{\rm{T,jet}}<140$ GeV/$c$, as well as the jet cross-section ratios of different $R$, and comparisons to two next-to-leading-order (NLO)-based theoretical predictions. For Pb-Pb collisions, we report the $R=0.2$ and $R=0.4$ jet spectra for $40<p_{\rm{T,jet}}<140$ GeV/$c$ and $60<p_{\rm{T,jet}}<140$ GeV/$c$, respectively. The scaled ratio of jet yields observed in Pb-Pb to pp collisions, $R_{\rm{AA}}$, is constructed, and exhibits strong jet quenching and a clear $p_{\rm{T}}$-dependence for $R=0.2$. No significant $R$-dependence of the jet $R_{\rm{AA}}$ is observed within the uncertainties of the measurement. These results are compared to several theoretical predictions.

The inclusive J/$\psi$ production in Pb-Pb collisions at the center-of-mass energy per nucleon pair $\sqrt{s_{\rm{NN}}}$ = 5.02 TeV, measured with the ALICE detector at the CERN LHC, is reported. The J/$\psi$ meson is reconstructed via the dimuon decay channel at forward rapidity ($2.5<y<4$) down to zero transverse momentum. The suppression of the J/$\psi$ yield in Pb-Pb collisions with respect to binary-scaled pp collisions is quantified by the nuclear modification factor ($R_{\rm{AA}}$). The $R_{\rm{AA}}$ at $\sqrt{s_{\rm{NN}}}$ = 5.02 TeV is presented and compared with previous measurements at $\sqrt{s_{\rm{NN}}}$ = 2.76 TeV as a function of the centrality of the collision, and of the J/$\psi$ transverse momentum and rapidity. The inclusive J/$\psi$ $R_{\rm{AA}}$ shows a suppression increasing toward higher $p_{\rm{T}}$, with a steeper dependence for central collisions. The modification of the J/$\psi$ average $p_{\rm{T}}$ and $p_{\rm{T}}^{2}$ is also studied. Comparisons with the results of models based on a transport equation and on statistical hadronization are also carried out.

Studies of the fragmentation of jets into charged particles in heavy-ion collisions can provide information about the mechanism of jet-quenching by the hot and dense QCD matter created in such collisions, the quark-gluon plasma. This paper presents a measurement of the angular distribution of charged particles around the jet axis in $\sqrt{s_{\mathrm{NN}}}=$ 5.02 TeV Pb+Pb and $pp$ collisions, using the ATLAS detector at the LHC. The Pb+Pb and $pp$ data sets have integrated luminosities of 0.49 nb$^{-1}$ and 25 pb$^{-1}$, respectively. The measurement is performed for jets reconstructed with the anti-$k_{t}$ algorithm with radius parameter $R = 0.4$ and is extended to an angular distance of $r= 0.8$ from the jet axis. Results are presented as a function of Pb+Pb collision centrality and distance from the jet axis for charged particles with transverse momenta in the 1$-$63 GeV range, matched to jets with transverse momenta in the 126$-$316 GeV range and an absolute value of jet rapidity of less than 1.7. Modifications to the measured distributions are quantified by taking a ratio to the measurements in $pp$ collisions. Yields of charged particles with transverse momenta below 4 GeV are observed to be increasingly enhanced as a function of angular distance from the jet axis, reaching a maximum at $r=0.6$. Charged particles with transverse momenta above 4 GeV have an enhanced yield in Pb+Pb collisions in the jet core for angular distances up to $r = 0.05$ from the jet axis, with a suppression at larger distances.

To assess the properties of the quark-gluon plasma formed in heavy-ion collisions, the ATLAS experiment at the LHC measures a correlation between the mean transverse momentum and the magnitudes of the flow harmonics. The analysis uses data samples of lead-lead and proton-lead collisions obtained at the centre-of-mass energy per nucleon pair of 5.02 TeV, corresponding to total integrated luminosities of $22 ~\mu b^{-1}$ and $28~nb^{-1}$, respectively. The measurement is performed using a modified Pearson correlation coefficient with the charged-particle tracks on an event-by-event basis. The modified Pearson correlation coefficients for the $2^{nd}$-, 3$^{rd}$-, and 4$^{th}$-order harmonics are measured as a function of event centrality quantified as the number of charged particles or the number of nucleons participating in the collision. The measurements are performed for several intervals of the charged-particle transverse momentum. The correlation coefficients for all studied harmonics exhibit a strong centrality evolution in the lead-lead collisions, which only weakly depends on the charged-particle momentum range. In the proton-lead collisions, the modified Pearson correlation coefficient measured for the second harmonics shows only weak centrality dependence. The data is qualitatively described by the predictions based on the hydrodynamical model.

The measurement of the deuteron and anti-deuteron production in the rapidity range $-1 < y < 0$ as a function of transverse momentum and event multiplicity in p-Pb collisions at $\sqrt{s_{\rm{NN}}}$ = 5.02 TeV is presented. (Anti-)deuterons are identified via their specific energy loss $\rm{d}E/\rm{d}x$ and via their time-of-flight. Their production in p-Pb collisions is compared to pp and Pb-Pb collisions and is discussed within the context of thermal and coalescence models. The ratio of integrated yields of deuterons to protons (d/p) shows a significant increase as a function of the charged-particle multiplicity of the event starting from values similar to those observed in pp collisions at low multiplicities and approaching those observed in Pb-Pb collisions at high multiplicities. The mean transverse momenta are extracted from the deuteron spectra and the values are similar to those obtained for p and $\Lambda$ particles. Thus, deuteron spectra do not follow mass ordering. This behaviour is in contrast to the trend observed for non-composite particles in p-Pb collisions. In addition, the production of the rare $^{3}{\rm{He}}$ and $^{3}\bar{\rm He}$ nuclei has been studied. The spectrum corresponding to all non-single diffractive p-Pb collisions is obtained in the rapidity window $-1 < y < 0$ and the $p_{\rm{T}}$-integrated yield d$N$/d$y$ is extracted. It is found that the yields of protons, deuterons, and $^{3}{\rm{He}}$, normalised by the spin degeneracy factor, follow an exponential decrease with mass number.

We report the energy dependence of mid-rapidity (anti-)deuteron production in Au+Au collisions at $\sqrt{s_\text{NN}} =\ $7.7, 11.5, 14.5, 19.6, 27, 39, 62.4, and 200 GeV, measured by the STAR experiment at RHIC. The yield of deuterons is found to be well described by the thermal model. The collision energy, centrality, and transverse momentum dependence of the coalescence parameter $B_2$ are discussed. We find that the values of $B_2$ for anti-deuterons are systematically lower than those for deuterons, indicating that the correlation volume of anti-baryons is larger than that of baryons at $\sqrt{s_\text{NN}}$ from 19.6 to 39 GeV. In addition, values of $B_2$ are found to vary with collision energy and show a broad minimum around $\sqrt{s_\text{NN}}=\ $20 to 40 GeV, which might imply a change of the equation of state of the medium in these collisions.

Measurements of anisotropic flow coefficients ($v_n$) and their cross-correlations using two- and multi-particle cumulant methods are reported in collisions of pp at $\sqrt{s} = 13$ TeV, p-Pb at $\sqrt{s_{_{\rm NN}}} = 5.02$ TeV, Xe-Xe at $\sqrt{s_{_{\rm NN}}} = 5.44$ TeV, and Pb-Pb at $\sqrt{s_{_{\rm NN}}} = 5.02$ TeV recorded with the ALICE detector. The multiplicity dependence of $v_n$ is studied in a very wide range from 20 to 3000 particles produced in the mid-rapidity region $|\eta|<0.8$ for the transverse momentum range $0.2 < p_{\rm T} < 3.0$ GeV/$c$. An ordering of the coefficients $v_2 > v_3 > v_4$ is found in pp and p-Pb collisions, similar to that seen in large collision systems, while a weak $v_2$ multiplicity dependence is observed relative to nucleus-nucleus collisions in the same multiplicity range. Using a novel subevent method, $v_{2}$ measured with four-particle cumulants is found to be compatible with that from six-particle cumulants in pp and p-Pb collisions. The magnitude of the correlation between $v_n^2$ and $v_m^2$, evaluated with the symmetric cumulants SC$(m,n)$ is observed to be positive at all multiplicities for $v_2$ and $v_4$, while for $v_2$ and $v_3$ it is negative and changes sign for multiplicities below 100, which may indicate a different $v_n$ fluctuation pattern in this multiplicity range. The observed long-range multi-particle azimuthal correlations in high multiplicity pp and p-Pb collisions can neither be described by PYTHIA 8 nor by IP-Glasma+MUSIC+UrQMD model calculations, and hence provide new insights into the understanding of collective effects in small collision systems.

The first ($v_1^{\text{even}}$), second ($v_2$) and third ($v_3$) harmonic coefficients of the azimuthal particle distribution at mid-rapidity, are extracted for charged hadrons and studied as a function of transverse momentum ($p_T$) and mean charged particle multiplicity density $\langle \mathrm{N_{ch}} \rangle$ in U+U ($\roots =193$~GeV), Au+Au, Cu+Au, Cu+Cu, $d$+Au and $p$+Au collisions at $\roots = 200$~GeV with the STAR Detector. For the same $\langle \mathrm{N_{ch}} \rangle$, the $v_1^{\text{even}}$ and $v_3$ coefficients are observed to be independent of collision system, while $v_2$ exhibits such a scaling only when normalized by the initial-state eccentricity ($\varepsilon_2$). The data also show that $\ln(v_2/\varepsilon_2)$ scales linearly with $\langle \mathrm{N_{ch}} \rangle^{-1/3}$. These measurements provide insight into initial-geometry fluctuations and the role of viscous hydrodynamic attenuation on $v_n$ from small to large collision systems.

We present two-particle $p_{\rm t}$ correlations as a function of event centrality for Au+Au collisions at $\sqrt{s_{\rm NN}}$ = 7.7, 11.5, 14.5, 19.6, 27, 39, 62.4, and 200 GeV at the Relativistic Heavy Ion Collider using the STAR detector. These results are compared to previous measurements from CERES at the Super Proton Synchrotron and from ALICE at the Large Hadron Collider. The data are compared with UrQMD model calculations and with a model based on a Boltzmann-Langevin approach incorporating effects from thermalization. The relative dynamical correlations for Au+Au collisions at $\sqrt{s_{\rm NN}}$ = 200 GeV show a power law dependence on the number of participant nucleons and agree with the results for Pb+Pb collisions at $\sqrt{s_{\rm NN}} = 2.76~ {\rm TeV}$ from ALICE. As the collision energy is lowered from $\sqrt{s_{\rm NN}}$ = 200 GeV to 7.7 GeV, the centrality dependence of the relative dynamical correlations departs from the power law behavior observed at the higher collision energies. In central collisions, the relative dynamical correlations increase with collision energy up to $\sqrt{s_{\rm NN}}$ = 200 GeV in contrast to previous measurements that showed little dependence on the collision energy.

The pseudorapidity density of charged particles, $\rm{d}\it{N}_\rm{ch}/\rm{d}\it{\eta}$, in p-Pb collisions has been measured at a centre-of-mass energy per nucleon-nucleon pair of $\sqrt{s_{\rm{NN}}}$ = 8.16 TeV at mid-pseudorapidity for non-single-diffractive events. The results cover 3.6 units of pseudorapidity, $|\eta|<1.8$. The $\rm{d}\it{N}_\rm{ch}/\rm{d}\it{\eta}$ value is $19.1\pm0.7$ at $|\eta|<0.5$. This quantity divided by $\langle N_\rm{part} \rangle/2$, is $4.73\pm0.20$, which is 9.5% higher than the corresponding value for p-Pb collisions at $\sqrt{s_{\rm{NN}}}$ = 5.02 TeV. Measurements are compared with models based on different mechanisms for particle production. All models agree within uncertainties with data in the Pb-going side, while HIJING overestimates, showing a symmetric behaviour, and EPOS underestimates the p-going side of the $\rm{d}\it{N}_\rm{ch}/\rm{d}\it{\eta}$ distribution. Saturation-based models reproduce the distributions well for $\eta>-1.3$. The $\rm{d}\it{N}_\rm{ch}/\rm{d}\it{\eta}$ is also measured for different centrality estimators, based both on the charged-particle multiplicity and on the energy deposited in the Zero-Degree Calorimeters. A study of the implications of the large multiplicity fluctuations due to the small number of participants for systems like p-Pb in the centrality calculation for multiplicity-based estimators is discussed, demonstrating the advantages of determining the centrality with energy deposited near beam rapidity.

The transverse structure of jets was studied via jet fragmentation transverse momentum ($j_{\rm{T}}$) distributions, obtained using two-particle correlations in proton-proton and proton-lead collisions, measured with the ALICE experiment at the LHC. The highest transverse momentum particle in each event is used as the trigger particle and the region $3 < p_{\rm{Tt}} < 15$ GeV/$c$ is explored in this study. The measured distributions show a clear narrow Gaussian component and a wide non-Gaussian one. Based on Pythia simulations, the narrow component can be related to non-perturbative hadronization and the wide component to quantum chromodynamical splitting. The width of the narrow component shows a weak dependence on the transverse momentum of the trigger particle, in agreement with the expectation of universality of the hadronization process. On the other hand, the width of the wide component shows a rising trend suggesting increased branching for higher transverse momentum. The results obtained in pp collisions at $\sqrt{s}$ = 7 TeV and in p-Pb collisions at $\sqrt{s_{\rm{NN}}}$ = 5.02 TeV are compatible within uncertainties and hence no significant cold nuclear matter effects are observed. The results are compared to previous measurements from CCOR and PHENIX as well as to Pythia 8 and Herwig 7 simulations.

The production yield of prompt D mesons and their elliptic flow coefficient $v_2$ were measured with the Event-Shape Engineering (ESE) technique applied to mid-central (10-30% and 30-50% centrality classes) Pb-Pb collisions at the centre-of-mass energy per nucleon pair $\sqrt{s_{\rm NN}} =5.02$ TeV, with the ALICE detector at the LHC. The ESE technique allows the classification of events, belonging to the same centrality, according to the azimuthal anisotropy of soft particle production in the collision. The reported measurements give the opportunity to investigate the dynamics of charm quarks in the Quark-Gluon Plasma and provide information on their participation in the collective expansion of the medium. D mesons were reconstructed via their hadronic decays at mid-rapidity, $|\eta|<0.8$, in the transverse momentum interval $1<p_{\rm T}<24$ GeV/$c$. The $v_2$ coefficient is found to be sensitive to the event-shape selection confirming a correlation between the D-meson azimuthal anisotropy and the collective expansion of the bulk matter, while the per-event D-meson yields do not show any significant modification within the current uncertainties.

We present the first measurements of femtoscopic correlations between the K$^0_{\rm S}$ and K$^{\rm \pm}$ particles in pp collisions at $\sqrt{s}=7$ TeV measured by the ALICE experiment. The observed femtoscopic correlations are consistent with final-state interactions proceeding solely via the $a_0(980)$ resonance. The extracted kaon source radius and correlation strength parameters for K$^0_{\rm S}$K$^{\rm -}$ are found to be equal within the experimental uncertainties to those for K$^0_{\rm S}$K$^{\rm +}$. Results of the present study are compared with those from identical-kaon femtoscopic studies also performed with pp collisions at $\sqrt{s}=7$ TeV by ALICE and with a K$^0_{\rm S}$K$^{\rm \pm}$ measurement in Pb-Pb collisions at $\sqrt{s_{\rm NN}}=2.76$ TeV. Combined with the Pb-Pb results, our pp analysis is found to be compatible with the interpretation of the $a_0(980)$ having a tetraquark structure instead of that of a diquark.