D-meson production in p-Pb collisions at $\sqrt{s_{\rm NN}}=5.02$ TeV and in pp collisions at $\sqrt{s}=7$ TeV

The ALICE collaboration Adam, Jaroslav ; Adamova, Dagmar ; Aggarwal, Madan Mohan ; et al.
Phys.Rev.C 94 (2016) 054908, 2016.
Inspire Record 1465513 DOI 10.17182/hepdata.73941

The production cross sections of the prompt charmed mesons D$^0$, D$^+$, D$^{*+}$ and D$_s$ were measured at mid-rapidity in p-Pb collisions at a centre-of-mass energy per nucleon pair $\sqrt{s_{\rm NN}}=5.02$ TeV with the ALICE detector at the LHC. D mesons were reconstructed from their decays D$^0\rightarrow{\rm K}^-\pi^+$, D$^+\rightarrow{\rm K}^-\pi^+\pi^+$, D$^{*+}\rightarrow D^0\pi^+$, D$_s^+\rightarrow\phi\pi^+\rightarrow{\rm K}^-{\rm K}^+\pi^+$, and their charge conjugates. The $p_{\rm T}$-differential production cross sections were measured at mid-rapidity in the interval $1<p_{\rm T}<24$ GeV/$c$ for D$^0$, D$^+$ and D$^{*+}$ mesons and in $2<p_{\rm T}<12$ GeV/$c$ for D$_s$ mesons, using an analysis method based on the selection of decay topologies displaced from the interaction vertex. The production cross sections of the D$^0$, D$^+$ and D$^{*+}$ mesons were also measured in three $p_{\rm T}$ intervals as a function of the rapidity $y_{\rm cms}$ in the centre-of-mass system in $-1.26<y_{\rm cms}<0.34$. In addition, the prompt D$^0$ cross section was measured in pp collisions at $\sqrt{s}=7$ TeV and p-Pb collisions at $\sqrt{s_{\rm NN}}=5.02$ TeV down to $p_{\rm T}=0$ using an analysis technique that is based on the estimation and subtraction of the combinatorial background, without reconstruction of the D$^0$ decay vertex. The nuclear modification factor $R_{\rm pPb}(p_{\rm T})$, defined as the ratio of the $p_{\rm T}$-differential D-meson cross section in p-Pb collisions and that in pp collisions scaled by the mass number of the Pb nucleus, was calculated for the four D-meson species and found to be compatible with unity within experimental uncertainties. The results are compared to theoretical calculations that include cold-nuclear-matter effects and to transport model calculations incorporating the interactions of charm quarks with an expanding deconfined medium.

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W$^\pm$-boson production in p$-$Pb collisions at $\sqrt{s_{NN}} = 8.16$ TeV and PbPb collisions at $\sqrt{s_{NN}} = 5.02$ TeV

The ALICE collaboration Acharya, Shreyasi ; Adamova, Dagmar ; Adler, Alexander ; et al.
JHEP 05 (2023) 036, 2023.
Inspire Record 2071184 DOI 10.17182/hepdata.133034

The production of the W$^\pm$ bosons measured in p$-$Pb collisions at a centre-of-mass energy per nucleon$-$nucleon collision $\sqrt{s_{NN}} = 8.16$ TeV and Pb$-$Pb collisions at $\sqrt{s_{NN}} = 5.02$ TeV with ALICE at the LHC is presented. The W$^\pm$ bosons are measured via their muonic decay channel, with the muon reconstructed in the pseudorapidity region $-4 < \eta^\mu_{\rm lab} < -2.5$ with transverse momentum $p_{\rm T}^\mu > 10$ GeV/$c$. While in Pb$-$Pb collisions the measurements are performed in the forward ($2.5 < y^\mu_{\rm cms} < 4$) rapidity region, in p$-$Pb collisions, where the centre-of-mass frame is boosted with respect to the laboratory frame, the measurements are performed in the backward ($-4.46 < y^\mu_{\rm cms} < -2.96$) and forward ($2.03 < y^\mu_{\rm cms} < 3.53$) rapidity regions. The W$^{-}$ and W$^{+}$ production cross sections, lepton-charge asymmetry, and nuclear modification factors are evaluated as a function of the muon rapidity. In order to study the production as a function of the p$-$Pb collision centrality, the production cross sections of the W$^{-}$ and W$^{+}$ bosons are combined and normalised to the average number of binary nucleon$-$nucleon collision $\langle N_\mathrm{coll} \rangle$. In Pb$-$Pb collisions, the same measurements are presented as a function of the collision centrality. Study of the binary scaling of the W$^\pm$-boson cross sections in p$-$Pb and Pb$-$Pb collisions is also reported. The results are compared with perturbative QCD (pQCD) calculations, with and without nuclear modifications of the Parton Distribution Functions (PDFs), as well as with available data at the LHC. Significant deviations from the theory expectations are found in the two collision systems, indicating that the measurements can provide additional constraints for the determination of nuclear PDF (nPDFs) and in particular of the light-quark distributions.

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First measurement of quarkonium polarization in nuclear collisions at the LHC

The ALICE collaboration Acharya, Shreyasi ; Adamova, Dagmar ; Adler, Alexander ; et al.
Phys.Lett.B 815 (2021) 136146, 2021.
Inspire Record 1797469 DOI 10.17182/hepdata.102403

The polarization of inclusive J/$\psi$ and $\Upsilon(1{\rm S})$ produced in Pb-Pb collisions at $\sqrt{s_{\rm{NN}}}=5.02$ TeV at the LHC is measured with the ALICE detector. The study is carried out by reconstructing the quarkonium through its decay to muon pairs in the rapidity region $2.5<y<4$ and measuring the polar and azimuthal angular distributions of the muons. The polarization parameters $\lambda_{\theta}$, $\lambda_{\phi}$ and $\lambda_{\theta\phi}$ are measured in the helicity and Collins-Soper reference frames, in the transverse momentum interval $2<p_{\rm T}<10$ GeV/$c$ and $p_{\rm T}<15$ GeV/$c$ for the J/$\psi$ and $\Upsilon(1{\rm S})$, respectively. The polarization parameters for the J/$\psi$ are found to be compatible with zero, within a maximum of about two standard deviations at low $p_{\rm T}$, for both reference frames and over the whole $p_{\rm T}$ range. The values are compared with the corresponding results obtained for pp collisions at $\sqrt{s}=7$ and 8 TeV in a similar kinematic region by the ALICE and LHCb experiments. Although with much larger uncertainties, the polarization parameters for $\Upsilon(1{\rm S})$ production in Pb-Pb collisions are also consistent with zero.

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$\Lambda_{\rm c}^+$ production in pp collisions at $\sqrt{s} = 7$ TeV and in p-Pb collisions at $\sqrt{s_{\rm NN}} = 5.02$ TeV

The ALICE collaboration Acharya, Shreyasi ; Torales - Acosta, Fernando ; Adamova, Dagmar ; et al.
JHEP 04 (2018) 108, 2018.
Inspire Record 1645239 DOI 10.17182/hepdata.81727

The $p_{\rm T}$-differential production cross section of prompt $\Lambda_{\rm c}^+$ charmed baryons was measured with the ALICE detector at the Large Hadron Collider (LHC) in pp collisions at $\sqrt{s} = 7$ TeV and in p-Pb collisions at $\sqrt{s_{\rm NN}} = 5.02$ TeV at midrapidity. The $\Lambda_{\rm c}^+$ and ${\overline{\Lambda}}_{\rm c}^-$ were reconstructed in the hadronic decay modes $\Lambda_{\rm c}^+\rightarrow {\rm p}{\rm K^-}\pi^+$, $\Lambda_{\rm c}^+\rightarrow {\rm p}{\rm K_{\rm S}^0}$ and in the semileptonic channel $\Lambda_{\rm c}^+\rightarrow {\rm e^+}\nu_{\rm e}\Lambda$ (and charge conjugates). The measured values of the $\Lambda_{\rm c}^+/{\rm D_0}$ ratio, which is sensitive to the c-quark hadronisation mechanism, and in particular to the production of baryons, are presented and are larger than those measured previously in different colliding systems, centre-of-mass energies, rapidity and $p_{\rm T}$ intervals, where the $\Lambda_{\rm c}^+$ production process may differ. The results are compared with the expectations obtained from perturbative Quantum Chromodynamics calculations and Monte Carlo event generators. Neither perturbative QCD calculations nor Monte Carlo models reproduce the data, indicating that the fragmentation of heavy-flavour baryons is not well understood. The first measurement at the LHC of the $\Lambda_{\rm c}^+$ nuclear modification factor, $R_{\rm pPb}$, is also presented. The $R_{\rm pPb}$ is found to be consistent with unity and with that of D mesons within the uncertainties, and consistent with a theoretical calculation that includes cold nuclear matter effects and a calculation that includes charm quark interactions with a deconfined medium.

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Z-boson production in p-Pb collisions at $\sqrt{s_{\mathrm{NN}}}=8.16$ TeV and Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV

The ALICE collaboration Acharya, Shreyasi ; Adamova, Dagmar ; Adler, Alexander ; et al.
JHEP 09 (2020) 076, 2020.
Inspire Record 1797444 DOI 10.17182/hepdata.97372

Measurement of Z-boson production in p-Pb collisions at $\sqrt{s_{\mathrm{NN}}}=8.16$ TeV and Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV is reported. It is performed in the dimuon decay channel, through the detection of muons with pseudorapidity $-4 < \eta_{\mu} < -2.5$ and transverse momentum $p_{\rm T}^{\mu} > 20$ GeV/$c$ in the laboratory frame. The invariant yield and nuclear modification factor are measured for opposite-sign dimuons with invariant mass $60 < m^{\mu\mu} < 120$ GeV$c^2$ and rapidity $2.5 < y_{cms}^{\mu\mu} < 4$. 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 ($-4.46< y_{cms}^{\mu\mu}<-2.96$) and forward ($2.03< y_{cms}^{\mu\mu}<3.53$) 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 $3.4\sigma$ 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.

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Measurement of spin-orbital angular momentum interactions in relativistic heavy-ion collisions

The ALICE collaboration Acharya, Shreyasi ; Adamova, Dagmar ; Adler, Alexander ; et al.
Phys.Rev.Lett. 125 (2020) 012301, 2020.
Inspire Record 1762362 DOI 10.17182/hepdata.127978

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.

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$\phi$-meson production at forward rapidity in p-Pb collisions at $\sqrt{s_{\rm NN}}$ = 5.02 TeV and in pp collisions at $\sqrt{s}$ = 2.76 TeV

The ALICE collaboration Adam, Jaroslav ; Adamova, Dagmar ; Aggarwal, Madan Mohan ; et al.
Phys.Lett.B 768 (2017) 203-217, 2016.
Inspire Record 1380453 DOI 10.17182/hepdata.77057

The first study of $\phi$-meson production in p-Pb collisions at forward and backward rapidity, at a nucleon-nucleon centre-of-mass energy $\sqrt{s_{\rm NN}} = 5.02$~TeV, has been performed with the ALICE apparatus at the LHC. The $\phi$-mesons have been identified in the dimuon decay channel in the transverse momentum ($p_{\rm T}$) range $1 < p_{\rm T} < 7$ GeV/$c$, both in the p-going ($2.03 < y < 3.53$) and the Pb-going ($-4.46 < y < -2.96$) directions, where $y$ stands for the rapidity in the nucleon-nucleon centre-of-mass, the integrated luminosity amounting to $5.01 \pm 0.19$~nb$^{-1}$ and $5.81 \pm 0.20$~nb$^{-1}$, respectively, for the two data samples. Differential cross sections as a function of transverse momentum and rapidity are presented. The forward-backward ratio for $\phi$-meson production is measured for $2.96<|y|<3.53$, resulting in a ratio $\sim 0.5$ with no significant $p_{\rm T}$ dependence within the uncertainties. The $p_{\rm T}$ dependence of the $\phi$ nuclear modification factor $R_{\rm pPb}$ exhibits an enhancement up to a factor 1.6 at $p_{\rm T}$ = 3-4 GeV/$c$ in the Pb-going direction. The $p_{\rm T}$ dependence of the $\phi$-meson cross section in pp collisions at $\sqrt{s}$ = 2.76 TeV, which is used to determine a reference for the p-Pb results, is also presented here for $1 < p_{\rm T} < 5$ GeV/$c$ and $2.5 <y < 4$ for a $78 \pm 3$~nb$^{-1}$ integrated luminosity sample.

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Kaon femtoscopy in Pb-Pb collisions at $\sqrt{s_{\rm{NN}}}$ = 2.76 TeV

The ALICE collaboration Acharya, Shreyasi ; Adam, Jaroslav ; Adamova, Dagmar ; et al.
Phys.Rev.C 96 (2017) 064613, 2017.
Inspire Record 1621809 DOI 10.17182/hepdata.79128

We present the results of three-dimensional femtoscopic analyses for charged and neutral kaons recorded by ALICE in Pb-Pb collisions at $\sqrt{s_{\rm{NN}}}$ = 2.76 TeV. Femtoscopy is used to measure the space-time characteristics of particle production from the effects of quantum statistics and final-state interactions in two-particle correlations. Kaon femtoscopy is an important supplement to that of pions because it allows one to distinguish between different model scenarios working equally well for pions. In particular, we compare the measured 3D kaon radii with a purely hydrodynamical calculation and a model where the hydrodynamic phase is followed by a hadronic rescattering stage. The former predicts an approximate transverse mass ($m_{\mathrm{T}}$) scaling of source radii obtained from pion and kaon correlations. This $m_{\mathrm{T}}$ scaling appears to be broken in our data, which indicates the importance of the hadronic rescattering phase at LHC energies. A $k_{\mathrm{T}}$ scaling of pion and kaon source radii is observed instead. The time of maximal emission of the system is estimated using the three-dimensional femtoscopic analysis for kaons. The measured emission time is larger than that of pions. Our observation is well supported by the hydrokinetic model predictions.

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K^0_S and {\Lambda} production in Pb-Pb collisions at sqrt(sNN) = 2.76 TeV

The ALICE collaboration Abelev, Betty Bezverkhny ; Adam, Jaroslav ; Adamova, Dagmar ; et al.
Phys.Rev.Lett. 111 (2013) 222301, 2013.
Inspire Record 1243863 DOI 10.17182/hepdata.61857

The ALICE measurement of K$^0_{\rm S}$ and $\rm\Lambda$ production at mid-rapidity in Pb-Pb collisions at $\sqrt{s_{\rm NN}} = 2.76$ TeV is presented. The transverse momentum ($p_{\rm T}$) spectra are shown for several collision centrality intervals and in the $p_{\rm T}$ range from 0.4 GeV/$c$ (0.6 GeV/$c$ for $\rm\Lambda$) to 12 GeV/$c$. The $p_{\rm T}$ dependence of the $\rm \Lambda$/K$^0_{\rm S}$ ratios exhibits maxima in the vicinity of 3 GeV/$c$, and the positions of the maxima shift towards higher $p_{\rm T}$ with increasing collision centrality. The magnitude of these maxima increases by almost a factor of three between most peripheral and most central Pb-Pb collisions. This baryon excess at intermediate $p_{\rm T}$ is not observed in pp interactions at sqrt(s) = 0.9 TeV and at sqrt(s) = 7 TeV. Qualitatively, the baryon enhancement in heavy-ion collisions is expected from radial flow. However, the measured $p_{\rm T}$ spectra above 2 GeV/$c$ progressively decouple from hydrodynamical-model calculations. For higher values of $p_{\rm T}$, models that incorporate the influence of the medium on the fragmentation and hadronization processes describe qualitatively the $p_{\rm T}$ dependence of the $\rm\Lambda$/K$^0_{\rm S}$ ratio.

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Multi-strange baryon production in p-Pb collisions at $\sqrt{s_\mathbf{NN}}=5.02$

The ALICE collaboration Adam, Jaroslav ; Adamova, Dagmar ; Aggarwal, Madan Mohan ; et al.
Phys.Lett.B 758 (2016) 389-401, 2016.
Inspire Record 1411084 DOI 10.17182/hepdata.73011

The multi-strange baryon yields in Pb--Pb collisions have been shown to exhibit an enhancement relative to pp reactions. In this work, $\Xi$ and $\Omega$ production rates have been measured with the ALICE experiment as a function of transverse momentum, ${p_{\rm T}}$, in p-Pb collisions at a centre-of-mass energy of ${\sqrt{s_{\rm NN}}}$ = 5.02 TeV. The results cover the kinematic ranges 0.6 GeV/$c<{p_{\rm T}} <$7.2 GeV/$c$ and 0.8 GeV/$c<{p_{\rm T}}<$ 5 GeV/$c$, for $\Xi$ and $\Omega$ respectively, in the common rapidity interval -0.5 $<{y_{\rm CMS}}<$ 0. Multi-strange baryons have been identified by reconstructing their weak decays into charged particles. The ${p_{\rm T}}$ spectra are analysed as a function of event charged-particle multiplicity, which in p-Pb collisions ranges over one order of magnitude and lies between those observed in pp and Pb-Pb collisions. The measured ${p_{\rm T}}$ distributions are compared to the expectations from a Blast-Wave model. The parameters which describe the production of lighter hadron species also describe the hyperon spectra in high multiplicity p-Pb. The yield of hyperons relative to charged pions is studied and compared with results from pp and Pb-Pb collisions. A statistical model is employed, which describes the change in the ratios with volume using a canonical suppression mechanism, in which the small volume causes a species-dependent relative reduction of hadron production. The calculations, in which the magnitude of the effect depends on the strangeness content, show good qualitative agreement with the data.

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Direct photon production in Pb-Pb collisions at $\sqrt{s_\rm{NN}}$ = 2.76 TeV

The ALICE collaboration Adam, Jaroslav ; Adamova, Dagmar ; Aggarwal, Madan Mohan ; et al.
Phys.Lett.B 754 (2016) 235-248, 2015.
Inspire Record 1394677 DOI 10.17182/hepdata.73093

Direct photon production at mid-rapidity in Pb-Pb collisions at $\sqrt{s_{_{\mathrm{NN}}}} = 2.76$ TeV was studied in the transverse momentum range $0.9 < p_\mathrm{T} < 14$ GeV$/c$. Photons were detected with the highly segmented electromagnetic calorimeter PHOS and via conversions in the ALICE detector material with the $e^+e^-$ pair reconstructed in the central tracking system. The results of the two methods were combined and direct photon spectra were measured for the 0-20%, 20-40%, and 40-80% centrality classes. For all three classes, agreement was found with perturbative QCD calculations for $p_\mathrm{T} \gtrsim 5$ GeV$/c$. Direct photon spectra down to $p_\mathrm{T} \approx 1$ GeV$/c$ could be extracted for the 20-40% and 0-20% centrality classes. The significance of the direct photon signal for $0.9 < p_\mathrm{T} < 2.1$ GeV$/c$ is $2.6\sigma$ for the 0-20% class. The spectrum in this $p_\mathrm{T}$ range and centrality class can be described by an exponential with an inverse slope parameter of $(297 \pm 12^\mathrm{stat}\pm 41^\mathrm{syst})$ MeV. State-of-the-art models for photon production in heavy-ion collisions agree with the data within uncertainties.

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Multi-particle azimuthal correlations in p-Pb and Pb-Pb collisions at the LHC

The ALICE collaboration Abelev, Betty Bezverkhny ; Adam, Jaroslav ; Adamova, Dagmar ; et al.
Phys.Rev.C 90 (2014) 054901, 2014.
Inspire Record 1300038 DOI 10.17182/hepdata.65710

Measurements of multi-particle azimuthal correlations (cumulants) for charged particles in p-Pb and Pb-Pb collisions are presented. They help address the question of whether there is evidence for global, flow-like, azimuthal correlations in the p-Pb system. Comparisons are made to measurements from the larger Pb-Pb system, where such evidence is established. In particular, the second harmonic two-particle cumulants are found to decrease with multiplicity, characteristic of a dominance of few-particle correlations in p-Pb collisions. However, when a $|\Delta \eta|$ gap is placed to suppress such correlations, the two-particle cumulants begin to rise at high-multiplicity, indicating the presence of global azimuthal correlations. The Pb-Pb values are higher than the p-Pb values at similar multiplicities. In both systems, the second harmonic four-particle cumulants exhibit a transition from positive to negative values when the multiplicity increases. The negative values allow for a measurement of $v_{2}\{4\}$ to be made, which is found to be higher in Pb-Pb collisions at similar multiplicities. The second harmonic six-particle cumulants are also found to be higher in Pb-Pb collisions. In Pb-Pb collisions, we generally find $v_{2}\{4\} \simeq v_{2}\{6\}\neq 0$ which is indicative of a Bessel-Gaussian function for the $v_{2}$ distribution. For very high-multiplicity Pb-Pb collisions, we observe that the four- and six-particle cumulants become consistent with 0. Finally, third harmonic two-particle cumulants in p-Pb and Pb-Pb are measured. These are found to be similar for overlapping multiplicities, when a $|\Delta\eta| > 1.4$ gap is placed.

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Charged-particle multiplicities in proton-proton collisions at $\sqrt{s}$ = 0.9 to 8 TeV

The ALICE collaboration Adam, Jaroslav ; Adamova, Dagmar ; Aggarwal, Madan Mohan ; et al.
Eur.Phys.J.C 77 (2017) 33, 2017.
Inspire Record 1394854 DOI 10.17182/hepdata.77011

A detailed study of pseudorapidity densities and multiplicity distributions of primary charged particles produced in proton-proton collisions, at $\sqrt{s} =$ 0.9, 2.36, 2.76, 7 and 8 TeV, in the pseudorapidity range $|\eta|<2$, was carried out using the ALICE detector. Measurements were obtained for three event classes: inelastic, non-single diffractive and events with at least one charged particle in the pseudorapidity interval $|\eta|<1$. The use of an improved track-counting algorithm combined with ALICE's measurements of diffractive processes allows a higher precision compared to our previous publications. A KNO scaling study was performed in the pseudorapidity intervals $|\eta|<$ 0.5, 1.0 and 1.5. The data are compared to other experimental results and to models as implemented in Monte Carlo event generators PHOJET and recent tunes of PYTHIA6, PYTHIA8 and EPOS.

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Anisotropic flow in Xe-Xe collisions at $\mathbf{\sqrt{s_{\rm{NN}}} = 5.44}$ TeV

The ALICE collaboration Acharya, S. ; Torales - Acosta, Fernando ; Adamova, Dagmar ; et al.
Phys.Lett.B 784 (2018) 82-95, 2018.
Inspire Record 1671792 DOI 10.17182/hepdata.84283

The first measurements of anisotropic flow coefficients $v_{\rm{n}}$ for mid-rapidity charged particles in Xe-Xe collisions at $\sqrt{s_{\rm{NN}}} = 5.44$ TeV are presented. Comparing these measurements to those from Pb-Pb collisions at $\sqrt{s_{\rm{NN}}} = 5.02$ TeV, $v_{2}$ is found to be suppressed for mid-central collisions at the same centrality, and enhanced for central collisions. The values of $v_{3}$ are generally larger in Xe-Xe than in Pb-Pb at a given centrality. These observations are consistent with expectations from hydrodynamic predictions. When both $v_{2}$ and $v_{3}$ are divided by their corresponding eccentricities for a variety of initial state models, they generally scale with transverse density when comparing Xe-Xe and Pb-Pb, with some deviations observed in central Xe-Xe and Pb-Pb collisions. These results assist in placing strong constraints on both the initial state geometry and medium response for relativistic heavy-ion collisions.

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Analysis of the apparent nuclear modification in peripheral Pb-Pb collisions at 5.02 TeV

The ALICE collaboration Acharya, Shreyasi ; Torales - Acosta, Fernando ; Adamova, Dagmar ; et al.
Phys.Lett.B 793 (2019) 420-432, 2019.
Inspire Record 1672944 DOI 10.17182/hepdata.89396

Charged-particle spectra at midrapidity are measured in Pb-Pb collisions at the centre-of-mass energy per nucleon-nucleon pair $\sqrt{s_{\rm NN}}$ = 5.02 TeV and presented in centrality classes ranging from most central (0-5%) to most peripheral (95-100%) collisions. Possible medium effects are quantified using the nuclear modification factor ($R_{\rm AA}$) by comparing the measured spectra with those from proton-proton collisions, scaled by the number of independent nucleon-nucleon collisions obtained from a Glauber model. At large transverse momenta ($8<p_{\rm T}<20$ GeV/$c$), the average $R_{\rm AA}$ is found to increase from about $0.15$ in 0-5% central to a maximum value of about $0.8$ in 75-85% peripheral collisions, beyond which it falls off strongly to below $0.2$ for the most peripheral collisions. Furthermore, $R_{\rm AA}$ initially exhibits a positive slope as a function of $p_{\rm T}$ in the $8$-$20$ GeV/$c$ interval, while for collisions beyond the 80% class the slope is negative. To reduce uncertainties related to event selection and normalization, we also provide the ratio of $R_{\rm AA}$ in adjacent centrality intervals. Our results in peripheral collisions are consistent with a PYTHIA-based model without nuclear modification, demonstrating that biases caused by the event selection and collision geometry can lead to the apparent suppression in peripheral collisions. This explains the unintuitive observation that $R_{\rm AA}$ is below unity in peripheral Pb-Pb, but equal to unity in minimum-bias p-Pb collisions despite similar charged-particle multiplicities.

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${\rm f}_{0}(980)$ production in inelastic pp collisions at $\sqrt{s} = 5.02$ TeV

The ALICE collaboration Acharya, Shreyasi ; Adamova, Dagmar ; Adler, Alexander ; et al.
Phys.Lett.B 846 (2023) 137644, 2023.
Inspire Record 2094796 DOI 10.17182/hepdata.136307

The measurement of the production of ${\rm f}_{0}(980)$ in inelastic pp collisions at $\sqrt{s} = 5.02$ TeV is presented. This is the first reported measurement of inclusive ${\rm f}_{0}(980)$ yield at LHC energies. The production is measured at midrapidity, $|y| < 0.5$, in a wide transverse momentum range, $0 < p_{\rm T} < 16$ GeV/$c$, by reconstructing the resonance in the ${\rm f}_{0}(980) \rightarrow \pi^{+}\pi^{-}$ hadronic decay channel using the ALICE detector. The $p_{\rm T}$-differential yields are compared to those of pions, protons and $\phi$ mesons as well as to predictions from the HERWIG 7.2 QCD-inspired Monte Carlo event generator and calculations from a coalescence model that uses the AMPT model as an input. The ratio of the $p_{\rm T}$-integrated yield of ${\rm f}_{0}(980)$ relative to pions is compared to measurements in ${\rm e}^{+}{\rm e}^{-}$ and pp collisions at lower energies and predictions from statistical hadronisation models and HERWIG 7.2. A mild collision energy dependence of the ${\rm f}_{0}(980)$ to pion production is observed in pp collisions from SPS to LHC energies. All considered models underpredict the $p_{\rm T}$-integrated $2{\rm f}_{0}(980)/(\pi^{+}+\pi^{-})$ ratio. The prediction from the canonical statistical hadronisation model assuming a zero total strangeness content of ${\rm f}_{0}(980)$ is consistent with the data within 1.9$\sigma$ and is the closest to the data. The results provide an essential reference for future measurements of the particle yield and nuclear modification in p$-$Pb and Pb$-$Pb collisions, which have been proposed to be instrumental to probe the elusive nature and quark composition of the ${\rm f}_{0}(980)$ scalar meson.

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Measurement of electrons from beauty-hadron decays in p-Pb collisions at $\mathbf{\sqrt{s_{\rm NN}}=5.02}$ TeV and Pb-Pb collisions at $\mathbf{\sqrt{s_{\rm NN}}=2.76}$ TeV

The ALICE collaboration Adam, Jaroslav ; Adamova, Dagmar ; Aggarwal, Madan Mohan ; et al.
JHEP 07 (2017) 052, 2017.
Inspire Record 1486391 DOI 10.17182/hepdata.77904

The production of beauty hadrons was measured via semi-leptonic decays at mid-rapidity with the ALICE detector at the LHC in the transverse momentum interval $1<p_{\rm T}<8$ GeV/$c$ in minimum-bias p-Pb collisions at $\sqrt{s_{\rm NN}}=5.02$ TeV and in $1.3<p_{\rm T}<8$ GeV/$c$ in the 20% most central Pb-Pb collisions at $\sqrt{s_{\rm NN}}=2.76$ TeV. The pp reference spectra at $\sqrt{s}=5.02$ TeV and $\sqrt{s}=2.76$ TeV, needed for the calculation of the nuclear modification factors $R_{\rm pPb}$ and $R_{\rm PbPb}$, were obtained by a pQCD-driven scaling of the cross section of electrons from beauty-hadron decays measured at $\sqrt{s}=7$ TeV. In the $p_{\rm T}$ interval $3<p_{\rm T}<8$ GeV/$c$ a suppression of the yield of electrons from beauty-hadron decays is observed in Pb-Pb compared to pp collisions. Towards lower $p_{\rm T}$, the $R_{\rm PbPb}$ values increase with large systematic uncertainties. The $R_{\rm pPb}$ is consistent with unity within systematic uncertainties and is well described by theoretical calculations that include cold nuclear matter effects in p-Pb collisions. The measured $R_{\rm pPb}$ and these calculations indicate that cold nuclear matter effects are small at high transverse momentum also in Pb-Pb collisions. Therefore, the observed reduction of $R_{\rm PbPb}$ below unity at high $p_{\rm T}$ may be ascribed to an effect of the hot and dense medium formed in Pb-Pb collisions.

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Measurement of prompt D-meson production in p-Pb collisions at sqrt(sNN) = 5.02 TeV

The ALICE collaboration Abelev, Betty Bezverkhny ; Adam, Jaroslav ; Adamova, Dagmar ; et al.
Phys.Rev.Lett. 113 (2014) 232301, 2015.
Inspire Record 1296081 DOI 10.17182/hepdata.63866

The $p_{\rm T}$-differential production cross sections of the prompt charmed mesons $D^0$, $D^+$, $D^{*+}$ and $D_{\rm s}^{+}$ and their charge conjugate in the rapidity interval $-0.96 < y_{\rm cms} < 0.04$ were measured in p-Pb collisions at a centre-of-mass energy $\sqrt{s_{\rm NN}} = 5.02$ TeV with the ALICE detector at the LHC. The nuclear modification factor $R_{\rm pPb}$, quantifying the D-meson yield in p-Pb collisions relative to the yield in pp collisions scaled by the number of binary nucleon-nucleon collisions, is compatible within the 15-20% uncertainties with unity in the transverse momentum interval $1 < p_{\rm T} < 24$ GeV/$c$. No significant difference among the $R_{\rm pPb}$ of the four D-meson species is observed. The results are described within uncertainties by theoretical calculations that include initial-state effects. The measurement adds experimental evidence that the modification of the momentum spectrum of D mesons observed in Pb-Pb collisions with respect to pp collisions is due to strong final-state effects induced by hot partonic matter.

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Multipion Bose-Einstein correlations in pp, p-Pb, and Pb-Pb collisions at the LHC

The ALICE collaboration Adam, Jaroslav ; Adamova, Dagmar ; Aggarwal, Madan Mohan ; et al.
Phys.Rev.C 93 (2016) 054908, 2016.
Inspire Record 1411653 DOI 10.17182/hepdata.72937

Three- and four-pion Bose-Einstein correlations are presented in pp, p-Pb, and Pb-Pb collisions at the LHC. We compare our measured four-pion correlations to the expectation derived from two- and three-pion measurements. Such a comparison provides a method to search for coherent pion emission. We also present mixed-charge correlations in order to demonstrate the effectiveness of several analysis procedures such as Coulomb corrections. Same-charge four-pion correlations in pp and p-Pb appear consistent with the expectations from three-pion measurements. However, the presence of non-negligible background correlations in both systems prevent a conclusive statement. In Pb-Pb collisions, we observe a significant suppression of three- and four-pion Bose-Einstein correlations compared to expectations from two-pion measurements. There appears to be no centrality dependence of the suppression within the 0-50% centrality interval. The origin of the suppression is not clear. However, by postulating either coherent pion emission or large multibody Coulomb effects, the suppression may be explained.

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First measurement of jet mass in Pb-Pb and p-Pb collisions at the LHC

The ALICE collaboration Acharya, S. ; Adamova, Dagmar ; Aggarwal, Madan Mohan ; et al.
Phys.Lett.B 776 (2018) 249-264, 2018.
Inspire Record 1512107 DOI 10.17182/hepdata.80519

This letter presents the first measurement of jet mass in Pb-Pb and p-Pb collisions at $\sqrt{s_{\rm NN}}$ = 2.76 TeV and 5.02 TeV, respectively. Both the jet energy and the jet mass are expected to be sensitive to jet quenching in the hot Quantum Chromodynamics (QCD) matter created in nuclear collisions at collider energies. Jets are reconstructed from charged particles using the anti-$k_{\rm T}$ jet algorithm and resolution parameter $R = 0.4$. The jets are measured in the pseudorapidity range $|\eta_{\rm{jet}}|<0.5$ and in three intervals of transverse momentum between 60 GeV/$c$ and 120 GeV/$c$. The measurement of the jet mass in central Pb-Pb collisions is compared to the jet mass as measured in p-Pb reference collisions, to vacuum event generators, and to models including jet quenching. It is observed that the jet mass in central Pb-Pb collisions is consistent within uncertainties with p-Pb reference measurements. Furthermore, the measured jet mass in Pb-Pb collisions is not reproduced by the quenching models considered in this letter and is found to be consistent with PYTHIA expectations within systematic uncertainties.

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Multiplicity dependence of light-flavor hadron production in pp collisions at $\sqrt{s}$ = 7 TeV

The ALICE collaboration Acharya, Shreyasi ; Torales - Acosta, Fernando ; Adamova, Dagmar ; et al.
Phys.Rev.C 99 (2019) 024906, 2019.
Inspire Record 1684320 DOI 10.17182/hepdata.84282

Comprehensive results on the production of unidentified charged particles, $\pi^{\pm}$, $\rm{K}^{\pm}$, $\rm{K}^{0}_{S}$, $\rm{K}$*(892)$^{0}$, $\rm{p}$, $\overline{\rm{p}}$, $\phi$(1020), $\Lambda$, $\overline{\Lambda}$, $\Xi^{-}$, $\overline{\Xi}^{+}$, $\Omega^{-}$ and $\overline{\Omega}^{+}$ hadrons in proton-proton (pp) collisions at $\sqrt{s}$ = 7 TeV at midrapidity ($|y| < 0.5$) as a function of charged-particle multiplicity density are presented. In order to avoid auto-correlation biases, the actual transverse momentum ($p_{\rm{T}}$) spectra of the particles under study and the event activity are measured in different rapidity windows. In the highest multiplicity class, the charged-particle density reaches about 3.5 times the value measured in inelastic collisions. While the yield of protons normalized to pions remains approximately constant as a function of multiplicity, the corresponding ratios of strange hadrons to pions show a significant enhancement that increases with increasing strangeness content. Furthermore, all identified particle to pion ratios are shown to depend solely on charged-particle multiplicity density, regardless of system type and collision energy. The evolution of the spectral shapes with multiplicity and hadron mass shows patterns that are similar to those observed in p-Pb and Pb-Pb collisions at LHC energies. The obtained $p_{\rm{T}}$ distributions and yields are compared to expectations from QCD-based pp event generators as well as to predictions from thermal and hydrodynamic models. These comparisons indicate that traces of a collective, equilibrated system are already present in high-multiplicity pp collisions.

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Scattering studies with low-energy kaon-proton femtoscopy in proton-proton collisions at the LHC

The ALICE collaboration Acharya, Shreyasi ; Adamova, Dagmar ; Adhya, Souvik Priyam ; et al.
Phys.Rev.Lett. 124 (2020) 092301, 2020.
Inspire Record 1737592 DOI 10.17182/hepdata.93732

The study of the strength and behaviour of the antikaon-nucleon ($\mathrm{\overline{K}N}$) interaction constitutes one of the key focuses of the strangeness sector in low-energy Quantum Chromodynamics (QCD). In this letter a unique high-precision measurement of the strong interaction between kaons and protons, close and above the kinematic threshold, is presented. The femtoscopic measurements of the correlation function at low pair-frame relative momentum of (K$^+$ p $\oplus$ K$^-$ $\overline{\mathrm{p}}$) and (K$^-$ p $\oplus$ K$^+$ $\overline{\mathrm{p}}$) pairs measured in pp collisions at $\sqrt{s}$ = 5, 7 and 13 TeV are reported. A structure observed around a relative momentum of 58 MeV/$c$ in the measured correlation function of (K$^-$ p $\oplus$ K$^+$ $\overline{\mathrm{p}}$) with a significance of 4.4. $\sigma$ constitutes the first experimental evidence for the opening of the $(\mathrm{\overline{K}^0 n} \oplus \mathrm{K^0 \overline{n}})$ isospin breaking channel due to the mass difference between charged and neutral kaons. The measured correlation functions have been compared to J\"{u}lich and Kyoto models in addition to the Coulomb potential. The high-precision data at low relative momenta presented in this work prove femtoscopy to be a powerful complementary tool to scattering experiments and provide new constraints above the $\mathrm{\overline{K}N}$ threshold for low-energy QCD chiral models.

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$\Lambda\rm{K}$ femtoscopy in Pb-Pb collisions at $\sqrt{s_{\rm{NN}}}$ = 2.76 TeV

The ALICE collaboration Acharya, Shreyasi ; Adamova, Dagmar ; Adler, Alexander ; et al.
Phys.Rev.C 103 (2021) 055201, 2021.
Inspire Record 1797451 DOI 10.17182/hepdata.104979

The first measurements of the scattering parameters of $\Lambda$K pairs in all three charge combinations ($\Lambda$K$^{+}$, $\Lambda$K$^{-}$, and $\Lambda\mathrm{K^{0}_{S}}$) are presented. The results are achieved through a femtoscopic analysis of $\Lambda$K correlations in Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}$ = 2.76 TeV recorded by ALICE at the LHC. The femtoscopic correlations result from strong final-state interactions, and are fit with a parametrization allowing for both the characterization of the pair emission source and the measurement of the scattering parameters for the particle pairs. Extensive studies with the THERMINATOR 2 event generator provide a good description of the non-femtoscopic background, which results mainly from collective effects, with unprecedented precision. Furthermore, together with HIJING simulations, this model is used to account for contributions from residual correlations induced by feed-down from particle decays. The extracted scattering parameters indicate that the strong force is repulsive in the $\Lambda\rm{K}^{+}$ interaction and attractive in the $\Lambda\rm{K}^{-}$ interaction. The data hint that the and $\Lambda\rm{K}^{0}_{S}$ interaction is attractive, however the uncertainty of the result does not permit such a decisive conclusion. The results suggest an effect arising either from different quark-antiquark interactions between the pairs ($\rm s\overline{s}$ in $\Lambda$K$^{+}$ and $\rm u\overline{u}$ in $\Lambda$K$^{-}$) or from different net strangeness for each system (S = 0 for $\Lambda$K$^{+}$, and S = $-2$ for $\Lambda$K$^{-}$). Finally, the $\Lambda$K systems exhibit source radii larger than expected from extrapolation from identical particle femtoscopic studies. This effect is interpreted as resulting from the separation in space-time of the single-particle $\Lambda$ and K source distributions.

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Version 2
Beauty production in pp collisions at $\sqrt{s}$ = 2.76 TeV measured via semi-electronic decays

The ALICE collaboration Abelev, Betty Bezverkhny ; Adam, Jaroslav ; Adamova, Dagmar ; et al.
Phys.Lett.B 738 (2014) 97-108, 2014.
Inspire Record 1296861 DOI 10.17182/hepdata.858

The ALICE collaboration at the LHC reports measurement of the inclusive production cross section of electrons from semi-leptonic decays of beauty hadrons with rapidity $|y|<0.8$ and transverse momentum $1<p_{\mathrm{T}}<10$ GeV/$c$, in pp collisions at $\sqrt{s} = $ 2.76 TeV. Electrons not originating from semi-electronic decay of beauty hadrons are suppressed using the impact parameter of the corresponding tracks. The production cross section of beauty decay electrons is compared to the result obtained with an alternative method which uses the distribution of the azimuthal angle between heavy-flavour decay electrons and charged hadrons. Perturbative QCD calculations agree with the measured cross section within the experimental and theoretical uncertainties. The integrated visible cross section, $\sigma_{\mathrm{b} \rightarrow \mathrm{e}} = 3.47\pm0.40(\mathrm{stat})^{+1.12}_{-1.33}(\mathrm{sys})\pm0.07(\mathrm{norm}) \mu$b, was extrapolated to full phase space using Fixed Order plus Next-to-Leading Log (FONLL) predictions to obtain the total b$\bar{\mathrm{b}}$ production cross section, $\sigma_{\mathrm{b\bar{b}}} = 130\pm15.1(\mathrm{stat})^{+42.1}_{-49.8}(\mathrm{sys})^{+3.4}_{-3.1}(\mathrm{extr})\pm2.5(\mathrm{norm})\pm4.4(\mathrm{BR}) \mu$b.

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Inclusive J/$\psi$ production at mid-rapidity in pp collisions at $\sqrt{s}$ = 5.02 TeV

The ALICE collaboration Acharya, Shreyasi ; Adamova, Dagmar ; Adhya, Souvik Priyam ; et al.
JHEP 10 (2019) 084, 2019.
Inspire Record 1735351 DOI 10.17182/hepdata.91186

Inclusive J/$\psi$ production is studied in minimum-bias proton-proton collisions at a centre-of-mass energy of $\sqrt{s}$ = 5.02 TeV by ALICE at the CERN LHC. The measurement is performed at mid-rapidity ($|y| < 0.9$) in the dielectron decay channel down to zero transverse momentum $p_{\rm T}$, using a data sample corresponding to an integrated luminosity of $L_{\rm int} = 19.4 \pm$ 0.4 nb$^{-1}$. The measured $p_{\rm T}$-integrated inclusive J/$\psi$ production cross section is d$\sigma$/d$y$ = 5.64 $\pm$ 0.22 (stat.) $\pm 0.33$ (syst.) $\pm 0.12$ (lumi.) $\mu$b. The $p_{\rm T}$-differential cross section d$^{2} \sigma$/d$p_{\rm T}$d$y$ is measured in the $p_{\rm T}$ range 0$-$10 GeV/$c$ and compared with state-of-the-art perturbative QCD calculations. The J/$\psi$ $\langle p_{\rm T} \rangle$ and $\langle p_{\rm T}^{2} \rangle$ are extracted and compared with results obtained at other collision energies.

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Version 2
Global polarization of $\Lambda$ and $\overline{\Lambda}$ hyperons in Pb-Pb collisions at the LHC

The ALICE collaboration Acharya, Shreyasi ; Adamova, Dagmar ; Adhya, Souvik Priyam ; et al.
Phys.Rev.C 101 (2020) 044611, 2020.
Inspire Record 1752507 DOI 10.17182/hepdata.94265

The global polarization of the $\Lambda$ and $\overline\Lambda$ hyperons is measured for Pb-Pb collisions at $\sqrt{s_{\rm{NN}}}$ = 2.76 and 5.02 TeV recorded with the ALICE at the LHC. The results are reported differentially as a function of collision centrality and hyperon's transverse momentum ($p_{\rm{T}}$) for the range of centrality 5-50%, $0.5 < p_{\rm{T}} <5$ GeV/$c$, and rapidity $|y|<0.5$. The hyperon global polarization averaged for Pb-Pb collisions at $\sqrt{s_{\rm{NN}}}$ = 2.76 and 5.02 TeV is found to be consistent with zero, $\langle P_{\rm{H}}\rangle$ (%) $\approx$ - 0.01 $\pm$ 0.05 (stat.) $\pm$ 0.03 (syst.) in the collision centrality range 15-50%, where the largest signal is expected. The results are compatible with expectations based on an extrapolation from measurements at lower collision energies at RHIC, hydrodynamical model calculations, and empirical estimates based on collision energy dependence of directed flow, all of which predict the global polarization values at LHC energies of the order of 0.01%.

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Inclusive J/$\psi$ production in Xe-Xe collisions at $\sqrt{s_{\rm NN}}$ = 5.44 TeV

The ALICE collaboration Acharya, Shreyasi ; Torales - Acosta, Fernando ; Adamova, Dagmar ; et al.
Phys.Lett.B 785 (2018) 419-428, 2018.
Inspire Record 1672800 DOI 10.17182/hepdata.84718

Inclusive J/$\psi$ production is studied in Xe-Xe interactions at a centre-of-mass energy per nucleon pair of $\sqrt{s_{\rm NN}}= 5.44$ TeV, using the ALICE detector at the CERN LHC. The J/$\psi$ meson is reconstructed via its decay into a muon pair, in the centre-of-mass rapidity interval $2.5<y<4$ and down to zero transverse momentum. In this Letter, the nuclear modification factors $R_{\rm AA}$ for inclusive J/$\psi$, measured in the centrality range 0-90% as well as in the centrality intervals 0-20% and 20-90% are presented. The $R_{\rm AA}$ values are compared to previously published results for Pb-Pb collisions at $\sqrt{s_{\rm NN}}= 5.02$ TeV and to the calculation of a transport model. A good agreement is found between Xe-Xe and Pb-Pb results as well as between data and the model.

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Direct photon elliptic flow in Pb-Pb collisions at $\sqrt{s_{\rm NN}}$ = 2.76 TeV

The ALICE collaboration Acharya, Shreyasi ; Torales - Acosta, Fernando ; Adamova, Dagmar ; et al.
Phys.Lett.B 789 (2019) 308-322, 2019.
Inspire Record 1672789 DOI 10.17182/hepdata.88050

The elliptic flow of inclusive and direct photons was measured at mid-rapidity in two centrality classes 0-20% and 20-40% in Pb-Pb collisions at $\sqrt{s_{\rm NN}}$ = 2.76 TeV by ALICE. Photons were detected with the highly segmented electromagnetic calorimeter PHOS and via conversions in the detector material with the $e^{+}e^{-}$ pairs reconstructed in the central tracking system. The results of the two methods were combined and the direct photon elliptic flow was extracted in the transverse momentum range $0.9 < p_{\rm T} < 6.2$ GeV/$c$. A comparison to RHIC data shows a similar magnitude of the measured direct-photon elliptic flow. Hydrodynamic and transport model calculations are systematically lower than the data, but are found to be compatible.

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Version 2
$\pi^0$ and $\eta$ meson production in proton-proton collisions at $\sqrt{s}=8$ TeV

The ALICE collaboration Acharya, Shreyasi ; Adam, Jaroslav ; Adamova, Dagmar ; et al.
Eur.Phys.J.C 78 (2018) 263, 2018.
Inspire Record 1620477 DOI 10.17182/hepdata.79044

An invariant differential cross section measurement of inclusive $\pi^{0}$ and $\eta$ meson production at mid-rapidity in pp collisions at $\sqrt{s}=8$ TeV was carried out by the ALICE experiment at the LHC. The spectra of $\pi^{0}$ and $\eta$ mesons were measured in transverse momentum ranges of $0.3<p_{\rm T}<35$ GeV/$c$ and $0.5<p_{\rm T}<35$ GeV/$c$, respectively. Next-to-leading order perturbative QCD calculations using fragmentation functions DSS14 for the $\pi^{0}$ and AESSS for the $\eta$ overestimate the cross sections of both neutral mesons, although such calculations agree with the measured $\eta/\pi^{0}$ ratio within uncertainties. The results were also compared with PYTHIA~8.2 predictions for which the Monash~2013 tune yields the best agreement with the measured neutral meson spectra. The measurements confirm a universal behavior of the $\eta/\pi^{0}$ ratio seen for NA27, PHENIX and ALICE data for pp collisions from $\sqrt{s}=27.5$ GeV to $\sqrt{s}=8$ TeV within experimental uncertainties. A relation between the $\pi^{0}$ and $\eta$ production cross sections for pp collisions at $\sqrt{s}=8$ TeV is given by $m_{\rm T}$ scaling for $p_{\rm T}>3.5$ GeV/$c$. However, a deviation from this empirical scaling rule is observed for transverse momenta below $p_{\rm T}<3.5$ GeV/$c$ in the $\eta/\pi^0$ ratio with a significance of $6.2\sigma$.

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K*(892)^0 and PHI(1020) production in Pb-Pb collisions at sqrt(sNN) = 2.76 TeV

The ALICE collaboration Abelev, Betty Bezverkhny ; Adam, Jaroslav ; Adamova, Dagmar ; et al.
Phys.Rev.C 91 (2015) 024609, 2015.
Inspire Record 1288320 DOI 10.17182/hepdata.66630

The yields of the K*(892)$^{0}$ and $\Phi$(1020) resonances are measured in Pb-Pb collisions at $\sqrt{s_{\rm NN}}$ = 2.76 TeV through their hadronic decays using the ALICE detector. The measurements are performed in multiple centrality intervals at mid-rapidity (|$y$|<0.5) in the transverse-momentum ranges 0.3 < $p_{\rm T}$ < 5 GeV/$c$ for the K*(892)$^{0}$ and 0.5 < $p_{\rm T}$ < 5 GeV/$c$ for the $\Phi$(1020). The yields of K*(892)$^{0}$ are suppressed in central Pb-Pb collisions with respect to pp and peripheral Pb-Pb collisions (perhaps due to rescattering of its decay products in the hadronic medium), while the longer lived $\Phi$(1020) meson is not suppressed. These particles are also used as probes to study the mechanisms of particle production. The shape of the $p_{\rm T}$ distribution of the $\Phi$(1020) meson, but not its yield, is reproduced fairly well by hydrodynamic models for central Pb-Pb collisions. In central Pb-Pb collisions at low and intermediate $p_{\rm T}$, the p/$\Phi$(1020) ratio is flat in $p_{\rm T}$, while the p/$\pi$ and $\Phi$(1020)/$\pi$ ratios show a pronounced increase and have similar shapes to each other. These results indicate that the shapes of the $p_{\rm T}$ distributions of these particles in central Pb-Pb collisions are determined predominantly by the particle masses and radial flow. Finally, $\Phi$(1020) production in Pb-Pb collisions is enhanced, with respect to the yield in pp collisions and the yield of charged pions, by an amount similar to the $\Lambda$ and $\Xi$.

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Measurement of pion, kaon and proton production in proton-proton collisions at $\sqrt{s}=7$ TeV

The ALICE collaboration Adam, Jaroslav ; Adamova, Dagmar ; Aggarwal, Madan Mohan ; et al.
Eur.Phys.J.C 75 (2015) 226, 2015.
Inspire Record 1357424 DOI 10.17182/hepdata.68129

The measurement of primary $\pi^{\pm}$, K$^{\pm}$, p and $\overline{p}$ production at mid-rapidity ($|y| <$ 0.5) in proton-proton collisions at $\sqrt{s} = 7$ TeV performed with ALICE (A Large Ion Collider Experiment) at the Large Hadron Collider (LHC) is reported. Particle identification is performed using the specific ionization energy loss and time-of-flight information, the ring-imaging Cherenkov technique and the kink-topology identification of weak decays of charged kaons. Transverse momentum spectra are measured from 0.1 up to 3 GeV/$c$ for pions, from 0.2 up to 6 GeV/$c$ for kaons and from 0.3 up to 6 GeV/$c$ for protons. The measured spectra and particle ratios are compared with QCD-inspired models, tuned to reproduce also the earlier measurements performed at the LHC. Furthermore, the integrated particle yields and ratios as well as the average transverse momenta are compared with results at lower collision energies.

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Elliptic flow of identified hadrons in Pb-Pb collisions at $\sqrt{s_{\rm{NN}}}$ = 2.76 TeV

The ALICE collaboration Abelev, Betty Bezverkhny ; Adam, Jaroslav ; Adamova, Dagmar ; et al.
JHEP 06 (2015) 190, 2015.
Inspire Record 1297103 DOI 10.17182/hepdata.68162

The elliptic flow coefficient ($v_{2}$) of identified particles in Pb-Pb collisions at $\sqrt{s_\mathrm{{NN}}} = 2.76$ TeV was measured with the ALICE detector at the LHC. The results were obtained with the Scalar Product method, a two-particle correlation technique, using a pseudo-rapidity gap of $|\Delta\eta| > 0.9$ between the identified hadron under study and the reference particles. The $v_2$ is reported for $\pi^{\pm}$, $\mathrm{K}^{\pm}$, $\mathrm{K}^0_\mathrm{S}$, p+$\overline{\mathrm{p}}$, $\mathrm{\phi}$, $\Lambda$+$\overline{\mathrm{\Lambda}}$, $\Xi^-$+$\overline{\Xi}^+$ and $\Omega^-$+$\overline{\Omega}^+$ in several collision centralities. In the low transverse momentum ($p_{\mathrm{T}}$) region, $p_{\mathrm{T}} < 2 $GeV/$c$, $v_2(p_\mathrm{T})$ exhibits a particle mass dependence consistent with elliptic flow accompanied by the transverse radial expansion of the system with a common velocity field. The experimental data for $\pi^{\pm}$ and $\mathrm{K}$ are described fairly well by hydrodynamical calculations coupled to a hadronic cascade model (VISHNU) for central collisions. However, the same calculations fail to reproduce the $v_2(p_\mathrm{T})$ for p+$\overline{\mathrm{p}}$, $\mathrm{\phi}$, $\Lambda$+$\overline{\mathrm{\Lambda}}$ and $\Xi^-$+$\overline{\Xi}^+$. For transverse momentum values larger than about 3 GeV/$c$, particles tend to group according to their type, i.e. mesons and baryons. However, the experimental data at the LHC exhibit deviations from the number of constituent quark (NCQ) scaling at the level of $\pm$20$\%$ for $p_{\mathrm{T}} > 3 $GeV/$c$.

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Suppression of $\psi$(2S) production in p-Pb collisions at $\sqrt{s_{\rm NN}}$ = 5.02 TeV

The ALICE collaboration Abelev, Betty Bezverkhny ; Adam, Jaroslav ; Adamova, Dagmar ; et al.
JHEP 12 (2014) 073, 2014.
Inspire Record 1296307 DOI 10.17182/hepdata.66529

The ALICE Collaboration has studied the inclusive production of the charmonium state $\psi(2S)$ in proton-lead (p-Pb) collisions at the nucleon-nucleon centre of mass energy $\sqrt{s_{NN}}$ = 5.02 TeV at the CERN LHC. The measurement was performed at forward ($2.03<y_{cms}<3.53$) and backward ($-4.46<y_{cms}<-2.96$) centre of mass rapidities, studying the decays into muon pairs. In this paper, we present the inclusive production cross sections $\sigma_{\psi(2S)}$, both integrated and as a function of the transverse momentum $p_{T}$, for the two $y_{cms}$ domains. The results are compared to those obtained for the 1S vector state (J/$\psi$), by showing the ratios between the production cross sections, as well as the double ratios $[\sigma_{\psi(2S)}/\sigma_{J/\psi}]_{pPb}/[\sigma_{\psi(2S)}/\sigma_{J/\psi}]_{pp}$ between p-Pb and proton-proton collisions. Finally, the nuclear modification factor for inclusive $\psi(2S)$ is evaluated and compared to the measurement of the same quantity for J/$\psi$ and to theoretical models including parton shadowing and coherent energy loss mechanisms. The results show a significantly larger suppression of the $\psi(2S)$ compared to that measured for J/$\psi$ and to models. These observations represent a clear indication for sizeable final state effects on $\psi(2S)$ production.

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Multi-strange baryon production at mid-rapidity in Pb-Pb collisions at sqrt(s_NN) = 2.76 TeV

The ALICE collaboration Abelev, Betty Bezverkhny ; Adam, Jaroslav ; Adamova, Dagmar ; et al.
Phys.Lett.B 728 (2014) 216-227, 2014.
Inspire Record 1243865 DOI 10.17182/hepdata.62098

The production of ${\rm\Xi}^-$ and ${\rm\Omega}^-$ baryons and their anti-particles in Pb-Pb collisions at $\sqrt{s_{\rm NN}}$ = 2.76 TeV has been measured using the ALICE detector. The transverse momentum spectra at mid-rapidity ($|y| < 0.5$) for charged $\rm\Xi$ and $\rm\Omega$ hyperons have been studied in the range $0.6 < p_{\rm T} < 8.0$ GeV/$c$ and $1.2 < p_{\rm T} < 7.0$ GeV/$c$, respectively, and in several centrality intervals (from the most central 0-10% to the most peripheral 60-80% collisions). These spectra have been compared with the predictions of recent hydrodynamic models. In particular, the Krak${\'o}$w and EPOS models give a satisfactory description of the data, with the latter covering a wider $p_{\rm T}$ range. Mid-rapidity yields, integrated over $p_{\rm T}$, have been determined. The hyperon-to-pion ratios are similar to those at RHIC: they rise smoothly with centrality up to $\langle N_{\rm part}\rangle$~150 and saturate thereafter. The enhancements (yields per participant nucleon relative to pp collisions) increase both with the strangeness content of the baryon and with centrality, but are less pronounced than at lower energies.

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Energy Dependence of the Transverse Momentum Distributions of Charged Particles in pp Collisions Measured by ALICE

The ALICE collaboration Abelev, Betty Bezverkhny ; Adam, Jaroslav ; Adamova, Dagmar ; et al.
Eur.Phys.J.C 73 (2013) 2662, 2013.
Inspire Record 1241422 DOI 10.17182/hepdata.61787

Differential cross sections of charged particles in inelastic pp collisions as a function of $p_{\rm T}$ have been measured at $\sqrt{s}=$ 0.9, 2.76 and 7 TeV at the LHC. The $p_{\rm T}$ spectra are compared to NLO-pQCD calculations. Though the differential cross section for an individual $\sqrt{s}$ cannot be described by NLO-pQCD, the relative increase of cross section with $\sqrt{s}$ is in agreement with NLO-pQCD. Based on these measurements and observations, procedures are discussed to construct pp reference spectra at $\sqrt{s} =$ 2.76 and 5.02 TeV up to $p_{\rm T}$ = 50 GeV/$c$ as required for the calculation of the nuclear modification factor in nucleus-nucleus and proton-nucleus collisions.

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Azimuthal anisotropy of charged jet production in $\sqrt{s_{\rm NN}}$ = 2.76 TeV Pb-Pb collisions

The ALICE collaboration Adam, Jaroslav ; Adamova, Dagmar ; Aggarwal, Madan Mohan ; et al.
Phys.Lett.B 753 (2016) 511-525, 2016.
Inspire Record 1394678 DOI 10.17182/hepdata.70825

We present measurements of the azimuthal dependence of charged jet production in central and semi-central $\sqrt{s_{\mathrm{NN}}}$ = 2.76 TeV Pb-Pb collisions with respect to the second harmonic event plane, quantified as $v_{2}^{\mathrm{ch~jet}}$. Jet finding is performed employing the anti-$k_{\mathrm{T}}$ algorithm with a resolution parameter $R$ = 0.2 using charged tracks from the ALICE tracking system. The contribution of the azimuthal anisotropy of the underlying event is taken into account event-by-event. The remaining (statistical) region-to-region fluctuations are removed on an ensemble basis by unfolding the jet spectra for different event plane orientations independently. Significant non-zero $v_{2}^{\mathrm{ch~jet}}$ is observed in semi-central collisions (30-50\% centrality) for 20 $<$ $p_{\mathrm{T}}^{\rm ch~jet}$ $<$ 90 ${\mathrm{GeV}\kern-0.05em/\kern-0.02em c}$. The azimuthal dependence of the charged jet production is similar to the dependence observed for jets comprising both charged and neutral fragments, and compatible with measurements of the $v_2$ of single charged particles at high $p_{\mathrm{T}}$. Good agreement between the data and predictions from JEWEL, an event generator simulating parton shower evolution in the presence of a dense QCD medium, is found in semi-central collisions.

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Forward-central two-particle correlations in p-Pb collisions at $\sqrt{s_{\rm NN}}$ = 5.02 TeV

The ALICE collaboration Adam, Jaroslav ; Adamova, Dagmar ; Aggarwal, Madan Mohan ; et al.
Phys.Lett.B 753 (2016) 126-139, 2016.
Inspire Record 1379977 DOI 10.17182/hepdata.70826

Two-particle angular correlations between trigger particles in the forward pseudorapidity range ($2.5 < |\eta| < 4.0$) and associated particles in the central range ($|\eta| < 1.0$) are measured with the ALICE detector in p-Pb collisions at a nucleon-nucleon centre-of-mass energy of 5.02 TeV. The trigger particles are reconstructed using the muon spectrometer, and the associated particles by the central barrel tracking detectors. In high-multiplicity events, the double-ridge structure, previously discovered in two-particle angular correlations at midrapidity, is found to persist to the pseudorapidity ranges studied in this Letter. The second-order Fourier coefficients for muons in high-multiplicity events are extracted after jet-like correlations from low-multiplicity events have been subtracted. The coefficients are found to have a similar transverse momentum ($p_{\rm T}$) dependence in p-going (p-Pb) and Pb-going (Pb-p) configurations, with the Pb-going coefficients larger by about $16\pm6$%, rather independent of $p_{\rm T}$ within the uncertainties of the measurement. The data are compared with calculations using the AMPT model, which predicts a different $p_{\rm T}$ and $\eta$ dependence than observed in the data. The results are sensitive to the parent particle $v_2$ and composition of reconstructed muon tracks, where the contribution from heavy flavour decays are expected to dominate at $p_{\rm T}>2$ GeV/$c$.

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Measurement of jet suppression in central Pb-Pb collisions at $\sqrt{s_{\rm NN}}$ = 2.76 TeV

The ALICE collaboration Adam, Jaroslav ; Adamova, Dagmar ; Aggarwal, Madan Mohan ; et al.
Phys.Lett.B 746 (2015) 1-14, 2015.
Inspire Record 1343112 DOI 10.17182/hepdata.68483

The transverse momentum ($p_{\rm T}$) spectrum and nuclear modification factor ($R_{\rm AA}$) of reconstructed jets in 0-10% and 10-30% central Pb-Pb collisions at $\sqrt{s_{\rm NN}}=2.76$ TeV were measured. Jets were reconstructed from charged and neutral particles, utilizing the ALICE tracking detectors and Electromagnetic Calorimeter (EMCal), with the anti-$k_{\rm T}$ jet algorithm with a resolution parameter of R=0.2. The jet $p_{\rm T}$ spectra are reported in the pseudorapidity interval of $|{\eta}_{\rm jet}|<0.5$ for $40<p_{\rm T,jet}<120$ GeV/$c$ in 0-10% and for $30<p_{\rm T,jet}<100$ GeV/$c$ in 10-30% collisions. Reconstructed jets were required to contain a leading charged particle with $p_{\rm T}>5$ GeV/$c$ to suppress jets constructed from the combinatorial background in Pb-Pb collisions. The effect of the leading charged particle requirement has been studied in both pp and Pb-Pb collisions and has been shown to have negligible effects on the $R_{\rm AA}$ within the uncertainties of the measurement. The nuclear modification factor is obtained by dividing the jet spectrum measured in Pb-Pb by that in pp collisions scaled by the number of independent nucleon-nucleon collisions estimated using a Glauber model. $R_{\rm AA}$ is found to be $0.28\pm0.04$ in 0-10% and $0.35\pm0.04$ in 10-30% collisions, independent of $p_{\rm T,jet}$ within the uncertainties of the measurement. The observed suppression is in fair agreement with expectations from two model calculations with different approaches to jet quenching.

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W and Z boson production in p-Pb collisions at $\sqrt{s_{\rm NN}}$ = 5.02 TeV

The ALICE collaboration Adam, Jaroslav ; Adamova, Dagmar ; Aggarwal, Madan Mohan ; et al.
JHEP 02 (2017) 077, 2017.
Inspire Record 1496634 DOI 10.17182/hepdata.77359

The W and Z boson production was measured via the muonic decay channel in proton-lead collisions at $\sqrt{s_{\rm NN}} = 5.02$ TeV at the Large Hadron Collider with the ALICE detector. The measurement covers backward ($-4.46 < y_{\rm cms} < -2.96$) and forward ($2.03 < y_{\rm cms} < 3.53$) rapidity regions, corresponding to Pb-going and p-going directions, respectively. The Z-boson production cross section, with dimuon invariant mass of $60<m_{\mu\mu}<120$ GeV/$c^2$ and muon transverse momentum ($p_{\rm T}^\mu$) larger than 20 GeV/$c$, is measured. The production cross section and charge asymmetry of muons from W-boson decays with $p_{\rm T}^\mu>10$ GeV/$c$ are determined. The results are compared to theoretical calculations both with and without including the nuclear modification of the parton distribution functions. The W-boson production is also studied as a function of the collision centrality: the cross section of muons from W-boson decays is found to scale with the average number of binary nucleon-nucleon collisions within uncertainties.

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Version 2
Anisotropic flow of charged particles in Pb-Pb collisions at $\sqrt{s_{\rm NN}}=5.02$ TeV

The ALICE collaboration Adam, Jaroslav ; Adamova, Dagmar ; Aggarwal, Madan Mohan ; et al.
Phys.Rev.Lett. 116 (2016) 132302, 2016.
Inspire Record 1419244 DOI 10.17182/hepdata.72886

We report the first results of elliptic ($v_2$), triangular ($v_3$) and quadrangular flow ($v_4$) of charged particles in Pb-Pb collisions at $\sqrt{s_{\rm NN}}=5.02$ TeV with the ALICE detector at the CERN Large Hadron Collider. The measurements are performed in the central pseudorapidity region $|\eta|<0.8$ and for the transverse momentum range $0.2<p_{\rm T}<5$ GeV/$c$. The anisotropic flow is measured using two-particle correlations with a pseudorapidity gap greater than one unit and with the multi-particle cumulant method. Compared to results from Pb-Pb collisions at $\sqrt{s_{\rm NN}}=2.76$ TeV, the anisotropic flow coefficients $v_{2}$, $v_{3}$ and $v_{4}$ are found to increase by ($3.0\pm0.6$)%, ($4.3\pm1.4$)% and ($10.2\pm3.8$)%, respectively, in the centrality range 0-50%. This increase can be attributed mostly to an increase of the average transverse momentum between the two energies. The measurements are found to be compatible with hydrodynamic model calculations. This comparison provides a unique opportunity to test the validity of the hydrodynamic picture and the power to further discriminate between various possibilities for the temperature dependence of shear viscosity to entropy density ratio of the produced matter in heavy-ion collisions at the highest energies.

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Version 2
Production of light nuclei and anti-nuclei in pp and Pb-Pb collisions at LHC energies

The ALICE collaboration Adam, Jaroslav ; Adamova, Dagmar ; Aggarwal, Madan Mohan ; et al.
Phys.Rev.C 93 (2016) 024917, 2016.
Inspire Record 1380491 DOI 10.17182/hepdata.72547

The production of (anti-)deuteron and (anti-)$^{3}$He nuclei in Pb-Pb collisions at $\sqrt{s_{\rm NN}}$ = 2.76 TeV has been studied using the ALICE detector at the LHC. The spectra exhibit a significant hardening with increasing centrality. Combined blast-wave fits of several particles support the interpretation that this behavior is caused by an increase of radial flow. The integrated particle yields are discussed in the context of coalescence and thermal-statistical model expectations. The particle ratios, $^3$He/d and $^3$He/p, in Pb-Pb collisions are found to be in agreement with a common chemical freeze-out temperature of $T_{\rm chem} \approx 156$ MeV. These ratios do not vary with centrality which is in agreement with the thermal-statistical model. In a coalescence approach, it excludes models in which nucleus production is proportional to the particle multiplicity and favors those in which it is proportional to the particle density instead. In addition, the observation of 31 anti-tritons in Pb-Pb collisions is reported. For comparison, the deuteron spectrum in pp collisions at $\sqrt{s} = 7$ TeV is also presented. While the p/$\pi$ ratio is similar in pp and Pb-Pb collisions, the d/p ratio in pp collisions is found to be lower by a factor of 2.2 than in Pb-Pb collisions.

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One-dimensional charged kaon femtoscopy in p-Pb collisions at $\sqrt{s_{\rm NN}}$ = 5.02 TeV

The ALICE collaboration Acharya, Shreyasi ; Adamova, Dagmar ; Adhya, Souvik Priyam ; et al.
Phys.Rev.C 100 (2019) 024002, 2019.
Inspire Record 1727337 DOI 10.17182/hepdata.90683

The correlations of identical charged kaons were measured in p-Pb collisions at $\sqrt{s_{\rm NN}}=5.02$ TeV by the ALICE experiment at the LHC. The femtoscopic invariant radii and correlation strengths were extracted from one-dimensional kaon correlation functions and were compared with those obtained in pp and Pb-Pb collisions at $\sqrt{s}=7$ TeV and $\sqrt{s_{\rm NN}}=2.76$ TeV, respectively. The presented results also complement the identical-pion femtoscopic data published by the ALICE collaboration. The extracted radii increase with increasing charged-particle multiplicity and decrease with increasing pair transverse momentum. At comparable multiplicities, the radii measured in p-Pb collisions are found to be close to those observed in pp collisions. The obtained femtoscopic parameters are reproduced by the EPOS 3 hadronic interaction model and disfavor models with large initial size or strong collective expansion at low multiplicities.

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Dielectron production in proton-proton and proton-lead collisions at $\sqrt{s_{\rm{NN}}}$ = 5.02 TeV

The ALICE collaboration Acharya, Shreyasi ; Adamova, Dagmar ; Adler, Alexander ; et al.
Phys.Rev.C 102 (2020) 055204, 2020.
Inspire Record 1797621 DOI 10.17182/hepdata.98625

The first measurements of dielectron production at midrapidity ($|\eta_{c}|<0.8$) in proton-proton and proton-lead collisions at $\sqrt{s_{\rm{NN}}}$ = 5.02 TeV at the LHC are presented. The dielectron cross section is measured with the ALICE detector as a function of the invariant mass $m_{\rm{ee}}$ and the pair transverse momentum $p_{\rm{T,ee}}$ in the ranges $m_{\rm{ee}}$ < 3.5 GeV/$c^{2}$ and $p_{\rm{T,ee}}$ < 8.0 GeV/$c^{2}$, in both collision systems. In proton-proton collisions, the charm and beauty cross sections are determined at midrapidity from a fit to the data with two different event generators. This complements the existing dielectron measurements performed at $\sqrt{s}$ = 7 and 13 TeV. The slope of the $\sqrt{s}$ dependence of the three measurements is described by FONLL calculations. The dielectron cross section measured in proton-lead collisions is in agreement, within the current precision, with the expected dielectron production without any nuclear matter effects for $\rm{e}^{+}\rm{e}^{-}$ pairs from open heavy-flavor hadron decays. For the first time at LHC energies, the dielectron production in proton-lead and proton-proton collisions are directly compared at the same $\sqrt{s_{\rm{NN}}}$ via the dielectron nuclear modification factor $R_{\rm{pPb}}$. The measurements are compared to model calculations including cold nuclear matter effects, or additional sources of dielectrons from thermal radiation.

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Exploration of jet substructure using iterative declustering in pp and Pb-Pb collisions at LHC energies

The ALICE collaboration Acharya, Shreyasi ; Adamova, Dagmar ; Adhya, Souvik Priyam ; et al.
Phys.Lett.B 802 (2020) 135227, 2020.
Inspire Record 1733684 DOI 10.17182/hepdata.104932

The ALICE collaboration at the CERN LHC reports novel measurements of jet substructure in pp collisions at $\sqrt{s}$= 7 TeV and central Pb-Pb collisions at $\sqrt{s_{\rm{NN}}}$ = 2.76 TeV. Jet substructure of track-based jets is explored via iterative declustering and grooming techniques. We present the measurement of the momentum sharing of two-prong substructure exposed via grooming, the $z_{\rm{g}}$, and its dependence on the opening angle, in both pp and Pb-Pb collisions. We also present the first measurement of the distribution of the number of branches obtained in the iterative declustering of the jet, which is interpreted as the number of its hard splittings. In Pb-Pb collisions, we observe a suppression of symmetric splittings at large opening angles and an enhancement of splittings at small opening angles relative to pp collisions, with no significant modification of the number of splittings. The results are compared to predictions from various Monte Carlo event generators to test the role of important concepts in the evolution of the jet in the medium such as color coherence.

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$\Upsilon$ suppression at forward rapidity in Pb-Pb collisions at $\sqrt{s_{\rm NN}}$ = 5.02 TeV

The ALICE collaboration Acharya, Shreyasi ; Torales - Acosta, Fernando ; Adamova, Dagmar ; et al.
Phys.Lett.B 790 (2019) 89-101, 2019.
Inspire Record 1672798 DOI 10.17182/hepdata.88408

Inclusive $\Upsilon$(1S) and $\Upsilon$(2S) production have been measured in Pb-Pb collisions at the centre-of-mass energy per nucleon-nucleon pair $\sqrt{s_{_{\rm NN}}}=5.02$ TeV, using the ALICE detector at the CERN LHC. The $\Upsilon$ mesons are reconstructed in the centre-of-mass rapidity interval $2.5<y<4$ and in the transverse-momentum range $p_{\rm T}<15$ GeV/$c$, via their decays to muon pairs. In this Letter, we present results on the inclusive $\Upsilon$(1S) nuclear modification factor $R_{\rm AA}$ as a function of collision centrality, transverse momentum and rapidity. The $\Upsilon$(1S) and $\Upsilon$(2S) $R_{\rm AA}$, integrated over the centrality range 0-90%, are $0.37 \pm 0.02 {\rm{(stat)}}\pm 0.03 {\rm{(syst)}}$ and $0.10 \pm 0.04 {\rm{(stat)}}\pm 0.02 {\rm{(syst)}}$, respectively, leading to a ratio $R_{\rm{AA}}^{\Upsilon(\rm2S)}/R_{\rm{AA}}^{\Upsilon(\rm1S)}$ of $0.28\pm0.12\text{(stat)}\pm0.06\text{(syst)}$. The observed $\Upsilon$(1S) suppression increases with the centrality of the collision and no significant variation is observed as a function of transverse momentum and rapidity.

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Production of muons from heavy-flavour hadron decays in pp collisions at $\sqrt{s}$ = 5.02 TeV

The ALICE collaboration Acharya, Shreyasi ; Adamova, Dagmar ; Adhya, Souvik Priyam ; et al.
JHEP 09 (2019) 008, 2019.
Inspire Record 1735344 DOI 10.17182/hepdata.91213

Production cross sections of muons from semi-leptonic decays of charm and beauty hadrons were measured at forward rapidity ($2.5<y<4$) in proton--proton (pp) collisions at a centre-of-mass energy $\sqrt{s}=5.02$ TeV with the ALICE detector at the CERN LHC. The results were obtained in an extended transverse momentum interval, $2 < p_{\rm T} < 20$ GeV/$c$, and with an improved precision compared to previous measurements performed in the same rapidity interval at centre-of-mass energies $\sqrt{s}= 2.76$ and 7 TeV. The $p_{\rm T}$- and $y$-differential production cross sections as well as the $p_{\rm T}$-differential production cross section ratios between different centre-of-mass energies and different rapidity intervals are described, within experimental and theoretical uncertainties, by predictions based on perturbative QCD.

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Neutral to charged kaon yield fluctuations in Pb$-$Pb collisions at $\sqrt{s_{\rm NN}}$ = 2.76TeV

The ALICE collaboration Acharya, Shreyasi ; Adamova, Dagmar ; Adler, Alexander ; et al.
Phys.Lett.B 832 (2022) 137242, 2022.
Inspire Record 1993200 DOI 10.17182/hepdata.131260

We present the first measurement of event-by-event fluctuations in the kaon sector in Pb-Pb collisions at $\sqrt {s_{\rm NN}}=$ 2.76 TeV with the ALICE detector at the LHC. The robust fluctuation correlator $\nu_{\rm dyn}$ is used to evaluate the magnitude of fluctuations of the relative yields of neutral and charged kaons, as well as the relative yields of charged kaons, as a function of collision centrality and selected kinematic ranges. While the correlator $\nu_{\rm dyn}[\rm K^+,\rm K^-]$ exhibits a scaling approximately in inverse proportion of the charged particle multiplicity, $\nu_{\rm dyn}[\rm K_S^0,\rm K^{\pm}]$ features a significant deviation from such scaling. Within uncertainties, the value of $\nu_{\rm dyn}[\rm K_S^0,\rm K^{\pm}]$ is independent of the selected transverse momentum interval, while it exhibits a pseudorapidity dependence. The results are compared with HIJING, AMPT and EPOS-LHC predictions, and are further discussed in the context of the possible production of disoriented chiral condensates in central Pb-Pb collisions.

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Charm-quark fragmentation fractions and production cross section at midrapidity in pp collisions at the LHC

The ALICE collaboration Acharya, Shreyasi ; Adamova, Dagmar ; Adler, Alexander ; et al.
Phys.Rev.D 105 (2022) L011103, 2022.
Inspire Record 1863128 DOI 10.17182/hepdata.127975

Recent $p_{\rm T}$-integrated cross section measurements of the ground-state charm mesons and baryons, D$^{\rm 0}$, D$^+$, D$_{\rm s}^{+}$, $\Lambda_{\rm c}^{+}$, and $\Xi_{\rm c}^0$, are used to evaluate the charm fragmentation fractions and production cross section per unit of rapidity at midrapidity ($|y|<0.5$), in pp collisions at $\sqrt{s} = 5.02$ TeV at the LHC. The latter is ${\rm d} \sigma^{\rm c \overline{c}}/{\rm d} y|_{|y| < 0.5}$ =1165 $\pm 44(\rm{stat})^{+134}_{-101}(\rm{syst})$$\mu b$. These measurements were obtained for the first time in hadronic collisions at the LHC including the charm baryon states, recently measured by ALICE at midrapidity. The charm fragmentation fractions differ significantly from the values measured in e$^+$e$^-$ and ep collisions, providing evidence of the dependence of the parton-to-hadron fragmentation fractions on the collision system, indicating that the assumption of their universality is not supported by the measured cross sections. An increase of a factor of about 3.3 for the fragmentation fraction for the $\Lambda_{\rm c}^{+}$ with a significance of $5\,\sigma$ between the values obtained in pp collisions and those obtained in e$^+$e$^-$ (ep) collisions is reported. The fragmentation fraction for the $\Xi_{\rm c}^0$ was obtained for the first time in any collision system. The measured fragmentation fractions were used to update the $\rm c \overline{c}$ cross sections per unit of rapidity at $|y|<0.5$ at $\sqrt{s} = 2.76$ and 7 TeV, which are about 40% higher than the previously published results. The data were compared with perturbative-QCD calculations and lie at the upper edge of the theoretical bands.

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K$^{*}$(892)$^{\pm}$ resonance production in Pb$-$Pb collisions at $\sqrt{s_{\rm NN}}$ = 5.02 TeV

The ALICE collaboration Acharya, Shreyasi ; Adamova, Dagmar ; Aglieri Rinella, Gianluca ; et al.
Phys.Rev.C 109 (2024) 044902, 2024.
Inspire Record 2692205 DOI 10.17182/hepdata.150017

The production of K$^*$(892)$^\pm$ meson resonance is measured at midrapidity ($|y|<0.5$) in Pb-Pb collisions at $\sqrt{s_{\rm NN}}=5.02$ TeV using the ALICE detector at the LHC. The resonance is reconstructed via its hadronic decay channel K$^*$(892)$^\pm \rightarrow \rm{K^0_S \pi^\pm}$. The transverse momentum distributions are obtained for various centrality intervals in the $p_{\rm T}$ range of 0.4-16 GeV/$c$. The reported measurements of integrated yields, mean transverse momenta, and particle yield ratios are consistent with previous ALICE measurements for K$^*$(892)$^0$. The $p_{\rm T}$-integrated yield ratio 2K$^*$(892)$^\pm$/($\rm{K^+ + K^-}$) in central Pb-Pb collisions shows a significant suppression (9.3$\sigma$) relative to pp collisions. Thermal model calculations overpredict the particle yield ratio. Although both simulations consider the hadronic phase, only HRG-PCE accurately represents the measurements, whereas MUSIC+SMASH tends to overpredict them. These observations, along with the kinetic freeze-out temperatures extracted from the yields of light-flavored hadrons using the HRG-PCE model, indicate a finite hadronic phase lifetime, which increases towards central collisions. The $p_{\rm T}$-differential yield ratios 2K$^*$(892)$^\pm$/($\rm{K^+ + K^-}$) and 2K$^*$(892)$^\pm$/($\rm{\pi^+ + \pi^-}$) are suppressed by up to a factor of five at $p_{\rm T}<2$ GeV/$c$ in central Pb-Pb collisions compared to pp collisions at $\sqrt{s} =$ 5.02 TeV. Both particle ratios and are qualitatively consistent with expectations for rescattering effects in the hadronic phase. The nuclear modification factor shows a smooth evolution with centrality and is below unity at $p_{\rm T}>8$ GeV/$c$, consistent with measurements for other light-flavored hadrons. The smallest values are observed in most central collisions, indicating larger energy loss of partons traversing the dense medium.

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Event-by-event mean $p_{\rm T}$ fluctuations in pp and Pb-Pb collisions at the LHC

The ALICE collaboration Abelev, Betty Bezverkhny ; Adam, Jaroslav ; Adamova, Dagmar ; et al.
Eur.Phys.J.C 74 (2014) 3077, 2014.
Inspire Record 1307102 DOI 10.17182/hepdata.66332

Event-by-event fluctuations of the mean transverse momentum of charged particles produced in pp collisions at $\sqrt{s}$ = 0.9, 2.76 and 7 TeV, and Pb-Pb collisions at $\sqrt{s_{NN}}$ = 2.76 TeV are studied as a function of the charged-particle multiplicity using the ALICE detector at the LHC. Dynamical fluctuations indicative of correlated particle emission are observed in all systems. The results in pp collisions show little dependence on collision energy. The Monte Carlo event generators PYTHIA and PHOJET are in qualitative agreement with the data. Peripheral Pb-Pb data exhibit a similar multiplicity dependence as that observed in pp. In central Pb-Pb, the results deviate from this trend, featuring a significant reduction of the fluctuation strength. The results in Pb--Pb are in qualitative agreement with previous measurements in Au-Au at lower collision energies and with expectations from models that incorporate collective phenomena.

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