Electroweak bosons are sensitive probes of the initial state of heavy-ion collisions, of which a precise knowledge is required in order to disentangle initial state effects from phenomena induced by the presence of the quark--gluon plasma (QGP). The production rate of the Z and W$^\pm$ bosons is especially sensitive to the nuclear modification of the Parton Distribution Functions (PDF), and the muonic decays (Z $\rightarrow μ^+μ^-$ and W$^\pm \rightarrow μ^\pm ν$) offer medium-blind processes carrying this information to the detector where it can be directly collected. In this contribution, new measurements of electroweak bosons in p--Pb collisions at $\sqrt{s_{_{\rm NN}}}$ = 8.16 TeV and Pb--Pb collisions at $\sqrt{s_{_{\rm NN}}}$ = 5.02 TeV measured by the ALICE Collaboration are reported. The data are collected at forward rapidity with the ALICE muon spectrometer and are compared to theoretical predictions with and without including nuclear modifications.
Recent measurements of the electroweak-boson production performed by the ALICE Collaboration are reported. The W-boson production was measured at midrapidity in pp collisions at $\sqrt{s} = 13$ TeV, via the electronic decay of the boson. It was also measured in association with a hadron emitted back-to-back with respect to the electron. In heavy-ion collisions, the W- and Z-boson production was measured at forward rapidity in p--Pb collisions at $\sqrt{s_{\mathrm{NN}}} = 8.16$ TeV and Pb--Pb collisions at $\sqrt{s_{\mathrm{NN}}} = 5.02$ TeV, in their muonic decay channel. Measurements in pp co…
We present recent results on short-lived hadronic resonances obtained by the ALICE experiment in pp, p-Pb and Pb-Pb collisions at LHC energies, including the most recent measurements of $Λ(1520)$ and $Ξ(1530)^{0}$ resonances.
We present recent results on short-lived hadronic resonances obtained by the ALICE experiment at LHC energies. Results include system-size and collision-energy evolution of transverse momentum spectra, yields and ratios of resonance yields to those of longer lived particles, and nuclear modification factors. The results are compared with model predictions and measurements at lower energies.
We present recent results on short-lived hadronic resonances obtained by the ALICE experiment at LHC energies, including results from the Xe--Xe run. The ALICE results on transverse momentum spectra, yields, their ratio to long-lived particles, and nuclear modification factors will be discussed. The results will be compared with model predictions and measurements at lower energies.
First experimental results are presented on event-by-event net-proton fluctuation measurements in Pb- Pb collisions at $\sqrt{s_{NN}}$ = 2.76 TeV, recorded by the ALICE detector at the CERN LHC. The ALICE detector is well suited for such studies due to its excellent particle identification capabilities and large acceptance, which is crucial for fluctuation analysis. The studies are focussed on second order cumulants, but the analysis technique used is more general and will be applied, in the near future, also to higher order cumulants.
ALICE is a general purpose experiment designed to investigate nucleus-nucleus collisions at the Large Hadron Collider (LHC), located at CERN. The ALICE detector is optimized for the reconstruction of quarkonia through the dimuon decay channel at foward rapidity as well as the dielectron decay channel at midrapidity. In this contribution, quarkonium measurements performed by the ALICE collaboration at both midrapidity and forward rapidity for various energies and colliding systems (pp, p-Pb and Pb-Pb), will be discussed and compared to theory.
We report on forward-rapidity charmonium production in pp collisions at a center of mass energy $\sqrt{s} = 13$ TeV, as measured by ALICE at the LHC. Differential cross sections for both J/ψ and ψ(2S) are presented as a function of the charmonium transverse momentum and rapidity. Results are compared to similar measurements performed by LHCb, to lower energy measurements and to state of the art model calculations.
We present recent result on strange and non-strange D-meson production measured with ALICE in Pb--Pb collisions at the LHC. In addition, the measurements of the $Λ_{\rm c}^+$-baryon production and of the $Λ_{\rm c}^+/{\rm D^0}$ ratio in pp, p--Pb, and, for the first time ever, Pb--Pb collisions are reported.
Open heavy-flavour and quarkonia measurements are important tools to study the hot and dense partonic medium formed in ultra-relativistic heavy-ion collisions. The modification of their production in those collisions, with respect to the pp and p-Pb ones, can help in the characterization of this medium. Quarkonia and open heavy-flavour production is measured in ALICE in the three different collision systems, at mid- and forward rapidity. A selection of those results recently obtained in Pb-Pb and p-Pb collisions by the ALICE Collaboration is presented.
The ALICE Collaboration has measured heavy-flavour production through the reconstruction of hadronic decays of D mesons at mid-rapidity and via semi-electronic (at mid-rapidity) and semi-muonic (at forward rapidity) decays of charm and beauty hadrons in pp, p-Pb and Pb-Pb collisions. A summary of the most recent results from p-Pb collisions at $\sqrt{s_{NN}}=5.02$ TeV and Pb-Pb collisions at $\sqrt{s_{NN}} = 2.76$ TeV is presented in this paper.
Measurements of electroweak-bosons in heavy-ion collisions with ALICE are reported. They are measured at large rapidities, via their (di)muonic decay: Z $\rightarrow μ^+ μ^-$ and W$^\pm \rightarrow μ^\pm ν$. The Z production and nuclear modification factor in Pb--Pb collisions at $\sqrt{s_{_{\rm NN}}}$ = 5.02 TeV are presented and compared to theoretical predictions with or without nuclear modifications of the Parton Distribution Functions. Measurements of electroweak-boson production in p--Pb collisions at $\sqrt{s_{_{\rm NN}}}$ = 5.02 and 8.16 TeV are also presented and discussed.
The baryon chemical potential $μ_B$ is a fundamental parameter for the statistical mechanical description of particle production in heavy-ion collisions: its value encodes the average net baryon content of the fireball at chemical freeze-out. The first $μ_B$ measurement in high-energy Pb-Pb collisions at the LHC was published in 2018 in Nature, and it was found that $μ_B=0.7\pm3.8$ MeV. In this contribution, an improved $μ_B$ measurement based on the study of antiparticle-to-particle ratios for protons, $^3\mathrm{He}$ and hypertriton ($^3_Λ\mathrm{H}$) using the data collected by ALICE in Run…
Measurements of the production of muons from heavy-flavour hadron decays at forward rapidity ($2.5 < y < 4.0$) in Pb--Pb collisions at $\sqrt{s_{\rm NN}} = 2.76$ and 5.02 TeV with the ALICE detector are presented along with the $R_{\rm AA}$ measurements in different centrality intervals as a function of transverse momentum, $p_{\rm T}$. Results of the measured $R_{\rm AA}$ at both energies are shown and are compared to the different model predictions.
The ALICE experiment at the Large Hadron Collider (LHC) at CERN consists of a central barrel, a muon spectrometer and additional detectors for trigger and event classification purposes. The low transverse momentum threshold of the central barrel gives ALICE a unique opportunity to study the low mass sector of central exclusive production at the LHC.
The ALICE collaboration has studied inclusive J/$ψ$ and $ψ$(2S) production at forward rapidities in pp collisions at $\sqrt{s} = 7$ TeV with the ALICE Muon Spectrometer. The analysis has been carried out on a data sample corresponding to an integrated luminosity $\mathcal{L}_{\rm int}$ = 1.35 pb$^{-1}$. The production cross-sections of J/$ψ$ and $ψ$(2S), integrated over \pt\ (0 $<$ \pt\ $<$ 20 GeV/$c$) and \y\ (2.5 $<$ \y\ $<$ 4), have been measured. The J/$ψ$ and $ψ$(2S) differential cross-sections, in transverse momentum and rapidity, have also been measured. The results have been compared w…
The ALICE Collaboration collected a large data sample of Pb-Pb collisions at $\sqrt{s_{\rm{NN}}}$ = 5.02 TeV in 2015 at the Large Hadron Collider (LHC) and the excellent particle identification (PID) capabilities allow for the detection of rarely produced (anti-)hypernuclei. In particular, the (anti-)hypertriton, $^3_Λ$H, which is a bound state of a proton, a neutron and a $Λ$, is the lightest known hypernucleus. The results on the $^3_Λ$H production are compared with the predictions from a model based on coalescence approach and from statistical-thermal models to investigate the production me…
Recent multiplicity-dependent analyses of pp and p--Pb collision data have revealed that particle production shares similar features with that in heavy-ion collisions. Studies using resonances could help to understand the possible onset of collective-like phenomena and the presence of a hadronic phase in small collision systems. Measurements of the differential yields of resonances with different lifetime, mass, quark content, and quantum numbers could enable understanding the mechanisms that influence the shape of particle momentum spectra, lifetime of the hadronic phase, strangeness producti…
Measurements of direct photon and neutral pion production in heavy-ion collisions provide a comprehensive set of observables characterizing properties of the hot QCD medium. Direct photons provide means to test the initial stage of an AA collision and carry information about the temperature and space-time evolution of the hot medium. Neutral pion suppression probes the parton energy loss in the hot medium. Measurements of neutral meson spectra in pp collisions at LHC energies $\sqrt{s}=$0.9, 2.76, 7 TeV serve as a reference for heavy-ion collisions and also provide valuable input data for para…
ALICE is an LHC experiment devoted to the study of strongly interacting matter in proton-proton, proton--nucleus and nucleus-nucleus collisions at ultra-relativistic energies. The ALICE VZERO system, made of two scintillator arrays at asymmetric positions, one on each side of the interaction point, plays a central role in ALICE. In addition to its core function as a trigger, the VZERO system is used to monitor LHC beam conditions, to reject beam-induced backgrounds and to measure basic physics quantities such as luminosity, particle multiplicity, centrality and event plane direction in nucleus…
Measurement of the nuclear modification factor of electrons from heavy-flavour hadron decays in Pb-Pb collisions at {\surd}sNN = 2.76 TeV with ALICE at the LHC
ALICE (A Large Ion Collider Experiment) is the LHC experiment dedicated to the investigation of the nature and the properties of the Quark-Gluon Plasma (QGP) using heavy-ion collisions. Among its characteristics, excellent particle identification capabilities stand out, which are a basic requirement to address QGP physics. The ALICE particle identification performance will be reviewed in this paper, focusing in particular on the LHC Run 2 period.
Reconstruction of jets in high-energy heavy-ion collisions is challenging due to the large and fluctuating background coming from the underlying event. We report results on full jet reconstruction, obtained from data collected in 2011 by the ALICE detector at LHC for Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}=2.76~\mathrm{TeV}$. The analysis makes use of the tracking system and the electromagnetic calorimeter. Signal jets, which come from hard scattered partons, are reconstructed using the anti-$k_{\mathrm{T}}$ jet finder algorithm. The average background is subtracted on a jet-by-jet basis t…
