Measurements of charged-particle production in pp and p-Pb collisions at $\sqrt{s}_{\rm NN}=5.02$ TeV in the toward, away and transverse regions are discussed. These three regions are defined event by event relative to the track with the largest transverse momentum ($p_{\rm T}^{\rm trig}$). The transverse region is sensitive to the underlying event (UE), but it also includes contributions from initial- and final-state radiation (ISR-FSR). Therefore, it is further subdivided in two regions, defined according to their relative multiplicity: trans-max (the sub-transverse region with the largest multiplicity) and trans-min (the sub-transverse region with the smallest multiplicity) regions which are sensitive to UE and ISR-FSR, respectively. KNO-like scaling properties are explored in the three defined transverse regions. Finally, the relationship between $p_{\rm T}^{\rm trig}$ and the energy detected in a region close to beam rapidity (very forward energy) is reported.
We present multiplicity and pseudorapidity distributions of inclusive photons at forward rapidity in proton-lead (p-Pb) collisions at $\sqrt{s\rm_{NN}}$ = 5.02 TeV using the data obtained from Photon Multiplicity Detector (PMD) of ALICE. The centrality dependence of pseudorapidity distributions of inclusive photons is also studied. Results are compared with the previous ALICE measurements of charged-particle production and with theoretical predictions from Monte Carlo models, DPMJET and HIJING.
Studying p-Pb collisions at LHC energies allows a quantitative evaluation of the cold nuclear matter (CNM) effects. Event activity dependence of the J/ψ production is under intense studies both theoretically and experimentally and is expected to provide important insights on the influence of CNM. This paper presents the first results on event activity dependence of the inclusive J/ψ production at backward (-4.46 < $y_{cms}$ < -2.96) and forward (2.03 < $y_{cms}$ < 3.53) rapidity in ALICE for p-Pb collisions at $\sqrt{s_{NN}}$ = 5.02 TeV.
Probes for the small-x parton densities and predicted effects of gluon saturation are discussed. At very low x and intermediate Q, only results on hadronic observables at the LHC are available, which do not provide unambiguous information. It is shown that the measurement of direct photons at forward rapidity at the LHC is particularly promising to provide a unique signal. We further discuss the possibilities to perform such measurements with a detector upgrade in the ALICE experiment and present the R&D activities ongoing.
The ALICE experiment measured the heavy-flavour production in the semi-muonic decay channel at forward rapidities ($2.5<y<4$) in pp and Pb--Pb collisions at $\sqrt{s_{NN}} = 2.76$ TeV. We report on the first results on the $p_{\rm T}$-differential cross-sections in pp collisions as well as on the nuclear modification factors as a function of the transverse momentum and centrality.
We report on the performance studies of two correction methods, namely the efficiency-purity method and the Bayesian unfolding method applied to the pseudorapidity distribution of photons. The pseudorapidity distribution of inclusive photons at forward rapidities in the range \mbox{\small $(2.3<η<3.9)$} in p\textendash Pb collisions at $\sqrt{\it{s}_{\rm{NN}}} = 8.16$ TeV is obtained with the HIJING Monte Carlo event generator. The simulated data samples were obtained from the Photon Multiplicity Detector (PMD) in ALICE.
In the ALICE experiment, at forward rapidity (2.5 < y < 4), the production of heavy quarkonium states is measured via their mu+ mu- decay channels. We present the first measurement of inclusive J/Psi production, down to pT = 0, from Pb-Pb data collected at the LHC at sqrt(s_NN) = 2.76 TeV. Preliminary results on the nuclear modification factor (R_AA) and the central to peripheral nuclear modification factor (R_CP) show J/Psi suppression with no significant centrality dependence and an integrated R_AA(0-80%) = 0.49 \pm 0.03(stat.) \pm 0.11(syst.).
ALICE has performed several measurements aimed at understanding the collective-like effects observed in small collision systems. New approaches may be needed to clarify particle-production mechanisms in high-multiplicity pp collisions. Transverse momentum ($p_{\rm T}$) spectra as a function of charged-particle multiplicity show intriguing features. For example, data exhibit a stronger-than-linear increase of the self-normalised high-$p_{\rm T}$ particle yields versus multiplicity. In order to understand the role of auto-correlations on these effects, it has been proposed to use the underlying …
The ALICE Forward Multiplicity Detector (FMD) is a silicon strip detector with 51,200 strips arranged in 5 rings, covering the range $-3.4 < η< 5.1$. It is placed around the beam pipe at small angles to extend the charged particle acceptance of ALICE into the forward regions, not covered by the central barrel detectors.
The production of muons from heavy flavour decays is measured at forward rapidity (2.5 < y < 4) with the muon spectrometer of the ALICE experiment at the LHC. In pp collisions at \sqrt{s} = 7 TeV, the measurement of the transverse momentum and rapidity differential production cross section of muons from heavy flavour decays is carried out from a data sample corresponding to an integrated luminosity of Lint = 16.5 nb^-1 and results are compared to predictions based on perturbative QCD calculations. In Pb-Pb collisions at \sqrt{s_{NN}}= 2.76 TeV, the analysis of a data sample corresponding to an…
ALICE is the experiment dedicated to the study of the quark gluon plasma in heavy-ion collisions at the CERN LHC. Improvements of ALICE sub-detectors are envisaged for the upgrade plans of year 2017. The Muon Forward Tracker (MFT) is a proposal in view of this upgrade, motivated both by the possibility to overcome the intrinsic limitations of the Muon Spectrometer, and by the possibility to perform new measurements of general interest for the whole ALICE physics. The measurement of the offset of single muons and dimuons will permit to disentangle open charm ($cτ\sim 150 μ$m) and beauty ($cτ\si…
Bottomonium production is a powerful tool to investigate hadron collisions and the properties of the medium created in heavy-ion collisions. According to the color-screening model, these mesons give important information about the deconfined medium called Quark-Gluon Plasma (QGP) produced in ultrarelativistic heavy-ion collisions. Cold nuclear matter (CNM) effects can modify the bottomonium production even in absence of deconfined matter: the study of proton-nucleus collisions is therefore essential to disentangle these effects from the hot ones. Last but not least, measurement in pp collision…
J/psi suppression induced by color screening of its constituent quarks was proposed 26 years ago as a signature of the formation of a quark gluon plasma in heavy-ion collisions. Recent results from ALICE in Pb-Pb collisions exhibit a smaller suppression with respect to previous measurements at the SPS and RHIC. The study of azimuthal anisotropy in particle production gives information on the collective hydrodynamic expansion at the early stage of the fireball, where the matter created in high-energy nuclear collisions is expected to be in a deconfined state. In particular, J/psi elliptic flow …
Long-range correlations between particles separated by a pseudorapidity gap are a powerful tool to explore the initial stages and evolution of the medium created in hadron-hadron collisions. An overview of the long-range correlations measured by the ALICE detector in pp, p-Pb and Pb-Pb will be presented. This includes analyses of forward-backward, two- and multi-particle correlations with the use of the central barrel and forward detectors.
The pseudorapidity densities of charged particles and inclusive photons produced in high energy nuclear collisions are essential observables to characterise the global properties of the collisions, such as the achieved energy density, and to provide important constraints for Monte Carlo model calculations. In the LHC Run 1 and Run 2 configurations, ALICE had large coverage to measure charged particles over a pseudorapidity range ($-3.4~<~η~<~5.0$), combining the data from the Silicon Pixel Detector (SPD) and the Forward Multiplicity Detector (FMD). The inclusive photons are measured at forward…
The study of formation of heavy quarkonia in relativistic heavy ion collisions provides important insight into the properties of the produced high density QCD medium. Lattice QCD studies show sequential suppression of quarkonia states with increasing temperature; which affirms that a full spectroscopy, can provide us a thermometer for the matter produced under extreme conditions in relativistic heavy ion collisions and one of the most direct probes of de-confinement. Muons from the decay of charmonium resonances are detected in ALICE Experiment in p+p and Pb+Pb collisions with a muon spectrome…
A forward electromagnetic calorimeter (FoCal) based on SiW technology is being considered as a possible upgrade to the ALICE detector. This device should in particular feature an extremely high granularity allowing gamma/pi0 discrimination out to very high momenta. The main option considered for the high granularity layers is the use of CMOS pixel sensors. We will discuss the motivation and design principles of the proposed calorimeter and will then focus on the experience gained with a full CMOS-pixel calorimeter prototype. Preliminary results of this device show very good capabilities for sh…
Heavy quarks are produced at the first instant of a nucleus--nucleus collision and therefore are an important tool to study the subsequent high energy-density medium formed in ultra-relativistic heavy-ion collisions. A series of experimental efforts for understanding the properties of the Quark--Gluon Plasma (QGP), a medium consisting of a deconfined state of quarks and gluons, are based on measuring the bound states of heavy quark--anti-quark pairs known as quarkonia. However, the medium modification of heavy-flavour hadron production includes also the contribution of Cold Nuclear Matter (CNM…
The ALICE apparatus at the LHC was designed and built to perform dedicated studies of the Quark-Gluon Plasma (QGP), a strongly interacting phase of QCD matter, expected to be created in heavy-ion collisions, where quarks and gluons are deconfined. In such collisions heavy flavours are produced at the very early stage of the interaction by the initial hard scattering processes and hence can be used to characterize the hot and dense medium. In particular the sequential suppression of quarkonia (charmonia and bottomonia) was proposed as a thermometer of the deconfined medium. The inclusive $Υ(1S)…
The similarity between small- and large-collision systems is explored using the charged-particle multiplicity in the transverse region, $N^{\rm T}_{\rm ch}$, which is sensitive to the underlying event. Measurements of charged-particle production as a function of $N^{\rm T}_{\rm ch}$ in pp, p-Pb and Pb-Pb collisions at $\sqrt{s_{\rm NN}}=5.02$ TeV in the toward, away and transverse regions are discussed. These three regions are defined relative to the track with the largest transverse momentum in the event ($p_{\rm T}^{\rm trig}$). The activity in the transverse region is subtracted from the ac…
ALICE is the experiment at the CERN LHC devoted to study heavy-ion collisions. An upgrade program of the ALICE detector is ongoing toward the LHC Run 3 starting in 2022 together with the upgrade of the data acquisition system and the detector control system (DCS). One of the main projects of the current ALICE upgrade program is the addition of the muon forward tracker (MFT), a new silicon pixel detector located at forward rapidity. In this paper, we describe the DCS of the MFT detector which is entirely controlled via a finite state machine in a hierarchical system.
The LHC is not only the highest energy collider for protons and heavy ions, but also for photon photon and photon hadron ($γ$p and $γ$Pb) interactions. This is because the protons and ions accelerated in the LHC carry an electromagnetic field, which can be viewed as a source of photons, and such photons can interact with either other photons or with hadrons. Ultra Peripheral Collisions (UPC) occur when the incoming ions pass beyond the range of the strong force, with impact parameters larger than the sum of the radii of the incoming projectiles, and are mediated by the exchange of virtual phot…
We present the results of measurements of two-particle angular correlations between trigger particles reconstructed in the ALICE Forward Muon Spectrometer ($-4.0 < η< -2.5$) and associated particles reconstructed in the central barrel detectors ($|η| < 1.0$) in p--Pb collisions at a nucleon-nucleon center-of-mass energy of 5.02 TeV. At low transverse momentum ($p_{\mathrm{T}}$), the reconstructed trigger particles mainly originate from weak decays of primary pions and kaons, whereas at high $p_{\mathrm{T}}$, they originate mainly from the decay of heavy-flavor particles. The ridge structure el…
The low-x gluon density in the proton and, in particular, in nuclei is only very poorly constrained, while a better understanding of the low-x structure is crucial for measurements at the LHC and also for the planning of experiments at future hadron colliders. In addition, deviations from linear QCD evolution are expected to appear at low x, potentially leading to gluon saturation and a universal state of hadronic matter, the color-glass condensate. However, these effects have not been unambiguously proven to date. Fortunately, data from the LHC can be used directly to provide better constrain…
Muons from the decay of charmonium resonances are detected in the ALICE Experiment at the Large Hadron Collider(LHC) for pp and Pb-Pb collisions with a muon spectrometer, covering the forward rapidity region 2.5$<$ $y$ $<$4.0. Analysis of the nuclear modification factor ($R_{\rm AA}$) at forward rapidity are presented and compared with mid-rapidity results from electrons in the central barrel covering $|y|<$0.9. The roles of suppression and regeneration mechanisms are discussed, as well as the importance of the results of the forthcoming p-Pb data taking for the estimate of cold nuclear matter…
We present the elliptic flow of inclusive J/$ψ$ measured in the $μ^{+}μ^{-}$ channel at forward rapidity ($2.5<y<4.0$), down to zero transverse momentum, in Pb-Pb collisions at $\sqrt{s_{_{\mathrm{NN}}}}=2.76$ TeV with the ALICE muon spectrometer. The $p_{\mathrm T}$ dependence of J/$ψ$ $v_2$ in non-central (20%-60%) Pb-Pb collisions at $\sqrt{s_{_{\mathrm{NN}}}}=2.76$ TeV is compared with existing measurements at RHIC and theoretical calculations. The centrality dependence of the $p_{\mathrm{T}}$-integrated elliptic flow, as well as the $p_{\mathrm{T}}$ dependence in several finer centrality …
This contribution focuses on latest ALICE results on charmonium forward production in proton-proton (pp), proton-lead (p-Pb) and lead-lead (Pb-Pb) collisions at the TeV scale. In p-Pb and Pb-Pb collisions, measurements are presented in the form of the charmonium nuclear modification factor (the properly normalized ratio of its production cross section in heavy ion collisions to its pp counterpart) as a function of the charmonium rapidity and transverse momentum. These measurements are compared to available theoretical calculations. Possible interpretations of these results in terms of gluon sa…
The relative J/$ψ$ yields as a function of relative charged-particle multiplicity in pp collisions at $\sqrt{s}$ = 5.02 TeV, measured at forward rapidity, are investigated for the first time. A linear increase of the relative J/$ψ$ yield with respect to multiplicity is observed. A comparison of the findings of the present work with the available ALICE measurements obtained in pp collisions at $\sqrt{s}$ = 13 TeV at forward and mid-rapidity indicates that the increase of J/$ψ$ with multiplicity is independent of energy but exhibits a strong dependence on the rapidity gap between the J/$ψ$ and m…
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…
Multiplicity distributions of charged particles for pp collisions at LHC Run 1 energies, from $\sqrt{s}=$ 0.9 to 8 TeV are measured over a wide pseudorapidity range ($-3.4<η<5.0$) for the first time. The results are obtained using the Forward Multiplicity Detector and the Silicon Pixel Detector within ALICE. The results are compared to Monte Carlo simulations, and to the IP-Glasma model.
Jets are produced by processes involving high momentum transfer of initial partons at high energies. Comparing jet production in pp and nucleus-nucleus collisions will allow us to study the jet-quenching effect caused by the hot and dense QCD medium produced in nucleus-nucleus collisions when energetic partons traverse the medium. In particular, systematic studies of jet production in different multiplicity environments will provide in-depth understanding of the medium properties and their evolution from small to large systems. In small systems and high multiplicity events, the bulk properties…
Forward-backward (FB) correlations are considered to be a powerful tool for the exploration of the early dynamics of hadronic interactions. The FB correlation functions can be constructed from different observables calculated event-by-event in two separated pseudorapidity regions. We report measurements of event-by-event average transverse momentum correlations for charged particles in two separated pseudorapidity regions in Pb-Pb collisions at $\sqrt{s_{\rm NN}}=2.76$ and 5.02 TeV recorded with ALICE at the LHC. The event-by-event mean transverse momenta correlations are robust against volume…
We report on the pseudo-rapidity dependence of the charged particle anisotropic flow in Pb-Pb collisions at 2.76 TeV. The measurement is done over a wide range of pseudo-rapidity, |η|<5 using the forward detectors of ALICE at the LHC. Results are obtained from two- and multi-particle correlation techniques with the latter being less sensitive to non-flow effects. Elliptic flow longitudinal scaling, comparison with RHIC data and AMPT model calculations for the LHC are discussed.
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 the transverse momentum (0 $<$ $p_{\mathrm T}$ $<$ 20 GeV/$c$) and rapidity (2.5 $<$ $y$ $<$ 4), have been measured. The J/$ψ$ and $ψ$(2S) differential cross-sections, in transverse momentum and rapidity, have also been measure…
The production of open heavy-flavour particles was studied in p-Pb collisions at $\sqrt{s_\mathrm{NN}}=5.02$ TeV using the ALICE detector. Three separate observables were used: the hadronic decays of D mesons at mid-rapidity, and semileptonic decays of heavy-flavour hadrons to electrons and muons at mid-rapidity and forward rapidity, respectively. The most recent ALICE measurements of the nuclear modification factor, $R_\mathrm{pPb}$, of open charm and beauty are reported, along with the centrality and multiplicity dependence of D-meson production in p-Pb collisions.
The ALICE Collaboration has studied the inclusive $ψ(\mathrm{2S})$ meson production in pp, p-Pb and Pb-Pb collisions at the CERN LHC. The $ψ(\mathrm{2S})$ is detected through its decay to a muon pair, using the forward Muon Spectrometer, which covers the pseudo-rapidity range $-4<η<-2.5$. The $ψ(\mathrm{2S})$ production cross sections in pp collisions are presented as a function of rapidity (y) and transverse momentum ($p_{\mathrm{T}}$). In p-Pb collisions, $ψ(\mathrm{2S})$ results are compared to the J/$ψ$ ones by the ratio of their production cross sections as a function of rapidity, transve…
W bosons are produced in hard scattering processes of partons in collisions of hadrons and they do not interact strongly with the medium produced in high-energy heavy-ion collisions. Therefore, in p-Pb collisions the measurement of W-boson yields represents a standard candle to check the validity of binary-collision scaling and can provide important constraints on the parton distribution functions, which can be modified in nuclei with respect to protons or neutrons. At the LHC, ALICE (A Large Ion Collider Experiment) is dedicated to the study of ultrarelativistic heavy-ion collisions, in which…
We report the recent measurements of the inclusive J/ψ production in pp collisions at \sqrt{s} = 2.76 TeV, in pp collisions at \sqrt{s} = 7 TeV and in Pb-Pb collisions at \sqrt{s_{NN}} = 2.76 TeV with the ALICE detector at the LHC. The J/ψ mesons are detected down to pT = 0 GeV/c via their di-muon decay channel at forward rapidity (2.5 < y < 4) and via their di-electron decay channel at mid-rapidity (|y| < 0.9). A special emphasis is put on the nuclear modification factor which is compared to the predictions of current J/ψ production models.
A precise measurement of the heavy-flavor production cross-sections in pp collisions is an essential baseline for the heavy-ion program. In addition it is a crucial test of pQCD models in the new energy regime at LHC. ALICE measures the muons from the decay of charmonium resonances and from the semileptonic decay of heavy-flavored hadrons in its forward (-4.0 $<$ $η$ $<$ -2.5) Muon Spectrometer. We discuss the status of the detector and present results of data taken in pp collisions at $\sqrt{s}$=7 TeV.
The ALICE Collaboration has studied inclusive $ψ$(2S) production in pp, p-Pb and Pb-Pb collisions with the ALICE Muon Spectrometer which covers the rapidity range 2.5 $<$ $y_{\rm lab}$ $<$ 4. The $ψ$(2S) measurement was performed in the dimuon decay channel. The $ψ$(2S) production cross-section and $ψ$(2S) to J/$ψ$ cross-section ratio in pp collisions will be presented, both integrated and differential in rapidity and in transverse momentum. In p-Pb collisions, $ψ$(2S) results will be compared to the J/$ψ$ ones by means of the production cross-section ratio and the double ratio [$ψ$(2S)/J/$ψ$]…
ALICE has measured quarkonium production in p-Pb collisions at backward ($-$4.46 $<$ $y_{\rm cms}$ $<$ $-$2.96), mid ($-$1.37 $<$ $y_{\rm cms}$ $<$ 0.43) and forward (2.03 $<$ $y_{\rm cms}$ $<$ 3.53) rapidity ($y$) regions down to zero transverse momentum ($p_{\rm T}$). The inclusive J/$ψ$ production has been studied at mid-$y$ in p-Pb interactions at $\sqrt{s_{\rm NN}}$ = 5.02 TeV and at forward and backward $y$ in p-Pb collisions at $\sqrt{s_{\rm NN}}$ = 5.02 TeV and 8.16 TeV. The comparison of the J/$ψ$ production to the one of the loosely bound $ψ$(2S) state is discussed, together with new…
Heavy quarks are produced in the early stages of ultra-relativistic hadron collisions via hard scatterings and are an important tool for studying different aspects of Quantum Chromodynamics (QCD) in hadronic collisions. Charged-particle multiplicity gives information on the global characteristics of the event and could be used to characterize particle production mechanisms. In hadronic collisions at Large Hadron Collider (LHC) energies, there is a significant contribution of multi-parton interactions. The measurement of heavy-flavour yields as a function of charged-particle multiplicity gives …
Latest results on open heavy favour measurements in pp collisions at 7 TeV and Pb-Pb collisions at sqrt(s_NN) = 2.76 TeV with the ALICE experiment are presented. The results of the single lepton analyses (electrons at central rapidity, muons at forward rapidity) and D meson reconstruction will be discussed.
The ALICE Collaboration has studied inclusive J/$ψ$ and $ψ$(2S) production in p-Pb collisions at $\sqrt{s_{\rm NN}} = 5.02$ TeV with the Muon Spectrometer. The measurement was performed at forward (2.03 $<$ $y_{\rm cms}$ $<$ 3.53) and backward ($-$4.46 $<$ $y_{\rm cms}$ $<$ $-$2.96) centre of mass rapidities. The nuclear modification factor of J/$ψ$ and $ψ$(2S) has been measured as a function of transverse momentum and event activity. Theoretical models based on nuclear shadowing, coherent energy loss or both are in reasonable agreement with the J/$ψ$ results but cannot describe the $ψ$(2S) be…
The pseudorapidity density and anisotropic flow of charged-particles provide fundamental information about global variables and correlations in heavy-ion collisions. The pseudorapidity density is related to the energy available for particle production while the anisotropic flow is related to collective effects from interactions between these particles. Extending these measurements to very forward pseudorapidities yields information about the longitudinal expansion of the system. The first measurements performed at the LHC over more than 8 units of pseudorapidity are presented. The longitudinal…
Quarkonia states are expected to provide essential information on the properties of the high-density strongly-interacting system formed in the early stages of high-energy heavy-ion collisions. ALICE is the LHC experiment dedicated to the study of nucleus-nucleus collisions and can study charmonia at forward rapidity (2.5 < y < 4) via the mu+ mu- decay channel and at mid rapidity (|y| < 0.9) via the e+ e- decay channel. In both cases charmonia are measured down to zero transverse momentum. The inclusive J/psi production as a function of transverse momentum and rapidity in pp collisions at sqrt{…
Measurement of heavy-flavour production in small systems can be used to test the Quantum ChromoDynamic (QCD) models. In this manuscript, the production cross section of D mesons at midrapidity and open heavy-flavour decay muons (HFM) measured at forward rapidity in pp collisions at $\sqrt{s}$ = 5.02 TeV, and open heavy-flavour decay electrons (HFE) measured at midrapidity in pp collisions at $\sqrt{s}$ = 13 TeV with ALICE detector will be presented. The self-normalized yield of open heavy-flavour decay electrons and muons as a function of multiplicity in pp and p$-$Pb collisions will be presen…
Charmonia, bound states of charm and anti-charm quarks, represent an interesting probe for the study of Quantum Chromodynamics (QCD) since their production involves both hard and soft energy scales. Several effective models are available to describe the production of charmonia, but so far none have been able to describe all experimental observables simultaneously. ALICE has studied the production of charmonia in different collision systems at all available LHC energies at both mid- and forward-rapidity down to zero transverse momentum. In this contribution, different measurements performed in …
Angular correlations of two and more particles are a sensitive probe of the initial state and the transport properties of the system produced in heavy-ion collisions. Two recent results of the ALICE collaboration are presented. Event-shape engineering, a novel method, is applied to Pb-Pb collisions which splits events within the same centrality interval into classes with different average flow. The results indicate an interplay between radial and elliptic flow likely related to the initial-state eccentricity. In pp and p-Pb collisions, recent results revealed intriguing long-range correlation …
Hadrons containing heavy quarks, i.e. charm or beauty, are unique probes of the properties of the hot and dense QCD medium produced in heavy-ion collisions. Due to their large masses, heavy quarks are produced at the initial stage of the collision, almost exclusively via hard partonic scattering processes. Therefore, they are expected to experience the full collision history propagating through the QCD medium losing energy via elastic and inelastic collisions with the medium constituents. The ALICE collaboration has measured the production of open heavy-flavour hadrons via their hadronic and s…
High energy p-p, p-Pb and Pb-Pb collisions at the CERN-LHC offer unprecedented opportunities for studying wide variety of physics at small Bjorken-x. Here we discuss capabilities of the ALICE experiment at the CERN-LHC for probing small-x QCD physics. A new forward electromagnetic calorimeter is being proposed as an ALICE upgrade to explore the small-x region in more detail.
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.
ALICE is the dedicated heavy-ion experiment at the LHC. Due to the unique particle identification capabilities of the central barrel detectors (|eta|<0.9), J/psi can be measured in the di-electron channel in the very demanding environment of central Pb-Pb collisions at the LHC. In addition J/psi are measured at forward rapidity (2.5<y<4) with a dedicated muon spectrometer. ALICE is the only LHC experiment with an acceptance for J/psi that reaches down to p_T=0 at both, mid- and forward rapidity. Preliminary results on the nuclear modification factor of the inclusive J/psi production at mid- an…
Heavy-flavour production measurements in pp collisions are important tools to test theoretical models based on perturbative quantum chromodymanics (pQCD) and to investigate the heavy-quark hadronization mechanisms. In ALICE, heavy quarks are measured via the hadronic and electronic decay channels at central rapidity (-0.9 $<$ $\textit{y}$ $<$ 0.9) and via the muon decay channels at forward rapidity (-4 $<$ $\textit{y}$ $<$ -2.5). In this contribution, the production cross-section measurements via the leptonic decay of heavy-flavour hadrons are presented and compared to pQCD theoretical calcula…
We report recent results from the ALICE experiment the Large Hadron Collider on open charmed hadron production in pp collisions at $\sqrt{s} = 2.76$ and 7 TeV, and Pb-Pb collisions at $\sqrt{\mathrm{s}_{_{\mathrm{NN}}}} = 2.76$ TeV. Open charmed hadrons are kinematically fully reconstructed in the hadronic decay channels \DtoKpi, \DtoKpipi, and \DstartoDpi %$D^0\rightarrow K^-π^+$, $D^+\rightarrow K^-π^+ π^+$, and $D^{*+} \rightarrow D^0 (K^-π^+) + π^+$ and identified through their invariant mass. Combinatorial background is minimized by selecting a displaced vertex topology. Inclusive charm a…
