In experimental high energy physics the analysis of data is one of our main activities. It is upstream the publication process and by far the longest step. Within the ALICE collaboration, the on-going data analyses are presented in their corresponding weekly Physics Analysis Group (PAG) meetings and monthly Physics Working Group (PWG) meeting, based on their physical process under study.

An analysis is internally reviewed by an Analysis Review Committee (ARC), composed of three senior physicists of the collaboration, relying on a detailed internal document, written by the analyzers, so-called Analysis Note (AN). Then, the results are presented and approved by the Physics Forum (PF) in which the Physics Board (PB) members, as well as all the collaboration members, participate.

Once a data analysis is approved, a Paper Committee (PC) composed of the main analyzers is formed to write the paper. In parallel, an Internal Review Committee (IRC), composed of three senior physicists of the collaboration, is created and reviews the quality of the draft via an iterative process. After the PC receives the green light from the IRC, the Editorial Board (EB) reviews the document and opens it for comments to the entire collaboration via two Collaboration Rounds (CR).

Finally, the document is sent to a journal and the external and blind peer-review process starts. In general, two or three referrees comment the document. The PC members are in charge to answer to them. The IRC and EB review the modified draft and the proposed answers. After several rounds with the journal referrees, the paper might be approved and finally published in the next edition of the journal.

Inclusive \(\Upsilon\mathrm{(1S)}\) and \(\Upsilon\mathrm{(2S)}\) production have been measured in Pb—Pb collisions at the centre-of-mass energy per nucleon pair \(\sqrt{s_{_{\mathrm{NN}}}}=5.02\) 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 \(p_{\mathrm T}<15\) GeV/\(c\), via their decays to muon pairs. In this Letter, we present results on the inclusive \(\Upsilon\mathrm{(1S)}\) nuclear modification factor \(R_{\mathrm AA}\) as a function of the collision centrality, transverse momentum and rapidity. The \(\Upsilon\mathrm{(1S)}\) and \(\Upsilon\mathrm{(2S)}\) \(R_{\mathrm AA}\), integrated over the centrality range 0—90% are \(0.37 \pm 0.02 {\mathrm{(stat)}}\pm 0.03 {\mathrm{(syst)}}\) and \(0.10 \pm 0.04 {\mathrm{(stat)}}\pm 0.02 {\mathrm{(syst)}}\), respectively, leading to a ratio \(R_{\mathrm{AA}}^{\Upsilon(\mathrm2S)}/R_{\mathrm{AA}}^{\Upsilon(\mathrm1S)}\) of \(0.28\pm0.12\text{(stat)}\pm0.06\text{(syst)}\). The observed \(\Upsilon\mathrm{(1S)}\) suppression increases with the centrality of the collision and no significant variation is observed as a function of transverse momentum and rapidity.

We report on the inclusive production cross sections of \(\mathrm{J}/\psi\), \(\psi(\mathrm{2S})\), \(\Upsilon\mathrm{(1S)}\), \(\Upsilon\mathrm{(2S)}\) and \(\Upsilon\mathrm{(3S)}\), measured at forward rapidity with the ALICE detector in pp collisions at a center-of-mass energy \(\sqrt{s}=8\) TeV. The analysis is based on data collected at the LHC and corresponds to an integrated luminosity of \(1.23~\mathrm{pb}^{-1}\). Quarkonia are reconstructed in the dimuon-decay channel. The differential production cross sections are measured as a function of the transverse momentum \(p_\mathrm{T}\) and rapidity \(y\), over the \(p_\mathrm{T}\) ranges \(0<p_\mathrm{T}<20\) GeV/\(c\) for \(\mathrm{J}/\psi\), \(0<p_\mathrm{T}<12\) GeV/\(c\) for all other resonances, and for \(2.5<y<4\). The cross sections, integrated over \(p_\mathrm{T}\) and \(y\), and assuming unpolarized quarkonia, are \(\sigma_{{\mathrm{J}/\psi}} = 8.98\pm 0.04\pm 0.82~\mu\mathrm{b}\), \(\sigma_{{\psi(\mathrm{2S})}} = 1.23\pm 0.08\pm 0.22~\mu\mathrm{b}\), \(\sigma_{\mathrm{\Upsilon }\mathrm{(1S)}} = 71\pm 6\pm 7~\mathrm{nb}\), \(\sigma_{\mathrm{\Upsilon }\mathrm{(2S)}} = 26\pm 5\pm 4~\mathrm{nb}\) and \(\sigma_{\mathrm{\Upsilon }\mathrm{(3S)}} = 9\pm 4\pm 1~\mathrm{nb}\), where the first uncertainty is statistical and the second one is systematic. These values agree, within at most \(1.4\sigma\), with measurements performed by the LHCb collaboration in the same rapidity range.

The production of \(\mathrm{J}/\psi\) and \(\psi(\mathrm{2S})\) was studied with the ALICE detector in Pb—Pb collisions at the LHC. The measurement was performed at forward rapidity \((2.5<y<4)\) down to zero transverse momentum \((p_{\mathrm T})\) in the dimuon decay channel. Inclusive \(\mathrm{J}/\psi\) yields were extracted in different centrality classes and the centrality dependence of the average \(p_{\mathrm T}\) is presented. The \(\mathrm{J}/\psi\) suppression, quantified with the nuclear modification factor \((R_{\mathrm{AA}})\), was measured as a function of centrality, transverse momentum and rapidity. Comparisons with similar measurements at lower collision energy and theoretical models indicate that the \(\mathrm{J}/\psi\) production is the result of an interplay between color screening and recombination mechanisms in a deconfined partonic medium, or at its hadronization. Results on the \(\psi(\mathrm{2S})\) suppression are provided via the ratio of \(\psi(\mathrm{2S})\) over \(\mathrm{J}/\psi\) measured in pp and Pb—Pb collisions.

The inclusive \(\mathrm{J}/\psi\) nuclear modification factor \((R_{\mathrm{AA}})\) in Pb—Pb collisions at \(\sqrt{s_{_{\mathrm{NN}}}} = 2.76\) TeV has been measured by ALICE as a function of centrality in the \(e^+e^−\) decay channel at mid-rapidity \((|y|<0.8)\) and as a function of centrality, transverse momentum and rapidity in the \(\mu^+\mu^-\) decay channel at forward-rapidity \((2.5<y<4)\). The \(\mathrm{J}/\psi\) yields measured in Pb—Pb are suppressed compared to those in pp collisions scaled by the number of binary collisions. The \(R_{\mathrm{AA}}\) integrated over a centrality range corresponding to 90% of the inelastic Pb—Pb cross section is \(0.72\pm0.06\mathrm{(stat.)}\pm0.10\mathrm{(syst.)}\) at mid-rapidity and \(0.58\pm0.01\mathrm{(stat.)}\pm0.09\mathrm{(syst.)}\) at forward-rapidity. At low transverse momentum, significantly larger values of \(R_{\mathrm{AA}}\) are measured at forward-rapidity compared to measurements at lower energy. These features suggest that a contribution to the \(\mathrm{J}/\psi\) yield originates from charm quark (re)combination in the deconfined partonic medium.

Quarkonium states are expected to provide essential information on the properties of the high-density strongly-interacting system formed in the early stages of heavy-ion collisions. In particular the \(\mathrm{J}/\psi\) suppression via color screening is a direct consequence of deconfinement. ALICE is the LHC experiment specifically designed to study nucleus-nucleus collisions. The production of heavy quarkonium states is measured by ALICE down to zero transverse momentum via the \(\mu^+\mu^-\) decay channel in the Forward Muon Spectrometer \((2.5<y<4)\) and via the \(e^+e^-\) decay channel in the central barrel at mid rapidity \((|y|<0.9)\). The analysis of the inclusive \(\mathrm{J}/\psi\) production in Pb—Pb collisions at a center of mass energy per nucleon pair \(\sqrt{s_{_{\mathrm{NN}}}}=2.76\) TeV is presented. The inclusive \(\mathrm{J}/\psi\) nuclear modification factor as a function of centrality, transverse momentum and rapidity is shown and compared to similar measurements by other experiments and to theoretical predictions. Finally, a hint of a low transverse momentum \(\mathrm{J}/\psi\) yield excess, with respect to the expected hadronic channel production, is discussed.

The ALICE experiment has measured the inclusive \(\mathrm{J}/\psi\) production in Pb—Pb collisions at \(\sqrt{s_{_{\mathrm{NN}}}}=2.76\) TeV down to zero transverse momentum in the rapidity range \(2.5<y<4\). A suppression of the inclusive \(\mathrm{J}/\psi\) yield in Pb—Pb is observed with respect to the one measured in pp collisions scaled by the number of binary nucleon-nucleon collisions. The nuclear modification factor, integrated over the 0—80% most central collisions, is \(0.545\pm0.032\mathrm{(stat.)}\pm0.083\mathrm{(syst.)}\) and does not exhibit a significant dependence on the collision centrality. These features appear significantly different from measurements at lower collision energies. Models including \(\mathrm{J}/\psi\) production from charm quarks in a deconfined partonic phase can describe our data.

\(\Upsilon\) production in p—Pb interactions is studied at the centre-of-mass energy per nucleon-nucleon collision \(\sqrt{s_{_{\mathrm{NN}}}}=8.16\) TeV with the ALICE detector at the CERN LHC. The measurement is performed reconstructing bottomonium resonances via their dimuon decay channel, in the centre-of-mass rapidity intervals \(2.03<y_{\mathrm{cms}}<3.53\) and \(-4.46<y_{\mathrm{cms}}<-2.96\), down to zero transverse momentum. In this work, results on the inclusive \(\Upsilon\mathrm{(1S)}\) production cross section as a function of rapidity and transverse momentum are presented. The corresponding nuclear modification factor shows a suppression of the \(\Upsilon\mathrm{(1S)}\) yields with respect to pp collisions, both at forward and backward rapidity. This suppression is stronger in the low transverse momentum region and shows no significant dependence on the centrality of the interactions. Furthermore, the \(\Upsilon\mathrm{(2S)}\) nuclear modification factor is also evaluated, suggesting a suppression similar to that of the \(\Upsilon\mathrm{(1S)}\). A first measurement of the \(\Upsilon\mathrm{(3S)}\) has also been performed. Finally, results are compared with previous measurements performed by ALICE in p—Pb collisions at \(\sqrt{s_{_{\mathrm{NN}}}}=5.02\) TeV and with theoretical calculations.

Inclusive \(\psi\mathrm{(2S)}\) production is measured in p—Pb collisions at the centre-of-mass energy per nucleon-nucleon pair \(\sqrt{s_{_{\mathrm{NN}}}}=8.16\) TeV, using the ALICE detector at the CERN LHC. The production of \(\psi\mathrm{(2S)}\) is studied at forward \((2.03<y_{cms}<3.53)\) and backward \((−4.46<y_{cms}<−2.96)\) centre-of-mass rapidity and for transverse momentum \(p_{\mathrm T}<12\) GeV/\(c\) via the decay to muon pairs. In this paper, we report the integrated as well as the \(y_{cms}-\) and \(p_{\mathrm T}-\)differential inclusive production cross sections. Nuclear effects on \(\psi\mathrm{(2S)}\) production are studied via the determination of the nuclear modification factor that shows a strong suppression at both forward and backward centre-of-mass rapidities. Comparisons with corresponding results for inclusive \(\mathrm{J}/\psi\) show a similar suppression for the two states at forward rapidity (p-going direction), but a stronger suppression for \(\psi\mathrm{(2S)}\) at backward rapidity (Pb-going direction). As a function of \(p_{\mathrm T}\), no clear dependence of the nuclear modification factor is found. The relative size of nuclear effects on \(\psi\mathrm{(2S)}\) production compared to \(\mathrm{J}/\psi\) is also studied via the double ratio of production cross sections \([\sigma_{\psi\mathrm{(2S)}}/\sigma_{\mathrm{J}/\psi}]_{\mathrm pPb} / [\sigma_{\psi\mathrm{(2S)}}/\sigma_{\mathrm{J}/\psi}]_{\mathrm pp}\) between p—Pb and pp collisions. The results are compared with theoretical models that include various effects related to the initial and final state of the collision system and also with previous measurements at \(\sqrt{s_{_{\mathrm{NN}}}}=5.02\) TeV.

In order to give a lecture in an international conference "on behalf of the ALICE collaboration" it is necessary to first be selected among a pool of nominated candidates, and then follow an internal validation process of the collaboration. The later is supervised by the Conference Committee (CC) that reviews the conference abstract, then the presentation slides and finally a rehearsal.

Besides those essential rendez-vous of the community, I also particated in other events like workshops and seminars. In that case, either I was invited by the organizers of the workshops, or I had submitted an abstract and then was selected by the supervising committee of the workshop. Click here for an exhaustive list of my contributions.

The researchers organize themself their conferences and workshops, as well as general-public and outreach events. To contribute to this effort, I took responsabilities as member of organization-committees, and also participated in different outreach events like student days, CERN visits, the international masterclass (IPPOG), etc.

The study of quarkonia \((\mathrm{J}/\psi,~\psi\mathrm{(2S)}\) and \(\Upsilon)\) in proton-proton collisions is an important tool to investigate their underlying production mechanism, while their corresponding yields in proton-nucleus collisions provide information on the influence of cold nuclear matter and other medium effects. In proton-proton collisions, the existing theoretical approaches (the color singlet model, the color evaporation model and the NRQCD framework) all face difficulties in reproducing consistently the wealth of experimental data on quarkonium production for more than 40 years. In proton-nucleus collisions, mechanisms such as nuclear modification of parton distribution functions, the presence of a color glass condensate and/or the coherent energy loss of the \(Q\bar{Q}\) pair in the medium have been shown to be the relevant processes to describe most of the features of the most tightly bound states, i.e. the \(\mathrm{J}/\psi\) and the \(\Upsilon\mathrm{(1S)}\). On the other hand, final state mechanisms, possibly related to the presence of a dense medium, are required to explain the stronger suppression observed for the loosely bound \(\psi\mathrm{(2S)}\) state.

ALICE has measured quarkonium production down to zero transverse momentum in pp collisions at all available LHC energies at central \((|y|<0.9)\) and forward \((2.5<y<4)\) rapidities and in p—Pb collisions over a wide kinematic range, covering the backward \((-4.46<y_{\mathrm{cms}}<-2.96)\), the mid \((-1.37<y_{\mathrm{cms}}<0.43)\) and the forward \((2.03<y_{\mathrm{cms}}<3.53)\) rapidity regions.

We will first report on the \(\mathrm{J}/\psi\) and \(\psi\mathrm{(2S)}\) production cross sections measured in pp collisions at \(\sqrt{s} = 5.02\) TeV and \(\sqrt{s} = 13\) TeV. Then, measurements of the nuclear modification factor \((R_{\mathrm{pPb}})\) obtained at mid-rapidity in p—Pb collisions at \(\sqrt{s_{_{\mathrm{NN}}}} = 5.02\) TeV and \(\sqrt{s_{_{\mathrm{NN}}}} = 8.16\) TeV, for prompt and non-prompt \(\mathrm{J}/\psi\), will be presented. Results on the transverse momentum, rapidity and centrality dependence of the \(\mathrm{J}/\psi\) and \(\Upsilon\mathrm{(1S)}\) \(R_{\mathrm{pPb}}\), measured at forward and backward rapidities at \(\sqrt{s_{_{\mathrm{NN}}}} = 8.16\) TeV, will also be shown. Finally, the production of the \(\psi\mathrm{(2S)}\) and \(\Upsilon\mathrm{(2S)}\) resonances in p—Pb collisions at \(\sqrt{s_{_{\mathrm{NN}}}} = 8.16\) TeV, at forward and backward rapidities, will be discussed and compared to their respective ground states. All results will also be compared to those obtained at lower energies and to available theoretical calculations.

The study of quarkonium in proton-nucleus collisions is an important tool to investigate how cold nuclear matter effects can influence the \(\mathrm{J}/\psi\), the \(\psi\mathrm{(2S)}\) or the \(\Upsilon\) production. Mechanisms as the modification of the parton distribution functions in nuclei, the presence of a color glass condensate or the coherent energy loss of the \(Q\bar{Q}\) pair in the medium have been shown to be the relevant processes to describe the production of the most tightly bound states, as the \(\mathrm{J}/\psi\) and the \(\Upsilon\mathrm{(1S)}\). On the contrary, final state mechanisms, possibly related to the presence of a dense medium, are required to explain the stronger suppression observed for the loosely bound \(\psi\mathrm{(2S)}\) state.

ALICE has measured quarkonium production in p—Pb collisions over a wide kinematic range, covering the backward \((-4.46<y_{\mathrm{cms}}<-2.96)\), the mid \((-1.37<y_{\mathrm{cms}}<0.43)\) and the forward \((2.03<y_{\mathrm{cms}}<3.53)\) rapidity regions, down to zero transverse momentum.

Measurements of the nuclear modification factor \((R_{\mathrm{pPb}})\) obtained at mid-rapidity in p—Pb collisions at \(\sqrt{s_{_{\mathrm{NN}}}}=5.02\) TeV and \(\sqrt{s_{_{\mathrm{NN}}}}=8.16\) TeV, for prompt and non-prompt \(\mathrm{J}/\psi\), will be presented. Results on the transverse momentum, rapidity and centrality dependence of the \(\mathrm{J}/\psi\) and \(\Upsilon\mathrm{(1S)}\) \(R_{\mathrm{pPb}}\), measured at forward and backward rapidities at \(\sqrt{s_{_{\mathrm{NN}}}}=8.16\) TeV, will also be shown. Finally, the production of the \(\psi\mathrm{(2S)}\) and \(\Upsilon\mathrm{(2S)}\) resonances in p—Pb collisions at √sNN=8.16 TeV, at forward and backward rapidities, will be discussed in comparison to the production of the most tightly charmonium and bottomonium states. All the results will also be compared to those obtained at lower energies and with the available theoretical calculations.

Heavy quarkonium states are expected to provide essential information on the properties of the deconfined state of nuclear matter, the Quark-Gluon Plasma (QGP), formed in the early stages of ultra-relativistic heavy-ion collisions. In particular, the suppression of the strongly bound quarkonium states via the color screening mechanism can be seen as an effect of deconfinement. ALICE results on charmonium suppression in Pb–Pb collisions at the LHC seem to indicate that additional mechanisms as \(\mathrm{J}/\psi\) production via recombination of charm and anti-charm quarks also play a role, leading to a more complex picture of the quarkonium melting in the QGP. The contribution of this so-called (re)generation mechanism is expected to be smaller for bottomonia as for charmonia.

In ALICE, quarkonia are measured down to zero transverse momentum via the dielectron (dimuon) decay channel in the central barrel (forward muon spectrometer) for the rapidity window \(|y|<0.9\) \((2.5<y<4)\). We will report on the recent charmonium and bottomonium measurements in nucleus-nucleus collisions with ALICE at the LHC energies. The \(\mathrm{J}/\psi\) and \(\Upsilon\mathrm{(1S)}\) nuclear modification factors in Pb—Pb collisions as a function of transverse momentum, rapidity and collision centrality will be presented as well as the \(\mathrm{J}/\psi\) elliptic flow. Results on \(\mathrm{J}/\psi\) production in Xe—Xe collisions will also be addressed. Finally, comparisons with other experimental measurements and theoretical calculations will be discussed.

The production of heavy quarkonia is an important observable to study the properties of the nuclear matter created in high-energy heavy-ion collisions. Lattice QCD calculations predict a phase transition of the hadronic matter to a deconfined medium of quarks and gluons, the Quark Gluon Plasma (QGP), at extreme energy densities. The bottomonium bound states while passing through the deconfined medium are dissociated into quark-antiquark pair due to color screening. This is visible in data as a suppression of \(\Upsilon\) resonances with respect to the proton-proton results scaled by the number of binary collisions. However, the cold nuclear matter effects can also lead to the suppression of \(\Upsilon\) resonances in heavy-ion collisions. Cold nuclear effects are studied in p—Pb collisions since the QGP is not expected to be produced. ALICE measures the bottomonium down to zero transverse momentum via the dimuon decay channel at forward rapidity \((2.5<y<4)\).

In this presentation, the final results on the nuclear modification factor of \(\Upsilon\) measured in Pb—Pb collisions at \(\sqrt{s_{_{\mathrm{NN}}}} = 5.02\) TeV will be shown as a function of centrality, transverse momentum and rapidity. The results will be compared with the existing theoretical models. In this context, the \(\Upsilon\) measurements in p—Pb collisions at \(\sqrt{s_{_{\mathrm{NN}}}} = 5.02\) TeV will be discussed as well. Finally, the ALICE results will be compared to results from other experiments.

Heavy quarkonium states are expected to provide essential information on the properties of the deconfined state of nuclear matter, the Quark-Gluon Plasma (QGP), formed in the early stages of ultra-relativistic heavy-ion collisions. In particular, the suppression of the strongly bound quarkonium states via the color screening mechanism can be seen as an effect of deconfinement. Furthermore, a weaker suppression is foreseen going from mid- to forward rapidity due to the decrease of the medium energy density. ALICE results on charmonium suppression in Pb—Pb collisions seem to indicate that additional mechanisms as \(\mathrm{J}/\psi\) production via recombination of charm and anti-charm quarks also play a role, leading to a more complex picture of the quarkonium melting in the QGP. This so-called regeneration mechanism is expected to be small for bottomonia due to the smaller number of initial \(b\bar{b}\) pairs produced compared to \(c\bar{c}\) pairs.

In ALICE, \(\Upsilon\) are measured down to zero transverse momentum via the dimuon decay channel in the Forward Muon Spectrometer \((2.5<y<4)\). After a brief description of the apparatus, we will report on the \(\Upsilon\) nuclear modification factor in p—Pb collisions at \(\sqrt{s_{_{\mathrm{NN}}}} = 5.02\) TeV and in Pb—Pb collisions at \(\sqrt{s_{_{\mathrm{NN}}}} = 2.76\) and 5.02 TeV. Finally, comparisons with other experimental measurements as well as with theoretical calculations will be discussed.

Heavy quarkonium states are expected to provide essential information on the properties of the deconfined state of nuclear matter, the Quark-Gluon Plasma (QGP), formed in the early stages of ultra-relativistic heavy ion collisions. In particular, the sequential suppression of the quarkonium states by color screening mechanism can be seen as a direct effect of deconfinement and a thermometer of the QGP. Results on charmonium suppression in Pb—Pb collisions at the LHC seem to indicate that additional mechanisms as \(\mathrm{J}/\psi\) production via (re)combination of charm and anti-charm quarks also play a role. This so-called regeneration mechanism is expected to be small for bottomonia due to the smaller number of initial \(b\bar{b}\) pairs produced compared to \(c\bar{c}\) pairs.

After a brief description of the apparatus, we will first report on the ALICE results from LHC run 1 on the quarkonium \((\mathrm{J}/\psi\) and \(\Upsilon)\) production in Pb—Pb collisions at \(\sqrt{s_{_{\mathrm{NN}}}} = 2.76\) TeV down to zero transverse momentum via the dimuon decay channel in the Forward Muon Spectrometer \((2.5<y<4)\). Then, these results will be compared to those obtained by other experiments and to theoretical predictions. Finally, we will report on the observation of a \(\mathrm{J}/\psi\) yield excess at very low \(p_{\mathrm T}\) \((<300\) MeV/\(c)\) and forward rapidity \((2.5<y<4)\) compared to expectations from hadronic production. Coherent photoproduction of \(\mathrm{J}/\psi\) is proposed as a plausible origin of this excess. It is worth noting that such a production has never been observed so far in Pb—Pb collisions at impact parameters smaller than twice the nuclear radius and would open new theoretical challenges. The procedure to quantify this excess and derive a \(\mathrm{J}/\psi\) coherent photo-production cross section will be presented. The implications of the observed excess on the \(\mathrm{J}/\psi\) nuclear modification factor previously reported will also be discussed.

Heavy quarkonium states are expected to provide essential information on the properties of the high-density strongly-interacting system formed in the early stages of heavy-ion collisions. In particular the \(\mathrm{J}/\psi\) suppression, via color screening mechanism, can be seen as a direct effect of deconfinement. During 25 years, the \(\mathrm{J}/\psi\) suppression has been extensively studied first at the SPS and then at RHIC and it was found to be significantly larger than the one due to cold nuclear matter effects, as shadowing and absorption in nuclear matter. In spite of the different center of mass energy of the two accelerators, the observed suppression patterns present similar features. To explain this unexpected behavior, other additional mechanisms as \(\mathrm{J}/\psi\) production via recombination of charm and anti-charm quarks were proposed. The measurement of \(\mathrm{J}/\psi\) suppression is especially promising at the Large Hadron Collider where the high energy density of the medium and the large number of charm quarks pairs produced in central Pb—Pb collisions should help to disentangle between the different suppression and recombination scenarios.

ALICE is the LHC experiment specifically designed to study nucleus-nucleus collisions. The production of heavy quarkonium states is measured down to zero transverse momentum via the \(\mu^+\mu^-\) decay channel in the Forward Muon Spectrometer \((2.5<y<4)\) and the \(e^+e^-\) decay channel in the central barrel at mid rapidity \((|y|<0.9)\). After a brief description of the apparatus, the analysis of the inclusive \(\mathrm{J}/\psi\) production in Pb—Pb collisions at a center of mass energy of \(\sqrt{s_{_{\mathrm{NN}}}} = 2.76\) TeV will be discussed. Thanks to the large statistics collected in 2011 the results on a fine-binned \(R_{\mathrm{AA}}\) differential study in centrality, transverse momentum and rapidity will be presented and compared to those obtained by other experiments and to theoretical predictions. Studies on coherent \(\mathrm{J}/\psi\) photo-production in Pb—Pb collisions, which is expected to probe the nuclear shadowing of gluon distribution function, will also be addressed.