Evidence of the presence of collective phenomena has been observed in the final state hadronic observables of the strongly-interacting system created in Pb-Pb collisions. In addition, measurements in pp and p-Pb collisions as a function of event multiplicity at LHC energies have shown some features reminiscent of collectivity. Thanks to its excellent PID capabilities and $p_{\rm T}$ coverage...
ALICE is an experiment dedicated to the study of heavy-ion collisions at the LHC, with the aim of understanding the physics of the hot and dense deconfined medium produced in such collisions. Since the start of its second phase of running the LHC is delivering collisions of protons and lead ions at the top energy of $\sqrt{s} = 13\,\text{TeV}$ for pp and $\sqrt{s_\text{NN}} =...
In this talk we revisit the global QCD análisis of the parton-to-kaon fragmentation functions at next-to-leading order accuracy using the latest experimental information on single-inclusive kaon production un electron-positron annihilation, lepton-nucleon deep-inelastic scattering, and proton-proton collisions. An excellent description of all data sets is achieved, and the remaining...
Quarkonium has been regarded as one of the golden probes to identify the phase transition from confined hadronic matter to the deconfined quark-gluon plasma (QGP) in heavy-ion collisions. Recent theoretical developments in the study of the J/ψ and ϒ families at the energies of Large Hadron Collider (LHC) are reviewed. In particular, the possible implications related to the production and...
The ALICE experiment is dedicated to study the properties of the Quark-Gluon Plasma (QGP) which is expected to be formed in ultra-relativistic heavy ion collisions. Measurements of hadron production in pp and p-Pb collisions are of importance to understand the properties of this hot and dense medium. In pp collisions, meson spectra serve as a reference for heavy-ion collisions and add...
EPOS3 is a minimum bias Monte-Carlo event generator used for Heavy Ion Collisions. It is successful in the description of particle spectra as well as flow-like observables and includes viscous hydrodynamics expansion, hadronic cascade, and heavy quark production.
In the beginning, we will present the general features of the model and show that multiple interactions play a central role for...
The measurement of heavy flavour production is a powerful tool to study the properties of the high-density QCD medium created in heavy-ion collisions as heavy quarks are sensitive to the transport properties of the medium and may interact with the QCD matter differently from light quarks. In particular, the comparison between the nuclear modification factors (RAA) of light- and heavy-flavour...
Beauty production and phenomena in heavy-ion collisions are considered to be one of the key measurements to address the flavour-dependence of in-medium energy loss in PbPb collisions at the LHC. The CMS experiment has excellent capabilities for measuring b-quark production thanks to the excellent performances of its muon and tracker system, allowing the measurement of J/$\Psi$ mesons from B...
The origin of flow-like effects in small systems, such as those produced in ultra-relativistic proton-proton and proton-lead collisions, is still widely debated. In this talk, the goal is to look at possible consequences if indeed a mini-Quark-Gluon Plasma is formed in these collisions. It is argued that this could indicate a duality between the QGP phase and the color fields in hadrons. A...
We use the linear sigma model coupled to quarks to compute the effective potential beyond the mean field approximation, including the contribution of the plasma screening effects, at finite temperature and density. We determine uniquely the model coupling constants (the only free parameters in the model) and use them to study the phase diagram in the temperature-baryon chemical potential plane...
To understand the origins of collective-like phenomena observed in pp collisions at LHC energies, underlying mechanisms have to be identified. In this context, event shape observables provide a possible tool to disentangle soft and hard contributions to particle production. We report on a study of the production of pions, kaons and protons as a function of transverse spherocity in high...
Identified hadron spectra from recent years are analyzed in the non-extensive thermodynamical framework. The Tsallis cut power-law is known to describe the p T distributions for a wide energy range, but its origin is still unknown. We pursue the physical origin of this observation by investigating the center-of-mass energy, multiplicity, mass and strangeness dependency of the Tsallis q and T...
A study of the universality of multihadron production in nucleus-nucleus and pp/{\bar p}p collisions is performed using the dependencies of the midrapidity pseudorapidity and transverse energy densities and of the mean multiplicity on the collision energy and on the number of nucleon participants, or centrality, in the energy range from a few GeV to a few TeV. The approach in which the...
In this work, we propose a tool to reveal the origin of the collective-like phenomena observed in proton–proton collisions. We exploit the fundamental difference between the underlying mechanisms, color reconnection and hydrodynamics, which produce radial flow patterns in Pythia 8 and Epos 3, respectively. Specifically, we proceed by examining the strength of the coupling between the soft and...
The study of the charged particle production as a function of the multiplicity in small colliding systems, as pp, is an attractive tool to understand the similarities and differences between small and large colliding systems. Evidence of similarities, like coherent and collective effects, well know in AA collisions, has been found experimentally even in small systems.
Recent results of the...
sPHENIX experiment is proposed to succeed the current PHENIX experiment at the Relativistic Heavy Ion Collider (RHIC). sPHENIX experiment is capable of measuring jets, jet correlations and upsilons to determine the temperature dependence of transport coefficients and the color screening length in the quark-gluon plasma. From January to February 2017, sPHENIX Collaboration conducted test beam...
In this talk I will present some of the challenges and opportunities to study nuclear matter under extreme conditions using the Multi-Purpose Detector (MPD) at the Nuclotron-‐based Ion Collider fAcility (NICA) which is located at the Joint Institute for Nuclear Research (JINR), in Dubna, Rusia. I will summarize the advances made by the collaboration MExNICA within the planned program for...
Small collision systems exhibit collective effects like those seen in AA collisions, which sets the foundation to postulate the formation of a QGP even in small systems.
While indeed most if not all observations between pPb and PbPb at the LHC look alike, clear final state effects as charged particle or jet suppression induced by parton energy loss as known from hot nuclear matter have not...
In this work a study of the fractional momentum loss ($S_{\rm loss}$) as a function of the characteristic path-length ($L$) and the Bjorken energy density times the equilibration time ($\epsilon_{\rm Bj}\tau_{0}$) for heavy-ion collisions at different $\sqrt{s_{\rm NN}}$ is presented. The study has been conducted using inclusive charged particles from intermediate to large transverse momentum...
A typical approach to study the quark gluon plasma produced in heavy ion
collisions is to understand the passage of elementary particles through it. As
electroweak bosons such as photons and Z bosons do not participate in the
strong interaction, their correlation with jets within the same event is a
clean probe of the medium-induced energy loss of jets. With high statistics
PbPb and pp...
As was pointed out long ago by Mueller and Tang, the BFKL hard Pomeron, at finite momentum transfer, can be investigated at hadron colliders by looking for the exclusive processes where the only observed radiation are two jets detected far apart in rapidity. The absence of any additional emission over a large rapidity region suggests that the color-singlet exchange contributes substantially to...
Nuclear like effects are produced in pp collisions as a consequence of the clustering of color sources. In this framework are discussed the long range rapidity correlations, ridge structure, elliptic flow, multiplicity dependence of quarqonium production, pt dependence of B/M ratios and quarqonium incoherent
production.
A possible phase transition of strongly interacting matter from hadron to
quark-gluon plasma state has received considerable interest in the past.
What conditions are necessary in the pre-equilibrium stage to achieve
deconfinement and perhaps subsequent quark-gluon plasma formation ?
In this talk the Color String Percolation Model (CSPM) has been explored to describe the initial stages in...
Observations of long rang azimuthal correlations in small collision systems (p+p/A) have triggered an enormous excitement in the heavy-ion community. However, it is presently unclear to what extent the experimentally observed correlations should be attributed to initial state momentum correlations and/or the final state response to the initial state geometry. Starting from a brief overview of...
We study the interplay of the contribution of bulk and shear viscosities in p-p and p-Pb collisions at LHC energies in the framework of the String Percolation Model which for high multiplicities exhibit a similar behavior as the geometric phase transition given in heavy ion collision. The results show that the bulk viscosity gives a relevant contribution to the overall viscosity of the formed system.
We discuss possible processes which can be used to pin down the presence of high gluon densities in both photon-proton and photon-nucleus collisions. The presence of such high gluon density itself can then be argued to be characteristic for a regime of QCD where the possible on-set of gluon saturation can be observed. To this end we use the spinor helicity formalism to calculate the cross...
