Recent measurements of the production of charm hadrons at midrapidity in pp collisions at $\sqrt s$ = 5.02 and 13 TeV showed that the baryon-to-meson yield ratios are significantly larger than those measured in $\rm e^{+}e^{-}$ collisions for different charm-baryon species. These observations suggest that the charm fragmentation fractions are not universal and that the baryon-to-meson ratios...
Heavy-flavor (charm and beauty) quarks are generated primarily via hard scattering processes in high-energy hadronic collisions, and then undergo parton shower (fragmentation) and hadronization. Two-particle azimuthal correlations of heavy-flavor particles is a differential measurement which allows for the study of the fragmentation of heavy quarks. By measuring the azimuthal correlation in...
The beauty quark is a unique probe to study the properties of quark-gluon plasma thanks to its large mass and relatively long thermal relaxation time compared with lighter partons. Traditional experimental observables such as elliptic flow v$_2$ and nuclear modification factor R$_{AA}$ of fully reconstructed beauty hadrons have been measured at the LHC. Moreover, indirect measurements on...
Beauty quarks are produced in hard-parton scatterings in the early stages of the partonic collisions. They are the ideal probe to investigate the properties of Quark-Gluon Plasma (QGP) produced in ultra-relativistic heavy-ion collisions as they experience the whole QGP evolution. Due to their large mass, their production can be calculated using perturbative Quantum Chromodynamics (pQCD), thus...
Quarkonium production is considered one of the golden probes of the quark-gluon plasma (QGP) formation in heavy-ion collisions.
Due to their large mass, the production of heavy-quarks is governed by hard scales of QCD, while the formation of the bound quarkonium state involves soft QCD scales.
The regeneration process of J/$\psi$ in the QGP or at the phase boundary is crucial for describing...
We present energy loss predictions of B and D-mesons at $\sqrt{s}=200$ GeV in pA collision systems. We assume that the medium produced in these collisions is strongly coupled, and show the centrality and momentum dependence of the nuclear modification factor at midrapidity. We also quantify the systematic theoretical uncertainties in these predictions that are a result of the mapping of...
Studies of charm production in proton-proton ($pp$) collisions are essential to understand some of the most fundamental aspects of Quantum Chromodynamics. They also provide the baseline for interpretation of charm data from larger colliding systems. Over the last decade, the measurement of the production cross-sections of charm mesons and baryons in $pp$ collisions has been at the centre of a...
Energy-energy correlators (EEC) offer a novel way to study the structure of jets. Defined as the energy-weighted cross section of particle pairs inside jets, the correlation strength as a function of the pair opening angle allows a distinct separation of the perturbative and non-perturbative regimes. The evolution of parton dynamics in jets to their confinement into hadrons can be studied....
Measurements of azimuthal correlations of charmed mesons in high-energy heavy-ion collisions can shed light on the transport properties of the Qaurk-Gluon Plasma. The STAR experiment at the Relativistic Heavy Ion Collider (RHIC) collected in 2014 and 2016 a large sample of Au+Au reactions at $\sqrt{s_{NN}}$ = 200 GeV making such a study possible. The sPHENIX experiment will also offer a...
The sPHENIX experiment at RHIC will begin commissioning with Au+Au data in Spring 2023. The Monolithic Active Pixel Sensor (MAPS) based Vertex Detector (MVTX), the Intermediate Silicon Tracker (INTT) and the Time Projection Chamber (TPC) at sPHENIX can provide high precision primary/displaced vertex and track reconstruction in the pseudorapidity region of $|\eta| \le 1.1$. The sPHENIX...
Heavy quarks serve as effective probes of relativistic heavy-ion collisions as they are created in the initial stages of the collision event and exist at all stages. We study the dynamics of heavy flavors using a hybrid framework that incorporates the MARTINI event generator, pythia8.1 for the initial production of heavy quarks, and Langevin dynamics to describe the evolution of heavy quarks...
The sPHENIX experiment will begin commissioning in Spring 2023 at the Relativistic Heavy Ion Collider (RHIC) at BNL, presenting a unique opportunity to study QGP properties using jets and heavy quarks with unprecedented precision. The successful construction and deployment of the three-layer Monolithic-Active-Pixel-Sensor (MAPS) based VerTeX detector (MVTX) for the sPHENIX experiment in 2023...
Heavy-quark hadrons are used to study the properties of the partonic stages of a heavy-ion collision, where a quark-gluon plasma medium is created. We are investigating charm quark production in and outside of jets via angular correlations of trigger hadrons and associated electrons from heavy-flavor hadron decays. As a first step, we are investigating the 5.02 TeV p-Pb collisions, where in a...
Measurements of the production of heavy-flavour hadrons in proton–proton (pp) collisions provide an important test of quantum chromodynamics (QCD).The heavy-flavour production cross section can be calculated using the factorisation approach as a convolution of three factors: the parton distribution functions, the partonic cross section, calculated with perturbative QCD calculations, and the...
Measurements of charm baryon and meson production in pp and p–Pb minimum bias collisions and as a function of multiplicity, help to investigate hadronization processes and to study their modification across the collision systems from pp to Pb–Pb, and from low to high multiplicities.
Recent measurements of the fragmentation fractions of charm hadrons in pp and p–Pb challenge the universality...
Heavy quarks are produced at the very early stage of heavy-ion collisions, and they experience the whole evolution of the Quark-Gluon Plasma (QGP) created in these collisions. Measurements of the elliptic flow and nuclear modification factor of charmed mesons in heavy-ion collisions at RHIC and the LHC provide ample evidence of strong interactions between charm quarks and the QGP. However, a...
The properties of the Quark-Gluon Plasma (QGP) produced in heavy-ion collisions can be studied using jets generated in hard scattering processes at the early stages of the collision. These jets lose energy and have their shower structures modified relative to that in the vacuum due to jet-medium interaction — known as `jet quenching'.
The transverse momentum ($p_{\rm T}$) fraction of the...
Compared to $\rm{e^+e^-}$ and ep collisions, the charm baryon production in pp collisions shows a substantial enhancement. This evidence is currently interpreted in terms of a modification of the hadronization mechanisms in hadronic collisions. Therefore, valuable information on how the charm quarks hadronize can be studied by measuring charm baryon production. In addition, by sorting out the...
$J/\psi$ serves as an important probe to study the properties of the quark-gluon plasma (QGP) created in heavy-ion collisions. In Ru+Ru and Zr+Zr collisions at $\sqrt{s_{NN}} = 200$ GeV, it has been observed that the $J/\psi$ yield is strongly suppressed and its elliptic flow ($v_{2}$) is consistent with zero, indicating $J/\psi$'s strong coupling with the medium and its potentially small...
Studying heavy flavor can enhance our comprehension of parton interactions with the Quark-Gluon Plasma (QGP). Due to their significant mass, heavy quarks (charm and bottom) are mainly generated during the initial phase of high-energy heavy-ion collisions when hard scatterings are prevalent, and experience the entire evolution of the QGP. One way to study the production of heavy quarks is...
The production of hadrons containing charm or beauty quarks in pp collisions provides an important test for quantum chromodynamics calculations. These measurements also serve as reference for more complex systems such as Pb--Pb collisions, helping to characterize the various in-medium partonic energy loss mechanisms and their dependence on the quark mass.
The excellent particle...
Quarkonia play a unique role in probing the properties of the quark-gluon plasma (QGP). The dissociation of quarkonia due to the color screening was proposed as a direct signature of the QGP formation. On top of that, different states of quarkonium are expected to dissociate at different temperatures depending on their binding energies. Therefore, measurement of the expected sequential...
Quarkonium production in high-energy proton-proton (pp) collisions is an important tool for studying perturbative and non-perturbative aspects of quantum chromodynamics (QCD) calculations. Charmonia are bound states of charm and anti-charm quark pairs. Their production process can be factorized into two stages: the heavy quark production and the formation of the bound state. The former...
Quarkonia have been long considered as key features in heavy ion collision to study the properties of the quark-gluon plasma. One of the key signatures is the sequential yield suppression for different quarkonium states in nucleus-nucleus (A+A) collisions compared to p+p collisions following the ordering of their binding energies. Moreover, sequential yield modification has also been observed...
Studying quarkonium production allows us to probe the properties of strongly interacting matter, such as the quark-gluon plasma and the gluonic matter in heavy nuclei. While such a probe is widely used, a complete understanding of the quarkonium production mechanism is not yet achieved, even for $p$+$p$ collisions. Therefore, quarkonium studies in $p$+$p$ collisions are essential for advancing...
Recent measurements of the baryon-to-meson production yield ratios between charm baryons ($\Lambda_\mathrm{c}^{+}$, $\Sigma_\mathrm{c}^{0,++}$, $\Xi_\mathrm{c}^{0,+}$, $\Omega_\mathrm{c}^{0}$) and $\mathrm{D}$ mesons ($\mathrm{D}^0$) in small collision systems show a significant enhancement with respect to the measurements performed in $e^{+}e^{-}$ collisions. These results were compared with...
We perform a non-perturbative calculation of quarkonium dissociation rates in the quark-gluon plasma (QGP) within a thermodynamic T-matrix approach. The latter resums an infinite series of ladder diagrams for heavy-light interactions appropriate for a strongly coupled QGP which are implemented via half-off-shell amplitudes accounting for recoil corrections and interference effects (related to...
The study of the production of non-prompt ${\rm J/\psi}$ originating from the decay of beauty hadrons, besides allowing to isolate the prompt ${\rm J/\psi}$ cross section from the inclusive ${\rm J/\psi}$ cross section, can be used to estimate open beauty-hadron production. Heavy-flavour particle production in pp collisions as a function of charged-particle multiplicity could provide insight...
The simple picture of a hard scattering per $p+p$ collision has been challenged by several measurements performed at LHC and RHIC, revealing a more complex dynamics of multiple parton interactions (MPI) which are essential to fully understanding particle production in hadronic collisions. Hard probe measurements at different particle multiplicity regimes in $p+p$ collisions provide a clean...
The $B^\pm$ meson is produced more frequently than any other meson containing beauty quarks in pp collisions at the LHC. Measuring its production cross-section is important for two reasons. Firstly, it allows for testing perturbative quantum chromodynamics calculations. Secondly, it provides an essential reference for measurements of its nuclear modification factor ($R_{\rm A \rm A}$) in...
The NA60+ experiment, proposed for data taking in the next years, aims to investigate the high baryochemical potential region of the QCD phase space diagram, exploiting the large intensity of CERN SPS beams.
NA60+ will have the possibility to access the high $\mu_{B}$ region of the QCD phase diagram, by studying rare probes via a beam-energy scan with PbPb and p-A collisions in the...
Quarkonia measurements in heavy-ion collisions are important for understanding both initial-state effects on heavy-quark production and final-state interactions between heavy quarks and the hot and dense nuclear matter created in high-energy heavy-ion collisions.
The sPHENIX experiment at RHIC will begin its commissioning and first Au+Au data-taking run in 2023, and plans to measure the...
We examine in detail the mass, lifetime and spin structure of quarkonium in a rotating vortical medium, where the quark spin is not necessarily aligned with the vortex.
After justifying this set-up in terms of spin hydrodynamics, and outlining the expected dependence of spin and vorticity, we examine the mass, lifetime and spin density matrix of quarkonium.
Our analysis implies a novel...
Quarkonium production in high-energy hadronic collisions is sensitive to both perturbative and non-perturbative aspects of quantum chromodynamics (QCD) calculations. Indeed, the production of the heavy-quark pair is described by perturbative QCD while the formation of the bound state is a non-perturbative process, treated in different ways by available theoretical models. Quarkonium...
The validity of the Statistical Hadronization Model (SHM) has been successfully tested to adequately reproduce hadronic particle abundances over nine orders of magnitude in high energy collisions of heavy ions. Assuming a thermally equilibrated system, experimental particle yields at RHIC and the LHC serve as an anchor for the determination of common freeze-out parameters in the QCD phase...
We discuss the transport coefficients of heavy quarkonia moving in high temperature QCD plasmas. The thermal width and mass shift for quarkonia are closely related to the momentum diffusion coefficient and its dispersive counterpart for heavy quarks, respectively. For quarkonium at rest in plasmas, the longitudinal gluon part of the color-singlet self-energy diagram is sufficient to determine the...
