The dominant interaction between a heavy quark and antiquark at low energy is described through the static potential. The real part of the potential becomes screened with a screening mass proportional to the temperature, and the imaginary part of the potential gives bound-states a non-zero width. As the temperature increases bound-states can disappear either because they are no longer...
Fragmentation functions, one of the key components of the factorisation theorem used for computing cross sections for heavy-flavour hadron production, are typically constrained in $\textrm e^{+}\textrm e^{-}$ and ep collisions due to their non-perturbative nature.
However, recent measurements of charm-hadron spectra and ratios at the LHC have questioned the universality of fragmentation...
Charm quarks, due to their significant mass, serve as an excellent tool for investigating the de-confined medium composed of quarks and gluons. These charm quarks interact with this medium and carry crucial information about it before they undergo hadronization to form heavy flavor hadrons. In this study, we employ the color string percolation model (CSPM) and the van der Waals Hadron...
The creation of a quark-gluon plasma (QGP) is expected in heavy ion collisions. It came as a surprise that proton-proton collisions at ultrarelativistic energies show as well a "QGP-like" behavior and signs of the creation of a fluid, although the corresponding system size is not more than a few cubic femtometers. Even more surprisingly, also heavy flavor particles seem to be part of the...
Selected experimental measurements on quarkonium production in proton-proton and heavy-ion collisions will be presented. Particular attention will be given to those that could help us to build a unified physics picture which can reconcile our understanding of particle production in all collision systems.
The investigation of heavy quarkonia can give insight into processes that occur during the evolution of the quark-gluon plasma and therefore allow conclusions about the properties of the medium. One advantage of the theoretical approaches is that due to the large masses of the heavy quarks it is possible to describe them non-relativistically. We choose a classical model to describe charm and...
We discuss the flow harmonics or the elliptic and triangular flow of J/ψ, ψ(2S), and χc1(1P) mesons in heavy ion collisions. Starting from the investigation on transverse momentum distributions of those charmonium states, we calculate their elliptic and triangular flow when they are produced at the quark-hadron phase boundary by quark recombination. We show that the wave function distribution...
QTRAJ is a computer code that simulates the propagation of quarkonium in the quark-gluon plasma (QGP) based on the quantum trajectories' algorithm. This algorithm solves a master equation in which the quarkonium is treated as an open quantum system (OQS). The specific master equation is obtained through the potential non-relativistic QCD (pNRQCD) approach, but so far has been restricted to the...
Being able to deal with the most acurate methods to describe the $Q\bar Q$ evolution in a quark gluon plasma is a prerequisite to match the precise quarkonium measurements of all URHIC experiments. Following our recent work [1], we present exact numerical solutions in a one-dimensional setting of quantum master equations previously derived in [2].
We focus on the dynamics of a single heavy...
The proposed Electron-Ion Collider (EIC) will utilize high-luminosity high-energy electron+proton ($e+p$) and electron+nucleus ($e+A$) collisions to solve several fundamental questions, which include searching for gluon saturation and studying the proton/nuclear structure. Due to their high masses ($M_{c,b} > \Lambda_{QCD}$), heavy quarks do not transfer into other quarks or gluons once they...
We present results for dipion transitions between heavy quarkonium states of large principal quantum number for which the multipole expansion does not hold. We combine the QCD effective string theory with the Chiral Lagrangian in order to get the appropriate vertexes.
We extend the results to transitions for which the initial estate is a heavy quarkonium hybrid. We observe that the dipion...
This presentation will discuss recent experimental discoveries in the realm of charmonium decays, containing four independent measurements at BESIII. 1) The observation of the ψ(3686) → 3ϕ decay. This observation sheds light on the rare decay process of the ψ(3686) resonance into three φ mesons, providing valuable insights into the dynamics of charmonium decays. No significant structure is...
The last decade has seen a wealth of discoveries of new hadronic states with heavy quarks, many of which are outside the scope of the naive quark model of conventional mesons and baryons. The LHCb experiment, designed to research heavy flavor hadrons in $pp$ collisions, is especially well suited to investigate the nature of these states. An under-exploited source of hadronic resonances are...
We study the potential of X(3872) at finite temperature in the Born-Oppenheimer approximation under the assumption that it is a tetraquark. We argue that, at large number of colors, it is a good approximation to assume that the potential consists in a real part plus a constant imaginary term. The real part is then computed adapting an approach by Rothkopf and Lafferty and using as input...
The diffusion of heavy quarks (HQ) in the quark-gluon plasma (QGP) produced in ultra-relativistic heavy-ion collisions has been a successful probe of the HotQCD matter, allowing to identify a marked non-perturbative dynamics and inferring a spatial diffusion $D_s$ coefficient in agreement with first quenched lattice QCD data, even if within still significant uncertainties.
I will review some...
