Erice: INTERNATIONAL SCHOOL OF NUCLEAR PHYSICS, 46th COURSE

Anisotropic phases are hypothesised to play an important role in the QCD phase diagram for small temperatures and large densities. I will present a study of such a phase, the chiral density wave (CDW), within a nucleon-meson model, taking also into account the nucleonic vacuum fluctuations. In particular, the main goal is exploring the possible existence of the CDW in the interior of neutron...

Dense QCD matter can feature a moat regime, where the static energy of mesons is minimal at nonzero momentum. We elucidate various features of this regime in this work. To capture the main effects, we use a two-flavor quark-meson model and put forward an efficient renormalization scheme to account for the nontrivial momentum dependence of meson self-energies in the moat regime.
We show that...

The Parity Doublet Model is a effective theory describing nucleon and negative parity resonances associated with each other in the parity doubling framework.
We present a renormalization group invariant formulation of the model, describing baryons and their negative-parity chiral partners in dense hadronic matter. By constructing the mesonic potential in terms of fermion masses and absorbing...

In this talk I will show how the functional renormalization group (FRG) can be used to constrain low energy model for quark-matter, with a focus on color superconductivity. Working in vacuum, I will explain how the FRG can be used describe both the non-pertubative behavior of the glue sector, and how low-energy degrees of freedom (in particular the sigma, pion and scalar diquark) can be...

The equation of state (EoS) of neutron star matter encodes the relationship between pressure and density at supranuclear densities, fundamentally governing the star’s structure and observable macroscopic properties, such as mass, radius, and tidal deformability. In this work, we apply Neural Posterior Estimation (NPE) with conditional normalising flows to infer the EoS from synthetic...

While symmetric nuclear matter has been studied in laboratories, neutron star matter is characterized by high asymmetry. Therefore, by examining the strongly interacting matter properties in a wide range of densities and isospin asymmetry we confront two regimes to understand how the enforced electric neutrality and beta equilibrium alter the onset density of quark matter. Particularly, we...

Strangeness production is a key signature of the formation of a hot and dense medium in heavy-ion collisions. Understanding the enhancement of strange particles in such environments remains a central challenge. Hybrid approaches—combining transport theory and hydrodynamics within the core–corona framework—have been successful in describing this behavior.

At the same time, signs of...

The High-Acceptance-Di-Electron-Spectrometer (HADES) at GSI, Darmstadt, measures heavy-ion and elementary collisions at beam energies of a few GeV, thereby accessing the QCD phase diagram at high densities, around 2-3 times the saturation density, and moderate temperatures in the order of tens of MeV.

Such conditions are similar to those expected in neutron star mergers, which provides a...

We explore some regularization prescriptions and how they impact the effective potential and the gap equation. We also explore the role of the integration measure/geometry in momentum space in symmetry breaking. We conclude that every regularization prescription and geometry greatly affect the properties of symmetry breaking/restoration. We also propose a modified representation of proper...

Summary: The Nambu-Jona-Lasinio model phase diagram for a 2 + 1 flavor quark system will be described using the temperature and chemical potential as thermodynamic properties. Various susceptibilities will be used in order to obtain several qualitatively different phase diagrams, and each will be analyzed in both the light and strange quark sectors. A crossover region will be defined for the...

We investigate the spectrum and wave functions of heavy mesons in terms
of the number of light flavours and mass, upon introducing a heavy quark
in the perturbative regime of the QCD conformal window. We then compute
the conformal Isgur-Wise function which is a central quantity of the
dynamics of heavy mesons. We further determine the impact of the
residual low energy confining dynamics....

Understanding the phase structure of Quantum Chromodynamics (QCD) remains the main goal of both experimental and theoretical studies of strongly interacting matter. Lattice QCD calculations at zero $\mu_B$ predict a smooth crossover between the hadronic phase and the quark-gluon plasma (QGP). One of the key experimental signatures of the formation of the QGP is the enhancement of strange...

An understanding of the properties of the quark-gluon plasma (QGP) is important for the interpretation of experimental data on the bulk observables, as well as on jet and heavy-quark attenuation in heavy-ion collisions. However, gaining this knowledge is a challenging task, since it pertains to the non-perturbative regime of QCD, for which only limited information from lattice QCD is currently...

The density functional renormalization group (density-fRG) is proposed to investigate the density fluctuations within the functional renormalization group approach, which allows us to quantify the medium effect and study physics of high densities. The density-fRG is applied to the nucleon-meson effective field theory, also known as the Walecka model, to study the properties of nuclear matter...

The observables computed in simulations of heavy ion collisions are known to be highly sensitive to the initial state of the evolution. Despite advances in modeling, fully understanding this initial state remains a challenge. In this work, we propose a method to relate final observables to the initial state, described as the sum of an average state and a random linear combination of...

Spin hydrodynamics is one of the leading techniques employed to understand spin polarization in heavy ion collisions. Given the topic is still in its infancy, there is a lot of debate about its most basic aspects like the form of the equilibrium distribution function. Current prevalent forms suffer from significant drawbacks, including issues with the normalization of mean spin polarization....

One of the challenging tasks for the heavy-ion community is the construction of spin hydrodynamics. As various formal issues require clarification, we investigate the application range of perfect spin hydrodynamics with different treatments of spin [1]. By considering a quantum spin density matrix (Wigner function) and a classical spin description, we derive fine constraints that connect the...

The study of relativistic heavy-ion collisions serves as a valuable tool for investigating the structure of nuclear matter and its behaviour under extreme conditions. Over the past two decades, this domain of nuclear physics has led to several significant discoveries, including the quark-gluon plasma at RHIC, in 2005, the Higgs boson at CERN, in 2012, and exotic hadrons by the LHCb...

Two particle correlations have shown the presence of long-range rapidity correlations in small collision systems. Several other measurements provided insight into the unexpected collective behaviour similar to the one exhibited in heavy-ion collisions. These properties can be explained by several models, which consider a microscopic description like PYTHIA 8 and a macroscopic treatment as...

Hybrid models are used to describe the evolution of the quark-gluon plasma produced in ultrarelativistic heavy-ion collisions. These models combine viscous relativistic hydrodynamics with pre-equilibrium dynamics and hadronic cascade models. The connection from the hydrodynamics stage to the particlization stage is made through a particlization model, based on the Cooper-Frye formalism. This...

Tetraquark systems are composed of two quarks and two antiquarks which could be understood
as diquark-antidiquark bound states or meson-meson molecules. In the latter case, the
antisymmetrisation of the molecular wave function against quark exchange becomes necessary.
We discuss the resulting Pauli-blocking effect for the all-charm tetraquark Tcc(6900) as a J/ψ-J/ψ
molecule [1] and the...

The finite-size effects on the phase diagram, fluctuations, and thermodynamics are investigated using the explicitly volume-dependent partition function. We reproduce the expected finite-size scaling behavior while discussing different physical quantities in a finite volume.

I will present the calculation of the propagator of a charged vector boson in the presence of an external magnetic field using the Ritus Eigenfunction method. Although this is not a novel result, the methodology used throughout the calculation is relevant in the sense that the calculation is done with a diagonalized equation of motion. This advantage allows a more direct interpretation of the...

In most fields of science, visualizations help to understand concepts and to identify potential issues. For these reasons, animations of relativistic heavy-ion collisions provide interesting visual insights into the simulation software used as well as the time evolution of the collisions. In our work, we produce animations for collisions at several beam energies below 200 GeV for different...

The violation of the conformal limit for the speed of sound, $c_s^2=1/3$, has emerged as a critical feature of dense strongly interacting matter. Astrophysical observations—including gravitational wave data from LIGO/Virgo and precise neutron star radius measurements from NICER—suggest that the equation of state must exhibit a rapid stiffening at intermediate densities. This behavior is...

We study one-flavor $\mathrm{SU}(2)$ and $\mathrm{SU}(3)$ lattice QCD in $1+1$ dimensions at zero temperature and finite density using matrix product states and the density matrix renormalization group. We compute physical observables such as the equation of state, chiral condensate, and quark distribution function as functions of the baryon number density. As a physical implication, we...

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Strong magnetic fields can be found in all systems where we believe the quark-gluon plasma is formed, such as the early universe, compact stars, and heavy-ion collisions. The most intense magnetic field estimated in the lab is in non-central heavy-ion collisions, which can reach up to 10^{19} G. The scale of the strong interaction is much larger than the electromagnetic interaction, and the...

The open quantum system framework allows one to compute quarkonium's evolution in a medium, keeping track of the needed quantum features. However, computing this evolution is a computationally demanding task. QTRAJ is an efficient code that allows one to simulate the behavior of quarkonium in a medium in the case in which the medium sees quarkonium as a small color dipole $rT\ll 1$. While this...

Recognizing that flavor changing processes can probe new physics (NP) at scales beyond the reach of current experiments, we analyze semileptonic heavy meson decays: $B$, $B_s$ and $B_c$ mesons using \emph{Relativistic Independent Quark Model - a QCD inspired model} emphasizing the harmonic potential model-dependent analysis. Our predicted branching fractions and physical observables such as...

In the theory of strong interaction, the quantum chromodynamics (QCD), quarks and gluons at low energy exist in colour singlet states, confined into hadrons. However, under the extreme conditions of high-energy heavy-ion collisions, quark–gluon plasma (QGP) can be formed. This state of matter features deconfined quarks and gluons with colour degrees of freedom. It is believed that such a...