$K_1$ and $K^*$ are chiral partners, both with vacuum widths smaller than 100 MeV, making them a suitable pair that can be realistically measured.
Based on the fact that the mass difference between the chiral partners is an order parameter of chiral phase transition and that the chiral order parameter reduces substantially at the chemical freeze-out point in ultra-relativistic heavy ion...
Strangeness production in heavy-ion collisions reveals the modification of the properties of strange hadrons in hot and dense nuclear matter. Adopting in-medium properties of antikaons $(\bar K = K^-, \bar K^0)$ described by the self-consistent coupled channel unitarized scheme based on a SU(3) chiral effective Lagrangian (G-matrix), we study strangeness production in heavy-ion collisions...
The Compressed Baryonic Matter (CBM) experiment is under construction at the Facility for Antiproton and Ion Research (FAIR). It aims to explore the phase structure of strongly interacting (QCD) matter at large net-baryon densities and moderate temperatures by means of heavy-ion collisions in the energy range sqrt(s_NN) = 2.9 - 4.9 GeV. As fixed-target experiment, CBM is equipped with fast...
Direct photons produced in heavy ion collisions are penetrating probes
and as such encode the entire space-time history of the collision, from
the initial hard scattering till the final kinetic freeze-out. For the
very same reason theoretical models are challenged to connect and balance
many different production mechanisms. Simultaneous observation of large
yields and large azimuthal...
There seem to exist two lightest axial mesons with charm whose masses are very similar but the associated widths and other properties are different. These mesons are denominated as D1(2430)D1(2430) and D1(2420)D1(2420). Although two mesons with similar masses are expected to exist, with such quantum numbers, within the traditional quark model, as we discuss the description of their decay...
We calculate the Next to Leading Order corrections to inclusive production of a quark-antiquark pair in a strong color field. We show that all possible divergences either cancel or are absorbed into evolution of physical quantities. We show how our results can be used for precision studies of quark production in ultra-peripheral heavy ion collisions.
Non-perturbative resummation at finite temperature via the Gribov gluon propagator was proposed by D. Zwanziger in 2005 [1]. Later, in 2013, it was used by K. Fukushima and N. Su [2] to study gluon thermodynamics. In 2015, N. Su and T. Tywoniuk showed that a novel massless excitation is ascribable to the magnetic scale in quark dispersion relations.
We recently used the non-perturbative...
We solve a Boltzmann equation that describes the dynamics of coupled massless quark and gluon fluids undergoing transversally homogeneous boost-invariant expansion. The quark and gluon components are taken to have the same dynamical anisotropy parameter, but we introduce a fugacity parameter that allows quarks to be out of chemical equilibrium, as expected right after the formation of the QGP...
Measurements at the LHC have provided evidence for collective behavior in high-multiplicity proton-proton (pp) and proton-lead (pPb) collisions through multiparticle correlation techniques. To investigate detailed properties of this collectivity, a comprehensive study of differential Fourier coefficients ($v_{n}$) in particle transverse momentum ($p_\mathrm{T}$) and event multiplicity is...
Due to the spin-orbit coupling, Dirac fermions, submerged in a thermal bath with finite macroscopic vorticity, exhibit a spin polarisation along the direction parallel to the vorticity vector Ω. Due to the symmetries of the Lagrangian for free massless Dirac particles, there are three independent and classically conserved currents corresponding to the vector, axial, and helical charges. We...
Authors: S. Glässel, V. Kireyeu, G. Coci, V. Voronyuk, M. Winn, J. Aichelin, C. Blume, and E. Bratkovskaya
We investigate the influence of the equation-of-state (EoS) of strongly interacting hadronic and partonic matter created in heavy-ion collisions on the light cluster and hypernuclei production within the Parton-Hadron-Quantum-Molecular Dynamics (PHQMD) microscopic transport approach...
NA61/SHINE is a multipurpose fixed-target experiment located at CERN SPS. One of its main goals is to study the phase diagram of strongly interacting matter. For this purpose, a unique two-dimensional scan in beam momentum 13A-150(8)A GeV/c and the system size including p+p, p+Pb, Be+Be, Ar+Sc, Xe+La, and Pb+Pb collisions was performed. The main goal of the strong interaction program is to...
The study of strongly interacting matter under extreme conditions is one of the most important topics in the exploration of Quantum
Chromodynamics (QCD).
In this talk, we highlight new measurements by HADES, the High-Acceptance Dielectron Spectrometer located at the SIS18 at GSI in Darmstadt, which is currently the only experimental setup with the unique ability to measure rare and...
Heavy-ion collision experiments are a valuable tool for studying nuclear properties. Accurately modeling entropy production at the initial collision time and subsequent collective evolution is crucial to connect the nuclear structure to heavy-ion measurements. In this talk, we argue that, based on experimental data, it is reasonable to assume scale-invariance at the initial state, meaning the...
In recent years, many new jet substructure observables have been studied, with particular attention given to those that can be calculated by perturbative QCD. N-point energy correlators are currently attracting both theoretical and experimental interest. The energy-energy correlators (EEC), or two-point correlator, which emphasize the angular structure of the energy flow within jets, allow for...
We present a new coherent jet energy loss model for heavy-ion collisions. It is implemented as a Monte Carlo perturbative final-state parton shower followed by elastic and radiative collisions with the medium constituents. Coherency is achieved by starting with trial gluons that act as field dressing of the initial jet parton. These are formed according to a Gunion-Bertsch seed. The QCD...
Shortly after the beginning of the LHC heavy ion program, the CMS Collaboration reported the observation of stronger suppressions of the excited $\Upsilon$ states compared to the lower $\Upsilon\mathrm{(1S)}$ state, first in lead-lead (PbPb) and then in proton-lead (pPb) collisions. Such feature, anticipated in the former as a signature of the presence of a quark-gluon plasma, was however...
Systematic studies of jet substructure offer precision tests of quantum chromodynamics (QCD) in vacuum as well as at the large particle densities and high temperatures of the quark-gluon plasma (QGP) produced in heavy-ion collisions. The jet invariant mass is a canonical jet substructure observable which has been broadly studied for decades, both experimentally and theoretically, to qualify...
Despite the f0(980) hadron having been discovered half a century ago, the question about its quark content has not been settled: it might be an ordinary quark-antiquark meson, a tetraquark exotic state, a kaon-antikaon molecule, or a quark-antiquark-gluon hybrid. We report strong evidence that the f0(980) state is an ordinary quark-antiquark meson, inferred from the scaling of elliptic...
