We study the thermal transitions of dense two colour QCD with two flavours of Wilson fermions at a fixed chemical potential $\mu=443$MeV on a coarse isotropic lattice $a=0.18$fm.
The results on a larger lattice volume ($N_s=24$) are compared with earlier results with the same lattice spacing but a smaller lattice volume ($N_s=16$). Only small finite volume effects are found.
We also...
In view of the usually encountered complexity of the quantum-field-theoretic approach to (two-particle) bound states by means of the homogeneous Bethe‒Salpeter equation, this formalism is frequently subjected to various simplifying approximations. If carried to its extremes, this procedure ultimately yields semirelativistic equations of motion believed to reproduce, at least coarsely, the...
The magnetic fields generated in non-central heavy-ion collisions are among the strongest fields produced in the universe, reaching magnitudes comparable to the scale of strong interactions. Backed by model simulations, the resulting field is expected to be spatially modulated, deviating significantly from the commonly considered uniform profile. In this work, we present the next step to...
In this article [1], we have explored the very important quantity of lepton pair production from a hot and dense QCD medium in presence of an arbitrary magnetic field for simultaneous nonzero values of both the parallel and perpendicular components of momentum. As opposed to the zero magnetic field case (the so-called Born rate) or the lowest Landau level approximated rate, where only the...
Aiming at a self-consistent description of multiquark hadrons (such as tetraquarks, pentaquarks, hexaquarks, etc.) by means of QCD sum rules, we note that the entirety of contributions to two- or three-point correlation functions involving, respectively, two or one multiquark interpolating operators may be straightforwardly disentangled into two disjoint subsets comprising of unambiguously...
We study the production of charm quarks in hot QCD medium utilizing the quasiparticle model (QPM). The deconfined matter is composed of the dynamical quarks and gluons dressed by the effective temperature-dependent masses. The temperature dependence is specified by a running coupling deduced from lattice QCD thermodynamics [1]. For the evolution of the QGP, we employ the results of...
In heavy nuclei, the distribution of neutrons extends out further than the proton distribution forming a so-called “neutron skin”. An accurate experimental determination of the neutron skin thickness of heavy nuclei would provide a unique constraint on the symmetry energy of the nuclear Equation Of State, which strongly depends on poorly constrained three-body forces. Photons have an advantage...
We use complex Langevin simulations to study the QCD phase diagram with two light quark flavours. In this study, we use Wilson fermions with an intermediate pion mass of ~500 MeV. By studying thermodynamic quantities, in particular at lower temperatures, we are able to describe the equation of state.
We present a novel strategy to strongly reduce the severity of the sign problem, using line integrals along paths of changing imaginary action. Highly oscillating regions along these paths cancel out, decreasing their contributions. As a result, sampling with standard Monte-Carlo techniques becomes possible in cases which otherwise requires methods taking advantage of complex analysis, such as...
We present a data-driven analysis of the $\gamma\gamma\to D^+D^-$ and $\gamma\gamma\to D^0\bar{D}^0$ reactions from threshold up to 4.0 GeV in the $D\bar{D}$ invariant mass. For the $S$-wave contribution, we adopt a partial-wave dispersive representation, which is solved using the $N/D$ ansatz. The left-hand cuts are accounted for using the model-independent conformal expansion. The $D$-wave...
The complexity of strong dynamics has triggered many different techniques used depending on the phenomena to be described. Often, they rely on quantization over the plane of constant time in Minkowski space, but there are other possibilities: when quantization is carried out over a light front, the theory is manifestly invariant under the boost transformation along the direction of the...
The ghost propagator in Landau gauge is studied at finite temperature below and above $T_c$ using lattice QCD simulations. For high temperatures, we find that the ghost propagator is enhanced, compared to the confined phase. The results suggest that the ghost propagator can be used to identify the phase transition, similarly to the gluon propagator case.
We explore the consequences of gluonic hot spots in the proton for coherent and incoherent exclusive vector meson production cross sections. For the proton we use the Color Glass Condensate framework in the dilute limit with Gaussian hot spots of fluctuating color charges, which we are able to average over analytically. The cross sections are computed using the lowest order dipole model and...
We report novel lattice QCD results for the three-gluon vertex from quenched lattice-QCD simulations. Using standard Wilson action, we have computed the three gluon vertex beyond the usual kinematic restriction to the symmetric (q² = r² = p²) and soft-gluon (p = 0) cases where it depends on a single momentum scale. We will present a detailed analysis of the asymmetric case (r² = q² ≠ p²) where...
One of the main subjects in current nuclear physics is to reveal rich
phase structure in high baryon density matter: the first-order chiral
transition line with the QCD critical point (CP), the color
superconducting (CSC) phase transition and so on. In the present
contribution, we calculate how the critical fluctuations that develop
around the QCD CP and CSC phase transition, affect...
Strongly coupled matter called quark–gluon plasma (QGP) is formed in heavy-ion collisions at RHIC and the LHC. The expansion of this matter, caused by pressure gradients, is known to be hydrodynamic. The computations show that the expanding QGP has a small shear viscosity to entropy density ratio (η/s), close to the known lower bound 1/4π. In such a medium one expects that jets passing through...
When colliding heavy ions, like Pb-Pb at the LHC, it is known that long-range
correlations is a collective flow effect of the quark gluon plasma produced in the
collision. Similar effects have also been observed in smaller collision systems such as
p-Pb and pp at the LHC. The origin of these long-range correlations in small systems,
and whether it is the same as in large collision systems,...
We show that the recent ALICE measurement of the hadronic lead-lead cross section implies a small nucleon width, which is inconsistent with all state-of-the-art current global analyses of a wide set of experimental results. This inconsistency has several consequences for global analyses, both at a fundamental level as well as for quantities such as the bulk viscosity. The updated global...
We discuss the existence of nets of vortices and monopoles for the SU(3) gauge group in the infrared regime of QCD. By appropriate gauge transformations, magnetic defects like monopoles, vortices and nets in SU(3) gauge group are studied in terms of its SU(2) subgroups. The resulted Lagrangian explicitly shows the above magnetic defects and their interactions. Confinement properties like...
