Related papers: Chiral restoration in excited nucleons versus SU(6…
We study the production of strange hadrons in nucleus-nucleus collisions from 4 to 160 A GeV within the Parton-Hadron-String Dynamics (PHSD) transport approach that is extended to incorporate essentials aspects of chiral symmetry…
Exploiting the recent lattice results for the infrared gluon propagator with light dynamical quarks, we solve the gap equation for the quark propagator. We thus model the chiral symmetry breaking mechanism with increasing number of flavours…
Applications imposing SU(3) chiral symmetry on non-relativistic field theory are considered. The first example is a calculation of the self-energy shifts of the spin-3/2 decuplet baryons in nuclear matter, from the chiral effective…
Recent results of meson photo-production at the existing electron machines with polarized real photon beams and the measurement of polarization observables of the final state baryons have provided high precision data that led to the…
We present results for masses of excited mesons from quenched calculations using chirally improved quarks at pion masses down to 350 MeV. The key features of our analysis are the use of a matrix of correlators from various source and sink…
We explore the effects of breaking and restoration of chiral and axial symmetries using an extended three-flavor Nambu-Jona-Lasinio model that incorporates explicitly the axial anomaly through the 't Hooft interaction. We implement a…
We investigate the axial U(1) anomaly of two-flavor QCD at temperatures 190--330 MeV. In order to preserve precise chiral symmetry on the lattice, we employ the Mobius domain-wall fermion action as well as overlap fermion action implemented…
Suggested holographic duals of QCD, based on AdS/CFT duality, predict that one should be able to vary the scales of colour confinement and chiral-symmetry breaking independently. Furthermore they suggest that such independent variation of…
We derive the chiral effective Lagrangian for excited heavy-light mesons from QCD under proper approximations. We focus on the chiral partners with $j_l^P=\frac{3}{2}^+$ and $j_l^P=\frac{3}{2}^-$ which amounts to ($1^+,2^+$) and ($1^-,2^-$)…
We show a novel charge structure of baryons in electromagnetic field due to the chiral anomaly. A key connection is to treat baryons as solitons of mesons. We use Skyrmions to calculate the charge distributions in a single nucleon and find…
The description of excitations in hot and dense (hadronic) matter is discussed with emphasis on the use of correlation functions as a common framework for comparing different model (and QCD lattice) calculations with each other. Typical…
We discuss the role of the U(1) axial symmetry for the phase structure of QCD at finite temperature. We expect that, above a certain critical temperature, also the U(1) axial symmetry will be restored. We will try to see if this transition…
We study the effect of the chiral symmetry restoration (CSR) on heavy-ion collisions observables in the energy range $\sqrt{s_{NN}}$=3-20 GeV within the Parton-Hadron-String Dynamics (PHSD) transport approach. The PHSD includes the…
Violation of the $U(1)$ axial symmetry in QCD is stricter than the chiral $SU(2)$ breaking, simply because of the presence of the quantum axial anomaly. If the QCD gauge coupling is sent to zero, the strength of the $U(1)$ axial breaking…
We calculate the electric charge radii of the SU(3) pseudoscalar mesons and the SU(3) octet baryons in quenched and partially quenched chiral perturbation theory. We work in the isospin limit, up to next-to-leading order in the chiral…
Quantum chromodynamics with light quarks features an approximate global symmetry, known as chiral symmetry, that is believed to be spontaneously broken by the vacuum expectation value of a scalar and isoscalar composite field, in addition…
In the early days of QCD, the axial $U(1)$ anomaly was considered as a trigger for the breaking of the $SU(2)_L\times SU(2)_R$ symmetry through topological excitations of gluon fields. However, it has been a challenge for lattice QCD to…
Excited state contributions represent a formidable challenge for hadron structure calculations in lattice QCD. For physical systems that exhibit an exponential signal-to-noise problem they often hinder the extraction of ground state matrix…
Lattice QCD simulations tend to get stuck in a single topological sector at fine lattice spacing, or when using chirally symmetric quarks. In such cases computed observables differ from their full QCD counterparts by finite size effects,…
Recent advances in the study of excited nucleons are discussed. Much of the progress has been achieved due to the availability of high precision meson production data in the photoproduction and electroproduction sectors, the development of…