Related papers: Study of Hadrons Using the Gaussian Functional Met…
We perform a 1/N-expansion of the partition function of the massive Gross-Neveu model in 1+1 dimensions. The procedure allows for the inclusion of the contribution of scalar and pseudoscalar composites (of order 1/N) to the equation of…
A symmetry conserving, non-perturbative treatment based on a variational squeezed vacuum state in conjunction with a well-defined class of RPA fluctuations is applied to the SU(3) linear-sigma-model. It is shown that the Goldstone theorem…
We present first results for a study with two mass-degenerate dynamical Chirally Improved (CI) fermions on lattices of spatial extent 2.4 fm. The CI Dirac operator obeys the Ginsparg-Wilson condition in good approximation. The pion mass we…
An effective potential in a meson-meson system is discussed based on the SU(3) chiral constituent quark model, and the analytic form of the potential is explicitly given. In addition, the effective potential is employed to study the bound…
Relations among the effective hadron masses and the effective interactions in nuclear matter are studied by using the generalized relativistic mean field theory. We found that we can make the effective omega-meson mass smaller and the…
In this study an effective description in the 2PI effective-action formalism for systems of quarks and mesons in and out of equilibrium within a numerical approach is developed, allowing to approximate the complexity of QCD by taking only…
The work presented at this workshop is divided into two parts. In the first part, the mass and decay width of the $\phi$-meson in cold nuclear matter are computed in an effective Lagrangian approach. The medium dependence of these…
We calculate the $m_\varrho / f_\pi$ ratio in the chiral and continuum limit for $SU(3)$ gauge theory coupled to $N_f = 2,3,4,5,6$ fermions in the fundamental representation. Keeping all systematic effects under full control we find no…
The quantum fluctuations of the quark condensate are calculated using a regulated Nambu Jona-Lasinio model. The corresponding quantum fluctuations of the chiral fields are compared to those which are predicted by an ''equivalent'' sigma…
Starting from the Hubbard model in the weak-coupling limit, we derive a spin-fermion model where the collective spin excitations are described by a non-linear sigma model. This result is used to compute the fermion spectral function $A({\bf…
We extend our recent computation of the low-energy limit of the linear O(4) Quark-Meson Model. The present analysis focuses on the transformation of the resulting effective action into a nonlinearly realized effective pion action, whose…
We calculate the baryon octet masses to fourth order in chiral perturbation theory employing dimensional and cut-off regularization. We analyze the pion and kaon mass dependences of the baryon masses based on the MILC data. We show that…
The pi pi scattering is studied in two-flavor chiral models with a finite pion mass to investigate the nature of the sigma meson which is observed as the lowest scalar-isoscalar resonance. We compare several models with different origins of…
We study the O(N) symmetric linear sigma model at finite temperature as the low-energy effective models of quantum chromodynamics(QCD) using the Cornwall-Jackiw-Tomboulis(CJT) effective action for composite operators. It has so far been…
We reconsider the question of mass generation for fermions coupled to a set of gauge bosons when the latter get their masses through the Goldstone bosons originating in a simple (i.e. not extended) technicolor sector. The fermion global…
Event-by-event fluctuations of the kaon to pion number ratio in nucleus-nucleus collisions are studied within the statistical hadron-resonance gas model (SM) for different statistical ensembles and in the Hadron-String-Dynamics (HSD)…
The statistical equilibrium properties of the linear sigma model are studied, with a view towards characterizing the field configurations employed as initial conditions for numerical simulations of the formation of disoriented chiral…
Bosonization of the strong interacting matter as a process of arising observable hadrons is studied in terms of the phase transition of the second kind. The spectrum of bosons which is free from the zero point energy is derived . The…
We consider the experimental data on var(phi)-meson production in hadron-nucleon collisions for a wide energy region. The Quark-Gluon String Model quantitatively describes the spectra of secondary var(phi), as well as the ratios of…
The $\phi$ meson and $\Omega$ baryon provide unique probes of the properties of the quark-gluon plasma (QGP) at hadronization in relativistic heavy-ion collisions. Using the quark recombination model with the quark phase-space information…