Related papers: Expectation values of four-quark operators in pion…
The quark antiquark components of the U(3) lightest scalar meson nonet are investigated by considering the Nambu-Jona-Lasinio model with flavor-dependent coupling constants that were derived by considering (non-perturbative) gluon…
We present preliminary results from exploring the phase diagram of finite temperature QCD with three degenerate flavors and with two light flavors and the mass of the third held approximately at the strange quark mass. We use an order…
We discuss the low-energy analysis of models involving quarks and four-fermion couplings. The relation with QCD and with other models of mesons and meson plus quarks at low energies is discussed. A short description of how the heat-kernel…
The bounds on the values of gluon, four-quark and quark-gluon condensates are derived from the requirement of consistency of the sum rules for various correlators of the hybrid current $a_{\mu}=g\bar d\gamma_{\rho}\tilde G_{\rho\mu}u$. The…
Temperature dependence of the quark condensate is studied in the Nambu--Jona-Lasinio model with meson loops. Substantial differences are found compared to the results with quark loops only.
QCD sum rules for $D$ and $B$ mesons in a strongly interacting environment require the decomposition of Gibbs averaged operators related to tensor structures. We present a procedure to decompose these operators into vacuum and…
We present preliminary results from exploring the phase diagram of finite temperature QCD with three degenerate flavors and with two light flavors and the mass of the third held approximately at the strange quark mass. We use an order…
We investigate the properties of charge-neutral $\beta$-equilibrium cold quark matter within the Nambu-Jona-Lasinio model. The calculations are carried out for different ratios of coupling constants characterizing the vector and scalar…
We discuss formulation of QCD in Minkowski-spacetime and effect of an operator product expansion by means of normal ordering of fields in the QCD Lagrangian. The formulation of QCD in the Minkowski-spacetime allows us to solve a constraint…
I discuss recent results obtained by our group within the Nambu-Jona Lasinio model with the Polyakov loop. I focus on the two flavor version of the model, discussing the phase diagram in the $\mu-T$ plane in the case in which electrical…
We propose an extended Nambu--Jona-Lasinio model to include the heavy mesons with the heavy quark symmetry. The quark current-current interaction is generalized to include the heavy quark currents. In order to comply with the heavy quark…
We perform a preliminary study of the 1/2+ and 3/2+ ground-state baryons containing a heavy quark in the framework of the chiral SU(3) quark model. By using the calculus of variations, masses of Lambda_Q, Sigma_Q, Xi_Q, Omega_Q, Sigma_Q^*,…
We determine the q-bar q condensate for quark masses from zero up to that of the strange quark within a phenomenologically successful modelling of continuum QCD by solving the quark Schwinger-Dyson equation. The existence of multiple…
We show that the quark condensates for the two light up and down flavors can have significantly different values in the hadronic phase at nonzero temperature, baryon and isospin chemical potentials. We quantify this difference using a…
We propose a theoretical framework for evaluating the effect of four-fermion operators on the mass of composite particles in confining strongly-coupled gauge theories. The confining sector is modelled by a non-local Nambu-Jona Lasinio…
We prove that the matrix elements of four fermion operators mediating the decay B^0 -> D^+ \pi^- and B^- -> D^0 \pi^- factor into the product of a form factor describing the B -> D transition and a convolution of a short distance…
The possibility of the pion condensation phenomenon in cold and electrically neutral dense baryonic matter is investigated in $\beta$-equilibrium. For simplicity, the consideration is performed in the framework of a NJL model with two quark…
The leading order low energy parameters like the pion decay constant or the quark condensate are well-known from "classical" low energy theorems and experiments. It is a challenge, however, to find these parameters based exclusively on an…
We compute the magnetic susceptibility of the quark condensate and the polarization of quarks at zero temperature and in a uniform magnetic background. Our theoretical framework consists of two chiral models that allow to treat…
To describe pion as a bound state of two quark, when their current masses are non equal to zero, is considered. In the framefowrk of the potential approximate the Schwinger-Dyson and Bethe-Salpeter equations are solved. The quark-antiquark…