Related papers: How tetraquarks can generate a second chiral phase…
When the quark masses are lighter than those in QCD, the standard lore is that a chiral transition of first order must emerge for three, light flavors. Recently, however, numerical simulations on the lattice suggest that the chiral…
We study the lowest-lying scalar mesons in the QCD sum rule by considering them as tetraquark states. We find that there are five independent currents for each state with a certain flavor structure. By forming linear combinations, we find…
In this article, we take the scalar diquarks as point particles and describe them as basic quantum fields, then introduce the SU(3) color gauge interaction and new vacuum condensates to study the nonet scalar mesons as tetraquark states…
Structure and production of doubly charmed tetraquarks T_cc (cc ubar dbar) are studied from the viewpoint of color configurations. Based on the diquark correlation, the tetraquark T_cc with I(JP)=0(1+) is considered to be stable against…
We investigate the chiral phase transition of a QCD-like theory, based the shape change of the effective potential near the critical point. The potential is constructed with the auxiliary field method, and a source term coupled to the field…
The finite temperature transition of QCD with two degenerate light quarks is studied on the lattice with a renormalization group improved gauge action and the Wilson quark action. We have made simulations on an $8^3\times 4$ lattice near…
Because too many interesting things are going on now, I have tried to squeeze three different subjects into one talk. The first is a brief summary of the color super-conductivity. During the last year we learned that instanton-induced…
The nature of the QCD phase transition in the chiral limit presents a challenging problem for lattice QCD. However, its study provides constraints on the phase diagram at the physical point. In this work, we investigate how the order of the…
The properties of cold and dense quark matter have been the subject of extensive investigation, especially in the last decade. Unfortunately, we still lack of a complete understanding of the properties of matter in these conditions. One…
We discuss random matrix models for the spontaneous breaking of both chiral and color symmetries at zero chemical potential and finite temperature. Exploring different Lorentz and gauge symmetric color structures of the random matrix…
We compute the QCD phase diagram in the plane of the chiral chemical potential and temperature using the linear sigma model coupled to quarks and to the Polyakov loop. The chiral chemical potential accounts for effects of imbalanced…
In extensions of the Standard Model with no dimensionful parameters the electroweak phase transition can be delayed to temperatures of order 100 MeV. Then the chiral phase transition of QCD can proceed with 6 massless quarks. The top-quark…
We discuss recent results for the phase transition in finite-temperature QCD from numerical (Monte Carlo) simulations of the lattice-regularized theory. Emphasis is given to the case of two degenerate light-quark flavors. The order of the…
Light-front quantization to many-particle systems of finite temperature and density provides a novel approach towards a relativistic description of quark matter and allows us to calculate the perturbative as well as the non-perturbative…
We investigate the phase diagram of QCD at small chemical potentials, ie, when chiral and flavour symmetry breaking involves the pairing of a quark and an antiquark. The phase diagram of two-flavour QCD at small chemical potentials involves…
We use a Landau theory and the epsilon expansion to study the superfluid phase transition of two-color QCD at nonzero temperature, T, and baryonic chemical potential, mu. At low T, and for N_f flavors of massless quarks, the global SU(N_f)…
Within the proper-time renormalization group approach, the chiral phase diagram of a two-flavor quark-meson model is studied. In the chiral limit, the location of the tricritical point which is linked to a Gaussian fixed point, is…
For very heavy quarks $Q$, relations derived from heavy-quark symmetry predict the existence of novel narrow doubly heavy tetraquark states of the form $Q_iQ_j \bar q_k \bar q_l$ (subscripts label flavors), where $q$ designates a light…
QCD with 2 massless colour-sextet quarks is studied as a model of Walking Technicolor. We simulate lattice QCD with 2 light color-sextet staggered quarks at finite temperature, and use the dependence of the coupling at the chiral transition…
We summarize our recent results on the phase diagram of QCD with N_f=2+1 quark flavors, as a function of temperature T and quark chemical potential \mu. Using staggered fermions, lattices with temporal extent N_t=4, and the exact RHMC…