Related papers: Mass Spectrum in SQCD and Problems with the Seiber…
We study SU(2) color QCD with even number of quark flavors. First, using QCD inequalities we show that at finite baryon chemical potential mu, condensation must occur in the channel with scalar diquark quantum numbers. This breaks the U(1)…
Compact stars may contain quark matter in their interiors at densities exceeding several times the nuclear saturation density. We explore models of such compact stars where there are two first-order phase transitions: the first from nuclear…
By the use of an effective superpotential in supersymmetric quantum chromodynamics (SQCD) with N_f flavors and N_c colors of quarks for N_f>=N_c+2, the influence of soft supersymmetry (SUSY) breakings is examined to clarify dynamics of…
We pursue the issue of the local quark-hadron duality at high energies in two- and four-dimensional QCD. A mechanism of the dynamical realization of the quark-hadron duality in two-dimensional QCD in the limit of large number of colors,…
We report on the first large-scale study of two flavor QCD with domain wall fermions (DWF). Simulation has been carried out at three dynamical quark mass values about 1/2, 3/4, and 1 $m_{strange}$ on $16^3\times 32$ volume with $L_s=12$ and…
Symplectic flavour symmetry group Sp(n/2) (n is even) of n Majorana states does not allow for invariant Majorana masses. Only specific mass matrices with diagonal and nondiagonal elements are possible here. As a result of the spontaneous…
We study $SU(N)$ Quantum Chromodynamics (QCD) in 3+1 dimensions with $N_f$ degenerate fundamental quarks with mass $m$ and a $\theta$-parameter. For generic $m$ and $\theta$ the theory has a single gapped vacuum. However, as $\theta$ is…
Doubly heavy tetraquark states are the prime candidates for tightly bound exotic states. We present a systematic study of the mass spectra of the $S$-wave doubly heavy tetraquark states $QQ\bar{q}\bar{q}$ ($q=u, d, s$ and $Q=c, b$) with…
The spectra of baryons containing two heavy quarks test the form of the $QQ$ potential through the spin-averaged masses and hyperfine splittings. The mass splittings in these spectra are calculated in a nonrelativistic potential model and…
CP-PACS and JLQCD collaborations are carrying out a joint project of the 2+1 flavor full QCD simulation. Gauge configurations are generated for the non-perturbatively $O(a)$-improved Wilson quark action and the Iwasaki gauge action using…
Lattice studies suggest that at zero baryon chemical potential and increasing temperature there are three characteristic regimes in QCD that are connected by smooth analytical crossovers: a hadron gas regime at T < T_ch ~ 155 MeV, an…
Starting from the approximate symmetries of QCD, namely chiral symmetry for light quarks and spin and flavor symmetry for heavy quarks, we investigate the low-energy properties of heavy hadrons. For this purpose we construct a consistent…
A Higgs description for the QCD vacuum in the limit of two quark flavors is proposed. Complete ``spontaneous breaking'' of color symmetry is realized by condensation of an adjoint quark-antiquark and a quark-quark pair. The vacuum is…
We consider the N=1 supersymmetric QCD with SU(N_c) gauge group involving N_f = N_c - 1 pairs of chiral matter multiplets in fundamental and antifundamental color representations. For this theory in the framework of the effective lagrangian…
Weinberg recently pointed out a flaw in the standard argument that large $N_c$ QCD with color-fundamental quarks [QCD(F)] cannot yield narrow tetraquark states. In particular, he observed that the argument does not rule out narrow…
We present our result of the many-flavor QCD. Information of the phase structure of many-flavor SU(3) gauge theory is of great interest, since the gauge theories with the walking behavior near the infrared fixed point are candidates of new…
We determine the phase diagram of complete asymptotically free SU($N_c$) gauge theories featuring $N_s$ complex scalars and $N_f$ Dirac quarks transforming according to the fundamental representation of the gauge group. The analysis is…
Our recent works revisit the proof of chiral symmetry breaking in the confining phase of four-dimensional QCD-like theories, i.e. $SU(N_c)$ gauge theories with $N_f$ flavors of vectorlike quarks in the fundamental representation. The…
We investigate quantum chromodynamics with two colors at nonvanishing density using Dyson-Schwinger equations. Lattice methods do not have a complex action problem in this theory. Thus, we can benchmark our results and the effect of…
We apply a random matrix model to the study of the phase diagram of QCD with two colors, two flavors, and a small quark mass. Although the effects of temperature are only included schematically, this model reproduces most of the ground…