Related papers: Dynamical study of bare $\sigma$ pole with $1/N_c$…
The 1/$N_c$ arguments are developed to classify the hadronic states in the correlators. Arguments applied to the $\sigma$ meson correlator enable to separate the instanton, glueball, and, in particular, the $\pi\pi$ scattering states by…
In this article, we take the tensor currents $\bar{Q}(x)\sigma_{\mu\nu}Q(x)$ to interpolate the $P$-wave spin-singlet heavy quarkonium states $h_Q$, and study the masses and decay constants with the Borel sum rules and moments sum rules.…
Gaussian QCD sum-rules are ideally suited to the study of mixed states of gluonium (glueballs) and quark ($q\bar q$) mesons because of their capability to resolve widely-separated states of comparable strength. The analysis of the Gaussian…
Correlations between the QCD coupling \alpha_s, the gluon condensate < \alpha_s G^2 >, and the c,b-quark running masses m_c,b in the MS-scheme are explicitly studied (for the first time) from the (axial-)vector and (pseudo)scalar charmonium…
In this article, we extend our previous work to study the $\Sigma$-type heavy baryons $\Sigma_c$ and $\Sigma_b$ in the nuclear matter using the QCD sum rules, and obtain three coupled QCD sum rules for the masses $M_{\Sigma_Q}^*$, vector…
We construct QCD sum rules for nonperturbative studies without assuming the quark-hadron duality for the spectral density at low energy on the hadron side. Instead, both resonance and continuum contributions to the spectral density are…
In multiquark correlator analyses with 1/Nc classifications, it is possible to separate the scattering background and to justify the factorization of condensates, which allows us to achieve an isolated peak saturation in the QCD sum rules…
We scrutinize, improve some determinations of the masses and couplings of light scalar quarkonia ($\bar qq$ and four-quark states) and present new results for the $\pi^+\pi^-,K^+K^-,\dots$ molecules using QCD Laplace Sum Rule (LSR)…
We study the $\sigma$ meson in QCD sum rules using a two quark interpolating field with derivatives. In the constituent quark model, the $\sigma$ meson is composed of a quark and an antiquark in the relative p-wave state and is thus…
We consider the scattering of two color dipoles (e.g., heavy quarkonium states) at low energy - a QCD analog of Van der Waals interaction. Even though the couplings of the dipoles to the gluon field can be described in perturbation theory,…
We discuss how the lightest scalars, in particular the broad sigma resonance, can be understood as unitarized (qbar q) states within a unitarized quark model (UQM). The bare (qbar q) scalars are strongly distorted by hadronic mass shifts,…
Various QCD correlators are calculated in the instanton liquid model in zeromode approximation and $1/N_c$ expansion. Previous works are extended by including dynamical quark loops. In contrast to the original "perturbative" $1/N_c$…
In these lectures, we present the behavior of conventional $\bar{q}q$ mesons, glueballs, and hybrids in the large-$N_{c}$ limit of QCD. To this end, we use an approach based on rather simple NJL-like bound-state equations. The obtained…
We analyze mesons in constant magnetic fields ($B$) within a non-relativistic constituent quark model. Our quark model contains a harmonic oscillator type confining potential, and we perturbatively treat short range correlations to account…
The QCD sum rules in the large-$N_c$ limit for the light non-strange vector, axial and scalar mesons are considered assuming a string-like linear spectrum for the radially excited states. We propose a improved method for combined analysis…
The properties of $\Lambda$-hyperons in pure $\Lambda$ matter are studied with the finite-density QCD sum rule approach. The first order quark and gluon condensates in $\Lambda$ nuclear matter are deduced from the chiral perturbation…
We employ a nonrelativistic version of QCD (NRQCD) to study heavy quark-antiquark bound states in the lowest approximation without fine structure. We use gluon configurations on a 16^3 by 48 lattice at beta=6.2 from the UKQCD collaboration.…
We provide first-principles non-perturbative determinations of the low-lying meson mass spectrum of large-$N$ QCD in the 't Hooft limit $N_{\scriptscriptstyle{\rm f}}/N\to 0$, as well as of three low-energy constants appearing in the QCD…
Within the framework of the $1/N_c$ expansion of four-fermion interaction models, we analyse the next to leading $1/N_c$ corrections to the well known large-$N_c$ result $M_S=2M_Q$ where $M_S$ is the mass of the scalar boson and $M_Q$ is…
We estimate the masses of the 1^{--} heavy four-quark and molecule states by combining exponential Laplace (LSR) and finite energy (FESR) sum rules known perturbatively to lowest order (LO) in alpha_s but including non-perturbative terms up…