相关论文: Broad Sub-Continuum Resonances and the Case for Fi…
A QCD Laplace sum rule framework is employed to investigate the relationship between the mass and the decay width of the sigma, the lowest-lying isoscalar resonance in the spin-zero meson channel. Our analysis differs from prior analyses,…
We investigate lowest-lying scalar meson properties predicted from QCD Laplace sum rules based upon isovector and isoscalar non-strange $\bar{q}q$ currents. The hadronic content of these sum rules incorporates deviations from the narrow…
QCD Laplace sum-rules for light-quark I=0,1 scalar currents are used to investigate candidates for the lightest $q\bar q$ scalar mesons. The theoretical predictions for the sum-rules include instanton contributions which split the…
We apply QCD Finite Energy Sum Rules to the scalar-isoscalar current to determine the lightest $u \bar{u} + d \bar{d}$ meson in this channel. We use `pinch-weights' to improve the reliability of the QCD predictions and reduce the…
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…
An updated investigation of QCD sum rules for the first two moments of rho meson spectral functions, both in vacuum and in-medium, is performed with emphasis on the role of the scale related to spontaneous chiral symmetry breaking in QCD.…
Global fits to the shape of the first QCD Laplace sum rule exhibiting sensitivity to pion-resonance [$\Pi (1300)$] parameters are performed, leading to predictions for the pion-resonance mass and decay constant. Two scenarios are considered…
It is argued that it is valid to use QCD sum rules to determine the scalar and pseudoscalar two-point functions at zero momentum, which in turn determine the ratio of the strange to non-strange quark condensates $R_{su} = \frac{<\bar{s}…
We rewiew and scrutinize the existing mass determinations of the pentaquarks from the exponential Laplace Sum Rules (LSR). We do not find any sum rule window for extracting optimal and reliable results from the LSR, due to the unusual slow…
A new technique based on H\"older's integral inequality is applied to QCD sum-rules to provide fundamental constraints on the sum-rule parameters. These constraints must be satisfied if the sum-rules are to consistently describe integrated…
The concept of QCD sum rules is extended to bound states composed of particles with finite mass such as scalar quarks or strange quarks. It turns out that mass corrections become important in this context. The number of relevant corrections…
QCD Laplace sum-rules are briefly reviewed and two sum-rule applications are presented. For scalar gluonium, upper bounds on the lightest state are obtained from ratios of Laplace sum-rules, and the role of instantons and the low-energy…
Sum rules for the variation of finite-density spectral density of vector channel with baryon density are derived based on dispersion relations and the operator product expansion. These sum rules may serve as constraints on the…
A visible improvement of the QCD sum-rule framework, achieved only recently by a slightly more sophisticated consideration of the hadron excitations and continuum, is applied to the extraction of the decay constants of heavy-light…
QCD sum-rules are related to an integral of a hadronic spectral function, and hence must satisfy integral inequalities which follow from positivity of the spectral function. Development of these Holder inequalities and their application to…
Instanton contributions to pseudoscalar finite-energy sum rules are extracted from the explicit single-instanton contribution to the pseudoscalar Laplace sum rule in the instanton liquid model.
Gaussian sum-rules relate a QCD prediction to a two-parameter Gaussian-weighted integral of a hadronic spectral function, providing a clear conceptual connection to quark-hadron duality. In contrast to Laplace sum-rules, the Gaussian…
We derive two sum rules by studying the low energy Compton scattering on a target of arbitrary (nonzero) spin j. In the first sum rule, we consider the possibility that the intermediate state in the scattering can have spin |j \pm 1| and…
Instanton effects and three-loop perturbative contributions are incorporated into QCD sum-rule analyses of pseudoscalar ($J^{PC}=0^{-+}$) gluonium. Gaussian sum-rules are shown to be superior to Laplace sum-rules in optimized predictions…
With the use of the world-line formalism, the heavy-quark condensate in the SU(N)-QCD is evaluated for the cases when the next-to-1/r term in the quark-antiquark potential at short distances is either quadratic, or linear. In the former…