Related papers: Scalar Nonets in Pole-Dominated QCD Sum Rules
The Operator Product Expansion (OPE) of current correlators at short distances beyond perturbation theory in QCD, together with Cauchy's theorem in the complex energy plane, are the pillars of the method of QCD sum rules. This technique…
We review our results in Refs.[1,2] for the masses and couplings of heavy-light DD(BB)-like molecules and (Qq)(Qq)-like four-quark states from relativistic QCD Laplace sum rules (LSR) where next-to-next-to-leading order (N2LO) PT…
The pion-baryon sigma terms and the strange-quark condensates of the octet and the decuplet baryons are calculated by employing the method of quantum chromodynamics (QCD) sum rules. We evaluate the vacuum-to-vacuum transition matrix…
We revisit QCD sum rules for the decay constants of heavy-light mesons. In the sum rules for the vector mesons B^*_(s) and D^*_(s) we improve the accuracy of OPE, taking into account the O(alpha_s^2) terms in the perturbative part and…
Despite the apparent simplicity of meson spectroscopy, light scalar mesons cannot be accommodated in the usual $q\bar q$ structure. We study the description of the scalar mesons below 2 GeV in terms of the mixing of a chiral nonet of…
In the framework of QCD sum rules one uses a scheme, allowing one to apply the conditions of both nonrelativistic heavy quark motion inside mesons and independence of nonsplitting nS-state density on the heavy quark flavours. In the leading…
In this article, we calculate the contributions of the vacuum condensates up to dimension-10 in the operator product expansion, and study the $C\gamma_\mu-C\gamma_\nu$ type scalar, axial-vector and tensor tetraquark states in details with…
The ${q}\bar{q}$ spectrum is studied within a chiral constituent quark model. It provides with a good fit of the available experimental data from light (vector and pseudoscalar) to heavy mesons including some recent results on charmonium.…
We propose a new method to renormalize lattice operators. The method is based on the technique to compute the spectral sum appearing in the Shifman-Vainshtein-Zakharov QCD sum rule from lattice correlators. The application of this technique…
The fully heavy scalar tetraquarks $T_{\mathrm{4Q}}=QQ\overline{Q}\overline{Q }$, ($Q=c, b$) are explored in the context of QCD sum rule method. We model $ T_{\mathrm{4Q}}$ as diquark-antidiquark systems composed of pseudoscalar…
Masses for $\{Q\bar{q}\}\{\bar{Q}^{(')}q\}$ molecular states are systematically studied in QCD sum rules. The interpolating currents representing the related molecular states are proposed. Technically, contributions of the operators up to…
We calculate the polarization operator of the nucleon current in the instanton medium. The medium (QCD vacuum) is assumed to be a composition of the instantons of large and small sizes. The former are described in terms of the local scalar…
Some new methods for the extraction of CKM phases $\alpha$ and $\gamma$ using flavor SU(3) symmetry have been suggested through the construction of rigid polygons in the complex plane with sides equal to the decay amplitudes of B mesons…
Lattice QCD allows us to probe the low-lying hadron spectrum in finite-volume using a basis of single- and multi-hadron interpolating operators. Here we examine the effect of including tetraquark operators on the spectrum in the scalar…
High-energy factorization in QCD is investigated beyond leading order and its relationship to the factorization theorem of mass singularities is established to any collinear accuracy. Flavour non-singlet observables are shown to be regular…
In this article, we perform a systematic study of the mass spectrum of the vector hidden charmed and bottomed tetraquark states using the QCD sum rules.
We discuss applications of QCD sum rules on the light-cone to the form factors of the exclusive transitions $B \rightarrow \pi$ and $D\rightarrow \pi$, and to the $B^*B \pi$ and $D^*D \pi$ coupling constants. In the light of our results we…
We measure correlations appropriate for favour-singlet mesons using dynamical quark configurations from UKQCD. Improved methods of evaluating the disconnected quark diagrams are presented. The scalar and pseudoscalar meson channels are…
A model independent approach based on a generalization of the operator product expansion is used to describe semileptonic decays of heavy flavors. In the first part of the dissertation we calculate differential distributions in the…
We present a next-to-leading order QCD sum rule analysis of $J^{PC}=1^{-+}$ light tetraquark states. By investigating various compact tetraquark and molecular configurations, we determine the mass spectrum of these states. Our calculations…