Related papers: An approach to the instanton effect in B system
The large mass limit of QCD uncovers symmetries that are not present in the QCD lagrangian. These symmetries have been applied to physical (finite mass) systems, such as B and D mesons. We explore the validity of this approximation in the…
We discuss the effects of instantons in partially broken gauge groups on the low-energy effective gauge theory. Such effects arise when some of the instantons of the original gauge group G are no longer contained in (or can not be gauge…
We describe the simplest example of an instanton bag in Euclidean space. It consists of a monopole wall and a Kaluza-Klein monopole wall, lifted to one higher dimension, trapping the instanton charge in the middle. This object has finite…
In 1976 't Hooft introduced an elegant approach towards understanding the physical consequences of the topological structures that appear in non-Abelian gauge theories. These effects are concisely summarized in terms of an effective…
We apply heavy-quark effective theory to separate long- and short-distance effects of heavy quarks in lattice gauge theory. In this approach, the inverse heavy-quark mass and the lattice spacing are treated as short distances, and their…
We analyze instantons in the very strongly coupled large-$N$ limit ($N\to\infty$ with $g^2$ fixed) of large-$N$ gauge theories, where the effect of the instantons remains finite. By using the exact partition function of four-dimensional…
A chiral extrapolation of the light vector meson masses in the up, down and strange quark masses of QCD is presented. We apply an effective chiral Lagrangian based on the hadrogenesis conjecture to QCD lattice ensembles of PACS-CS,…
We revisit the QCD+QED axial anomaly low-energy theorems which give an exact relation between the matrix elements of the gluon and photon parts of the axial anomaly operator equation within the framework of the {\em effective action}…
In QCD the spontaneous breaking of chiral symmetry and the U(1) axial anomaly can be understood considering instantons as the gauge configurations mediating quark-quark interaction. The existence of an exact zero mode solution of the Dirac…
QCD exhibits complex dynamics near S-wave two-body thresholds. For light mesons, we see this in the failure of quark models to explain the $f_0(500)$ and $K_0^*(700)$ masses. For charmonium, an unexpected $X(3872)$ state appears at the open…
The talk is an introduction into diquark condensation phenomena which occur in QCD at high energy density. They are driven by instantons and instanton-antiinstanton pairs (or ``molecules''), which generate attraction in some qq channels. A…
We perform a coupled-channels calculation of the masses of light mesons with the quantum numbers $IJ^{P=-}$, $(I,J)=0,1$, by including $q\bar{q}$ and $(q\bar{q})^2$ components in a nonrelativistic chiral quark model. The coupling between…
After discussing the intrinsic ambiguity in determining the light quark mass ratio $m_u/m_d$, we reexamine the recent proposal that this ambiguity can be resolved by applying the QCD multipole expansion for the heavy quarkonium decays. It…
The mass shifts for two-fermion bound and scattering P-wave states subject to the long-range interactions due to QED in the non-relativistic regime are derived. Introducing a short range force coupling the spinless fermions to one unit of…
We investigate the chiral restoration at finite temperature $(T)$ under the strong external magnetic field $\vec{B}=B_{0}\hat{z}$ of the SU(2) light-flavor QCD matter. We employ the instanton-liquid QCD vacuum configuration accompanied with…
We investigate the $\epsilon^{\prime} /\epsilon$ for $K\to \pi\pi$ in a sequential fourth generation model. By giving the basic formulae for $\epsilon^{\prime}/\epsilon$ in this model, we analyze the numerical results which are dependent of…
We report on the status of an ALPHA Collaboration project to extract quantities for B physics phenomenology from Nf=2 lattice simulations. The framework is Heavy Quark Effective Theory (HQET) expanded up to the first order of the inverse…
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…
It is usually assumed that $4D$ instantons can only arise in non-Abelian theories. In this paper we re-examine this conventional wisdom by explicitly constructing instantons in an Abelian gauge theory: ${\rm QED}_4$ with $N_f$ flavors of…
QCD inequalities are derived for the masses of mesons and baryons containing a single heavy quark using the heavy quark effective field theory. A rigorous lower bound is obtained for the $\bar\Lambda$ parameters of the heavy quark effective…