相关论文: Connected and Disconnected Contractions in Pion-Pi…
We use chiral perturbation theory to study the extraction of pion electromagnetic polarizabilities from lattice QCD. Chiral extrapolation formulae are derived for partially quenched QCD, and quenched QCD simulations. On a torus, volume…
Anchoring our understanding of low-energy nuclear and hadronic physics to the fundamental theory of strong interactions, QCD, remains and outstanding challenge for physicists. Lattice QCD and chiral perturbation theory are the most powerful…
The magnetic polarisability of the neutral pion has been calculated using the background field method in lattice QCD. These early results do not consider the effect of the disconnected loop contractions arising from the breaking of charge…
Broken chiral symmetry has become the basis for a unified treatment of hadronic interactions at low energies. After reviewing mechanisms for spontaneous chiral symmetry breaking, I outline the construction of the low--energy effective field…
A survey is given on selected topics of physics in the non-perturbative, hadronic sector of the QCD phase diagramme. Following a brief QCD primer, some highlights of Lattice QCD are summarised. Chiral effective field theory as the…
Chiral effective field theory is utilized for extrapolating results on the $\Lambda_c N$ interaction, obtained in lattice QCD at unphysical (large) quark masses, to the physical point. The pion-mass dependence of the components that…
We investigate the $S$-wave scatterings of $\Lambda_c\Lambda_c$ and $\Lambda_{c}\bar \Lambda_{c}$ systems within a unified chiral effective field theory framework up to next-to-leading order. The contact low-energy coupling constants are…
We perform a systematic study of the correlation functions of two quark currents in a pion using lattice QCD. We obtain good signals for all but one of the relevant Wick contractions of quark fields. We investigate the quark mass dependence…
The background magnetic-field formalism of Lattice QCD has been used recently to calculate the magnetic polarizability of the charged pion. These $n_f = 2 + 1$ numerical simulations are electro-quenched, such that the virtual sea-quarks of…
We derive the scattering amplitude for Goldstone bosons of chiral symmetry off the pseudoscalar charmed mesons up to leading one-loop order in a covariant chiral effective field theory, using the so-called extended-on-mass-shell…
A model field theory, in which the interaction between quarks is mediated by dressed vector boson exchange, is used to analyse the pionic sector of QCD. It is shown that this model, which incorporates dynamical chiral symmetry breaking,…
In order to model pions of two-flavor QCD we consider a lattice field theory involving two flavors of staggered quarks interacting strongly with U(1) gauge fields. For massless quarks, this theory has an $SU_L(2)\times SU_R(2) \times…
In recent years, detailed studies of three-pion systems have become possible in lattice QCD. This has in turn led to interest in 3-to-3 scattering of pions in the chiral perturbation theory framework. In addition to being an interesting…
We present the first direct $N_f=2$ lattice QCD computation of two- and three-$\pi^+$ scattering quantities that includes an ensemble at the physical point. We study the quark mass dependence of the two-pion phase shift, and the…
Computing disconnected diagrams in Lattice QCD (operator insertion in a quark loop) entails the computationally demanding problem of taking the trace of the all to all quark propagator. We first outline the basic algorithm used to compute a…
We present simulation results for lattice QCD with light pions. For the quark fields we apply chirally symmetric lattice Dirac operators, in particular the overlap hypercube operator, along with the standard overlap operator for comparison.…
After a general introduction to the structure of effective field theories, the main ingredients of chiral perturbation theory are reviewed. Applications include the light quark mass ratios and pion-pion scattering to two-loop accuracy. In…
We give a brief review of the theoretical description of low energy pion-pion scattering by the combined use of Chiral Perturbation Theory and Roy equations, an update of the Regge parametrization of $\pi\pi$ cross sections at high…
After a brief introduction to chiral perturbation theory, the effective field theory of the standard model at low energies, two recent applications are reviewed: elastic pion-pion scattering to two-loop accuracy and the complete…
Pion-pion elastic scattering in the isospin I=2 channel is investigated in two-flavor dynamical lattice QCD. Six ensembles are used with lattices elongated in one of the spatial dimensions at two quark masses corresponding to a pion mass of…