相关论文: Effective Action and Electromagnetic Polarizabilit…
A nonperturbative approach to QCD describing confinement and chiral symmetry breaking is discussed. It is based on the path integral representation of Green's function of quarks and leads to the QCD string theory. The effective actions for…
The effective action for light mesons in the external uniform static electromagnetic fields was obtained on the basis of QCD string theory. We imply that in the presence of light quarks the area law of the Wilson loop integral is valid. The…
We calculate the nucleons' electromagnetic polarizabilities in heavy baryon chiral perturbation theory including all terms to order ${\cal O} (q^4)$. The chiral prediction of the electric polarizabilities for the neutron and the proton are…
We have constructed a heavy baryon effective field theory with photon as an external field in accordance with the symmetry requirements similar to the heavy quark effective field theory. By treating the heavy baryon and anti-baryon equally…
Nucleon properties are investigated in background electric fields. As the magnetic moments of baryons affect their relativistic propagation in constant electric fields, electric polarizabilities cannot be determined without knowledge of…
We discuss the extraction of the electromagnetic and spin polarisabilities of nucleons from lattice QCD. We show that the external field method can be used to measure all the electromagnetic and spin polarisabilities including those of…
Understanding the nucleon spin structure in the regime where the strong interaction becomes truly strong poses a challenge to both experiment and theory. At energy scales below the nucleon mass of about 1 GeV, the intense interaction among…
We generalize the sum rules for the nucleon electric plus magnetic polarizability $\Sigma=\alpha+\beta$ and for the nucleon spin-polarizability $\gamma$, to virtual photons with $Q^2>0$. The dominant low energy cross sections are…
We discuss the extraction of the electromagnetic and spin polarisabilities of nucleons from lattice QCD. We show that the external field method can be used to measure all the electromagnetic and spin polarisabilities including those of…
Chiral perturbation theory makes definitive predictions for the extrinsic behavior of hadrons in external electric and magnetic fields. Near the chiral limit, the electric and magnetic polarizabilities of pions, kaons, and nucleons are…
The strong interaction is not well understood at low energy, or for interactions with low momentum transfer $Q^2$, but one of the clearest insights we have comes from Chiral Perturbation Theory ($\chi$PT). This effective treatment gives…
By simulating a uniform electric field on a lattice and measuring the change in the rest mass, we calculate the electric polarizability of neutral mesons and baryons using the methods of quenched lattice QCD. Specifically, we measure the…
We investigate the electric polarizabilities of neutral baryons using the method of QCD sum rules. The diagrams in the operator product expansion are taken into account up to dimension 6. We obtain different values of the polarizabilities…
We compute the polarisability of the nucleon to leading order in chiral perturbation theory. The contributions from kaons and baryon resonances as intermediate states are included in addition to the contribution from pions and nucleons that…
The electromagnetic form factors of the nucleon, in the space-like region, are determined from three-point function Finite Energy QCD Sum Rules. The QCD calculation is performed to leading order in perturbation theory in the chiral limit,…
Electromagnetic properties of the nucleon are explored with lattice QCD using a novel technique. Focusing on background electric fields, we show how the electric polarizability can be extracted from nucleon correlation functions. A crucial…
The polarizabilities $\alpha$ (electric), $\beta$ (magnetic) and $\gamma_\pi$ (backward spin) of the nucleon are investigated in terms of degrees of freedom of the nucleon using recent results for the CGLN amplitudes and resonance couplings…
Lattice QCD with background magnetic fields is used to calculate the magnetic moments and magnetic polarizabilities of the nucleons and of light nuclei with $A\le4$, along with the cross-section for the $M1$ transition $np\rightarrow…
Different approaches to describe Compton scattering and the polarizability of the nucleon have been discussed up to now. We show that the most appropriate ones are provided by non-subtracted dispersion theories of the fixed-$t$ and…
The static electric polarizability of the neutron is evaluated using domain-wall valence quarks on a MILC asqtad sea quark ensemble corresponding to a pion mass of m_pi = 357 MeV. Both connected as well as disconnected contributions are…