相关论文: Hadron electric polarizability -- finite volume co…
In Ref. [1], a method was proposed to calculate QED corrections to hadronic self energies from lattice QCD without power-law finite-volume errors. In this paper, we extend the method to processes which occur at second-order in the weak…
We present a lattice QCD calculation of the electric polarizability of the charged kaon using a four-point function approach, which is the Euclidean analog of low-energy Compton scattering. In the case of the charged kaon, the…
The chiral expansion of nucleon properties such as mass, magnetic moment, and magnetic polarizability are investigated in the framework of chiral perturbation theory, with and without the heavy-baryon expansion. The analysis makes use of a…
I present higher loop order results for several calculations in Chiral perturbation Theory. 1) Two-loop results at finite volume for hadronic vacuum polarization. 2) A three-loop calculation of the pion mass and decay constant in…
The invariant amplitudes for pion electroproduction on the nucleon are evaluated by dispersion relations at constant t with MAID as input for the imaginary parts of these amplitudes. In the threshold region these amplitudes are confronted…
Differential distributions in the $\pi_0\pi_0\gamma$ system created in the annihilation channel of an electron-positron collision are considered. The energy fractions of the pions (Dalitz-plot) distribution are presented in a general form…
Recent models of soft diffraction include a hard pomeron pole besides the usual soft term. Such models violate the black-disk limit around Tevatron energies, so that they need to be supplemented by a unitarisation scheme. Several such…
An extended multi-hadron operator is developed to extract the spectra of irreducible representations in the finite volume. The irreducible representations of the cubic group are projected using a coordinate-space operator. The correlation…
It was shown that an infinite convergent sequence of improving non-increasing upper bounds to the ground state energy of a slow-moving acoustical polaron can be obtained by means of generalized variational method. The proposed approach is…
Pion decay width in a uniform magnetic background, constructed within chiral perturbation theory, is compared with lattice QCD for which results are available in the muon channel. While the results are consistent for large magnetic fields,…
The muon $g-2$ is a compelling quantity due to the current standing tensions among the experimental average, data-driven theoretical results, and lattice results. Matching the final target accuracy of the experiments at Fermilab and J-PARC…
The main experimental works, where dipole polarizabilities of charged pions have been determined, are considered. Possible reasons for the differences between the experimental data are discussed. In particular, it is shown that the account…
For finite volume field theories with discrete translational invariance, conserved currents can be additively renormalized by infrared effects. We demonstrate this for pions using chiral perturbation theory coupled to electromagnetism in a…
The hyperfine structure of bound electrons in hydrogen-like ions is considered with corrections to the energy levels due to vacuum polarization (VP). Corrections to the wave function as well as the magnetic potential are determined for both…
Electromagnetic properties of hadrons can be computed by lattice simulations of QCD in background fields. We demonstrate new techniques for the investigation of charged hadron properties in electric fields. Our current calculations employ…
We review progress on hadron structure using lattice QCD simulations at or near to physical values of the QCD parameters. In particular, we discuss recent results on hadron masses, the nucleon charges, spin, gluon and quark unpolarized…
We consider the effects of single impurities on polarons in three-dimensions (3D) using a continuous time quantum Monte-Carlo algorithm. An exact treatment of the phonon degrees of freedom leads to a very efficient algorithm and we are able…
We discuss main experimental works, where dipole polarizabilities of charged pions have been determined. Possible reasons for the differences between the experimental data are discussed. In particular, it is shown that the account of the…
New measurements to test the neutrality of matter by acoustic means are reported. The apparatus is based on a spherical capacitor filled with gaseous SF$_6$ excited by an oscillating electric field. The apparatus has been calibrated…
The electric alpha and magnetic beta pion Compton polarizabilities characterize the pion's deformation in the electromagnetic field of the gamma during gamma-pi Compton scattering. The chi_PT effective Lagrangian, using data from radiative…