Related papers: Axial coupling constant in a magnetic background
We study the excitation of the electric current of chiral fermions along the external magnetic field, known as the chiral magnetic effect, in the presence of the background axial-vector field. The calculation of the current is based on the…
In the framework of the soft-wall model of AdS/QCD we calculated the $\rho$ meson nucleon coupling constant. Bulk-to boundary propagators for the free vector and spinor fields are presented, whose boundary values correspond to $\rho$ meson…
The ground states of few electrons confined in two vertically coupled quantum rings in the presence of an external magnetic field are studied systematically within the current spin-density functional theory. Electron-electron interactions…
In a chiral quark model where chiral symmetry is introduced via a non-linear sigma model, we evaluate the axial couplings g_A(0), g_A^8(0) and g_A^0(0 )related to the spin structure of the nucleon. Our calculation includes one-body and…
The magnetic moment and magnetic polarisability of the neutron and proton are investigated using the uniform background-field method and lattice QCD. The results are calculated using 32^3 x 64 dynamical QCD lattices provided by the PACS-CS…
We are calculated the expectation value of the axial-vector current induced by the vacuum polarization effect of the Dirac field in constant external electromagnetic field. In calculations we use Schwinger's proper time method. The…
Due to a pion-pole contribution, the nucleon axial current matrix elements can be visualized in position space as becoming delocalized as the chiral limit is approached, with one-third of the current at distance of order the inverse pion…
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…
Using heavy baryon chiral perturbation theory to one loop, we derive an analytic and parameter-free expression for the momentum dependence of the strange magnetic form factor of the nucleon $G_M^{(s)} (Q^2)$ and its corresponding radius.…
The comparison of magnetic moments of neutron and proton reveals three possible states of a nucleon with the same correction of 0.033 for the central quarks. This may be interpreted as the contribution of a universal coupling as the common…
We report on a neutron particle physics experiment, which provides for the first time an upper limit on the strength of an axial coupling constant for a new light spin 1 boson in the millimeter range. Such a new boson would mediate a new…
The thermodynamics of quarks and gluons strongly depends on the vacuum colormagnetic field, which grows with the temperature $T$, so that spatial string tension $\sigma_s ={\rm const}~ g^4 (T) T^2$. We investigate below what happens when…
We calculate the leading direct-instanton contributions to the operator product expansion of the nucleon correlator in a magnetic background field and set up improved QCD sum rules for the nucleon magnetic moments. Remarkably, the instanton…
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,…
An insight into bispinor analysis makes it possible to describe the electron in selfaction as a fundamental steady state. The electromagnetic theory, and the Dirac equation for the study of an electron in presence of external potentials,…
The parity violation programs at MIT-Bates, Jefferson Lab and Mainz are presently focused on developing a better understanding of the sea-quark contributions to the vector matrix elements of nucleon structure. The success of these programs…
In nuclear $\beta$-decay calculations, the axial-vector coupling constant $g_A \approx 1.27$ usually needs to be quenched phenomenologically by a factor $q~\approx$ 0.75 to reproduce {the Gamow-Teller (GT) transition strengths}. We propose…
Experimental searches for new, "fifth" forces are attracting a lot of attention because they allow to test theoretical extensions to the standard model. Here, we report a new experimental search for possible fifth forces, specifically…
We study the quark mass expansion of the axial-vector coupling constant g_A of the nucleon. The aim is to explore the feasibility of chiral effective field theory methods for extrapolation of lattice QCD results - so far determined at…
We study the effect of bound nucleon form factors on charged-current neutrino-nucleus scattering. The bound nucleon form factors of the vector and axial-vector currents are calculated in the quark-meson coupling model. We compute the…