相关论文: Electromagnetic polarizabilities and the excited s…
The low-energy electromagnetic form factors of the $\Delta$(1232)-to-nucleon transition are derived combining dispersion theory techniques and chiral perturbation theory. The form factors are expressed in terms of the well-understood pion…
The nonlinear polaronic response of electrons solvated in liquid 2-propanol is studied by two-dimensional terahertz spectroscopy. Solvated electrons with a concentration of c$_e \approx$ 800 $\mu$M are generated by femtosecond…
The electromagnetic polarizabilities are fundamental properties of the proton that characterize its response to an external EM field. The generalization of the EM polarizabilities to non-zero four-momentum transfer opens up a powerful path…
It is currently a big challenge to accurately determine the symmetry energy $E_{\text{sym}}(\rho)$ and the pure neutron matter equation of state $E_{\text{PNM}}(\rho)$, even their values around saturation density $\rho_0 $. We find that the…
The electromagnetic polarizabilities of the nucleon are fundamental properties that describe its response to external electric and magnetic fields. They can be extracted from Compton-scattering data --- and have been, with good accuracy, in…
Electron polarization induced by magnetic fields can modify the potentials relevant for describing neutrino conversions in media with magnetic fields. The magnitudes of polarization potentials are determined for different conditions. We…
A new nonlinear electromagnetic wave mode in a magnetized plasma is predicted. Its existence depends on the interaction of an intense circularly polarized electromagnetic wave with a plasma, where quantum electrodynamical photon--photon…
We use the background field method to extract the "connected" piece of the neutron electric polarizability. We present results for quenched simulations using both clover and Wilson fermions and discuss our experience in extracting the mass…
Fixed-$t$ subtracted dispersion relations are presented for Compton scattering off the nucleon at energies $E_\gamma \leq 500$ MeV, as a formalism to extract the nucleon polarizabilities from the data with a minimum of model dependence. The…
We present a theory for how nucleon polarizability could be used to extract energy from nucleons by special electromagnetic conditions. A presentation of an experiment that validates the theory is presented. Also an new theory for a long…
The nucleon electromagnetic form factors have been studied in the past extensively from unpolarized electron scattering experiments. With the development in polarized beam, recoil polarimetry, and polarized target technologies, polarization…
The reaction $\gamma+p\to\gamma'+p+\pi^0$ has been suggested as a means to deduce the $\Delta^+$ magnetic moment. The cross section for this process is estimated in both the constituent quark model and an effective Lagrangian procedure. The…
We analyze polarization phenomena for elastic lepton-nucleon scattering, parametrizing the $2\gamma$-exchange contribution, as the product of lepton and nucleon axial vector currents, that correspond to $C=+1$ exchange in the annihilation…
The background field method for measuring the electric polarizability of the neutron is adapted to the dynamical quark case, resulting in the calculation of (certain space-time integrals over) three- and four-point functions. Particular…
Eta photo- and electroproduction off the nucleon is investigated in an effective lagrangian approach that contains Born terms and both vector meson and nucleon resonance contributions. In particular, we review and develop the formalism for…
Total and differential cross sections for the reaction p(gamma, eta)p have been measured for photon energies in the range from 750 MeV to 3 GeV. The low-energy data are dominated by the S11 wave which has two poles in the energy region…
The radiative decay of the massive neutrino $\nu_i \rightarrow \nu_j \gamma$ in a circularly polarized electromagnetic wave is investigated within the Standard theory with lepton mixing. The decay probability in the wave field does not…
The first measurement is reported of the double-polarization observable G in photoproduction of neutral pions off protons, covering the photon energy range from 620 to 1120 MeV and the full solid angle. G describes the correlation between…
The effective action for baryons in the external electromagnetic fields is obtained on the basis of the QCD string theory. The area law of the Wilson loop integral, the approximation of the Nambu-Goto straight-line strings, and the…
An effective Lagrangian calculation of pion photoproduction including all nucleon resonances up to $\sqrt s = 1.7$ GeV is presented. We compare our results to recent calculations and show the influence of different width parametrizations…