相关论文: Double polarization experiments at intermediate en…
First results from the longitudinally polarized frozen-spin target (FROST) program are reported. The double-polarization observable E, for the reaction $\vec \gamma \vec p \to \pi^+n$, has been measured using a circularly polarized…
The electric form factor of the neutron was determined from measurements of the \vec{d}(\vec{e},e' n)p reaction for quasielastic kinematics. Polarized electrons were scattered off a polarized deuterated ammonia target in which the deuteron…
Of all nuclear physics experiments none are more fundamental than ``elastic'' $p,p$ and, secondarily, $p,d$ or $d,d$ scattering. Recognizing that these particles are themselves composite, ``elastic'' scattering may be accompanied by…
The electric form factor of the neutron, G_En, has been measured at the Mainz Microtron by recoil polarimetry in the quasielastic D(e_pol,e'n_pol)p reaction. Three data points have been extracted at squared four-momentum transfers Q^2 =…
EDMs probe fundamental symmetries and underpin BSM searches. We give a symmetry-based description, analogous to the Zeeman effect, that puts magnetic and electric dipoles on equal footing under EM duality. In hydrogen, $\vec B$…
Measurements of the polarization of the final proton in elastic e-p scattering drastically changed our knowledge about the electromagnetic form factors of the proton. Here we present our results of the calculation of the polarization of the…
We report on a kinematically complete measurement of double ionization of helium by a single 1100 eV circularly polarized photon. By exploiting dipole selection rules in the two-electron continuum state, we observed the angular emission…
There is a significant discrepancy between the values of the proton electric form factor, $G_E^p$, extracted using unpolarized and polarized electron scattering. Calculations predict that small two-photon exchange (TPE) contributions can…
Recent polarization transfer measurements of the proton form factors disagree with previous Rosenbluth extractions. In addition to providing insight into the proton structure, the form factors also provide crucial input for the analysis of…
The electric dipole strength distribution in $^{58}$Ni between 6 and 20 MeV has been determined from proton inelastic scattering experiments at very forward angles at RCNP, Osaka. The experimental data are rather well reproduced by…
Exclusive and kinematically complete high-statistics measurements of quasifree polarized $\vec{n}p$ scattering have been performed in the energy region of the narrow resonance structure $d^*$ with $I(J^P) = 0(3^+)$, $M \approx$ 2380…
Heavy quarks, namely, the top and bottom quarks, may show great sensitiveness to new physics effects. In particular, they might have unusually large electric dipole moments. This possibility is analyzed via the corresponding one-loop…
[Background] The electromagnetic form factors of the proton measured by unpolarized and polarized electron scattering experiments show a significant disagreement that grows with the squared four momentum transfer ($Q^{2}$). Calculations…
The multipole expansion is a key tool in the study of light-matter interactions. All the information about the radiation of and coupling to electromagnetic fields of a given charge-density distribution is condensed into few numbers: The…
The proton elastic form factor ratio can be measured either via Rosenbluth separation in an experiment with unpolarized beam and target, or via the use of polarization degrees of freedom. However, data produced by these two approaches show…
New polarization potentials have been determined based on: 1) the latest photo-neutron cross section evaluation and a missing factor of two in previous work, and 2) the mass dependency of the symmetry energy, $a_{sym}(A)$. The magnitude of…
Future high-energy $\textrm{e}^+\textrm{e}^-$ colliders will provide some of the most precise tests of the Standard Model. Statistical uncertainties on electroweak precision observables and triple gauge couplings are expected to improve by…
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…
A measurement of beam helicity asymmetries in the reaction 3He(e,e'n)pp has been performed at the Mainz Microtron in quasielastic kinematics in order to determine the electric to magnetic form factor ratio of the neutron, GEn/GMn, at a four…
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…