Related papers: Nonidentical protons
Systematic differences in the the proton's charge radius, as determined by ordinary atoms and muonic atoms, have caused a resurgence of interest in elastic lepton scattering measurements. The proton's charge radius, defined as the slope of…
In light of the proton radius puzzle, the discrepancy between measurements of the proton charge radius from muonic hydrogen and those from electronic hydrogen and electron-proton scattering measurements, we reexamine the charge radius…
There is a long-standing discrepancy between different measurements of the electric and magnetic radii of the proton. Lattice QCD calculations are a well-suited tool for theoretical investigations of the structure of the nucleon from first…
The first determination of the nuclear charge radius by laser spectroscopy for a five-electron system is reported. This is achieved by combining high-accuracy ab initio mass-shift calculations and a high-resolution measurement of the…
The size is a key property of a nucleus. Accurate nuclear radii are extracted from elastic electron scattering, laser spectroscopy, and muonic atom spectroscopy. The results are not always compatible, as the proton-radius puzzle has shown…
We have made the comparison of three parametrizations of the proton electromagnetic form factors in the space-like region using the largest data set on $e^{\pm} p$ elastic scattering ever used. All models have a correct analytical structure…
We reanalyze electron-proton scattering data in the momentum transfer region $Q^2 < 1\ GeV^2$, which were used to determine proton electric radius, with main focus on the Mainz experiment (Bernauer et al., 2010). We examine dependence of…
We investigate the feasibility of measuring the proton charge radius through dimuon photoproduction off a proton target. Our findings indicate that the Bethe-Heitler mechanism, which dominates at small momentum transfers, allows for an…
We update Jaffe's estimate of the strange isoscalar radius and magnetic moment of the nucleon. We make use of a recent dispersion--theoretical fit to the nucleon electromagnetic form factors and an improved description of symmetry breaking…
The proton is a fundamental constituent of matter. It is an extended object with finite size that can be inferred with some degree of accuracy from several measurements. Using constraints from the analytic behavior of the form factors we…
Proton-$^{133}$Cs elastic scattering at low momentum transfer is performed using an in-ring reaction technique at the Cooler Storage Ring at the Heavy Ion Research Facility in Lanzhou. Recoil protons from the elastic collisions between the…
Data for coherent photoproduction of $\pi^0$ mesons from nuclei ($^{12}$C, $^{40}$Ca, $^{93}$Nb, $^{nat}$Pb), recently measured with the TAPS detector at the Mainz MAMI accelerator, have been analyzed in view of the mass form factors of the…
We study the charge and mass distributions within a nucleon and compute the associated squared radii based on a potential model approach. Different constituent quark configurations such as $\Delta$, $Y$, and quark-diquark are considered and…
Collinear laser spectroscopy measurements were performed on $^{68-74}$Ge isotopes ($Z = 32$) at ISOLDE-CERN, by probing the $4s^2 4p^2 \, ^3\!P_1 \rightarrow 4s^2 4p 5s \, ^3\!P_1^o$ atomic transition (269~nm) of germanium. Nuclear charge…
In this paper, we apply the Maximum Entropy Method to estimate the proton radius and determine the valence quark distributions in the proton at extremely low resolution scale Q$^{2}_{0}$. Using the simplest functional form of the valence…
Background: Precise measurements of atomic transitions affected by electron-nucleus hyperfine interactions offer sensitivity to explore basic properties of the atomic nucleus and study fundamental symmetries, including the search for new…
We examined several low-$Q^2$ elastic $ep$ and $ed$ scattering data sets using various models to extract the proton and deuteron rms radii and developed a comprehensive algorithm for estimating the systematic bias of each extracted radius.…
Charge radii of hadrons are back in the focus since precision spectroscopic measurements in muonic hydrogen revealed a proton charge radius considerably smaller than generally accepted ever since R.~Hofstaedter's pioneering experiments.…
The electromagnetic form factors of the proton and neutron encode information on the spatial structure of their charge and magnetization distributions. While measurements of the proton are relatively straightforward, the lack of a free…
We report the most precise measurement to date of a parity-violating asymmetry in elastic electron-proton scattering. The measurement was carried out with a beam energy of 3.03 GeV and a scattering angle <theta_lab>=6 degrees, with the…