Related papers: The Proton Radius Puzzle
We review recent experiments on HD$^+$ spectroscopy. The reduced proton-deuteron mass to electron mass ratio, $\mu_{pd}/m_e$, is inferred from the comparison of theory and experiment. Theoretical issues related to the calculations of the…
The radiative muon capture(RMC) on a proton is analyzed by means of heavy baryon chiral perturbation theory. The emitted photon energy spectrum is calculated and compared with the experimental data by taking the spin sum on the muonic atom…
Our present knowledge of the nuclear equation of state is briefly reviewed in this article intended for a wider readership. Particular emphasis is given to the asymmetric-matter equation of state required for modeling neutron stars,…
Since the announcement of the proton spin crisis by the European Muon Collaboration there has been considerable progress in unravelling the distribution of spin and orbital angular momentum within the proton. We review the current status of…
The neutron is electrically neutral, but its substructure consists of charged quarks so it may have an internal charge distribution. In fact it is known to have a negative mean square charge radius (MSCR), the second moment of the radial…
We report a new, high-precision measurement of the proton elastic form factor ratio \mu_p G_E/G_M for the four-momentum transfer squared Q^2 = 0.3-0.7 (GeV/c)^2. The measurement was performed at Jefferson Lab (JLab) in Hall A using recoil…
The measurement of the 2P^{F=2}_{3/2} to 2S^{F=1}_{1/2} transition in muonic hydrogen by Pohl et al. and subsequent analysis has led to the conclusion that the rms radius of the proton differs from the accepted (CODATA) value by…
Accepted values of the masses of several subatomic particles have been under debate since recent measurements in Penning traps produced more precise yet incompatible results, implying possible inconsistencies in closely related physical…
The muon g-2 collaboration has measured the anomalous magnetic g value of the positive muon to within a relative uncertainty of 0.7 parts per million. The result, a_{\mu^+} = 11 659 204(7)(5) x 10^{-10} is in good agreement with the…
Proton-proton total cross sections are measured with present day high energy colliders up to 2 TeV in the centre-of-mass of the system (10^{15}) eV in the laboratory). Several parameterizations, very succesful at low energies, can then be…
We propose a short summary of the present situation concerning the proton spin decomposition. We briefly discuss some of the main controversies about the issues of gauge invariance, uniqueness and measurability. As a conclusion, we argue…
The mean square radius of the proton charge distribution was studied in the framework of the relativistic quasipotential quark model in assumption of the SU(6)-symmetry. It was shown that the proton charge radius is represented as function…
By measuring the lifetime of the negative muon in pure protium (hydrogen-1), the MuCap experiment determines the rate of muon capture on the proton, from which the proton's pseudoscalar coupling g_p may be inferred. A precision of 15% for…
Among measurements of the neutron lifetime, there is a 1% difference between proton-counting methods and neutron-counting methods. In this paper, a new electron-counting method with a magnetic field aiming for a 0.1% accuracy is proposed,…
A geometrical model of hadron-proton interactions has been extended to describe gamma-proton total cross section measured in deep-inelastic scattering at small x (x<0.04). Experimental data are consistent with this model assuming that the…
It has been suggested that the uncertainty in the measurement of a particle's momentum could be made arbitrarily small by observing the particle at two ends of an arbitrarily long flight path. However, consideration of the nature of the…
The fact that the spins of the quarks in the proton, as measured in deep inelastic lepton scattering, only add up to about 30$\%$ of the spin of the proton is still not understood after 30 years. We show that our newly developed model for…
The discovery of the proton-radius puzzle and the subsequent deuteron-radius puzzle is fueling an on-going debate on possible explanations for the difference in the observed radii obtained from muonic atoms and from electron-nucleus…
The binding energies, shapes and sizes of even-even beta-stable nuclei with A >= 40 and a few chains of isotopes with Z=50, 56, 82, 94 protons and isotones with N=50, 82, 126 neutrons are analyzed. The average isospin dependence of the…
Parity violating electron scattering can measure the neutron density of a heavy nucleus accurately and model independently. This is because the weak charge of the neutron is much larger then that of the proton. The Parity Radius Experiment…