Electromagnetic characteristics of physical and lattice nuclei
Johannes Kirscher🇺🇸 · Ehoud Pazy🇮🇱 · Jonathan Drachman🇮🇱 · Nir Barnea🇮🇱
We analyze the quark-mass dependence of electromagnetic properties of two and three-nucleon states. To that end, we apply the pionless effective field theory to experimental data and numerical lattice calculations which simulate QCD at pion masses of 450~MeV and 806~MeV. At the physical pion mass, we postdict the magnetic moment of helium-3, nNM, and the magnetic polarizability of deuterium, fm. Magnetic polarizabilities of helium-3, fm, and the triton, fm, are predictions. Postdictions of the effective theory for the magnetic moments are found consistent with QCD simulations at 806~MeV pion mass while our EFT result fm was not extracted from the lattice. The deuteron would thus be relatively pliable compared to a three-nucleon state for which we postdict fm. At MeV, the magnetic moment of the triton is predicted, nNM, based on a conjecture of its binding energy, ~MeV. For all three pion masses, we compare the point-charge radii of the two and three-nucleon bound states. The sensitivity of the electromagnetic properties to the Coulomb interaction between protons is studied in anticipation of lattice calculations with dynamical QED.