Zooming in on inner light-years of a dark matter halo

Nuclear Physics Seminar with Nicolas Dronchi and Lorenzo Andreoli

Nicolas Dronchi and Lorenzo Andreoli will be presenting the latest efforts of their research

"Measurement of p/γ Branching Ratio for 2+ State in 36Ca" presented by Nicolas Dronchi from Washington University in St. Louis

The Nuclear Equation of Sate is a driving question for some of the most fundamental problems in physics including properties of neutron stars, heavy ion collisions, giant resonances, and neutron skin thickness. Recently, B. A. Brown showed that L, the slope parameter of symmetry energy, could be related to the radii of mirror nuclei pairs. This method requires high accuracy charge radii measurements which are available for the 36Ca/36S mirror pair. The missing part of the puzzle is a correction to the charge radius of 36Ca, requiring a B(E2↑) measurement. A previous experiment measured the cross section for Coulomb excitation to the 36Ca(2+) state followed by gamma-ray emission. This experiment aims to measure the p/γ branching ratio of the 2+ state, a requirement to relate the cross section measurement to the B(E2↑) due to the state being above the proton decay threshold.

"Electron Scattering from A≤12 Nuclei in the Short-Time-Approximation" presented by Lorenzo Andreoli from Washington University in St. Louis

Quantum Monte Carlo methods, together with the phenomenological potentials Argonne v18 and Urbana-IX, are used to obtain accurate nuclear wave functions and evaluate the interaction of nuclei with external electromagnetic probes. Using the short time approximation we evaluate longitudinal and transverse response densities and functions in A≤12 nuclei. This approach consistently retains two-body physics both in the nuclear interaction and the electromagnetic currents. In addition to these results, I will present various nucleon-nucleon kinematics relevant for experiments currently conducted e.g. at JLAB, and the relative contributions to the responses coming from nn, pp, and nn pairs.