Neutron skin studies of medium and heavy nuclei

M Thiel,C Sfienti,D Becker,M Ferretti,K Kumar,M Battaglieri,G Salmè,A Pascolini,R De Vita,A D'Angelo

doi:10.1051/epjconf/20147307007

Abstract

The recent PREX experiment at JLab has demonstrated the sensitivity of parity violating electron scattering to the neutron density, meanwhile outlining its major experimental challenges. On the other side, intermediate energy photons are an ideal probe for studying the properties of strongly interacting matter from the nuclear scale down to the sub-nuclear components of the nucleus. Among others coherent pion photoproduction can provide information on the existence and nature ofneutron skins in nuclei. Thesimultaneous combination of different techniques allows a systematic determination across the periodic table thus benchmarking modern calculation. Recently a systematic investigation of the latter method has been exploited at MAMI (Mainz). At MESA the same setup as in the measurement of the weak mixing angle can be used to determine the parity-violating asymmetry for polarized electrons scattered on heavy nuclei with a 1% resolution. Status and prospects of the projects are presented.

Highlights

One of the most fundamental observables of nuclei are the neutron and proton density distributions
At MESA the same setup as in the measurement of the weak mixing angle can be used to determine the parity-violating asymmetry for polarized electrons scattered on heavy nuclei with a 1% resolution
Even though heavy nuclei and neutron stars are orders of magnitude in size and weight apart, both quantities are sensitive to the nuclear equation of state (EOS)

Summary

Equation of state

One of the most fundamental observables of nuclei are the neutron and proton density distributions. Concerning symmetric nuclear matter both density distributions and the corresponding radii are similar, the accuracy of the experimentally determined neutron radii is poor compared to the one of the proton radii. An accurate experimental determination of the neutron skin thickness of heavy nuclei would provide considerable constraints on the density dependence of the nuclear symmetry energy, in addition of being of substantial importance by itself.

The neutron skin story

Coherent 0 photoproduction at MAMI

Parity violating electron scattering at MESA

Findings

Conclusions