[Prex] CREX at Ep 295 MeV

[Jay Benesch]

https://arxiv.org/abs/1810.11796

Direct determination of the neutron skin thicknesses in 40,48Ca from 
proton elastic scattering at Ep=295 MeV
J. Zenihiro, H. Sakaguchi, S. Terashima, T. Uesaka, G. Hagen, M. Itoh, 
T. Murakami, Y. Nakatsugawa, T. Ohnishi, H. Sagawa, H. Takeda, M. 
Uchida, H.P. Yoshida, S. Yoshida, M. Yosoi
(Submitted on 28 Oct 2018)

     The neutron density distributions and neutron skin thicknesses in 
40,48Ca are determined from the angular distributions of the cross 
sections and analyzing powers of polarized proton elastic scattering at 
Ep=295 MeV. Based on the framework of the relativistic impulse 
approximation with the density-dependent effective NN interaction, the 
experimental data is successfully analyzed, providing precise 
information of neutron and proton density profiles of 40,48Ca with small 
uncertainties. The extracted neutron and proton density distributions 
give neutron skin thicknesses in 40,48Ca for −0.010+0.022−0.024 fm and 
0.168+0.025−0.028 fm, respectively. The results of the density profiles 
and the neutron skin thickness in 48Ca are directly compared with the 
{\it ab initio} coupled-cluster calculations with interactions derived 
from chiral effective field theory, as well as relativistic and 
non-relativistic energy density functional theories.

Comments: 	5 pages, 4 figures