English

Neutron skin of $^{48}$Ca consistent with experimental data on skins

Nuclear Theory 2020-12-16 v1 Nuclear Experiment

Abstract

[Background]: In our previous paper, we predicted rskinr_{\rm skin}, rpr_{\rm p}, rnr_{\rm n}, rmr_{\rm m} for 4060,62,64^{40-60,62,64}Ca after determining the neutron dripline, using the Gogny-D1S HFB with and without the angular momentum projection (AMP). We found that effects of the AMP are small. Very lately, Tanaka {\it et al.} measured interaction cross sections σI\sigma_{\rm I} for 4251^{42-51}Ca, determined rmr_{\rm m} from the σI\sigma_{\rm I}, and deduced skin rskinr_{\rm skin} and rnr_{\rm n} from the rmr_{\rm m} and the rp(exp)r_{\rm p}(\rm {exp}) evaluated from the electron scattering. Comparing our results with the data, we find for 4248^{42-48}Ca that GHFB and GHFB+AMP reproduce the data on rskinr_{\rm skin}, rnr_{\rm n}, rmr_{\rm m}, but not for rp(exp)r_{\rm p}(\rm {exp}). [Aim]: Our purpose is to determine a value of rskin48r_{\rm skin}^{48} by using GHFB+AMP and the constrained GHFB (cGHFB) in which the calculated value is fitted to rp(exp)r_{\rm p}(\rm {exp}). [Results]: For 42,44,46,48^{42,44,46,48}Ca, cGHFB hardly changes rskinr_{\rm skin}, rmr_{\rm m}, rnr_{\rm n} calculated with GHFB+AMP, except for rskin48r_{\rm skin}^{48}. For rskin48r_{\rm skin}^{48}, the cGHFB result is rskin48=0.190r_{\rm skin}^{48}=0.190fm, while rskin48=0.159r_{\rm skin}^{48}=0.159fm for GHFB+AMP. We should take the upper and the lower bound of GHFB+AMP and cGHFB. The result rskin48=0.1590.190r_{\rm skin}^{48}=0.159-0.190fm consists with the rskin48(σI)r_{\rm skin}^{48}(\sigma_{\rm I}) and the data rskin48(r_{\rm skin}^{48}(\rm E1pE)pE) obtained from high-resolution E1E1 polarizability experiment (E1E1pE). Using the rskin48r_{\rm skin}^{48}-rskin208r_{\rm skin}^{208} relation with strong correlation of Ref.[3], we transform the data rskin208r_{\rm skin}^{208} determined by PREX and E1E1pE to the corresponding values, rskin48(tPREX)r_{\rm skin}^{48}(\rm tPREX) and rskin48(tr_{\rm skin}^{48}(\rm tE1pE)pE). Our result is consistent also for rskin48(tPREX)r_{\rm skin}^{48}(\rm tPREX) and rskin48(tr_{\rm skin}^{48}(\rm tE1pE)pE).

Keywords

Cite

@article{arxiv.2005.13197,
  title  = {Neutron skin of $^{48}$Ca consistent with experimental data on skins},
  author = {Shingo Tagami and Jun Matsui and Maya Takechi and Masanobu Yahiro},
  journal= {arXiv preprint arXiv:2005.13197},
  year   = {2020}
}