Measurement of proton-distribution radii of neutron-rich nitrogen isotopes

S Bagchi ,Toshio Suzuki,Satbir Kaur,Hooi Jin Ong,D Cortina‐Gil ,J E Ramirez Vargas ,J Tanaka ,R Kanungo ,M Mostazo ,G Hagen ,Y K Tanaka ,F Farinon ,Titus Morris ,B Sitár ,A Estradé ,S Piétri ,C Scheidenberger ,I Mukha ,H Weick ,J Atkinson ,Steven Stroberg ,J Kurcewicz ,H Geißel ,P Strmeň ,I Tanihata ,G Guastalla ,A Evdokimov ,S Terashima ,W Horiuchi ,M Marta ,R Knöbel ,Yury Litvinov,C Nociforo ,A Procházka ,R Janik ,I Dillmann ,Y Ayyad ,F Ameil ,M Takechi ,J S Winfield

doi:10.1051/epjconf/201922301003

Abstract

Measurement of root-mean-square radii of proton distributions of 17–22N from charge-changing cross section shows the emergence of thick neutron skin towards the neutron-drip line. Signature of N = 14 shell gap has been found in nitrogen isotopes along with the emergence of neutron halo in 22N. The measured radii are in good agreement with the shell model calculations.

Highlights

With large neutron-to-proton ratios far from the valley of stability, nuclei develop exotic structures such as neutron skin, nuclear halo, modifications of conventional shells and apperance of new shell gaps
Evidence for breaking down of N = 8 shell gap has been found in 11Li and 11Be [1,2,3] while a new shell gap at the neutron number N = 16 has been found in carbon, nitrogen and oxygen isotopes at the drip line [4]
Since nitrogen is in the transitional region between oxygen and carbon, it is interesting to investigate the presence of the N = 14 shell gap in nitrogen

Summary

Introduction

With large neutron-to-proton ratios far from the valley of stability, nuclei develop exotic structures such as neutron skin, nuclear halo, modifications of conventional shells and apperance of new shell gaps. Evidence for breaking down of N = 8 shell gap has been found in 11Li and 11Be [1,2,3] while a new shell gap at the neutron number N = 16 has been found in carbon, nitrogen and oxygen isotopes at the drip line [4]. Another sub-shell gap at N = 14 has been found in oxygen and is predicted to disappear in carbon [5].

Results

Conclusion