https://doi.org/10.1140/epja/s10050-022-00705-x
Regular Article - Theoretical Physics
Investigating the proton-halo structure of 
B via the extended THSR wave function
1
School of Physics, Nanjing University, 210093, Nanjing, China
2
School of Physics Science and Engineering, Tongji University, 200092, Shanghai, China
3
School of Science, Huzhou University, 313000, Huzhou, Zhejiang, China
4
School of Physics and Optoelectronics, South China University of Technology, 510641, Guangzhou, China
5
College of Physics, Nanjing University of Aeronautics and Astronautics, 210016, Nanjing, China
6
Key Laboratory of Aerospace Information Materials and Physics (NUAA), MIIT, 211106, Nanjing, China
7
Key Laboratory of Advanced Micro-Structure Materials, Ministry of Education, 200092, Shanghai, China
8
Research Center for Nuclear Physics (RCNP), Osaka University, 567-0047, Osaka, Japan
9
Institut für Physik, Universität Rostock, 18051, Rostock, Germany
10
National Research Nuclear University (MEPhI), 115409, Moscow, Russia
11
Université Paris-Saclay, CNRS-IN2P3, IJCLab, 91405, Orsay, France
12
Université Grenoble Alpes, CNRS, LPMMC, 38000, Grenoble, France
13
Institute of Modern Physics, Fudan University, 200433, Shanghai, China
14
Faculty of Science, Hokkaido University, 060-0810, Sapporo, Japan
e
mengjiao.lyu@nuaa.edu.cn
f
zren@tongji.edu.cn
Received:
31
October
2021
Accepted:
11
March
2022
Published online:
31
March
2022
Due to the proton-halo structure, the B nucleus has been attractive for many experimental and theoretical studies. In this work, we perform theoretical calculations on the ground state of B through a further extended Tohsaki–Horiuchi–Schuck–Röpke (THSR) wave function. The B nucleus is treated as an 
+ 
He + p system where the two clusters move inside modified containers, which are formulated in this work to describe the various modes of cluster motion. Through variational calculations, it is found that our new THSR wave functions are very efficient in describing the ground state of B, which can be accurately described by a superposition of only two basis states, namely the spindle shaped one and the elliptical one. It is of particular interest to find that the latter basis has a dominant contribution to the proton-halo structure. We further illustrate the property of the proton halo in B by calculating the radius and the electric quadrupole moment of B. The obtained result shows a large electric quadrupole moment in the ground state of B, which is in good agreement with the experimental data and other theoretical calculations. It is found that in one basis state, the large electric quadrupole moment is contributed by the polarization of the 
Be core, while in the other basis it is primarily due to the proton halo structure.
© The Author(s), under exclusive licence to Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature 2022
