Quasi-free Neutron Knockout Reaction Reveals a Small $s$-orbital Component in the Borromean Nucleus ${}^{17}$B

Abstract

A kinematically complete quasi-free $(p,pn)$ experiment in inverse kinematics was performed to study the structure of the Borromean nucleus ${}^{17}$B, which had long been considered to have neutron halo. By analyzing the momentum distributions and exclusive cross sections, we obtained the spectroscopic factors for $1s_{1/2}$ and $0d_{5/2}$ orbitals, and a surprisingly small percentage of 9(2)$\%$ was determined for $1s_{1/2}$. Our finding of such a small $1s_{1/2}$ component and the halo features reported in prior experiments can be explained by the deformed relativistic Hartree-Bogoliubov theory in continuum, revealing a definite but not dominant neutron halo in ${}^{17}$B. The present work gives the smallest $s$- or $p$-orbital component among known nuclei exhibiting halo features, and implies that the dominant occupation of $s$ or $p$ orbitals is not a prerequisite for the occurrence of neutron halo.

arXiv commentAccepted for publication in Physical Review Letters,8 pages, 4 figures

References in corpus (39)

• Relativistic Continuum Hartree Bogoliubov Theory for Ground State Properties of Exotic Nuclei
• Evolution of shell structure in exotic nuclei
• New effective interactions in RMF theory with non-linear terms and density-dependent meson-nucleon coupling
• An optimized chiral nucleon-nucleon interaction at next-to-next-to-leading order
• Microscopic Clustering in Light Nuclei
• Gamow Shell Model Description of Neutron-Rich Nuclei
• A nucleus-dependent valence-space approach to nuclear structure
• Shell Model in the Complex Energy Plane
• Neutron halo in deformed nuclei
• Halos in medium-heavy and heavy nuclei with covariant density functional theory in continuum
• ${}^{78}$Ni revealed as a doubly magic stronghold against nuclear deformation
• Deformed relativistic Hartree Bogoliubov theory in continuum
• DALI2: A NaI(Tl) detector array for measurements of $\gamma$ rays from fast nuclei
• Shell-model study of boron, carbon, nitrogen and oxygen isotopes based on monopole-based-universal interaction
• Measurement of two-halo neutron transfer reaction p(${}^{11}$Li,${}^9$Li)t at 3$A$ MeV
• Deformed Base Antisymmetrized Molecular Dynamics and its Application to ^{20}Ne
• One-neutron removal reactions on light neutron-rich nuclei
• Efimov States in Nuclear and Particle Physics
• Shrunk halo and quenched shell gap at $N=16$ in ${}^{22}$C: Inversion of $sd$ states and deformation effects
• A two-neutron halo is unveiled in ${}^{29}$F
• Halos and related structures
• Antisymmetrized molecular dynamics studies for exotic clustering phenomena in neutron-rich nuclei
• Study of ground state properties of carbon isotopes with deformed relativistic Hartree-Bogoliubov theory in continuum
• Emergent properties of nuclei from ab initio coupled-cluster calculations
• Odd systems in deformed relativistic Hartree Bogoliubov theory in continuum
• Spectroscopy of 13,14B via the one-neutron knockout reaction
• Surface localization of the dineutron in ${}^{11}$Li
• Living on the edge of stability, the limits of the nuclear landscape
• Efimov Physics around the neutron rich Calcium-60 isotope
• Mass-number and isotope dependence of the local microscopic optical potential for polarized proton scattering
• Shell evolution of $N=40$ isotones towards ${}^{60}$Ca: First spectroscopy of ${}^{62}$Ti
• Two-neutron halo structure of ${}^{31}$F
• Single-Proton Removal Reaction Study of 16B
• Evolution of Surface Deformations of Weakly-Bound Nuclei in the Continuum
• Emergence of simple patterns in many-body systems: from macroscopic objects to the atomic nucleus
• Emergence of clusters: Halos, Efimov states, and experimental signals
• Structure of 13Be probed via quasi-free scattering
• Shell evolution in neutron-rich carbon isotopes: Unexpected enhanced role of neutron-neutron correlation
• How different is the core of ${}^{25}$F from ${}^{24}$O${}_{g.s.}$?

Cited by in corpus (24)

• Predictive power for superheavy nuclear mass and possible stability beyond the neutron drip line in deformed relativistic Hartree-Bogoliubov theory in continuum
• Deformed relativistic Hartree-Bogoliubov theory in continuum with a point-coupling functional. II. Examples of odd Nd isotopes
• Rotating deformed halo nuclei and shape decoupling effects
• Collapse of the $N=28$ shell closure in the newly discovered ${}^{39}$Na and the development of deformed halos towards the neutron dripline
• Possible bound nuclei beyond the two-neutron drip line in the $50⩽Z⩽70$ region
• Missed prediction of the neutron halo in ${}^{37}$Mg
• Angular momentum projection in the deformed relativistic Hartree-Bogoliubov theory in continuum
• Shape coexistence and neutron skin thickness of Pb isotopes by the deformed relativistic Hartree-Bogoliubov theory in continuum
• Optimized Dirac Woods-Saxon basis for covariant density functional theory
• Possible existence of bound nuclei beyond neutron drip lines driven by deformation
• Proton decays in ${}^{16}$Ne and ${}^{18}$Mg and isospin-symmetry breaking in carbon isotopes and isotones
• Examination of the evidence for a proton halo in ${}^{22}$Al
• Recent progress in configuration-interaction shell model
• Opening angle and dineutron correlations in knockout reactions with Borromean two-neutron halo nuclei
• Accuracy of the mean-field theory in describing ground-state properties of light nuclei
• Symmetry Energy from Two-Nucleon Separation Energies of Pb and Ca Isotopes
• Nuclear shape evolution of neutron-deficient Au and kink structure of Pb isotopes
• Triaxial relativistic Hartree-Bogoliubov theory in continuum for exotic nuclei
• Spectroscopic factor calculations in the \textit{ab initio} no-core shell model
• Effective polarization in proton-induced $\alpha$ knockout reactions
• Manifestation of the divergence between antisymmetrized-molecular-dynamics and container pictures of ${}^9$Be via ${}^9$Be($p,pn$)${}^8$Be knockout reaction
• Considering non-locality in the optical potentials within eikonal models
• Nuclear Pairing Energy vs Mean Field Energy: Do They Talk To Each Other For Searching The Energy Minimum?
• Exploratory study on the masses of odd-$Z$ nuclei and $r$-process simulation based on the deformed relativistic Hartree-Bogoliubov theory in continuum