Spectroscopy of ${}^{26}$F to probe proton-neutron forces close to the drip line

Abstract

A long-lived $J^{\pi }=4_1^{+}$ isomer, $T_{1/2}=2.2(1)$ms, has been discovered at 643.4(1) keV in the weakly-bound ${}_9^{26}$F nucleus. It was populated at GANIL in the fragmentation of a ${}^{36}$S beam. It decays by an internal transition to the $J^{\pi }=1_1^{+}$ ground state (82(14)%), by $\beta$-decay to ${}^{26}$Ne, or beta-delayed neutron emission to ${}^{25}$Ne. From the beta-decay studies of the $J^{\pi }=1_1^{+}$ and $J^{\pi }=4_1^{+}$ states, new excited states have been discovered in ${}^{25,26}$Ne. Gathering the measured binding energies of the $J^{\pi }=1_1^{+}-4_1^{+}$ multiplet in ${}_9^{26}$F, we find that the proton-neutron $\pi 0d_{5/2}\nu 0d_{3/2}$ effective force used in shell-model calculations should be reduced to properly account for the weak binding of ${}_9^{26}$F. Microscopic coupled cluster theory calculations using interactions derived from chiral effective field theory are in very good agreement with the energy of the low-lying $1_1^{+},2_1^{+},4_1^{+}$ states in ${}^{26}$F. Including three-body forces and coupling to the continuum effects improve the agreement between experiment and theory as compared to the use of two-body forces only.

arXiv comment5 pages, 3 figures, accepted for publication in Physical Review Letters

References in corpus (21)

• Accurate Charge-Dependent Nucleon-Nucleon Potential at Fourth Order of Chiral Perturbation Theory
• Nuclear magic numbers: new features far from stability
• Three-body forces and the limit of oxygen isotopes
• Ab Initio Calculations of Medium-Mass Nuclei with Normal-Ordered Chiral NN+3N Interactions
• Evolution of shell structure in neutron-rich calcium isotopes
• Shell Model in the Complex Energy Plane
• Ab initio coupled-cluster approach to nuclear structure with modern nucleon-nucleon interactions
• Continuum effects and three-nucleon forces in neutron-rich oxygen isotopes
• Shell Structure of Exotic Nuclei
• Density-dependent effective nucleon-nucleon interaction from chiral three-nucleon forces
• Three-body forces and shell structure in calcium isotopes
• New precision mass measurements of neutron-rich calcium and potassium isotopes and three-nucleon forces
• Evidence for the ground-state resonance of 26O
• The N = 16 spherical shell closure in 24O
• Chiral three-nucleon interaction and the carbon-14 dating beta decay
• Quenching of spectroscopic factors for proton removal in oxygen isotopes
• Ab initio coupled-cluster theory for open-shell nuclei
• Evolution of the N=28 shell closure: a test bench for nuclear forces
• Migration of nuclear shell gaps studied in the d(24Ne,p gamma)25Ne reaction
• Exploring the Low-$Z$ Shore of the Island of Inversion at $N=19$
• Spectroscopy of ${}^{26}$F

Cited by in corpus (18)

• Coupled-cluster computations of atomic nuclei
• Neutron matter from chiral effective field theory interactions
• Nuclear forces and their impact on neutron-rich nuclei and neutron-rich matter
• Ground and excited states of doubly open-shell nuclei from ab initio valence-space Hamiltonians
• In-Medium Similarity Renormalization Group for Closed and Open-Shell Nuclei
• Probing Nuclear forces beyond the drip-line using the mirror nuclei ${}^{16}$N and ${}^{16}$F
• Extending the Southern Shore of the Island of Inversion to ${}^{28}$F
• An {\it ab-initio} Gamow shell model approach with a core
• Effective interactions in the sd shell
• Spherical coupled-cluster theory for open-shell nuclei
• Effective proton-neutron interaction near the drip line from unbound states in ${}^{25,26}$F
• Density matrix renormalization group description of the island of inversion isotopes ${}^{28-33}$F
• Excited states in the neutron-rich nucleus 25F
• Shell Evolutions and Nuclear Forces
• Spectroscopy of ${}^{28}$Na: shell evolution toward the drip line
• Probing nuclear forces beyond the nuclear drip line: The cases of ${}^{16}$F and ${}^{15}$F
• The Core of ${}^{25}$F in the Rotational Model
• Nuclear Structure Studies of Neutron-Rich Nuclei : Astrophysical Implications