Observation of mutually enhanced collectivity in self-conjugate ${}_{38}^{76}$Sr${}_{38}$

Abstract

The lifetimes of the first 2${}^{+}$ states in the neutron-deficient ${}^{76,78}$Sr isotopes were measured using a unique combination of the $\gamma$-ray line-shape method and two-step nucleon exchange reactions at intermediate energies. The transition rates for the 2${}^{+}$ states were determined to be $B$(E2;2${}^{+}$$\to 0^{+}$) = 2220(270) e${}^2$fm${}^4$ for ${}^{76}$Sr and 1800(250) e${}^2$fm${}^4$ for ${}^{78}$Sr, corresponding to large deformation of ${\beta }_2$ = 0.45(3) for ${}^{76}$Sr and 0.40(3) for ${}^{78}$Sr. The present data provide experimental evidence for mutually enhanced collectivity that occurs at $N$ = $Z$ = 38. The systematic behavior of the excitation energies and $B$(E2) values indicates a signature of shape coexistence in ${}^{76}$Sr, characterizing ${}^{76}$Sr as one of most deformed nuclei with an unusually reduced $E$(4${}^{+}$)/$E$(2${}^{+}$) ratio.

arXiv commentAccepted for publication in Physical Review C Rapid Communication

References in corpus (11)

• Nuclear Ground-State Masses and Deformations
• Structure of even-even nuclei using a mapped collective Hamiltonian and the D1S Gogny interaction
• Global study of quadrupole correlation effects
• Deformation of the N=Z nucleus 76Sr using beta-decay studies
• Is there np pairing in odd-odd N=Z nuclei?
• Ground state properties of exotic nuclei near Z=40 in the relativistic mean-field theory,
• Shape and structure of N=Z 64Ge; Electromagnetic transition rates from the application of the Recoil Distance Method to knock-out reaction
• Phase transition in exotic nuclei along the $N=Z$ line
• Collective T=0 pairing in N=Z nuclei? Pairing vibrations around 56Ni revisited
• Shape mixing and beta-decay properties of neutron-deficient Kr and Sr isotopes
• In-beam gamma-ray spectroscopy of very neutron-rich nuclei: Excited states in 46S and 48Ar

Cited by in corpus (6)

• Nilsson-SU3 selfconsistency in heavy N=Z nuclei
• Shape changes in the mirror nuclei ${}^{70}$Kr and ${}^{70}$Se
• Isospin nonconserving interaction in the T=1 analogue states of the mass-70 region
• Ab initio computations of strongly deformed nuclei around ${}^{80}$Zr
• Spectroscopy and lifetime measurements near the proton drip line: ${}^{26,27,28}$P
• Shell model results for $T=1$ and $T=0$ bands in ${}^{66}$As