S. L. Tabor – Florida State University ATLAS Users Meeting August 8, 2009 Sam Tabor - Florida State University Intruder states approaching the Island of Inversion

S. L. Tabor – Florida State University ATLAS Users Meeting August 8, Al FROM THE 18 O( 14 C,pnγ) REACTION T. Hinners et al., Phys. Rev. C 77, (2008)‏ N = 17 (4 - )‏ (5 - )‏ (6 - )‏ (7 - )‏ 30 Al

S. L. Tabor – Florida State University ATLAS Users Meeting August 8, 2009 WBP-a 1519 P.C. Bender et al., Phys. Rev. C 80, (2009) GAMMASPHERE + MICROBALL (2009)

S. L. Tabor – Florida State University ATLAS Users Meeting August 8, 2009 OCCUPATION PROBABILITIES WITH WBP-a AND WBP-b INTERACTIONS Predicted energies agree well for 1p-1h states doublet have similar wavefunctions. 2p-2h states overpredicted by ~2 MeV. WBP-b is closer to believed π f 7/2 x ν f 7/2 configuration. Compared to original WBP interaction (for A ~20), the f 7/2 shell is lowered by 1.8 MeV in both WBP-a and WBP-b. In WBP-a, the p 3/2 orbital is also lowered 0.5 MeV.

S. L. Tabor – Florida State University ATLAS Users Meeting August 8, 2009 WBP-a interaction also works rather well for the 1p-1h (relative to ground state configuration) intruder states. Narrow second 2177 keV line in thick target experiment implies a long lifetime for the 7489 keV state, i.e. a multi-intruder configuration.

S. L. Tabor – Florida State University ATLAS Users Meeting August 8, 2009 SYSTEMATICS OF LOWEST FP INTRUDER STATES T. Hinners et al., Phys. Rev. C 77, (2008)‏

S. L. Tabor – Florida State University ATLAS Users Meeting August 8, 2009 SYSTEMATICS OF LOWEST FP INTRUDER STATES T. Hinners et al., Phys. Rev. C 77, (2008)‏ N - Z = 2 N - Z = 4

S. L. Tabor – Florida State University ATLAS Users Meeting August 8, 2009 END NOTES * The energies of 4 - 1p-1h states with the same N – Z are equal to keV, an order of magnitude better accuracy than the best theories. Is this leading us to a more comprehensive theory or just a fluke? * Intruder states fall with increasing N – Z approaching the Island of Inversion. * More comprehensive spectroscopic techniques are needed to explore these excited intruder states. * The shell model using the WBP-a interaction reproduces the 1 particle – 1 hole states in this region rather well, but not the 2p-2h states. More spectroscopic information from nuclei with larger N – Z is needed to better determine the interaction and test its dependence on neutron excess.

S. L. Tabor – Florida State University ATLAS Users Meeting August 8, 2009 SHELL MODEL: UNIVERSAL S-D INTERACTION B. Alex Brown and W. A. Richter, Phys. Rev. C74, (2006)‏ USDA interaction Differences between theoretical and experimental ground-state binding energies. “Island of Inversion” appears in red and orange.

S. L. Tabor – Florida State University ATLAS Users Meeting August 8, 2009 T. Otsuka, Eur. Phys. J. A 20, 69 (2004)‏ Y. Utsuno et al., PRC70, (2004)‏ CHANGING SHELL GAP N=19