Particle- $\gamma$ γ coincidence spectroscopy of the N = 90 nucleus 154Gd by ( $p,t\gamma$ p , t γ )
2017; Springer Science+Business Media; Volume: 53; Issue: 3 Linguagem: Inglês
10.1140/epja/i2017-12253-2
ISSN1434-601X
AutoresJ. M. Allmond, C. W. Beausang, Thomas J. Ross, P. Humby, M. S. Basunia, L. A. Bernstein, D. L. Bleuel, W. K. Brooks, Nathan P. Brown, J. T. Burke, B. Darakchieva, Kelsey Dudziak, K. E. Evans, P. Fallon, H. B. Jeppesen, Justin D. LeBlanc, Shelly Lesher, M. A. McMahan, David Meyer, L. Phair, John Rasmussen, N. D. Scielzo, S. R. Stroberg, M. Wiedeking,
Tópico(s)Quantum Chromodynamics and Particle Interactions
ResumoA segmented Si-telescope and HPGe array, STARS-LIBERACE, was used to study the 156Gd( $p,t\gamma$ )154Gd direct reaction by particle- $ \gamma$ coincidence spectroscopy. New cross sections with a 25MeV proton beam are reported and compared to previous (p,t) and (t,p) studies. Furthermore, additional evidence for coexisting $ K^{\pi}=0_{1}^{+},2_{1}^{+}$ and $0_{2}^{+}$ , $2_{2}^{+}$ configurations at N = 90 is presented. Direct and indirect population patterns of the low-lying states are also explored. Review of the new and existing evidence favors an interpretation based on a configuration-dependent pairing interaction. The weakening of monopole pairing strength and an increase in quadrupole pairing strength could bring 2p-2h $0^{+}$ states below $2\Delta$ . This may account for a large number of the low-lying $0^{+}$ states observed in two-nucleon transfer reactions. A hypothesis for the origin of the $0_{2}^{+}$ and $ 0_{3}^{+}$ states is provided.
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