Search for in-band transitions in the candidate superdeformed band in Si-28

doi:10.1103/PhysRevC.104.054323

	Search for in-band transitions in the candidate superdeformed band in Si-28
	Morris, L.11; Jenkins, D. G.11,12; Harakeh, M. N.13,14; Isaak, J.13,15; Kobayashi, N.13; Tamii, A.13; Adachi, S.13; Adsley, P.16; Aoi, N.13; Bracco, A.17,18
刊名	PHYSICAL REVIEW C
	2021-11-30
卷号	104 期号:5 页码:8
ISSN号	2469-9985
DOI	10.1103/PhysRevC.104.054323
通讯作者	Jenkins, D. G.(david.jenkins@york.ac.uk)
英文摘要	Background: Superdeformed (SD) bands are suggested by theory around Ca-40 and in lighter alpha-conjugate nuclei such as Mg-24, Si-28, and S-32. Such predictions originate from a number of theoretical models including mean-field models and antisymmetrized molecular dynamics (AMD) calculations. While SD bands have been identified in Ca-40 and its near neighbors, evidence of their existence in the lighter, midshell nuclei is circumstantial at best. The key evidence of superdeformation would be the observation of transitions with high B(E2) transition strengths connecting states in a rotational sequence. This is challenging information to obtain since the bands lie at a high excitation energy and competition from out-of-band decay is dominant. Purpose: The purpose of the present study is to establish a new methodology to circumvent the difficulties in identifying and quantifying in-band transitions through directly populating candidate states in the SD band in Si-28 through inelastic alpha scattering, selecting such states with a spectrometer, and measuring their gamma-ray decay with a large array of high-purity germanium detectors, allowing direct access to electromagnetic transition strengths. Methods: Excited states in Si-28 were populated in the Si-28(alpha, alpha') reaction using a 130-MeV He-4 beam from the K140 AVF cyclotron at the Research Center for Nuclear Physics. Outgoing alpha particles were analyzed using the Grand Raiden spectrometer positioned at an angle of 9.1 degrees to favor the population of states with J approximate to 4. Coincident gamma rays were detected with the CAGRA array of 12 HPGe clover detectors augmented by a set of four large LaBr3 detectors. Results: Data analysis showed that it was possible to identify additional low-energy transitions in competition with high-energy decays from excited states in Si-28 in the vicinity of 10 MeV. However, while the candidate 4(+) SD state at 10.944 MeV was populated, a 1148-keV transition to the candidate 2(+) SD state at 9.796 MeV was not observed, and only an upper limit for its transition strength of B(E2) < 43 W.u. could be established. This contradicts AMD predictions of approximate to 200 W.u. for such a transition. Conclusion: The present study strongly rejects the hypothesis that the candidate set of states identified in 28 Si represents an SD band, which demonstrates the potential of the methodology devised here.
资助项目	International Joint Research Promotion Program of Osaka University ; Deutsche Forschungsgemeinschaft (DFG)[SFB 1245] ; Deutsche Forschungsgemeinschaft (DFG)[279384907]
WOS关键词	NUCLEUS
WOS研究方向	Physics
语种	英语
出版者	AMER PHYSICAL SOC
WOS记录号	WOS:000725661600002
资助机构	International Joint Research Promotion Program of Osaka University ; Deutsche Forschungsgemeinschaft (DFG)
内容类型	期刊论文
源URL	[http://119.78.100.186/handle/113462/140052]
专题	中国科学院近代物理研究所
通讯作者	Jenkins, D. G.
作者单位	1.PAN, Inst Nucl Phys, PL-31342 Krakow, Poland 2.Michigan State Univ, Natl Superconducting Cyclotron Lab, E Lansing, MI 48824 USA 3.Univ Cologne, Inst Nucl Phys, D-50937 Cologne, Germany 4.GSI Helmholtzzentrum Schwerionenforsch GmbH, D-64291 Darmstadt, Germany 5.Argonne Natl Lab, Phys Div, 9700 S Cass Ave, Argonne, IL 60439 USA 6.Army Res Lab, DEVCOM, Adelphi, MD 20783 USA 7.Univ Strasbourg, IPHC, F-67037 Strasbourg, France 8.Tohoku Univ, Dept Phys, Sendai, Miyagi 9808578, Japan 9.Univ Tokyo, Ctr Nucl Study CNS, Bunkyo Ku, Tokyo 1130033, Japan 10.Chinese Acad Sci, Inst Modern Phys, Lanzhou 730000, Peoples R China
推荐引用方式 GB/T 7714	Morris, L.,Jenkins, D. G.,Harakeh, M. N.,et al. Search for in-band transitions in the candidate superdeformed band in Si-28[J]. PHYSICAL REVIEW C,2021,104(5):8.
APA	Morris, L..,Jenkins, D. G..,Harakeh, M. N..,Isaak, J..,Kobayashi, N..,...&Zhu, S..(2021).Search for in-band transitions in the candidate superdeformed band in Si-28.PHYSICAL REVIEW C,104(5),8.
MLA	Morris, L.,et al."Search for in-band transitions in the candidate superdeformed band in Si-28".PHYSICAL REVIEW C 104.5(2021):8.