Narrow α + 28Si elastic-scattering states at high excitation in 32S

Autor: P. Manngård, K. M. Källman, V. Z. Goldberg, M. Brenner, A.E. Pakhomov, V.V. Pankratov, T. Lönnroth
Rok vydání: 2003
Předmět:
Zdroj: The European Physical Journal A. 16:159-169
ISSN: 1434-601X
1434-6001
DOI: 10.1140/epja/i2000-10158-9
Popis: The excitation function and angular distributions of elastic α-particle scattering on 28Si have been measured in the laboratory energy range 6-28 MeV using a backscattering technique on a thick target, yielding a continuous energy distribution. More than 200 narrow states are observed, with widths in the range ∼ 30-100 keV at excitation energies E * = 13-32 MeV. Angular distributions at backward angles were measured, and angular momentum values of more than 83 states have been deduced. The analysis gives spin-parities J π, α-partial widths Γα and reduced widths of the narrow high-lying resonant states in 32S. The experimentally observed states display both the negative- and the positive-parity rotational-like sequences with seemingly no parity splitting, a finding which is at variance with most potential-model predictions. The deduced effective moment of inertia indicates a more extended structure than the ground-state configuration. The observed strength of each l-value is analyzed in terms of an underlying split doorway state of Lorentzian form, which yields an interpretation as fragmented rotational α + 28Si states.
Databáze: OpenAIRE
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