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

A1 Journal article (refereed)

Internal Authors/Editors

Publication Details

List of Authors: Kallman KM, Brenner M, Goldberg VZ, Lonnroth T, Manngard P, Pakhomov AE, Pankratov VV
Publication year: 2003
Journal: European Physical Journal A: Hadrons and Nuclei
Journal acronym: EUR PHYS J A
Volume number: 16
Issue number: 2
Start page: 159
End page: 169
Number of pages: 11
ISSN: 1434-6001
eISSN: 1434-601X


The excitation function and angular distributions of elastic alpha-particle scattering on Si-28 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 similar to 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(pi), alpha-partial widths Gamma(alpha) and reduced widths of the narrow high-lying resonant states in S-32. 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 alpha + Si-28 states.

Last updated on 2020-24-02 at 05:30