Köln 2025 – wissenschaftliches Programm
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HK: Fachverband Physik der Hadronen und Kerne
HK 48: Structure and Dynamics of Nuclei XI
HK 48.5: Vortrag
Donnerstag, 13. März 2025, 16:45–17:00, HS 2 Physik
Deviations from the Porter-Thomas distribution due to non-statistical gamma decay — •Johann Isaak1, Oliver Papst1, Volker Werner1, Deniz Savran2, Norbert Pietralla1, Maike Beuschlein1, Sean Finch3, Robert Janssens3,4, Jörn Kleemann1, Miriam Müscher5, Werner Tornow3, and Andreas Zilges5 — 1TU Darmstadt, IKP, Darmstadt, Germany — 2GSI, Darmstadt, Germany — 3TUNL, Durham, USA — 4UNC, Chapel Hill, USA — 5Universität zu Köln, IKP, Köln, Germany
Fluctuations of partial transition widths in nuclear reactions are usually
considered following the so-called Porter-Thomas (PT) distribution [1].
While fluctuations have been studied extensively for
thermal neutron resonances, partly with inconclusive results,
the region below particle thresholds is untouched so far [2].
In this contribution, we introduce a new method for the study of fluctuations of partial transition widths based on nuclear resonance fluorescence experiments with quasimonochromatic linearly-polarized photon beams below particle separation thresholds.
Results for 150Nd will be presented and discussed.
The data suggest deviations from the PT distribution, which can be explained by
non-statistical effects in the γ-decay channel.
*Supported by the DFG Project-ID 499256822 - GRK 2891 and Project-ID 279384907 - SFB 1245.
[1] Porter and Thomas, PR 104, 483 (1956).
[2] Weidenmüller and Mitchell, RMP 81, 539 (2009).
Keywords: Statistical gamma decay; Partial width fluctuations; Photon scattering