Deviations from the Porter-Thomas Distribution due to Nonstatistical $γ$ Decay below the $^{150}$Nd Neutron Separation Threshold

Fuente: arXiv
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Main Authors: Papst, O., Isaak, J., Werner, V., Savran, D., Pietralla, N., Battaglia, G., Beck, T., Beuschlein, M., Finch, S. W., Friman-Gayer, U., Ide, K. E., Janssens, R. V. F., Jones, M. D., Kleemann, J., Löher, B., Scheck, M., Spieker, M., Tornow, W., Zidarova, R., Zilges, A.
Format: Preprint
Published: 2025
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author Papst, O.
Isaak, J.
Werner, V.
Savran, D.
Pietralla, N.
Battaglia, G.
Beck, T.
Beuschlein, M.
Finch, S. W.
Friman-Gayer, U.
Ide, K. E.
Janssens, R. V. F.
Jones, M. D.
Kleemann, J.
Löher, B.
Scheck, M.
Spieker, M.
Tornow, W.
Zidarova, R.
Zilges, A.
author_facet Papst, O.
Isaak, J.
Werner, V.
Savran, D.
Pietralla, N.
Battaglia, G.
Beck, T.
Beuschlein, M.
Finch, S. W.
Friman-Gayer, U.
Ide, K. E.
Janssens, R. V. F.
Jones, M. D.
Kleemann, J.
Löher, B.
Scheck, M.
Spieker, M.
Tornow, W.
Zidarova, R.
Zilges, A.
contents 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. It is based on the average branching of decays of $J=1$ states of an even-even nucleus to the $2^+_1$ state in comparison to the ground state. Between 5 and 7 MeV, a constant average branching ratio for $γ$ decays from $1^-$ states of 0.490(16) is observed for the nuclide $^{150}$Nd. Assuming $χ^2$-distributed partial transition widths, this average branching ratio is related to a degree of freedom of $ν= 1.93(12)$, rejecting the validity of the Porter-Thomas distribution, requiring $ν=1$. The observed deviation can be explained by nonstatistical effects in the $γ$-decay behavior with contributions in the range of 9.4(10)% up to 94(10)%.
format Preprint
id arxiv_https___arxiv_org_abs_2501_19185
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Deviations from the Porter-Thomas Distribution due to Nonstatistical $γ$ Decay below the $^{150}$Nd Neutron Separation Threshold
Papst, O.
Isaak, J.
Werner, V.
Savran, D.
Pietralla, N.
Battaglia, G.
Beck, T.
Beuschlein, M.
Finch, S. W.
Friman-Gayer, U.
Ide, K. E.
Janssens, R. V. F.
Jones, M. D.
Kleemann, J.
Löher, B.
Scheck, M.
Spieker, M.
Tornow, W.
Zidarova, R.
Zilges, A.
Nuclear Experiment
Nuclear Theory
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. It is based on the average branching of decays of $J=1$ states of an even-even nucleus to the $2^+_1$ state in comparison to the ground state. Between 5 and 7 MeV, a constant average branching ratio for $γ$ decays from $1^-$ states of 0.490(16) is observed for the nuclide $^{150}$Nd. Assuming $χ^2$-distributed partial transition widths, this average branching ratio is related to a degree of freedom of $ν= 1.93(12)$, rejecting the validity of the Porter-Thomas distribution, requiring $ν=1$. The observed deviation can be explained by nonstatistical effects in the $γ$-decay behavior with contributions in the range of 9.4(10)% up to 94(10)%.
title Deviations from the Porter-Thomas Distribution due to Nonstatistical $γ$ Decay below the $^{150}$Nd Neutron Separation Threshold
topic Nuclear Experiment
Nuclear Theory
url https://arxiv.org/abs/2501.19185