Refilwe Emil Molaeng
(School of Physics, University of the Witwatersrand SSC Laboratory, iThemba LABS)
This work investigates the Pygmy Dipole Resonance (PDR) in the deformed $^{154}$Sm nucleus. The study uses the ($\vec{\gamma}$,$\vec{\gamma}^{\prime}$) reaction to excite dipole states at energies ranging from 3.5 MeV to 7.05 MeV, approaching the neutron separation energy at 8 MeV. Measurements were taken with the Clover Array at the HI$\gamma$S facility of the Triangle Universities Nuclear Laboratory. The facility's polarised photon beam enables measurements using the asymmetry method to distinguish between $1^{-}$ and $1^{+}$ states. The high-resolution beam mode (with an energy spread below 2%) allows for the determination of decay branching ratios to the first $2^{+}$ state thereby enabling the identification of the $K$ quantum number for the excited states. Additionally, the current study extends the investigation of the Alaga rules to the PDR region of $^{154}$Sm, as they have so far only been investigated for $^{150}$Nd$^{[1]}$. We provide preliminary results and discuss prospects for future analysis.
This work is based on the research supported in part by the National Research Foundation of South Africa (Grants No. MND210503598725, No. REP_SARC180529336567) and the US Department of Energy (Grants No. DE-FG02-97ER41041 (UNC), No. DE-FG02-97ER41033 (TUNL)).
References
1. O. Papst et al., Deviations from the Porter-Thomas distribution due to non-statistical gamma decay below the $^{150}$Nd neutron separation threshold (2025), arXiv:2501.19185 [nucl-ex].
Refilwe Emil Molaeng
(School of Physics, University of the Witwatersrand SSC Laboratory, iThemba LABS)
Dr
Lindsay Michelle Donaldson
(SSC Laboratory, iThemba LABS)
Prof.
Iyabo Usman
(School of Physics, University of the Witwatersrand)
Philip Adsley
(Department of Physics & Astronomy and Cyclotron Institute, Texas A&M University)
Prof.
Luna Pellegri
(School of Physics, University of the Witwatersrand and SSC Laboratory, iThemba LABS )
Akaa Daniel Ayangeakaa
(Department of Physics and Astronomy, University of North Carolina and Triangle Universities Nuclear Laboratory )
James Carroll
(U.S. Army Combat Capabilities Development Command Army Research Laboratory)
Christopher Chiara
(U.S. Army Combat Capabilities Development Command Army Research Laboratory)
Sean Finch
(Department of Physics, Duke University and Triangle Universities Nuclear Laboratory)
David Gribble
(Department of Physics and Astronomy, University of North Carolina and Triangle Universities Nuclear Laboratory, )
Amrita Gupta
(Technische Universität Darmstadt, Department of Physics, Institute for Nuclear Physics)
Johann Isaak
(Technische Universität Darmstadt, Department of Physics, Institute for Nuclear Physics)
Xavier James
(Department of Physics and Astronomy, University of North Carolina and Triangle Universities Nuclear Laboratory)
Robert Janssens
(Department of Physics and Astronomy, University of North Carolina and Triangle Universities Nuclear Laboratory )
Samantha Johnson
(Department of Physics and Astronomy, University of North Carolina and Triangle Universities Nuclear Laboratory )
Jörn Kleemann
(Technische Universität Darmstadt, Department of Physics, Institute for Nuclear Physics)
Tyler Kowalewski
(Department of Physics and Astronomy, University of North Carolina and Triangle Universities Nuclear Laboratory)
Bastian Löher
(GSI Helmholtzzentrum für Schwerionenforschung GmbH)
Oliver Papst
(Technische Universität Darmstadt, Department of Physics, Institute for Nuclear Physics)
Norbert Pietralla
(Technische Universität Darmstadt, Department of Physics, Institute for Nuclear Physics)
Kiriaki Prifti
(Technische Universität Darmstadt, Department of Physics, Institute for Nuclear Physics)
Deniz Savran
(GSI Helmholtzzentrum für Schwerionenforschung GmbH)
Antonella Saracino
(Department of Physics and Astronomy, University of North Carolina and Triangle Universities Nuclear Laboratory)
John Santucci
(Department of Physics & Astronomy and Cyclotron Institute, Texas A&M University)
Benjamin Wellons
(Department of Physics & Astronomy and Cyclotron Institute, Texas A&M University)
Volker Werner
(Technische Universität Darmstadt, Department of Physics, Institute for Nuclear Physics)
