Recent advancements in post-accelerated unstable isotopes have unlocked a new frontier in nuclear research, enabling the study of an unprecedented number of new isotopes. Various techniques for investigating nuclear structure yield complementary insights, but direct transfer reactions stand out. They provide a unique opportunity to explore the nuclear wavefunction by effectively combining the reaction dynamics with the nuclear structure. The formalism behind direct transfer reactions allows for a rigorous comparison between experimental cross sections and theoretical models, offering a deeper understanding
of the nuclear many-body quantum system.
Departures from the conventional liquid-drop-like saturated density of the nucleus represent one of the key interests in the realm of nuclear structure, where phenomena of nucleon localisation such as clustering or bubble structures consist of macroscopic effects of the underlying nuclear interaction.
The seminar will highlight the role of direct reactions in probing nuclear structure, with a focus on a recent experiment conducted at GANIL, France. The experiment investigated the proton wavefunction of 46Ar by means of a (3He,d) direct reaction. The comparison of experimental data with calculations rooted on the fundamental properties of the strong interaction, so-called ab initio, gives indication of the occurrence of a central charge depletion in 46Ar, while offering a new perspective on the long-standing
puzzle of the transition probabilities in this isotope [1]. The experiment relied on a state-of-the-art setup, allowing the detection and identification of all reaction fragments. The key components consisted of the high-acceptance magnetic spectrometer, VAMOS [3], the high-granularity silicon DSSSD detector MUGAST [4], and the gamma-ray tracking array AGATA [5].
References:
[1] A. Gade et al., Phys. Rev. C 74, 034322 (2006)
[2] S. Calinescu et al., Phys. Rev. C 93, 044333 (2016)
[3] M.Rejmund et al., Nucl. Inst. Meth. A 646, 184-191 (2012)
[4] M. AssiÅLe, et al., Nucl. Inst. Meth. A 1014, 165743 (2021)
[5] S. Akkoyun et al., Nucl. Inst. Meth. A 668, 26-58 (2012)
Denise Piatti and Franco Galtarossa