Speaker
Description
The formal concept of isospin has been introduced to explain the apparent exchange symmetry between neutrons and protons. However, if the nuclear force were the same for protons and neutrons properties such as masses and excitation energies would depend only on the mass number A. Recent studies have shown that the Coulomb force cannot account for all deviations, suggesting that other isospin-symmetry-breaking components must be present. N⁓Z systems present the perfect testing ground to probe isospin symmetry phenomena [1-3]. In addition, pairing correlations have a significant importance in the description of the nuclear structure of N=Z nuclei, where protons and neutrons are arranged occupying the same orbits, allowing T=0 np pairing in addition to the normal T=1. It was recently suggested that spin-aligned T=0 np pairs dominate the wavefunction of the y-rast sequence in 92Pd [4]. Subsequent theoretical studies were devoted to probe the contribution of np pairs in other N=Z A>90 nuclei [5-6], suggesting that a similar pairing scheme strongly influences the structure of these nuclei.
In an effort to answer these questions further, a recoil-beta-tagging experiment has been performed to study the excited T=0 and T=1 states in the odd–odd N = Z nucleus 94Ag, populated via the 40Ca(58Ni,1p3n)94Ag reaction. The experiment was conducted using the MARA recoil separator and JUROGAM3 array at the Accelerator Laboratory of the University of Jyväskylä. Through correlating fast, high-energy beta decays at the MARA focal plane with prompt γ rays emitted at the reaction target, a number of transitions between excited states in 94Ag have been identified for the first time [7].
The detailed goals of the experiment, the setup, the identified transitions and the experimental CED will be shown in this presentation. The results will also be compared with nuclear shell model predictions and a preliminary interpretation will also be discussed.
[1] K. Wimmer, et al., Phys. Rev. Lett. 126, 072501 (2021).
[2] R.D.O. Llewellyn, et al., Phys. Lett. B 797, 135873 (2019).
[3] A. Boso, et al., Phys. Lett. B 797, 134835 (2019).
[4] B. Cederwall, et al., Nature 469, 6871 (2011).
[5] G.J. Fu, et al., Phys. Rev. C 87, 044312 (2013).
[6] Z.X. Xu, et al., Nucl. Phys. A 877 (2012) 51-58.
[7] X. Pereira-Lopez, et al., Eur. Phys. J. A (2023) 59:44.
