The ⁴⁶Ar(³He,d)⁴⁷K direct reaction as a probe of the ⁴⁶Ar proton wavefunction

The discrepancy between shell-model calculations and intermediate-energy Coulomb excitation measurements in (46) Ar still stands as an unsolved puzzle in understanding the N = 28 shell evolution. This phenomenon has significant relevance considering the remarkable achievements of the shell model and the SDPF-U interaction in the region which is able to predict the fading of the N = 28 shell gap in neutron-rich S-44. Recent measurements narrowed down this discrepancy to an overestimation of the proton amplitude to the quadrupole transition matrix element. The current work aims to propose a different perspective on the puzzle, by studying a direct proton-transfer reaction on (46) Ar as a means to directly probe the proton wavefunction of the ground state this isotope. By measuring the amount of l = 0 transfer to the ground state (1/2(+)) of K-47 with respect to the l = 2 to the first excited state (3/2(+)), we aim to gain insight into the ground state proton wavefunction of 46 Ar. We will present a brief description of the experiment performed at the SPIRAL1 facility in GANIL (France). The experimental apparatus allowed a full reconstruction of the two-body reaction thanks to the combination of AGATA, VAMOS, MUGAST, CATS2, and HECTOR.