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Description
The region around $N$ = 28 and the 2nd island of inversion is rich in nuclear structure information, where both core breaking and deformation have been previously observed. Between the doubly-magic nucleus $^{48}$Ca and the collective $^{44}$Si lies $^{46}$Ar; $B(E2)$ values from states in $^{46}$Ar can be used to study how deformation evolves at $N$ = 28. The evolution of $B(E2)$ values across $N$ = 28 from $^{46}$Ar to $^{48}$Ar can also be used as a probe for core breaking. Here, we present the preliminary results from an experiment at INFN-LNL using the $\gamma$-ray spectrometer AGATA coupled to the recoil mass separator PRISMA where lifetimes of excited states $^{46,47,48}$Ar were measured using the Doppler-shift attenuation method (DSAM) and recoil distance Doppler-shift (RDDS) techniques.