Isomeric character of the 4$_{1}^{+}$ state in $^{44}$S: Mechanisms of breaking of the N$=$28 shell

The N$=$28 nucleus $^{44}$S exhibits a rich structure of excitations which illustrates different mechanisms of breaking the N$=$28 shell. A Coulomb excitation measurement [1] and an implantation-decay experiment [2] established the coexistence of 2p2h-deformed and 0p0h-spherical configurations. A two-proton knockout reaction [3] indicated a 4$^{+}$ state which shell model calculations suggest is likely isomeric, prolate-deformed and formed from a 1p1h configuration. A recent two-proton knockout experiment measured the lifetime of this 4$^{+}$ state using the recoil distance method and the GRETINA array. Results for the lifetime of the 4$^{+}$ state will be presented and its implication for the mechanisms of breaking the N$=$28 shell will be discussed. \\[4pt] [1] T. Glasmacher etal., Phys.Lett. B 395 (1997), 163\\[0pt] [2] C. Force etal., Phys.Rev.Lett. 105, 102501 (2010)\\[0pt] [3] D. Santiago-Gonzalez et al., Phys.Rev. C 83, 061305 R (2012)