Lifetime Measurements in $^{74}$As

The irregular signature-splitting pattern in the positive-parity band in $^{74}$As has recently been suggested to result from an underlying triaxial shape. Lifetime measurements could be used as a way to test this assertion, but so far they are unavailable for high-spin states. Thus the goal of this work was to measure as many lifetimes as possible in $^{74}$As using the Doppler-shift attenuation method in order to test the existing interpretation of its positive-parity structure. High-spin states in $^{74}$As were populated using the $^{14}$C($^{62}$Ni, $pn$) reaction at 50 MeV performed at Florida State University. Gamma decays were measured in coincidence using a Compton-suppressed array of 10 Ge detectors. Three lifetimes were measured within the positive-parity band and used to infer the quadrupole deformation parameter $\beta_2$ as a function of spin. The experimental $\beta_2$ values were then compared with theoretical ones extracted from total Routhian surface calculations. Although the experimental trend in the $\beta_2$ values are not reproduced by the calculations, the magnitudes of two experimental values are in agreement and triaxial shapes appear to be favored.