Is the 7/2^<->_<1> isomer state of ^<43>S spherical?

We report on the spectroscopic quadrupole moment measurement of the 7/2^<−>_<1> isomeric state in ^<43>_<16>S_<27> [E^∗ =320.5(5) keV , T_<1/2>=415(3) ns], using the time dependent perturbed angular distribution technique at the RIKEN RIBF facility. Our value, ∣Q_s∣=23(3) efm^2 , is larger than that expected for a single-particle state. Shell model calculations using the modern SDPF-U interaction for this mass region reproduce remarkably well the measured ∣Q_s∣, and show that non-negligible correlations drive the isomeric state away from a purely spherical shape.