New excited states in sd-shell nucleus ³³P

Isospin-symmetry breaking in nuclear physics is mainly described by Mirror-Energy Differences (MED) for mirror nuclei or Triplet-Energy Differences (TED) for isobaric triplets. Modified USD-calculations successfully reproduce MED for T=1,3/2,2 sd-shell nuclei. Refined tests of theory are given by lifetime measurements in order to deduce transition-strength values. In order to study the mirror pair ³³Ar and ³³P, the fusion-evaporation reaction ¹³C+²⁶Mg at 46 MeV was measured at the Cologne tandem accelerator and the HORUS spectrometer employing the Doppler-Shift-Attenuation-Method (DSAM). First results yielded new γ-ray transitions in ³³P and ³³S. The level scheme of ³³P was extended up to excitation energies of 10 MeV. Spins and parities of the new levels were determined exploiting γγ-angular correlations. Together with values from the proton-rich T_z = - 3/2 partner, the levels are compared to shell model calculations, describing excitation energies of sd -shell mirror pairs. The understanding of isospin symmetry and isospin-symmetry breaking is a fundamental question in nuclear physics. Isospin-symmetry breaking is mainly described by Mirror-Energy Differences (MED) for mirror nuclei or Triplet-Energy Differences (TED) for isobaric triplets. Modified USD^m_1,2,3-calculations successfully reproduced MED for the mirror nuclei ³³Ar and ³³P. Both ³³P and ³³S were produced at the Cologne FN tandem accelerator employing the fusion-evaporation reaction ¹³C+²⁶Mg at 46 MeV and spectroscopically investigated using 14 HPGe detectors. Several new energy states (in ³³P) and γ-ray transitions (in ³³P and ³³S) were detected. Spins and parities of the new levels in ³³P were determined exploiting γγ-angular correlations. The level scheme of ³³P was extended up to excitation energies of 10 MeV.