Systematic study of odd-even staggering in elemental fragmentation cross sections for N=Z nuclei from 36Ar to 28Si at ~ 300 MeV/nucleon**The work is supported by the National Natural Science Foundation of China ( 12325506, U1832211)

Elemental fragmentation cross sections (EFCSs) of the (Formula presented) nuclei (Formula presented) Ar, (Formula presented) Cl, (Formula presented) S, (Formula presented) P, and (Formula presented) Si on a carbon target were measured at approximately 300 MeV/nucleon using the RIBLL2 fragment separator at HIRFL. Among these, the cross sections for (Formula presented) Cl and (Formula presented) P are reported here for the first time, providing new data and extending EFCS measurements along the (Formula presented) chain. The measured cross sections exhibit significant odd-even staggering as a function of the charge change (Formula presented). The experimental results are compared with several empirical parametrizations, including Cummings, EPAX3, and FRACS, as well as with the isospin-dependent quantum molecular dynamics model (IQMD) coupled to the statistical decay code GEMINI. The IQMD+GEMINI calculations reproduce the experimental cross sections with an accuracy of approximately 7% and reasonably reproduce the observed odd-even staggering. Consistent with previous studies, comparisons of model predictions at different reaction stages demonstrate that the odd-even staggering in EFCSs predominantly originates from the de-excitation of excited primary fragments. These results further establish the robustness of this interpretation by extending its validity to the (Formula presented) region.