Dominance of correlation and relativistic effects on photodetachment time delay well above threshold.

Wigner time delay [1] in photodetachment from the 3$p_{\mathrm{3/2}}$ and 3$p_{\mathrm{1/2}}$ subshells of Cl have been studied in the vicinity of the 2$p_{\mathrm{3/2}}$ and 2$p_{\mathrm{1/2}}$ thresholds, using the relativistic-random- phase approximation (RRPA). The results show time delay spectra dominated by many-body correlations along with very complicated dependence on the energy over a broad energy range. In addition, the time delay spectra of the two spin-orbit split 3$p $subshells differ significantly from one another, thereby revealing the importance of relativistic effects even in the case of a low-Z system. Work partially supported by SERB (India) and the US DOE. [1] E. P. Wigner, Phys. Rev. \textbf{98}, 145 (1955).