Recently, $B(E2, 0^+_1 \to 2^+_1)$ transition strength have been measured in $^{ 36}$Ca and $^{ 38}$Ca. Surprisingly, the measured value in $^{ 36}$Ca: $B(E2\ \uparrow) = 131(20)$ e$^2$fm$^4$, is significantly larger than in $^{ 38}$Ca, where $B(E2\ \uparrow) = 101(11)$ e$^2$fm$^4$, whereas an opposite tendency of $B(E2)$ values is seen in the mirror nuclei $^{ 36}$S and $^{ 38}$Ar. The resonance $2^+_1$ in $^{ 36}$Ca lies 465 keV above the proton emission threshold and its description requires inclusion of the coupling to the continuum. In this work, we are analyzing $B(E2\ \uparrow)$ values in $^{ 36}$Ca, $^{ 36}$S, $^{ 38}$Ca, and $^{ 38}$Ar using the real-energy continuum shell model, the so-called shell model embedded in the continuum, in the $(1s_{ 1/2}\, 0d_{ 3/2}\, 0f_{ 7/2}\, 1p_{ 3/2})$ model space with the monopole adjusted effective interaction ZBM-IO.
Categories: nucl-th nucl-ex