Isovector Quadrupole Resonance observed in the $^{60}$Ni($^{13}$C,$^{13}$N)$^{60}$Co reaction at \emph{E/A} = 100 MeV

The charge-exchange reaction $^{60}$Ni($^{13}$C,$^{13}$N)$^{60}$Co at $E/A$ = 100 MeV has been studied to locate isovector ($\Delta T$ = 1) non-spin-flip ($\Delta S = 0$) giant resonances. Besides the giant dipole resonance at $E_x$ = 8.7 MeV, another resonance has been observed at $E_x$ = 20 MeV with a width of 9 MeV. DWBA analysis on the angular distribution clearly indicated the $L$ = 2 multipolarity, attributing the $E_x$ = 20 MeV state to the giant isovector quadrupole resonance. The present analysis further indicates that the observed peak exhausts approximately 50 \% strength of the isovector L=2 classical energy-weighted sum rule. The same ($^{13}$C,$^{13}$N) reactions at $E/A$ = 100 MeV for other target nuclie will be also presented and discussed. A part of this result can be found at the reference of T. Ichihara \emph{et al.}, Phys.\ Rev. Lett. {\bf 89}, 142501 (2002).