Study of spin dipole strength in $^{12}{\rm N}$ via complete polarization transfer measurements

Spin-isospin excitations in nuclei have been studied intensively in the past decades. While Gamow-Teller ($\Delta S=1,\ \Delta T=1,\ \Delta L=0$) excitaitons have been investigated exhaustively, the understanding of spin dipole (SD) ($\Delta S=1,\ \Delta T=1,\ \Delta L=1$) excitations is still rather limited with respect to the three different spin-parity states of $J^{\pi}=0^-, 1^-, 2^-$. The strength distribution of each SD state gives us fundamental information on the tensor correlations. In order to deduce the SD strength distributions in $^{12}{\rm N}$, we have measured cross sections and complete sets of polarization transfer observables for $^{12}{\rm C}(\vec{p},\vec{n})$ reaction. The measured polarization transfer observables are used to separate cross section into spin-longitudinal $ID_q$ and spin-transverse $ID_p$ polarized cross sections. These polaried cross sections enable us to separate the SD components into each $J^{\pi}$. In this talk, we will report on the obtained SD strength distributions.