${}^{T}T_{20}$ analyzing powers from ${}^{12}\mathrm{C}({}^7\mathrm{Li},\alpha ){}^{15}\mathrm{N}$

The transverse analyzing powers ${}^{T}T_{20}$ were obtained from a polarized beam study of the reaction ${}^{12}\mathrm{C}({}^7\mathrm{Li},\alpha ){}^{15}\mathrm{N}$ at $E_{\text{lab}}\left({}^7\text{Li}\right)=34$ MeV for several well known, strongly populated and isolated states in ${}^{15}\mathrm{N}$ to determine if they contained a sufficiently distinctive signature to be used to provide a test against which selectively populated and strong, but not well understood states, such as the one at $13.17$ MeV could be used to determine their spins and parities. Unfortunately, current finite range distorted wave Born approximation and coupled channels Born approximation calculations were not able to describe the data to the well-known states. The current work presents these experimental analyzing powers with the expectation that they can be used as a test of future detailed reaction model calculations.

Figure 1

${}^{12}\text{C}({}^7\text{Li},\alpha ){}^{15}\text{N}$ spectra collected at ${\theta }_{\text{lab}}={10}^{\circ }, E_{\text{lab}}=$ 34 MeV. The lower panel contains an unpolarized beam spectrum where states in ${}^{15}\text{N}$ are identified with accepted excitation energies [6]. The upper panel displays the difference between polarized beam spectra corresponding to $m_I=-\frac{3}{2}$ and $\frac{3}{2}$ and demonstrates that selectively populated ${}^{15}\text{N}$ states have varying analyzing powers.

Figure 2

Experimental ${}^T{T}_{20}$ angular distributions obtained from a study of the beam polarized ${}^{12}\text{C}({}^7\text{Li},\alpha ){}^{15}\text{N}$ reaction at $E_{\text{lab}}\left({}^7\text{Li}\right)=34$ MeV. The data correspond to the states in (a) 8.57 MeV, $3/2^{+}$ (solid circles) and 6.32 MeV, $3/2^{-}$ (open circles). In (b) 9.155 MeV, $5/2^{+}$ (solid triangles up), 7.16 MeV, $5/2^{+}$ (open triangles up).

Figure 3

Experimental ${}^T{T}_{20}$ angular distributions obtained from a study of the beam polarized ${}^{12}\text{C}({}^7\text{Li},\alpha ){}^{15}\text{N}$ reaction at $E_{\text{lab}}\left({}^7\text{Li}\right)=34$ MeV. The data correspond to the states (a) 7.57 MeV, $7/2^{+}$ (solid squares) and 10.69 MeV, $9/2^{+}$ (open squares); (b) 13.00 MeV, $11/2^{-}$ (solid diamonds) and 15.37 MeV, $13/2^{+}$ (open diamonds). Error bars are not displayed when their sizes are comparable to or smaller than the corresponding symbol size.

Figure 4

Experimental ${}^T{T}_{20}$ angular distribution obtained for a state in ${}^{15}\text{N}$ detected at 13.17 MeV (solid triangles right) compared to the angular distributions of the states in (a) at 8.57 MeV, $3/2^{+}$ (solid circles) and 6.32 MeV, $3/2^{-}$ (open circles); in (b) at 9.155 MeV, $5/2^{+}$ (solid triangles up), 7.16 MeV, $5/2^{+}$ (open triangles up). Error bars are not displayed when their sizes are comparable to or smaller than the corresponding symbol size.

Figure 5

Experimental ${}^T{T}_{20}$ angular distribution obtained for a state in ${}^{15}\mathrm{N}$ detected at 13.17 MeV (solid triangles right) compared to the angular distributions of the states in (a) at 7.57 MeV, $7/2^{+}$ (solid squares) and 10.69 MeV, $9/2^{+}$ (open squares); in (b) at 13.00 MeV, $11/2^{-}$ (solid diamonds) and 15.37 MeV, $13/2^{+}$ (open diamonds). Error bars are not displayed when their sizes are comparable to or smaller than the corresponding symbol size.