Study ofT=32states inF17

Abstract

The first seven $T=\frac{3}{2}$ states in ${}_{}{}^{17}{}_{}{}^{}\mathrm{F}$ have been studied as resonances in the ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}+p$ entrance channel, observing the ($p_0$), ($p_1+p_2$), ($p_3+p_4$), and (${\alpha }_0$) exit channels. In a survey of the energy region $E_p=13.23\mathrm{} \mathrm{to} 16.60$ MeV in steps of less than 5 keV at six laboratory angles, the previously unobserved fourth and fifth $T=\frac{3}{2}$ states were found at $E_p=13.271\mathrm{}\pm 0.004 \mathrm{and} 14.017\pm 0.004$ MeV, respectively. Complete elastic scattering angular distributions (at 29 angles from ${\theta }_{\mathrm{lab}}=25\mathrm{}$ to 165°) were measured from $E_p=9.0\mathrm{} \mathrm{to} 20.35$ MeV in 50-keV steps and were analyzed using the optical-model code JIB3 to extract phase-shift information across this region. These results were used in a phase-shift analysis of the individual $T=\frac{3}{2}$ resonances to obtain the following assignments for the second through the seventh $T=\frac{3}{2}$ states in ${}_{}{}^{17}{}_{}{}^{}\mathrm{F}$: $\left\{E_p \right(\mathrm{MeV}),E_x({}_{}{}^{17}{}_{}{}^{}\mathrm{F}\left) \right(\mathrm{MeV}),\Gamma (\mathrm{keV}),\frac{{\Gamma }_{p_0}}{\Gamma },J^{\pi }\}\{12.708\pm 0.00412.5513\pm 1,0.26\pm 0.04{\frac{3}{2}}^{-}\}\{13.250\pm 0.00413.0612\pm 1,0.15\pm 0.04{\frac{5}{2}}^{-}\}\{13.271\pm 0.00413.0802\pm 1,0.04\pm 0.02({\frac{1}{2}}^{+}\left)\right\}\{14.017\pm 0.00413.78212\pm 5,0.02\pm 0.01{\frac{5}{2}}^{+}\}\{14.438\pm 0.00614.17727\pm 5,0.04\pm 0.02{\frac{3}{2}}^{-}\}\{14.579\pm 0.01014.31020\pm 5,0.11\pm 0.03{\frac{7}{2}}^{-}\}$