The radiative proton capture cross section to the $15.1\text{MeV}$ $T=1$ state in ${}^{12}\mathrm{C}$ has been measured in the reaction ${}^{11}\mathrm{B}\left(p,\gamma \right){}^{12}\mathrm{C}$ at the proton energies of $7.2\text{MeV}$ and $17–24\text{MeV}$ in $1\text{MeV}$ steps. The capture $\gamma$ ray was detected in coincidence with the $15.1\text{MeV}$ $\gamma$ ray arising from the subsequent decay of the $T=1$ state to the ground state. The measured cross sections, for $E_p=17–24\text{MeV}$, are much larger than the direct capture model prediction whereas the agreement with the model is good at $E_p=7.2\text{MeV}$. A semidirect capture model, including the excitation of the giant dipole resonance on the $15.1\text{MeV}$ state, reasonably explains the data. The energy and the width of the resonance are extracted.

• Received 20 November 2003

DOI:https://doi.org/10.1103/PhysRevC.69.021602