Mass of lowestT=2state ofC12

A precise measurement of the excitation energy of the lowest $T=2\mathrm{}$ state in ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ has been made via the ${}_{}{}^{14}{}_{}{}^{}\mathrm{C}\mathrm{}(p,t)\mathrm{}{}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ reaction. The value obtained, 27.5950 ± 0.0024 MeV, is in agreement with earlier (less precise) measurements and therefore does not explain the failure to observe the $T=2\mathrm{}$ state in isospin-forbidden resonance reactions. Also reported in this work are an upper limit of 30 keV for the total width of the $T=2\mathrm{}$ state and an excitation energy of 3.3492 ± 0.0012 MeV for the first excited state of ${}_{}{}^{10}{}_{}{}^{}\mathrm{C}$.