Electroexcitation of discrete levels in 12C and 13C at high momentum transfers

Form factors for transverse electron scattering from ¹²C and ¹³C have been determined for momentum transfers as high as q=4.6 fm^-1. Data are presented for the elastic (M1), 3.088 MeV (E1), and 9.50 MeV (M4) transitions in ¹³C, and for the 15.11 MeV (M1), 16.11 MeV (E2), and 16.58 MeV (M2) transitions in ¹²C. It is found that calculations in the lowest-order shell-model space fail to account for the measured q dependences of E1, M1, and E2 form factors beyond q=2 fm^-1. On the other hand, form factor shapes observed for M2 and M4 multipoles are satisfactorily described to q=4 fm^-1 within the minimal 1ħω configuration space.