Coupled channel analysis of proton scattering fromAr40

Angular distributions for the elastic and inelastic scattering of 29.6 and 35.1 MeV protons from the $0_1^{+}$ (g.s.), $2_1^{+}$ (1.461 MeV), $0_2^{+}$ (2.121 MeV), $2_2^{+}$ (2.524 MeV), $4_1^{+}$ (2.893 MeV), $2_3^{+}$ (3.208 MeV), $3_1^{\mathrm{-}}$ (3.681 MeV), and $2_4^{+}$ (3.919 MeV) states in ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ar}$ have been measured. Coupled channel calculations for the $0_1^{+}$, $2_1^{+}$, and $4_1^{+}$ levels have been performed in the framework of the rigid-rotor and harmonic vibrator models. Both analyses give satisfactory descriptions of the data with slight differences in the values of the deformation parameters. Two different analyses have been performed for the $0_2^{+}$ and $2_2^{+}$ levels. In the first, they have been considered as belonging to the β band and analyzed using the rotor-vibrator model. In the second, the coupling strengths between the various states have been treated as free parameters not linked to rigid ratios from models. The intrinsic quadrupole moment of the β band extracted from the two analyses is in agreement with that deduced from γ-decay studies. The distorted wave Born approximation has been used for the analysis of the $3_1^{\mathrm{-}}$ level. The $3_1^{\mathrm{-}}$, $2_3^{+}$, and $2_4^{+}$ levels have also been analyzed with different coupled channel calculations in which their coupling amplitudes to the ground state and $2_1^{+}$ state have been adjusted as free parameters.