First Extraction of the Matter Radius of ${}^{132}$Sn via Proton Elastic Scattering at 200 MeV/Nucleon

The angular distribution of the differential cross sections for proton elastic scattering from ${}^{132}$Sn at 196-210 MeV/nucleon was successfully measured over a momentum transfer range of 0.80 to 2.1 fm${}^{-1}$. Using a relativistic impulse approximation, the root-mean-square matter radius of ${}^{132}$Sn was extracted to be $4.758_{-0.024}^{+0.023}$ fm, which was compared with the state-of-the-art ab initio calculations. Combined with the charge radius measured at ISOLDE, there are no theoretical calculations consistent with both matter and charge radii within the experimental errors.