Asymptotic Normalization Coefficient of 27P →26Si + p and Radius of 27P Halo

Abstract

The asymptotic normalization coefficient of the virtualdecay 27P → 26Si + p is extracted to be1840±240 fm−1 from the peripheral26Mg(d,p)27Mg reaction using charge symmetry of mirrorpair, for the first time. It is then used to derive therms radius of the valence proton in the ground state of 27P. Weobtain the rms radius ⟨r2⟩1/2 = 4.57±0.36 fm,significantly larger than the matter radius of 27P. The probabilityof the valence proton outside the matter radius of 27P is found tobe 73%. The present work supports the conclusion that the 27P groundstate has a proton halo structure.