Absolute spectroscopic factors from neutron knockout on the halo nucleus ¹⁵C

An accurate determination of the partial cross sections to four final states in the ⁹Be(¹⁵C,¹⁴C)X reaction has been carried out at 103 MeV∕nucleon. The cross section of 101(5) mb to the ¹⁴C 0⁺ ground state is of special interest. Relative to the theoretical cross section calculated on the basis of the spectroscopic factor from effective-interaction theory, this amounts to a quenching factor R_s=0.90(4)(5). Here the first number in parentheses is the experimental error, and the second is the error on the theoretical unit (reaction) cross section. The result gives support to the idea that weakly bound halolike states have quenching factors that approach unity, in contrast to factors of 0.5–0.6 characteristic of well-bound states in nuclei near stability.