We study low-lying multipole strength in neutron-halo nuclei. The strength depends only on a few low-energy constants: the neutron separation energy, the asymptotic normalization coefficient of the bound-state wave function, and the scattering length that contains the information on the interaction in the continuum. The shape of the transition probability shows a characteristic dependence on few scaling parameters and the angular momenta. The total $E1$ strength is related to the root-mean-square radius of the neutron wave function in the ground state and shows corresponding scaling properties. We apply our approach to the $E1$ strength distribution of ${}^{11}\mathrm{B}\mathrm{e}$.

• Received 22 June 2004

DOI:https://doi.org/10.1103/PhysRevLett.93.142502