Effective field theory analysis of the Coulomb breakup of the one-neutron halo nucleus ¹⁹ C

We analyse the Coulomb breakup of ¹⁹ C measured at 67A MeV at RIKEN. We use the Coulomb-Corrected Eikonal (CCE) approximation to model the reaction and describe the one-neutron halo nucleus ¹⁹ C within Halo Effective Field Theory (Halo EFT). At leading order we obtain a fair reproduction of the measured cross section as a function of energy and angle. The description is insensitive to the choice of optical potential, as long as it accurately represents the size of ¹⁸ C. It is also insensitive to the interior of the ¹⁹ C wave function. Comparison between theory and experiment thus enables us to infer asymptotic properties of the ground state of ¹⁹ C: these data put constraints on the one-neutron separation energy of this nucleus and, for a given binding energy, can be used to extract an asymptotic normalisation coefficient (ANC). These results are confirmed by CCE calculations employing next-to-leading order Halo EFT descriptions of ¹⁹ C: at this order the results for the Coulomb breakup cross section are completely insensitive to the choice of the regulator. Accordingly, this reaction can be used to constrain the one-neutron separation energy and ANC of ¹⁹ C.