The Coulomb-breakup method to extract the cross section for neutron radiative capture at astrophysical energies is analyzed in detail. In particular, its sensitivity to the description of the neutron-core continuum is ascertained. We consider the case of 14 C(n, γ) 15 C for which both the radiative capture at low energy and the Coulomb breakup of 15 C into 14 C+n on Pb at 68 MeV/nucleon have been measured with accuracy. We confirm the direct proportionality of the cross section for both reactions to the square of the asymptotic normalization constant of 15 C observed by Summers and Nunes [Phys. Rev. C 78, 011601 (2008)], but we also show that the 14 C-n continuum plays a significant role in the calculations. Fortunately, the method proposed by Summers and Nunes can be improved to absorb that continuum dependence. We show that a more precise radiative-capture cross section can be extracted selecting the breakup data at forward angles and low 14 C-n relative energies.

Erratum: Reconciling Coulomb breakup and neutron radiative capture [Phys. Rev. C 96, 015801 (2017)]The idea to infer radiative-capture cross sections of astrophysical interest, viz. at low energy, from Coulomb-breakup measurements was first suggested by Baur et al. [1]. The latter reaction can be seen as an exchange of virtual photons between the initially bound projectile and the target and hence as the time-reversed reaction of the former in which the nucleus is synthesized by the fusion of two clusters and the emission of a photon. At the first order of the perturbation theory, it is possible to directly relate the Coulomb-breakup cross section to the radiative-capture one by a detailed balance [1][2][3]. Because breakup measurements can be performed at higher energies where the cross sections are higher and therefore easier to measure, many breakup experiments have been performed following this idea. Unfortunately, it has been shown later that significant higher-order effects in the breakup process spoil this nice picture [4,5].In Refs. [6,7], Summers and Nunes have suggested comparing accurate breakup calculations, i.e., including both the nuclear and the Coulomb interactions between the projectile and the target at all orders, to experimental data and to extract from this comparison the asymptotic normalization constant (ANC) for the bound state of the nucleus under investigation. This ANC can then be used to constrain radiative-capture calculations. They have tested their idea on the particular case of 15 C for which accurate measurements have been performed for both its Coulomb breakup [8] and its synthesis by radiative capture [9]. Their radiative-capture calculations, constrained by the Coulomb-breakup data, are in seemingly good agreement with the direct measurement [6,7]. A similar agreement has been obtained by Esbensen using a different model of the breakup reaction [10].In the original paper, we have pushed this idea further and studied its sensitivity to the description of the 14 C-n continuum. Albeit smaller than the role of the ANC of the ground state, this part of the description of the nucleus is not negligible as shown earlier in Ref. [11]. However, following Refs. [12,13], it is possible to account for this effect by selecting the breakup data at forward angle and low energy in the projectile continuum (see the original paper). In this way, it seemed that even better agreement could be obtained between direct and Coulomb-breakup estimates.This excellent agreement was obtained following the prescription of Summers and Nunes to rescale the low-energy data point, assuming it corresponded to a Maxwellian average on the neutron energy. Unfortunately, as pointed out by Esbensen and Reifarth [14], this is not the case. To be properly compared to the capture measurements, calculations should be averaged over the energy distribution of the neutron beams used in the experiment [15] (see Fig. 3 of Ref. [9]).In this Erratum, we perform this averaging in a systematic way for the 12 14 C-n potentials dev...

Coulomb breakup is used to infer radiative-capture cross sections at astrophysical energies. We test theoretically the accuracy of this indirect technique in the particular case of 15 C, for which both the Coulomb breakup to 14 C+n and the radiative capture 14 C(n,γ) 15 C have been measured. We analyse the dependance of Coulomb-breakup calculations on the projectile description in both its initial bound state and its continuum. Our calculations depend not only on the Asymptotic Normalisation Coefficient (ANC) of the 15 C ground state, but also on the 14 C-n continuum. This questions the method proposed by Summers and Nunes [Phys. Rev. C 78, 011601 (2008), ibid. 069908 (2008)], which assumes that an ANC can be directly extracted from the comparison of calculations to breakup data. Fortunately, the sensitivity to the continuum description can be absorbed in a normalisation constant obtained by a simple χ 2 fit of our calculations to the measurements. By restricting this fit to low 14 C-n energy in the continuum, we can achieve a better agreement between the radiative-capture cross sections inferred from the Coulomb-breakup method and the exact ones. This result revives the Coulomb-breakup technique to infer neutron radiative-capture capture to loosely-bound states, which would be very useful for r-and s-process modelling in explosive stellar environments. 78,

Coulomb breakup is used to infer radiative-capture cross sections at astrophysical energies. We test theoretically the accuracy of this indirect technique in the particular case of 15 C, for which both the Coulomb breakup to 14 C+n and the radiative capture 14 C(n,γ) 15 C have been measured. We analyse the dependence of Coulomb-breakup calculations on the projectile description in both its initial bound state and its continuum. Our calculations depend not only on the Asymptotic * Speaker.