The complete quantification of parametric uncertainties in (d,p) transfer reactions

TL;DR

This paper quantifies the full parametric uncertainties in (d,p) transfer reactions by combining optical potential and bound state parameters using Bayesian methods, significantly reducing uncertainties with experimental constraints.

Contribution

It extends previous uncertainty quantification by including bound state parameters and demonstrates the impact of experimental constraints on transfer reaction uncertainties.

Findings

Using asymptotic normalization coefficients reduces uncertainty in transfer observables.

Constraints from elastic scattering and ANCs decrease the 68% confidence interval uncertainties.

Uncertainty in transfer cross sections drops from ~140-185% to ~15-30% with constraints.

Abstract

Previous work quantified the uncertainty associated with the optical potentials between the nucleons and the target. In this study, we extend that work by also including the parameters of the mean field associated with the overlap function of the final bound state, thus obtaining the full parametric uncertainty on transfer observables. We use Bayesian Markov Chain Monte Carlo simulations to obtain parameter posterior distributions. We use elastic-scattering cross sections to constrain the optical potential parameters and use the asymptotic normalization coefficient of the final state to constrain the bound state interaction. We then propagate these posteriors to the transfer angular distributions and obtain confidence intervals for this observable. We study (d,p) reactions on 14C, 16O, and 48Ca at energies in the range E=10-24 MeV. Our results show a strong reduction in uncertainty by using the asymptotic normalization coefficient as a constraint, particularly for those reactions most sensitive to ambiguities in the mean-field. For those reactions, the importance of constraining the bound state interaction is equal to that of constrain the optical potentials. The case of 14C is an outlier because it populates a halo state, and the observable is less sensitive to the nuclear interior. We conclude that when minimal constraints are used on the parameters of the nucleon-target interaction, the 68% confidence interval uncertainties on the differential cross sections are very large (~ 140-185%). However, if elastic-scattering data and the asymptotic normalization coefficient are used in the analysis, with an error of 10% (5%), this uncertainty reduces to ~30% (~15%).