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DOE OSTI · 1463318

Constraining transfer cross sections using Bayes' theorem

Lovell, A. E.·Nunes, F. M.
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Abstract

Background: Being able to rigorously quantify the uncertainties in reaction models is crucial to moving this field forward. Even though Bayesian methods are becoming increasingly popular in nuclear theory, they have yet to be implemented and applied in reaction theory problems. Purpose: The purpose of this work is to investigate, using Bayesian methods, the uncertainties in the optical potentials generated from fits to elastic-scattering data and the subsequent uncertainties in the transfer predictions. We also study the differences in two reaction models where the parameters are constrained in a similar manner, as well as the impact of reducing the experimental error bars on the data used to constrain the parameters. Method: We use Bayes' theorem combined with a Markov chain Monte Carlo to determine posterior distributions for the parameters of the optical model, constrained by neutron-, proton-, and/or deuteron-target elastic scattering. These potentials are then used to predict transfer cross sections within the adiabatic wave approximation or the distorted-wave Born approximation. Results: We study a number of reactions involving deuteron projectiles with energies in the range 10–25 MeV/nucleon on targets with mass A = 48–208. The case of 48 Ca(d,p) 49 Ca transfer to the ground state is described in detail. A comparative study of the effect of the size of experimental errors is also performed. Five transfer reactions are studied, and their results are then compiled in order to systematically identify trends.

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73 NUCLEAR PHYSICS AND RADIATION PHYSICSUncertainty Quanti cationdirect reaction theoryelastic scatteringinelastic scatteringoptical, coupled-channel & distorted wave modelstransfer reactions

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BibTeXRIS

Lovell, A. E., Nunes, F. M.. 2018-06-21. Constraining transfer cross sections using Bayes' theorem. https://doi.org/10.1103/physrevc.97.064612

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