Uncertainty quantification due to optical potentials in models for (d ,p ) reactions
Abstract
Background: Recent work has studied the uncertainty in predictions for A (d ,p )B reactions using the distorted-wave Born approximation (DWBA), coming from the parametrization of the effective d A interactions [Lovell et al. Phys. Rev. C 95, 024611 (2017), 10.1103/PhysRevC.95.024611]. There are different levels of sophistication in reaction theories for one-nucleon transfer reactions, including the adiabatic wave approximation (ADWA) which takes deuteron breakup into account to all orders.
Purpose: In this paper, we quantify the uncertainties associated with the ADWA method that come from the parametrization of the NA interactions and compare ADWA with DWBA. Method: Similar to Lovell et al. [Phys. Rev. C 95, 024611 (2017), 10.1103/PhysRevC.95.024611], we use nucleon elastic-scattering data on a wide variety of targets at the appropriate incoming and outgoing energies to constrain the optical potential input to the ADWA theory. Pulling from the χ2 distribution, we obtain 95% confidence bands for the elastic distributions. From the resulting parameters, we predict 95% confidence bands for the (d ,p ) transfer cross sections. Results obtained with the standard uncorrelated χ2 are compared to those using the correlated χ2 of Lovell et al. [Phys. Rev. C 95, 024611 (2017), 10.1103/PhysRevC.95.024611]. We also repeat the DWBA calculations for the exact same reactions for comparison purposes. Results: We find that NA elastic-scattering data provide a significant constraint to the interactions, and, when the uncertainties are propagated to the transfer reactions using ADWA, predictions are consistent with the transfer data. Conclusions: The angular distributions for ADWA differ from those predicted by DWBA, particularly at small angles. As in Lovell et al. [Phys. Rev. C 95, 024611 (2017), 10.1103/PhysRevC.95.024611], confidence bands obtained using the uncorrelated χ2 function are unrealistically narrow and become much wider when the correlated χ2 function is considered. For most cases, the uncertainty bands obtained in ADWA are narrower than DWBA when using elastic data of similar quality and range. However, given the large uncertainties predicted from the correlated χ2 function, at this point, the transfer data cannot discriminate between these two methods.- Publication:
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Physical Review C
- Pub Date:
- October 2018
- DOI:
- 10.1103/PhysRevC.98.044623
- arXiv:
- arXiv:1810.06129
- Bibcode:
- 2018PhRvC..98d4623K
- Keywords:
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- Nuclear Theory
- E-Print:
- 10 pages, 7 figures