How well do we understand ⁷Be + p → ⁸B + γ? An Effective Field Theory perspective

¹ Physics Department, University of Washington, Seattle, WA 98195, USA
² Institute of Nuclear and Particle Physics and Department of Physics and Astronomy, Ohio University, Athens, OH 45701, USA
³ Department of Physics, San Diego State University, 5500 Campanile Drive, San Diego, California 92182-1233, USA
⁴ Department of Physics and Astronomy, University of South Carolina, 712 Main Street, Columbia, South Carolina 29208, USA

^a e-mail: xilinz@uw.edu
^b e-mail: nollett@mailbox.sc.edu
^c e-mail: phillid1@ohio.edu

Published online: 25 March 2016

Abstract

We have studied the ⁷Be(p, γ)⁸B reaction in the Halo effective field theory (EFT) framework. The leading order (LO) results were published in Ref. [1] after the isospin mirror process, ⁷Li(n, γ)⁸Li, was addressed in Ref. [2]. In both calculations, one key step was using the final shallow bound state asymptotic normalization coefficients (ANCs) computed by ab initio methods to fix the EFT couplings. Recently we have developed the next-to-LO (NLO) formalism [3], which could reproduce other model results by no worse than 1% when the ⁷Be-p energy was between 0 and 0:5 MeV. In our recent report [4], a different approach from that in Ref. [1] was used. We applied Bayesian analysis to constrain all the NLO-EFT parameters based on measured S-factors, and found tight constraints on the S -factor at solar energies. Our S (E = 0 MeV) = 21.3 ± 0.7 eV b. The uncertainty is half of that previously recommended. In this proceeding, we provide extra details of the Bayesian analysis, including the computed EFT parameters’ probability distribution functions (PDFs) and how the choice of input data impacts final results.