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Big bang nucleosynthesis provides the earliest probe of standard modelphysics, at a time when the universe was less than a thousand seconds old. Itdetermines the abundances of the lightest nuclides, which give rise to thesubsequent history of the visible matter in the Universe. This work derives new$^7$Be(n,p)$^7$Li thermonuclear reaction rates based on all availableexperimental information. This reaction sensitively impacts the primordialabundances of $^{7}$Be and $^7$Li during big bang nucleosynthesis. Wecritically evaluate all available data and disregard experimental results thatare questionable. For the nuclear model, we adopt an incoherent sum ofsingle-level, two-channel R-matrix approximation expressions, which areimplemented into a hierarchical Bayesian model, to analyze the remaining sixdata sets we deem most reliable. In the fitting of the data, we consistentlymodel all known sources of uncertainty, including discrepant absolutenormalizations of different data sets, and also take the variation of theneutron and proton channel radii into account, hence providing less biasedestimates of the $^7$Be(n,p)$^7$Li thermonuclear rates. From the resultingposteriors, we extract R-matrix parameters ($E_r$, $\gamma^2_n$, $\gamma^2_p$)and derive excitation energies, partial and total widths. Our fit is sensitiveto the contributions of the first three levels above the neutron threshold.Reaction rates were computed by integrating 10,000 samples of the reduced crosssection. Our $^7$Be(n,p)$^7$Li thermonuclear rates have uncertainties between1.5% and 2.0% at temperatures of $\leq$1 GK. We compare our rates to previousresults and find that the $^7$Be(n,p)$^7$Li rates most commonly used in bigbang simulations have too optimistic uncertainties.

Hierarchical Bayesian Thermonuclear Rate for the $^7$Be(n,p)$^7$Li Big Bang Nucleosynthesis Reaction