Simultaneous inference of effective range parameters and truncation uncertainty within effective field theory in 3He-α scattering

Artikel i vetenskaplig tidskrift, 2026

We extend previous halo effective field theory analyses of low-energy elastic scattering of 3He-4He, including the 7 2 power counting scheme depending on the kinematic region. Therefore, we construct a theory uncertainty model at the partial wave amplitude level, allowing us to generate a sophisticated theory covariance matrix that captures the way the theory error structure changes as energy increases. We then perform a Bayesian analysis and simultaneously estimate the joint posterior distributions of the effective range theory parameters and the parameters that characterize the effective field theory truncation uncertainty. We compare two different analyses: no f-wave interactions for data up to Emax = 2.6 MeV and including f-wave interactions for data up to Emax = 5.5 MeV. The inferred breakdown scales in each analysis are consistent with previous work. We find that f-wave interactions are needed to describe data for Elab >= 3.6 MeV. f-wave resonance as an explicit degree of freedom. The presence of this resonance necessitates a changing