Speaker
Description
Chiral effective field theory ($\chi$EFT) is an approach to describe the force between nucleons as arising from the more fundamental principles of quantum chromodynamics. A vital part is to have a power counting (PC) that quantifies the relative importance of the EFT order-by-order contributions to nuclear observables. The definition of the PC is not unique, and the fact that nuclear systems are non-perturbative makes finding a proper PC a non-trivial problem. We are investigating a PC [1] that is constructed to possess an infinite limit for the momentum cutoff, where sub-leading contributions to the interaction are treated in perturbation theory. In [2] we investigate this PC at leading order (LO) by analyzing the posterior probability densities of low-energy constants (LECs) in a Bayesian framework. In recent works, [3,4], we added up to third-order corrections to LO perturbatively and found a good description of both neutron-proton scattering cross sections and $S$-wave low-energy theorems. I will present these promising results and discuss our next steps towards a robust Bayesian inference of the LECs as well as the prospect of predicting properties of atomic nuclei.
[1] B. Long, C.J. Yang, Phys. Rev. C 86, 024001 (2012)
[2] O. Thim, E. May, A. Ekström, C. Forssén, Phys. Rev. C 108, 054002 (2023)
[3] O. Thim, A. Ekström, C. Forssén, arXiv:2402.15325 (2024)
[4] O. Thim, arXiv:2403.10292
