Improved convergence of chiral effective field theory for 1S0 of NN scattering

TL;DR

This paper introduces a modified effective field theory incorporating a dibaryon to account for fine-tuning in NN scattering, leading to improved convergence of the 1S0 partial-wave amplitude.

Contribution

It develops a new EFT with a dibaryon to handle fine-tuning, avoiding perturbative one-pion exchange, and demonstrates rapid convergence up to order Q.

Findings

Rapid convergence of the 1S0 partial-wave amplitude achieved

Effective field theory with dibaryon accounts for fine-tuning

Improved theoretical description of NN scattering in 1S0 channel

Abstract

It is argued that the fine-tuning due to the unnaturally large, generalized effective range in the 1S0 channel of NN scattering must be incorporated in order for one to obtain satisfactory convergence for chiral effective field theory. Without the proposition of perturbative one-pion exchange, an effective field theory with the spin-0, isospin-1 dibaryon is developed to account for this fine-tuning, and is demonstrated up to O(Q) where the leading irreducible two-pion exchange arises. The approach shown in the paper results in rapid convergence of the 1S0 partial-wave amplitude.