Low energy expansion in the three body system to all orders and the triton channel Original Research Article

We extend and systematise the power counting for the three-body system, in the context of the “pion-less” Effective Field Theory approach, to all orders in the low-energy expansion. We show that a sub-leading part of the three-body force appears at the third order and delineate how the expansion proceeds at higher orders. After discussing the renormalisation issues in a simple bosonic model, we compute the phase shifts for neutron–deuteron scattering in the doublet S wave (triton) channel and compare our results with phase shift analysis and potential model calculations.