Contributions of 2π exchange, 1π exchange, and contact three-body forces in NNLO chiral effective field theory to H<mml:…

Faddeev calculations of hypertriton (_Λ³H) separation energy are carried out, incorporating all next-to-next-to-leading-order ΛNN three-body forces (3BFs) in chiral effective field theory: 2π exchange, 1π exchange, and contact interactions. The 1π exchange and contact interactions are rewritten in a form suitable for evaluating partial-wave matrix elements. The Λ-deuteron folding potentials constructed from these 3BFs are evaluated to demonstrate their contributions to _Λ³H. The 1π exchange interaction provides an attractive effect in which the d-state component of the deuteron wave function plays an important role. The attractive contribution tends to cancel the repulsive ones from the 2π exchange and contact 3BFs. Faddeev calculations show that the net effect of the 3BFs to the _Λ³H separation energy is small in a range between -5 to $+20$ keV, depending on the $NN$ interaction used. Although these results are based on speculative low-energy constants, they can serve as a reference for further investigations.