Zero-energy neutron-triton and proton-Helium-3 scattering with \eftnopi

Understand

Model-independent constraints for the neutron-triton and proton-Helium-3 scattering lengths are calculated with a leading-order interaction derived from an effective field theory without explicit pions.

• Using the singlet neutron-proton scattering length, the deuteron, and the triton binding energy as input, the predictions $\ants=9.2\pm2.6 $fm, $\antt=7.6\pm1.6 $fm, $\aphes=3.6\pm0.32 $fm, and $\aphet=3.1\pm 0.23 $fm are obtained.
• The calculations employ the resonating group method and include the Coulomb interaction when appropriate.
• The theoretical uncertainty is assessed via a variation of the regulator parameter of the short-distance interaction from $400 $MeV to $1.6 $GeV.