Relativistic SU(3) chiral baryon-baryon Lagrangian up to order q^2

Understand

We construct the most general chiral effective Lagrangian for baryon-baryon contact interactions in flavor SU(3) up to order q^2 using a covariant power counting.

• A subset of these contact terms contributes to the baryon-baryon potential in chiral effective field theory.
• The Lorentz invariant effective Lagrangian is constructed to fulfill the invariance under charge conjugation, parity transformation, Hermitian conjugation and the local chiral symmetry group SU(3)_L x SU(3)_R.
• Goldstone bosons and external fields are included as well, thus providing additional four-baryon contact vertices involving e.g.