Leading three-baryon forces from SU(3) chiral effective field theory

Leading three-baryon forces are derived within SU(3) chiral effective field theory. Three classes of irreducible diagrams contribute: three-baryon contact terms, one-meson exchange, and two-meson exchange diagrams. We provide the minimal nonrelativistic terms of the chiral Lagrangian that contribute to these diagrams. SU(3) relations are given for the strangeness S = 0 and -1 sectors. In the strangeness-zero sector we recover the well-known three-nucleon forces from chiral effective field theory. Explicit expressions for the Lambda NN chiral potential in isospin space are presented.