  We conjecture that QCD can be tuned to an infrared limit cycle in the
three-nucleon system by adjusting the up and down quark masses to critical
values at which the binding energies of the deuteron and its spin-singlet
partner are tuned to zero. At the critical point, the triton would have
infinitely many arbitrarily-shallow excited states with the ratio of the
binding energies of successive states approaching a universal constant close to
515.
