  Lattice QCD simulations have shown unequivocally that the transition from
hadrons to quarks and gluons is a crossover when the baryon chemical potential
is zero or small. Many model calculations predict the existence of a critical
point at a value of the chemical potential where current lattice simulations
are unreliable. We show how to embed a critical point in a smooth background
equation of state so as to yield the critical exponents and critical amplitude
ratios expected of a transition in the same universality class as the
liquid-gas phase transition and the 3D Ising model. The resulting equation of
state has parameters which may be inferred by hydrodynamic modeling of heavy
ion collisions in the Beam Energy Scan II at the Relativistic Heavy Ion
Collider or in experiments at other accelerators.
