Covariant coalescence model for relativistically expanding systems

We develop a covariant coalescence model for relativistically expanding fireballs formed in high-energy nuclear collisions and apply it to predict the formation rate of light nuclei and antinuclei (d,d¯) as well as of the H dibaryon and the pentaquark ${\mathit{P}}^0$ in relativistic heavy-ion collisions at the CERN Super Proton Synchrotron and the Brookhaven Alternating Gradient Synchrotron Accelerators. For the d¯ and H, our predictions differ significantly from previous results based on a nonrelativistic analysis.