GeV/c.

For antihelium, the coalescence prescription is nearly identical. When more than three particles are involved there are two obvious ways to define the coalescence mechanism. One can either require that each of the relative momenta lie within a ‘minimum bounding momentum-sphere’ of diameter $p_0^{A=3}$ (dubbed MBS here), or we can require that the relative invariant 4-momenta of each particle-pair is less than $p_0^{A=3}$ (dubbed particle-pairing or PP here). If we consider a triangle with sides equal to the relative momenta of two particles, the two methods coincide for obtuse and right triangles. For acute triangles, however, the value of $p_0^{A=3}$ required to form a nucleus can be up to 15% larger than the PP case. The MBS prescription also avoids unnatural kinks in the required value of $p_0^{A=3}$ as the inclusive angle of this triangle is varied. We therefore choose MBS which *always* underestimates the yield with respect to the particle-pairing method for identical values of $p_0^{A=3}$. From a simple Monte-Carlo which assumes an isotropic distribution of nucleon momenta, we estimate that MBS produces only approximately 6% fewer antihelium, although this difference becomes compounded exponentially for heavier elements. Without an understanding of the strong dynamics of nuclear formation, it 