Antimatter with Heavy-Ion Beam

 Zhangbu Xu (BNL, for the STAR Collaboration)

We report the first observation of an antimatter hypernucleus, the antihypertriton. 
Our ability to produce and measure these exotic nuclei opens up the study of a new 
octant in the 3D chart of the nuclides along the antimatter and positive strangeness 
axes. The (anti)hypernuclei are believed to be produced at the final stage in relativistic 
heavy-ion collisions via the quantum wave-function overlapping (coalescence) of its 
constituents. Therefore, their yields provide an effective measure of the baryon-strangeness 
correlation. We discuss the contrasting results obtained at RHIC and AGS and their 
implications for RHIC beam energy scan program. Furthermore, we propose to 
search for other exotic antimatter (anti-alpha), and to create first antinucleus atomcules 
at RHIC for possible precision measurements of antinucleus masses.