Until a few years ago, it was believed that some experiments showed the existence of "pentaquarks" exotic baryons made of four quarks and one antiquark.
It is a candidate for being a tetraquark: a particle composed of two quarks and two antiquarks.
This type of reaction will occur between any baryon (particle consisting of three quarks) and any antibaryon (consisting of three antiquarks).
Every quark carries one of three color charges of the strong interaction; antiquarks similarly carry anticolor.
The two types of hadrons are the mesons (one quark, one antiquark) and the baryons (three quarks).
It is the equivalent of the phi (strange quark, strange antiquark), psi (charm quark, charm antiquark) and upsilon (bottom quark, bottom antiquark) mesons.
The experiment will also examine the modifications to the antiquark structure of the proton from nuclear binding.
Because mesons are made of one quark and one antiquark, they can be found in triplet and singlet spin states.
