Color-Singlet and Color-Octet qq Quark Matters

Quarks and antiquarks carry color and electric charges and belong to the color-triplet 3 group and the color-antitriplet 3- group respectively. The product groups of 3 and 3- consist of the color-singlet 1 and the color-octet 8 subgroups. Therefore, quarks and antiquarks combine to form color-singlet [qq-]1 quark matter and color-octet [qq-]8 quark matter. The color-octet quark matter corresponds to the conventional understanding of qq- quark matter whereas the colorsinglet quark matter remains largely unexplored and is proposed here for investigation. The color-singlet quark matter with two flavors can be separated into charged and neutral colorsinglet quark matters. In the neutral color-singlet quark matter, the quark and the antiquark interacting only via the QED interaction may form stable and confined colorless QED mesons non-perturbatively at about 17 MeV and 38 MeV (PRC81,064903(2010) and JHEP(2020(8), 165)). It is proposed that the possible existence of such QED mesons may be a signature of the neutral color-singlet quark matter at T = 0. The observations of the anomalous soft photons at CERN, and the anomalous bosons with masses of about 17 at ATOMKI, DUBNA, and HUS, and about 38 MeV at DUBNA, provide promising experimental indications for the existence of such QED mesons, pending further confirmations.