This particle is the heaviest theorized to occur in a stable three-particle mixture proposed by Bodler and Witten. The “eta–eta-prime puzzle” concerns two composite particles with different numbers of this particle. Pair production of this particle occurring from gluon fusion is used (-5[1])to determine (-5[1])the formation of QGPs. (10[1]-5[1])This particle occurs in the lightest lambda baryons. (-5[1])Electric charge and a property (-5[1])characterizing this particle were proposed to describe (10[2])the “eightfold (10[1])way” (10[1])classification (10[2]-5[2])of (10[1])mesons (10[2]-5[1])and (-5[1])hadrons. (10[1])This fundamental particle is the lightest to have an isospin of zero. The unusually long lifetime of kaons is due to this (10[1])particle, (-5[1])since they consist of one of these second-generation particles along (-5[1])with an up or down quark. (10[1])For 10 points, name this quark paired with charm. (10[8])■END■ (10[27]0[1])