▁ex otic ▁Standard ▁Model ▁states ▁might ▁apply ▁to ▁these ▁new ▁unique ▁particles . ▁One ▁proposed ▁state ▁is ▁the ▁hy brid ▁state ▁of ▁a ▁qu ark , ▁anti - qu ark , ▁and ▁a ▁gl u on , ▁sometimes ▁mentioned ▁with ▁charm ▁qu arks ▁as ▁an ▁excited ▁char mon ium . ▁A ▁multi - qu ark ▁state ▁of ▁ 4 ▁or ▁more ▁qu arks ▁( t etra qu ark , ▁p enta qu ark , ▁etc .) ▁is ▁also ▁proposed ▁as ▁well ▁as ▁a ▁mole c ule - like ▁state ▁of ▁multiple ▁mes ons . ▁While ▁each ▁of ▁these ▁three ▁types ▁of ▁states ▁have ▁had ▁some ▁success ▁of ▁explaining ▁the ▁newly ▁discovered ▁particle , ▁a ▁complete ▁explanation ▁has ▁not ▁been ▁found . ▁ ▁Types ▁of ▁particle ▁The ▁first ▁char mon ium ▁state ▁with ▁an ▁un pred icted ▁mass ▁was ▁X ( 3 8 7 2 ). ▁The ▁Belle ▁collaboration ▁was ▁searching ▁for ▁the ▁B ▁-> ▁K ▁ π + ▁ π - ▁J / ψ ▁decay ▁when ▁they ▁discovered ▁a ▁peak ▁in ▁the ▁ π + ▁ π - ▁J / ψ ▁invariant ▁energy ▁at ▁ 3 8 7 2 ▁with ▁J CP ▁quantum ▁numbers ▁of ▁ 1 ++ . ▁X ( 3 8 7 2 ) ▁was ▁quickly ▁confirmed ▁by ▁Ba Bar , ▁C DF , ▁and ▁D 0 . ▁The ▁mass ▁of ▁X ( 3 8 7 2 ) ▁is ▁close ▁to ▁the ▁mass ▁of ▁D D * ▁and ▁makes ▁it ▁a ▁candidate ▁as ▁a ▁mes on ▁mole c ule ▁or ▁a