c

Leptoquarks are hypothetical particles carrying both baryon number (B) and lepton number (L). The possible quantum num-bers of leptoquark states can be restricted by assuming that their direct interactions with the ordinary SM fermions are di-mensionless and invariant under the standard model (SM) gauge group. Table 1 shows the list of all possible quantum numbers with this assumption [1]. The columns of SU(3)C, SU(2)W, and U(1)Y in Table 1 indicate the QCD representation, the weak isospin representation, and the weak hypercharge, respec-tively. The spin of a leptoquark state is taken to be 1 (vector leptoquark) or 0 (scalar leptoquark). Table 1: Possible leptoquarks and their quan-tum numbers