Contributions of gauge and scalar leptoquarks to KL0→ li+lj- and B0→ li+lj- decay and constraints on leptoquark masses from the decays KL0→ e±μ± and B0→ e±τ±

The contributions of vector and scalar leptoquarks to the branching ratios for KL0→ li+lj- and B0→ li+lj- decays within a minimal model featuring a four-color symmetry of the vector type and the Higgs mechanism of mass generation for quarks and leptons are calculated along with the contributions of chiral leptoquarks that are predicted by a four-color symmetry of the chiral type. Limits on the masses of gauge (vector and chiral) and scalar leptoquarks are obtained from data on the decays KL0→ e±μ± and B0→ e±τ±. It is shown that, in contrast to what we have for gauge leptoquarks, the limits on the masses of scalar leptoquarks are much more lenient, on the order of the lower limits on their masses from direct searches for leptoquarks. Searches for such scalar leptoquarks at LHC, as well as searches for B0→ li+lj- decays, are of interest.