We study the impact of triple-leptoquark interactions on matter stability for two specific proton decay topologies that arise at the tree- and one-loop level. We demonstrate that the one-loop level topology is much more relevant than the tree-level one when it comes to the proton decay signatures despite the usual loop-suppression factor. Since the two proton decay topologies necessarily coexist, our study renders any phenomenological limits inferred from the tree-level topology redundant for all practical purposes. We subsequently present detailed analysis of the triple-leptoquark interaction effects on the proton stability within one representative scenario to support our claim, where the scenario in question simultaneously features a tree-level topology that yields three-body proton decay p→e+e+e− and a one-loop level topology that induces two-body proton decays p→π0e+ and p→π+ν¯. We also provide a comprehensive classification of all non-trivial cubic and quartic contractions involving three scalar leptoquark multiplets that generate triple-leptoquark interactions of our interest, where in the latter case one of the scalar multiplets is the Standard Model Higgs doublet.
https://indico.ijs.si/event/1417/