Signatures of Leptoquarks at the LHC and Right-handed Neutrinos

In this paper, we argue that an extension of the Standard Model with a single leptoquark and three right-handed neutrinos can explain the excess in the first-generation leptoquark search at the LHC. We also find that when the leptoquark has similarly sized couplings to all three generations, it produces additional signals which will soon be tested in the second- and third-generation leptoquark searches, as well as in decay channels consisting of two mixed flavor leptons and two jets. If the leptoquark only couples to the first generation, on the other hand, two of the right-handed neutrinos need to be fairly degenerate in mass with the leptoquark while the other right-handed neutrinos mass should be much lighter. This hierarchical structure could explain dark matter and the baryon asymmetry of the Universe. These simple models may be regarded as benchmark models for explaining the excess, which can be tested in the next stage of the LHC running.