Low-scale quark-lepton unification

We investigate the possibility that quarks and leptons are unified at a low energy scale much smaller than the grand unified scale. A simple theory for quark-lepton unification based on the gauge group $\mathrm{SU}(4{)}_C\otimes \mathrm{SU}(2{)}_L\otimes \mathrm{U}(1{)}_R$ is proposed. This theory predicts the existence of scalar leptoquarks which could be produced at the Large Hadron Collider. In order to have light neutrinos without fine-tuning, their masses are generated through the inverse seesaw mechanism.