Speaker
Description
We propose an $E_6$ inspired Pati-Salam (PS) model that naturally accommodates multi-TeV leptoquark gauge bosons, X, with a softly broken discrete $Z_2$ symmetry. Standard Model (SM) fermions are $Z_2$-even in this framework, whereas exotic fermions are $ Z_2$-odd. An interesting feature of the model is that the PS gauge bosons are $Z_2$-odd, enabling them to couple exclusively between ordinary and exotic fermions, except in the down-type sector, where mixing arises due to the soft breaking of $Z_2$. This structure leads to helicity suppression of meson decays at the tree level, with unsuppressed contributions appearing only at the one-loop level, which allows a lower PS breaking scale. Such a scale offers exciting collider prospects, particularly for probing leptoquark gauge bosons, as well as the distinctive signature of a vector-like down-type quark carrying a fractional baryon number of -$\frac{2}{3}$.
