Speaker
Description
We propose a $E_6$-inspired Pati-Salam (PS) model that naturally accommodates multi-TeV leptoquark gauge bosons, $X_{\mu}$, while incorporating a softly broken $Z_2$ 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 right-handed 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, and the distinctive signature of vector-like down-type quark carrying a fractional baryon number of $ \pm 2/3$.
