Extended Color Twin Higgs

Abstract

We describe a novel variation of the mirror Twin Higgs model in which the color gauge group in both sectors is extended to SU(4$)_c$ and spontaneously broken to SU(3$)_c$ exclusively in the visible sector. Through this process, the mirror $Z_2$ symmetry is spontaneously broken, allowing for a phenomenologically viable electroweak vacuum alignment. This structure produces interesting collider signatures, including heavy vectors and fermions with fractional electric charges. The twin sector, with unbroken SU(4$)_c$, produces interesting cosmological characteristics, such as the possibility to reduce $\Delta N_\text{eff}$ and stable spin-0 baryons. The enlarged top quark sector required by the extended color gauge symmetry preserves naturalness, with even less tuning than the original twin Higgs in many circumstances.