The Resonaances discussion of the $4$ sigma CDF bump points out an intriguing peak around $275$ GeV, suggested as a potential origin for the bump. Is this a sign of a new top quark, such as a mirror quark? At the fixed top quark Koide scale of $23$ GeV, the top masses lie around $275$ GeV for a range of candidate mirror phases, such as $(\pi/2 - 2/9)/3$, using Dave's $r$ parameter for the phase. In fact, the phase $\pi/2$ gets us close to $275$ GeV. Recall that mirror quarks might be suggested by the existence of mirror neutrinos, whose known phases are used to confirm the MINOS measurement of their mass differences.
But would we not already have observed lighter mirror quarks? In the abovementioned Koide triplet, the lightest quark has a mass of roughly $14$ GeV. As always, nothing is nearly as massive as the top, or its mirror. For small Koide phases, using Dave's $r$ parameter, the top mass is around $150$ GeV. Something to ponder.
6 years ago