Decadal Mission for the New Physics Higgs/Flavor Era

Abstract

The LHC has not discovered any New Physics beyond the anticipated $h(125)$ boson, and new ideas abound for out-of-the-box searches, or Effective Field Theories with multi-TeV cutoff. But, have we exhausted dimension-4 operators involving sub-TeV particles that are {\it not} exotic (non-XLP)? We advocate the existence of an extra Higgs doublet that carry extra Weinberg couplings, where {\it emergent} mass-mixing hierarchies {\it and} alignment have hidden their effects very well so far. $\mathcal{O}(1)$ Higgs quartics can induce first order electroweak phase transition and imply sub-TeV $H,A,H^{\pm }$ spectrum. The extra Weinberg couplings, led by ${\rho }_{tt}$ and ${\rho }_{tc}$ at $\mathcal{O}(1)$, can drive electroweak baryogenesis, while $|{\rho }_{ee}/{\rho }_{tt}|\propto {\lambda }_e/{\lambda }_t$, the ratio of usual electron and top Weinberg couplings, can tame electron EDM. Finding these extra Higgs bosons via $cg\to tH/A\to tt\bar{c}$, $tt\bar{t}$ and $cg\to b{H}^{+}\to bt\bar{b}$ processes (and those allowed by Higgs boson splittings) at the LHC, and pushing the flavor frontier to break the flavor code, would usher in a new Higgs/flavor era. A new scale at 10--20 TeV, possibly related to the Landau pole of the scalar sector, may emerge.

Comments: 18 pages, 9 figures, invited review to be submitted to Chinese Journal of Physics