Semi-aligned two Higgs doublet model

TL;DR

This paper introduces the semi-aligned two Higgs doublet model, a framework where heavy scalar particles induce flavor-changing neutral currents, providing a potential signature of left-right symmetric models independent of new gauge bosons.

Contribution

It proposes a novel semi-aligned two Higgs doublet model that isolates FCNC effects as signatures of left-right symmetry, with specific predictions for meson mixing and CP violation.

Findings

Predicts correlations among FCNC processes

Suggests meson mixing measurements can reveal the model

Provides a framework for indirect detection of left-right symmetry

Abstract

In the left-right symmetric model based on $SU(2)_L\times SU(2)_R\times U(1)_{B-L}$ gauge symmetry, there appear heavy neutral scalar particles mediating quark flavor changing neutral currents (FCNCs) at tree level. We consider a situation where such FCNCs give the only sign of the left-right model while $W_R$ gauge boson is decoupled, and name it "semi-aligned two Higgs doublet model" because the model resembles a two Higgs doublet model with mildly-aligned Yukawa couplings to quarks. We predict a correlation among processes induced by quark FCNCs in the model, and argue that future precise calculation of meson-antimeson mixings and CP violation therein may hint at the semi-aligned two Higgs doublet model and the left-right model behind it.