Higgs and Z-boson FCNC decays correlated with B-meson decays in littlest Higgs model with T-parity

TL;DR

This paper investigates correlated flavor-changing neutral current decays involving Z, Higgs, and B-mesons within the littlest Higgs model with T-parity, revealing potential deviations from Standard Model predictions under current experimental constraints.

Contribution

It provides a collective analysis of FCNC decays in the LHT model, highlighting possible significant deviations from SM predictions in Z and Higgs decays due to new flavor-changing interactions.

Findings

Z -> bs̄ branching ratio can be enhanced to 10^{-7}

H -> bs̄ decay can be suppressed below SM levels

Decays remain significantly affected within current experimental constraints

Abstract

In the littlest Higgs model with T-parity (LHT) new flavor-changing interactions between mirror fermions and the Standard Model (SM) fermions can induce various FCNC decays for B-mesons, Z-boson and Higgs boson. Since all these decays induced in the LHT model are correlated, we in this work perform a collective study for these decays, namely the Z-boson decay Z -> b s_bar, the Higgs boson decay h -> b s_bar, and the B-meson decays B -> X_s \gamma, B_s -> \mu^+\mu^- and B -> X_s \mu^+ \mu^-. We find that under the current experimental constraints from the B-decays, the branching ratios of both Z -> b s_bar and h -> b s_bar can still deviate from the SM predictions significantly. In the parameter space allowed by the B-decays, the branching ratio of Z -> b s_bar can be enhanced to 10^{-7} (about one order above the SM prediction) while h -> b s_bar can be much suppressed relative to the SM prediction (about one order below the SM prediction).