Neutral meson mixing induced by box diagrams in the 3-3-1 model with heavy leptons

TL;DR

This paper analyzes how box diagrams in the 3-3-1 model with heavy leptons affect neutral meson mixing, showing that new physics contributions can be suppressed, making standard model effects dominant in certain parameter ranges.

Contribution

It provides a detailed calculation of box diagram contributions in the 3-3-1 model, including effects of a 125 GeV scalar with non-diagonal quark couplings, and discusses parameter regions where new physics is suppressed.

Findings

New physics contributions can be suppressed by interference effects.

Standard model contributions may dominate in certain parameter ranges.

Results are applicable to the minimal 3-3-1 model without sextet.

Abstract

We consider in the 3-3-1 model with heavy leptons the box contributions to the mass difference in $K$ and $B$ neutral mesons induced by neutral (pseudo)scalars, exotic charged quarks, singly and doubly charged scalar and gauge bosons. In particular, we include the effects of a real scalar with mass near 125 GeV but with non-diagonal couplings to quarks. We show that, as in the tree level case, there are ranges of the parameters in which these contributions can be enough suppressed by negative interference among several amplitudes. Hence, in this model these $\Delta F=2$ processes may be dominated by the standard model contributions. In addition, our results are valid in the minimal 3-3-1 model without the sextet.