New Flavor Interactions at the LHC

TL;DR

This paper explores the potential for discovering a new gauge boson at the LHC that couples predominantly to third-family fermions, focusing on its production, detection, and implications for flavor physics.

Contribution

It introduces a model for a third-family-coupled gauge boson at around 1 TeV and analyzes strategies for its detection and the effects of family mixing.

Findings

The $X$ boson can be reconstructed from $ au^+ au^-$ final states.

Specific cuts can enhance the signal over background.

Mass mixing influences the $X$ boson couplings and potential $Z$ mixing.

Abstract

For a new family-nonuniversal gauge interaction to be accessible at the LHC it will most likely couple preferentially to the third family. By coupling to all members of the third family the production of a new gauge boson (the $X$ with $M_X\approx1$ TeV) will lead to final states with a distinctive $\tau^+\tau^-$ pair. We study the mass reconstruction of the $X$ and the cuts that can enhance signal to background. The $X$ boson should be associated with the physics of flavor and in the simplest picture a fourth family. We discuss how the mass mixing between the third and fourth families affects the $X$ couplings and a possible mixing with the $Z$.