Top-philic $Z'$ Forces at the LHC

TL;DR

This paper investigates the production and detection of a top-philic $Z'$ boson at the LHC, addressing theoretical subtleties, providing computational recipes, and exploring implications for B meson decay anomalies.

Contribution

It introduces a comprehensive analysis of top-philic $Z'$ models, clarifies theoretical issues in production calculations, and assesses collider constraints and discovery prospects.

Findings

Proper computation methods for $Z'+j$ production are established.

Future high-luminosity LHC runs can probe much of the relevant parameter space.

The study connects $Z'$ models to potential explanations of B meson decay anomalies.

Abstract

Despite extensive searches for an additional neutral massive gauge boson at the LHC, a $Z^\prime$ at the weak scale could still be present if its couplings to the first two generations of quarks are suppressed, in which case the production in hadron colliders relies on tree-level processes in association with heavy flavors or one-loop processes in association with a jet. We consider the low-energy effective theory of a top-philic $Z'$ and present possible UV completions. We clarify theoretical subtleties in evaluating the production of a top-philic $Z'$ at the LHC and examine carefully the treatment of an anomalous $Z'$ current in the low-energy effective theory. Recipes for properly computing the production rate in the $Z'+j$ channel are given. We discuss constraints from colliders and low-energy probes of new physics. As an application, we apply these considerations to models that use a weak-scale $Z'$ to explain possible violations of lepton universality in $B$ meson decays, and show that the future running of a high luminosity LHC can potentially cover much of the remaining parameter space favored by this particular interpretation of the $B$ physics anomaly.