Baryonic Z' Explanation for the CDF Wjj Excess

TL;DR

This paper proposes a baryonic Z' model to explain the CDF Wjj excess, demonstrating it can fit the data within existing experimental constraints and suggesting further collider tests for validation.

Contribution

The paper introduces a baryonic Z' model that accounts for the CDF anomaly while satisfying constraints from UA2 and LEP, and proposes new collider signatures for testing.

Findings

The model explains the Wjj excess within experimental constraints.

Associated production channels can be used to test the model.

Improved cuts and systematics enhance detection prospects.

Abstract

The latest CDF anomaly, the excess of dijet events in the invariant-mass window 120-160 GeV in associated production with a $W$ boson, can be explained by a baryonic $Z'$ model in which the $Z'$ boson has negligible couplings to leptons. Although this $Z'$ model is hardly subject to the Drell-Yan constraint from Tevatron, it is constrained by the dijet data from UA2 ($\sqrt{s} = 630$ GeV), and the precision measurements at LEP through the mixing with the SM $Z$ boson. We show that under these constraints this model can still explain the excess in the M_{jj} \sim 120 - 160 GeV window, as well as the claimed cross section $\sigma(W Z') \sim 4$ pb. Implications at the Tevatron would be the associated production of $\gamma Z',\; Z Z'$, and $Z'Z'$ with the $Z' \to jj$. We show that with tightened jet cuts and improved systematic uncertainties both $\gamma Z' \to \gamma jj$ and $Z Z' \to \ell^+ \ell^- j j$ channels could be useful to probe this model at the Tevatron.