Search for Maximal Flavor Violating Scalars in Same-Charge Lepton Pairs in $p\bar{p}$ Collisions at $\sqrt{s} = 1.96$ TeV

TL;DR

This paper searches for signs of Maximal Flavor Violation scalars in same-charge lepton pairs in proton-antiproton collisions, setting limits on their properties based on collider data, with no significant signal observed.

Contribution

It provides the first experimental search for MxFV scalars in same-charge lepton pairs at the Tevatron, establishing constraints on their coupling and mass.

Findings

No significant excess of events observed over background.

Limits set on the coupling $\xi_{13}$ for scalar masses 180-300 GeV/$c^2$.

Approximately 11 signal events expected for certain parameters.

Abstract

Models of Maximal Flavor Violation (MxFV) in elementary particle physics may contain at least one new scalar SU$(2)$ doublet field $\Phi_{FV} = (\eta^0,\eta^+)$ that couples the first and third generation quarks ($q_1,q_3$) via a Lagrangian term $\mathcal{L}_{FV} = \xi_{13} \Phi_{FV} q_1 q_3$. These models have a distinctive signature of same-charge top-quark pairs and evade flavor-changing limits from meson mixing measurements. Data corresponding to 2 fb$^{-1}$ collected by the CDF II detector in $p\bar{p}$ collisions at $\sqrt{s} = 1.96$ TeV are analyzed for evidence of the MxFV signature. For a neutral scalar $\eta^0$ with $m_{\eta^0} = 200$ GeV/$c^2$ and coupling $\xi_{13}=1$, $\sim$ 11 signal events are expected over a background of $2.1 \pm 1.8$ events. Three events are observed in the data, consistent with background expectations, and limits are set on the coupling $\xi_{13}$ for $m_{\eta^0} = 180-300$ GeV/$c^2$.