Unitarity Constraints on non-minimal Universal Extra Dimensional Model

TL;DR

This paper investigates unitarity constraints in a non-minimal Universal Extra Dimensional model, deriving bounds on boundary parameters and KK-masses based on scattering amplitude analyses.

Contribution

It provides the first unitarity-based bounds on boundary-localized parameters in non-minimal UED models, considering multiple KK modes.

Findings

Unitarity constraints impose upper bounds on boundary-localized parameters.

The bounds decrease as the number of KK modes increases.

Results are independent of the inverse compactification radius.

Abstract

We examine the unitarity constraints in gauge and scalar sectors of non-minimal Universal Extra Dimensional model. We show that some of the tree-level two-body scattering amplitudes in gauge and scalar sectors do not respect partial wave unitarity. Unitarity analysis of this model leads to an upper bound on corresponding boundary-localized (BLT) parameter which depends on the maximum number of Kaluza-Klein (KK) mode considered in the analysis. This upper bound of the relevant BLT parameter decreases with the increasing KK-modes. The results are, in effect, independent of the inverse of compactifiaction radius. The upper bound on BLT parameter also results in a lower bound on gauge and scalar KK-masses.