Vacuum Stability Constraints and LHC Searches for a Model with a Universal Extra Dimension

TL;DR

If the Higgs boson mass is confirmed between 122-127 GeV, vacuum stability in minimal universal extra dimension models implies a lower cutoff, significantly impacting LHC search prospects for certain Kaluza-Klein states.

Contribution

This paper demonstrates how Higgs mass constraints affect the cutoff scale and phenomenology of minimal universal extra dimension models, altering LHC search expectations.

Findings

Lower cutoff scale required for vacuum stability at Higgs mass 122-127 GeV

Reduced prospects for detecting n=1 Kaluza-Klein states at the LHC

Potentially undetectable n=2 resonant states at the LHC

Abstract

If the new boson is lying in the narrow mass range between 122 - 127 GeV is confirmed to be a Higgs boson, then stability of the electroweak vacuum in a minimal model with a universal extra dimension (mUED) will require a much lower cutoff for the theory than has been envisaged earlier. We show that this low cutoff would lead to important changes in much of the mUED phenomenology studied till now. In particular, prospects for LHC searches for n = 1 states are rather limited, while resonant n = 2 states may go completely undetected. Prospects for detection at the ILC and CLIC are less affected.