Radiative corrections to masses and couplings in Universal Extra Dimensions

TL;DR

This paper calculates finite radiative corrections to KK particle masses and couplings in Universal Extra Dimensions, revealing significant effects on the mass spectrum and introducing new collider signatures.

Contribution

It provides the first computation of finite, non-logarithmic boundary terms affecting KK masses and couplings, enhancing the precision of phenomenological predictions in UED models.

Findings

Finite boundary terms significantly alter KK mass spectrum.

New KK-number violating interactions enable novel collider processes.

Finite corrections are numerically comparable to logarithmic terms for typical cut-offs.

Abstract

Models with an orbifolded universal extra dimension receive important loop-induced corrections to the masses and couplings of Kaluza-Klein (KK) particles. The dominant contributions stem from so-called boundary terms which violate KK number. Previously, only the parts of these boundary terms proportional to $\ln(\Lambda R)$ have been computed, where $R$ is the radius of the extra dimension and $\Lambda$ is cut-off scale. However, for typical values of $\Lambda R \sim 10 \cdots 50$, the logarithms are not particularly large and non-logarithmic contributions may be numerically important. In this paper, these remaining finite terms are computed and their phenomenological impact is discussed. It is shown that the finite terms have a significant impact on the KK mass spectrum. Furthermore, one finds new KK-number violating interactions that do not depend on $\ln(\Lambda R)$ but nevertheless are non-zero. These lead to new production and decay channels for level-2 KK particles at colliders.