Productions of second Kaluza-Klein gauge bosons in the minimal universal extra dimension model at LHC

TL;DR

This paper calculates the production rates of second Kaluza-Klein gauge bosons at the LHC within the minimal Universal Extra Dimension model, highlighting new production mechanisms and their significance for model discrimination.

Contribution

It introduces KK number violating operators including top Yukawa effects, enabling precise calculation of second KK particle production and decay processes in MUED.

Findings

Second KK gauge bosons can be produced abundantly at the LHC.

KK number violating operators significantly enhance production rates.

Estimated event numbers range from 10^2 to 10^6 for various compactification scales.

Abstract

We calculate the production rates of the second Kaluza-Klein (KK) photon $\gamma^{(2)}$ and Z boson $Z^{(2)}$ at the LHC including all significant processes in the minimal Universal Extra Dimension (MUED) model. For discrimination of the MUED model from other TeV scale models at the LHC, $\gamma^{(2)}$ and $Z^{(2)}$ play a crucial role. In order to discuss the discrimination and calculate their production rates, we derive KK number violating operators including the contribution of the top Yukawa coupling. Using these operators, we accurately calculate branching ratios of second KK particles. In addition we find that these KK number violating operators provide new processes for $\gamma^{(2)}$ and $Z^{(2)}$ productions, such as cascade decay from second KK quarks produced through these operators. They have large contributions to their total production rates. In particular, these production processes give the dominant contribution for $\gamma^{(2)}$ production for $1/R \gtrsim 800$ GeV. As a result, with an integrated luminosity of 100 fb$^{-1}$, the number of produced $\gamma^{(2)}$ and $Z^{(2)}$ are estimated as 10$^6$ - 10$^2$ for the compactification scale between 400 GeV and 2000 GeV.