Probing the Nature of Compactification with Kaluza-Klein Excitations at the Large Hadron Collider

TL;DR

This paper investigates how the characteristics of Kaluza-Klein excitations in theories with extra dimensions can be studied at the LHC to determine the nature of compactification, including the number and type of extra dimensions.

Contribution

It demonstrates that LHC processes, especially dilepton interference patterns, can reveal the number and type of extra dimensions and compactification schemes in large radius compactification theories.

Findings

LHC can discover KK modes up to ~6 TeV with 100 fb^{-1}

Interference patterns encode information on compactification

Effects studied for one and two extra dimensions with various orbifolds

Abstract

It is shown that the nature of compactification of extra dimensions in theories of large radius compactification can be explored in several processes at the Large Hadron Collider (LHC). Specifically it is shown that the characteristics of the Kaluza-Klein (KK) excitations encode information on the nature of compactification, i.e., on the number of compactified dimensions as well as on the type of compactification, e.g., of the specific orbifold compactification. The most dramatic signals arise from the interference pattern involving the exchange of the Standard Model spin 1 bosons ($\gamma$ and Z) and their Kaluza-Klein modes in the dilepton final state $pp\to l^+l^-X$. It is shown that LHC with 100$fb^{-1}$ of luminosity can discover Kaluza-Klein modes up to compactification scales of $\approx 6$ TeV as well as identify the nature of compactification. Effects of the Kaluza-Klein excitations of the W boson and of the gluon are also studied. Exhibition of these phenomena is given for the case of one extra dimension and for the case of two extra dimensions with $Z_2\times Z_2, Z_3$, and $Z_6$ orbifold compactifications.