Electroweak precision measurements and collider probes of the Standard Model with large extra dimensions

TL;DR

This paper investigates how large extra dimensions affect electroweak precision measurements and collider signals, showing that current data constrain the size of extra dimensions and Higgs properties, with future colliders capable of probing much higher scales.

Contribution

It provides a comprehensive analysis of collider and precision data constraints on large extra dimensions, including the role of the Higgs sector and potential discovery prospects at future colliders.

Findings

Current limits depend on Higgs sector details.

Large extra dimensions can fit data with heavy Higgs if confined to 3+1 dimensions.

Future colliders can probe Kaluza-Klein scales up to 31 TeV.

Abstract

The elementary particles of the Standard Model may live in more than 3+1 dimensions. We study the consequences of large compactified dimensions on scattering and decay observables at high-energy colliders. Our analysis includes global fits to electroweak precision data, indirect tests at high-energy electron-positron colliders (LEP2 and NLC), and direct probes of the Kaluza-Klein resonances at hadron colliders (Tevatron and LHC). The present limits depend sensitively on the Higgs sector, both the mass of the Higgs boson and how many dimensions it feels. If the Higgs boson is trapped on a 3+1 dimensional wall with the fermions, large Higgs masses (up to 500 GeV) and relatively light Kaluza-Klein mass scales (less than 4 TeV) can provide a good fit to precision data. That is, a light Higgs boson is not necessary to fit the electroweak precision data, as it is in the Standard Model. If the Higgs boson propagates in higher dimensions, precision data prefer a light Higgs boson (less than 260 GeV), and a higher compactification scale (greater than 3.8 TeV). Future colliders can probe much larger scales. For example, a 1.5 TeV electron-positron linear collider can indirectly discover Kaluza-Klein excitations up to 31 TeV if 500 fb^-1 integrated luminosity is obtained.