Collider Signatures from the Brane World

TL;DR

This paper explores collider signatures of brane world models, focusing on localized twisted string modes that could produce observable effects at TeV energies, potentially surpassing traditional gravity mode signals.

Contribution

It introduces the significance of twisted string modes localized in extra dimensions and their potential observable effects at TeV-scale colliders, expanding beyond standard bulk mode interactions.

Findings

Twisted modes can produce resonances in dijet invariant mass distributions.

Localized twisted fields may have larger collider effects than KK gravity modes.

Collider signatures include effects of anomalous U(1) gauge symmetries.

Abstract

We discuss some collider signatures of the brane world. In addition to the usual bulk (closed string) fields and brane (open string) fields in the Type I string picture, there are closed string fields, namely, twisted modes, which are not confined on the branes but nonetheless are localized in the extra compactified dimensions. While the coupling of the Standard Model (brane) fields with a bulk mode (such as the graviton) is suppressed by powers of the Planck mass, their coupling to a twisted mode is suppressed only by powers of the string scale M_s, which can be as low as a few TeV. This means these localized twisted fields can have important observable effects in the TeV range, including resonances in dijet invariant mass distributions in \bar p p, pp \to jets + X. Given the current lower bound on the fundamental higher-dimensional Planck scale, the experimental effects of these twisted fields may turn out to be larger than the effects of virtual and real KK gravity modes. The collider signatures of anomalous U(1) gauge symmetries as well as other phenomenological implications of the brane world are also discussed.