Collider signatures from the brane world

We discuss some collider signatures of the brane world. Tn addition to the usual bulk (closed string) fields and brane (open string) fields in the Typ e I string picture, there are closed string fields, namely, twisted modes, which are not confined on the branes but nonetheless are localized in the e xtra compactified dimensions. While the coupling of the Standard Model (bra ne) fields with a bulk mode (such as the graviton) is suppressed by powers of the Planet 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 mean s these localized twisted fields can have important observable effects in t he TeV range, including resonances in dijet invariant mass distributions in (p) over bar p,pp --> jets + X. Given the current lower bound on the funda mental higher-dimensional Planck scale, the experimental effects of these t wisted fields may turn out to be larger than the effects of virtual and rea l KK gravity modes. The collider signatures of anomalous U(1) gauge symmetr ies as well as other phenomenological implications of the brane world are a lso discussed. (C) 1999 Published by Elsevier Science B.V. All fights reser ved.