Vector Bosons in the Randall-Sundrum 2 and Lykken-Randall models and unparticles

TL;DR

This paper demonstrates how unparticle behavior emerges in Randall-Sundrum 2 and Lykken-Randall models through brane-localized currents coupled to bulk vector fields, revealing connections to conformal field theories and unitarity constraints.

Contribution

It shows the realization of unparticle phenomena in RS 2 and LR models via AdS/CFT correspondence and analyzes the implications for unitarity bounds on vector operators.

Findings

Unparticle behavior is realized in RS 2 and LR models.

Positivity of bulk mass ensures unitarity of brane-to-brane scattering.

Scalar and vector correlators are contrasted at different distances.

Abstract

Unparticle behavior is shown to be realized in the Randall-Sundrum 2 (RS 2) and the Lykken-Randall (LR) brane scenarios when brane-localized Standard Model currents are coupled to a massive vector field living in the five-dimensional warped background of the RS 2 model. By the AdS/CFT dictionary these backgrounds exhibit certain properties of the unparticle CFT at large N_c and strong 't Hooft coupling. Within the RS 2 model we also examine and contrast in detail the scalar and vector position-space correlators at intermediate and large distances. Unitarity of brane-to-brane scattering amplitudes is seen to imply a necessary and sufficient condition on the positivity of the bulk mass, which leads to the well-known unitarity bound on vector operators in a CFT.