Matter and Gravity in Warped Extradimensional Models: Reinterpreting Randall-Sundrum

Abstract

Warped extra dimension claims remarkable success: solving the hierarchy problem; explaining hierarchies in particle phenomenology; yielding standard cosmology, plus interesting nonstandard scenarios. Yet it has marked shortcomings: we over-rely on a single toy model, Randall-Sundrum; we treat matter and gravity in an ad hoc, asymmetric way; and we conceptualize integrated 4D effective field theory inconsistently. I here construct sounder 4D effective field theories for matter and gravity in warped extra dimension -- whether Randall-Sundrum or higher codimension. I track both Planck and particle scales through brane formation, beginning with fully extradimensional matter and gravity, at unified scale, in gravitationally warped backgrounds with bulk electroweak symmetry-breaking. This validates hierarchy solution, as warp generically drives 4D effective Planck and particle scales apart. It evades classic obstacles to warped confinement of matter: colocalizing particles and assuring effective charge universality. Diverse particles do fail to colocalize, generically and in discussed models; however, aggregate 4D effective field theory still holds, since hierarchy solution fixes unresolvably small extradimensional radius. Electromagnetic charge universality emerges generically, and weak charge universality in the Randall-Sundrum case.