Big signals of Little Randall–Sundrum models

Abstract

We examine signals at the Large Hadron Collider (LHC) of Kaluza–Klein modes, in volume-truncated “Little Randall–Sundrum” (LRS) models of flavor, characterized by 5D cutoff scales M5 that are small compared to the 4D Planck mass MP∼1019 GeV. In particular, for the phenomenologically viable choice M5∼104 TeV, the discovery of a 2 (3)-TeV “Little”Z′ at the LHC requires about 1 (4) fb−1 at s=10 (14) TeV, in the clean di-lepton channel. Our results highlight the possibility of probing interesting values of M5, starting with the early LHC data. With M5∼104 TeV, discovering the second KK mode Z″, at about 4.3 TeV, requires O(100) fb−1 at s=14 TeV, providing a probe of the warped nature of the bulk that is encoded in the mass ratio of the first two KK modes, at design luminosity. By comparison, discovering a 3-TeV Z′ of the Planck-weak hierarchy models (with M5∼MP), in any channel, would require upwards of O(300) fb−1 at s=14 TeV. We also point out that discovery prospects markedly improve for Little KK gluons as well, but the challenging reconstruction of their tt¯ decay products may hamper their early discovery.