Warped gravitons at the CERN LHC and beyond

We study the production and decay of Kaluza-Klein (KK) gravitons at the CERN Large Hadron Collider (LHC), in the framework of a warped extra dimension in which the standard model (SM) fields propagate. Such a scenario can provide solutions to both the Planck-weak hierarchy problem and the flavor puzzle of the SM. In this scenario, the production via $q\overline{q}$ annihilation and decays to the conventional photon and lepton channels are highly suppressed. However, we show that graviton production via gluon fusion followed by decay to longitudinal $Z/W$ can be significant; vector boson fusion is found to be a subdominant production mode. In particular, the golden $ZZ$ decay mode offers a distinctive 4-lepton signal that could lead to the observation at the LHC with $300\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ (SLHC with $3\text{ }\text{ }{\mathrm{ab}}^{\ensuremath{-}1}$) of a KK graviton with a mass up to $\ensuremath{\sim}2$ ($\ensuremath{\sim}3$) TeV for the ratio of the ${\mathrm{AdS}}_{5}$ curvature to the Planck scale modestly above unity. We argue that (contrary to the lore) such a size of the curvature scale can still be within the regime of validity of the framework. Upgrades beyond the SLHC luminosity are required to discover gravitons heavier than $\ensuremath{\sim}4\text{ }\text{ }\mathrm{TeV}$, as favored by the electroweak and flavor precision tests in the simplest such models.

Hali tarjima qilinmagan