TeV-Scale String Resonances at Hadron Colliders

Abstract

We construct tree-level four-particle open-string amplitudes relevant to dilepton and diphoton production at hadron colliders. We expand the amplitudes into string resonance (SR) contributions and compare the total cross-section through the first SR with the $Z^{\prime}$ search at the Tevatron. We establish a current lower bound based on the CDF Run I results on the string scale to be about $1.1-2.1$ TeV, and it can be improved to about $1.5-3$ TeV with 2 fb$^{-1}$. At the LHC, we investigate the properties of signals induced by string resonances in dilepton and diphoton processes. We demonstrate the unique aspects of SR-induced signals distinguishable from other new physics, such as the angular distributions and forward-backward asymmetry. A 95% C.L. lower bound can be reached at the LHC for $M_S>8.2-10$ TeV with an integrated luminosity of 300 fb$^{-1}$. We emphasize the generic features and profound implications of the amplitude construction.