Direct Signals for Large Extra Dimensions in the Production of Fermion Pairs at Linear Colliders

Abstract

We analyze the potentiality of the new generation of $e^+e^-$ linear colliders to search for large extra dimensions via the production of fermion pairs in association with Kaluza-Klein gravitons (G), i.e. $e^+e^- \leftarrow f\bar{f}G$. This process leads to a final state exhibiting a significant amount of missing energy in addition to acoplanar lepton or jet pairs. We study in detail this reaction using full tree level contibutions due to the graviton emission and the standard model backgrounds. After choosing the cuts to enhance the signal, we show that a linear collider with a center-of-mass energy of 500 GeV will be able to probe quantum gravity scales from 0.96(0.86) up to 4.1(3.3) TeV at 2(5)$σ$ level, depending on the number of extra dimensions.

19 pages, 5 figures. Using RevTex, axodraw.sty. Discussion was extended. No changes in the results. Accepted for publication by Phys. Rev. D