Direct signals for large extra dimensions in the production of fermion pairs at linear colliders - art. no. 035005

We analyze the potential of the next generation of e(+)e(-) linear collider s to search for large extra dimensions via the production of fermion pairs in association with Kaluza-Klein gravitons (G), i.e., e(+)e(-)f (f) over ba rG. 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 de tail this reaction using the full tree level contributions due to the gravi ton 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 e nergy of 500 GeV will be able to probe quantum gravity scales from 0.96 (0. 86) up to 4.1 (3.3) TeV at a 2 (5)sigma level, depending on the number of e xtra dimensions.