LHC ( s=7 TeV) LHC ( s=10 TeV) LHC ( s=14 TeV) Tevatron M$_{Z'}$ (TeV)  (p p(pbar) $^{→}$  Z') (pb) 10 -5 10 -4 10 -3 10 -2 10 -1 1 1 1.5 2 2.5 3 3.5 4 FIG. 2: Cross sections for pp ( p ) → Z ′ B − L at the Tevatron and at the LHC (for √$_{s}$ = 7 , 10 and 14 TeV) for g ′ 1 = 0 . 1 . A. LHC at √ s = 7 TeV The first years of the LHC work will be at a CM energy of 7 TeV, where the total integrated luminosity is likely to be of the order of 1 fb − $^{1}$. Figure 3 shows the discovery potential under these conditions, as well as the most recent limit from LEP [3]: 11 M$_{Z}$ ′ g ′ 1 ≥ 7 TeV (21)