we are considering. Moreover, the better resolution for the electron channel means that the sensitivity of this channel will always be better than (or equal to) the muon channel. FIG. 1: Comparison of the CMS electron resolution according to eqs. (11) and (13), with the two different constant terms as described in the text, compared to Γ$_{Z}$ ′ / 2 for g ′ 1 = 0 . 23 and g ′ 1 = 0 . 44 . In the next section we will compare the LHC and Tevatron discovery reach. In the derivation of the experimental constraints, we refer to the latest publications, being the DØ analysis of Ref. [4] for the electron case and the CDF analysis of Ref. [5] for the muon final state. Hence, we have considered the typical acceptance cuts (for electrons and muons) for the respective detector: and the following requirements on the di-lepton invariant mass, M$_{ℓℓ}$ , depending on whether 7 p e T > 25 GeV , | η $^{e}$| < 1 . 1 , (15) p µ T > 18 GeV , | η $^{µ}$| < 1 , (16) CMS res (2%) CMS res (0.5%) $_{Z'}$/2 (g'$_{1}$=0.23) $_{Z'}$/2 (g'$_{1}$=0.44) M$_{Z'}$ (GeV) M e + e -  (GeV) 0 10 20 30 40 50 60 70 80 500 1000 1500 2000 2500 3000 3500 4000