Table II: Number of signal and background events for LHeC/QCDE-1 with L$_{int}$ $^{= 1}$fb − $^{1}$. Table III: Achievable compositeness scale ( Λ in TeV units) at LHeC/QCDE-1 for $^{5}$σ ( $^{3}$σ ) statistical significance. B. LHeC/QCDE-2 stage 8 used mass windows as M$_{e}$ 8 − 2Γ$_{e}$ 8 < M$_{ej}$ < M$_{e}$ 8 + 2Γ$_{e}$ 8 for Γ$_{e}$ 8 > 10 GeV and M$_{e}$ 8 − 20 GeV < M$_{ej}$ < M$_{e}$ 8 + 20 GeV for Γ$_{e}$ 8 < 10 GeV. It is seen that resonant production of color octet electron will provide very clean signature for masses up to M$_{e}$ 8 ≃ 1 TeV. In Table 3 we present reachable compositeness scale values for L$_{int}$ = 1 and L$_{int}$ = 10 fb − $^{1}$. It is seen that multi-hundred TeV scale can be searched for M$_{e}$ 8 = 500 GeV. Then, increase of the luminosity by one order results in two times higher values for Λ . Lastly, for a given L$_{int}$ = 1 fb − $^{1}$, the upper mass limits for 5 σ discovery at LHeC/QCDE-1 stage are M$_{e}$ 8 = 1100 GeV and M$_{e}$ 8 = 1275 GeV for Λ = 10 TeV and Λ = M$_{e}$ 8 , respectively. In order to determine corresponding cuts we present p$_{T}$ , η$_{j}$ and η$_{e}$ distributions for signal and background processes in Figs 9, 10 and 11, respectively. The figures indicate that significant change takes place only for η$_{j}$ . In this subsections we will use p$_{T}$ > 150 , | η$_{e}$ | < 4 and − 0 . 5 < η$_{j}$ < 4 . The invariant mass distributions obtained with this cuts are given in Fig. 12. M$_{e}$ 8 , GeV ∧ = M$_{e}$ 8 ∧ = 10 TeV S B S B 500 $^{1}$.1 × 10 7 $^{1}$.1 × 10 3 $^{3}$.3 × 10 4 700 750 $^{6}$.4 × 10 5 630 $^{4}$.2 × 10 3 280 1000 $^{2}$.2 × 10 4 1 65 250 53 1250 81 6 1 1 M$_{e}$ 8 , GeV L$_{int}$ $^{= 1}$fb − 1 L$_{int}$ $^{= 10}$fb − 1 500 150 ( 200 ) 275 ( 350 ) 750 65 ( 90 ) 125 ( 160 ) 1000 22 ( 30 ) 45 ( 58 )