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An important feature of the Z ′ gauge boson in the B − L model is the chiral structure of its couplings to fermions: since the B − L charges do not distinguish between left-handed and right-handed fermions, the B − L neutral current is purely vector-like, with a vanishing axial part $^{2}$. As a consequence, we decided not to study the asymmetries of the decay products stemming from Z ′ B − L boson, given their trivial distribution at the peak, the region we study here. However, asymmetries become important in the interference region, especially just before the Z ′ boson peak, where the Z − Z ′ interference will effectively provide an asymmetric distribution somewhat milder than the case in which there is no Z ′ boson. This is a powerful method of discovery and identification of a Z ′ boson and it will be reported on separately. 

## III. COMPUTATIONAL DETAILS 

The study we present in this paper has been performed using the CalcHEP package [24]. The model under discussion had been implemented in this package using the LanHEP tool [25], as already discussed in Ref. [10]. 

The process we are interested in is di-lepton production. We define our signal as pp → γ, Z, Z ′ B − L → ℓ $^{+}$ℓ − ( ℓ = e, µ ), i.e., all possible sources together with their mu- tual interferences, and the background as pp → γ, Z → ℓ $^{+}$ℓ − ( ℓ = e, µ ), i.e., SM Drell-Yan production (including interference). No other sources of background, such as W W , ZZ , W Z , or tt have been taken into account. These can be suppressed or/and are insignificant [4, 32]. For both the signal and the background, we have assumed standard acceptance cuts (for both electrons and muons) at the LHC: 

<img src='content_image/362640.jpg'>

and we apply the following requirements on the di-lepton invariant mass, M$_{ℓℓ}$ , depending on whether we are considering electrons or muons. We distinguish two different scenarios: an “early” one (for √$_{s}$ = 7, 10 TeV) and an “improved” one (for √$_{s}$ = 14 TeV), and, in 

