m + [GeV] Events/50 GeV/ 30 fb −1 0 500 1000 1500 2000 2500 5 10 15 20 25 30 35 SM background Signal (m = 700 GeV) (a) m$_{T}$ 0  [GeV] Events/ 50 GeV/ 30 fb −1 0 500 1000 1500 2000 5 10 15 20 25 30 35 40 SM background Signal (m = 700 GeV) (b) FIG. 5: (a) Reconstructed invariant mass of the heavy charged lepton. (b) Reconstructed transverse mass of the neutral heavy lepton. E. Obtaining flavor constraints Our analysis allows us to test two of these predictions, namely For the flavored cross section ratio estimates, we considered events within a window of 150 GeV around the mass peak of both m$_{χ}$ ± and m χ 0 T . As is evident in Fig. 5, standard model background in this region is negligible. In Fig. 6, the reconstructed transverse mass m χ 0 T is shown separately for the three different flavor compositions, e $^{+}$e $^{−}$, µ $^{+}$µ − and e $^{±}$µ$^{∓}$. Ideally, there should be no events in the eµ final state. In practice, however, a small number of the signal events are reconstructed as such, mostly due to misclassification of leptons in the event. Another possible source of contamination are τ pairs, decaying to e and µ , however this contribution was found to be negligible. 13 N$_{ee}$ = N$_{µµ}$, N$_{eµ}$ = 0 . (3.7) N$_{ee}$ = N$_{µµ}$ = N$_{τ τ}$, N$_{eµ}$ = N$_{eτ}$ = N$_{µτ}$ = 0 . (3.6) We focus here on model LL, which has three quasi-degenerate heavy leptons, each de- caying to one of the light lepton flavors, e, µ, τ . Events are classified by the flavor of the two leptons associated with the heavy pair decay. We are interested in N$_{ij}$ , the observed numbers of events in each flavor composition ℓ ± i ℓ ∓ j . The MLFV prediction is that