Resonant slepton production yields CMS $eejj$ and $e{\cancel{p}}_{T}jj$ excesses

Recent CMS searches for dileptoquark production report local excesses of $2.4\sigma$ in an $eejj$ channel and $2.6\sigma$ in an $e{\cancel{p}}_{T}jj$ channel. Here, we simultaneously explain both excesses with resonant slepton production in $\mathcal{R}$-parity violating supersymmetry. We consider resonant slepton production, which decays to a lepton and a chargino/neutralino, followed by three-body decays of the neutralino/chargino via an $\mathcal{R}$-parity violating coupling. There are regions of parameter space which are also compatible at the 95% confidence level with a $2.8\sigma$ $eejj$ excess in a recent CMS $W_R$ search, while being compatible with other direct search constraints. Phase II of the GERDA neutrinoless double beta decay ($0\nu \beta \beta$) experiment will probe a sizable portion of the good-fit region.

Figure 1

Feynman diagrams for single slepton production leading to an $eejj(e\nu jj)$ signal at the LHC. Other diagrams, where the ${\chi }_1^0$ is replaced by ${\chi }_1^{\pm }$ (among other replacements), also contribute.

Figure 2

A comparison of the measured (“Data”), background (“B”) and example signal plus background (“$\mathrm{S}+\mathrm{B}$”) distributions for $m_{ej}^{\min }(eejj)$, $m_{ej}(e\nu jj)$ and the scalar sum of the $p_T$’s of visible objects for (lower left) $eejj$ and (lower right) $e\nu jj$. $m_{ej}^{\min }$ is the invariant mass of the electron-jet pairing combination for which the difference between the $m_{ej}$ for each pair is smallest. The vertical axis measures the number of events falling in a bin after imposing cuts. The signal point corresponds to ${\lambda }_{111}^{\prime }=0.175$, $m_{\tilde{l}}=2\mathrm{TeV}$ and $M_{{\chi }_1^0}=0.9\mathrm{TeV}$ (S2). Data and SM backgrounds are taken from [1].

Figure 3

Constraints in the $m_{\tilde{l}}-{\lambda }_{111}^{\prime }$ plane assuming $M_{{\chi }_1^0}=0.9\mathrm{TeV}$ in scenarios (top) S1, (middle) S2 and (bottom) S3, where the nuclear matrix elements have been adopted from [19]. The parameter space fitting the $eejj$, $e\nu jj$ dileptoquark search excesses and the $W_R$ $eejj$ excess to 95% CL is shown in the key. The region above the lines (except for the one labeled “GERDA Phase-II Search”) is excluded, labeled near the edge of exclusion: either the 90% CL constraint from current combined neutrinoless double beta decay bounds ($0\nu \beta \beta$) or at the 95% CL from the CMS dijets shape analysis. The expected 90% CL exclusion reach from GERDA phase II [25] is shown as the region above the solid black line. The cross in the middle panel shows the location of our example point.