Z'-Mediated Slepton and Sneutrino Signatures at HL-LHC

Abstract

We investigate the discovery potential of a heavy $Z^{\prime }$ boson as a portal to charged sleptons and right-handed sneutrinos within the $B-L$ Supersymmetric Standard Model (BLSSM) at the High-Luminosity LHC. Using a detector-level simulation and Boosted Decision Trees to suppress Standard Model backgrounds, we find that the direct slepton decay $pp\to Z^{\prime }\to {\tilde{\ell }}^{+}{\tilde{\ell }}^{-}\to 2\ell +E_{\mathrm{T}}^{\mathrm{miss}}$ yields a significance exceeding $5\sigma$ at 3000 fb${}^{-1}$, while the cascade $(\text{mbox}multileptons+E_{\mathrm{T}}^{\mathrm{miss}})$ mode is unobservable due to rate suppression. For right-handed sneutrinos, the hadronic channel $pp\to Z^{\prime }\to {\tilde{\nu }}_R{\tilde{\nu }}_I\to 2\ell +4j+E{\mathrm{T}}^{\mathrm{miss}}$ emerges as the most promising signature. These results establish the $2\ell +E_{\mathrm{T}}^{\mathrm{miss}}$ and $2\ell +4j+E_{\mathrm{T}}^{\mathrm{miss}}$ final states as the principal discovery channels for the scalar leptonic sector of the BLSSM at the HL-LHC.

Comments: 22 pages, 6 figures, 6 tables