Revisiting the Electroweakino Sector of the Baryon Number Violating MSSM at the HL-LHC with Deep Neural Networks

We study the projected sensitivity of direct electroweakino production $pp\to {\tilde{\chi }}_1^{\pm }{\tilde{\chi }}_2^0$ at the HL-LHC in a simplified framework with wino-like, mass degenerate ${\tilde{\chi }}_1^{\pm }$ and ${\tilde{\chi }}_2^0$, and a bino-like lightest neutralino ${\tilde{\chi }}_1^0$, assuming R-parity violating~(RPV) through the baryon number violating ${\lambda }_{112}^{\mathrm{\prime }\mathrm{\prime }}{u}^c{d}^c{d}^c$ and ${\lambda }_{113}^{\mathrm{\prime }\mathrm{\prime }}{u}^c{d}^c{b}^c$ operators. We consider three channels with the ${\lambda }_{112}^{\mathrm{\prime }\mathrm{\prime }}{u}^c{d}^c{d}^c$ RPV operator: $Wh$ mediated $1\mathrm{\ell }+2b+\mathrm{E}{\text{\hspace{0.17em}⁣}\text{\hspace{0.17em}⁣}\text{\hspace{0.17em}⁣}\mathrm{/}}_{\mathrm{T}}$, $Wh$ mediated $1\mathrm{\ell }+(\ge 2j)+2\gamma +\mathrm{E}{\text{\hspace{0.17em}⁣}\text{\hspace{0.17em}⁣}\text{\hspace{0.17em}⁣}\mathrm{/}}_{\mathrm{T}}$, and $WZ$ mediated $3\mathrm{\ell }+(\ge 2j)+\mathrm{E}{\text{\hspace{0.17em}⁣}\text{\hspace{0.17em}⁣}\text{\hspace{0.17em}⁣}\mathrm{/}}_{\mathrm{T}}$. In each channel, we train benchmark-specific multi-layer perceptrons (MLPs), analogous to signal-region classifiers, on the four-momenta of the final state particles along with a small set of higher-level observables to distinguish the signal from the dominant SM backgrounds. We find that the HL-LHC will be able to probe winos up to $\sim 900$GeV, $\sim 780$GeV, and $\sim 880$GeV in the $Wh$ mediated $1\mathrm{\ell }+2b+\mathrm{E}{\text{\hspace{0.17em}⁣}\text{\hspace{0.17em}⁣}\text{\hspace{0.17em}⁣}\mathrm{/}}_{\mathrm{T}}$, $Wh$ mediated $1\mathrm{\ell }+(\ge 2j)+2\gamma +\mathrm{E}{\text{\hspace{0.17em}⁣}\text{\hspace{0.17em}⁣}\text{\hspace{0.17em}⁣}\mathrm{/}}_{\mathrm{T}}$, and $WZ$ mediated $3\mathrm{\ell }+(\ge 2j)+\mathrm{E}{\text{\hspace{0.17em}⁣}\text{\hspace{0.17em}⁣}\text{\hspace{0.17em}⁣}\mathrm{/}}_{\mathrm{T}}$ channels, respectively, for $m_{{\tilde{\chi }}_1^0}\sim 50$GeV, in the presence of ${\lambda }_{112}^{\mathrm{\prime }\mathrm{\prime }}{u}^c{d}^c{d}^c$ couplings, at $2\sigma$ sensitivity. In case the ${\lambda }_{113}^{\mathrm{\prime }\mathrm{\prime }}{u}^c{d}^c{b}^c$ operator is solely switched on, the projected sensitivity for winos reach up to $\sim 700$GeV for $Wh$ mediated $1\mathrm{\ell }+(\ge 1b)+(\ge 1j)+2\gamma +\mathrm{E}{\text{\hspace{0.17em}⁣}\text{\hspace{0.17em}⁣}\text{\hspace{0.17em}⁣}\mathrm{/}}_{\mathrm{T}}$ and $\sim 850$GeV for the $WZ$ mediated $3\mathrm{\ell }+(\ge 1b)+\mathrm{E}{\text{\hspace{0.17em}⁣}\text{\hspace{0.17em}⁣}\text{\hspace{0.17em}⁣}\mathrm{/}}_{\mathrm{T}}$ channel.