Probing light bino and higgsinos at the LHC

Motivated by the naturalness, we study a simplified MSSM scenario where only the bino-like LSP and higgsino-like NLSP are light. We first scan the parameter space of this scenario, considering the constraints from the Higgs mass, flavor physics, electroweak precision measurements and dark matter experiments. Then in the allowed parameter space, we perform a Monte Carlo simulation for the $\tilde{\chi}^\pm_1 \tilde{\chi}^0_{2,3}$ production followed by $\tilde{\chi}^\pm_1 \to W^\pm \tilde{\chi}^0_1$ and $\tilde{\chi}^0_{2,3} \to Z\tilde{\chi}^0_1$. By examining the presently available trilepton bounds on the wino-like chargino/neutralino, we find that only a narrow region $40\,\rm{GeV} \lesssim m_{\tilde{\chi}^0_1} \lesssim 50\,\rm{GeV}$ and $160\,\rm{GeV} \lesssim m_{\tilde{\chi}^0_{2,3}} \lesssim 170\,\rm {GeV}$ on the plane of $m_{\tilde{\chi}^0_1}-m_{\tilde{\chi}^0_{2,3}}$ can be excluded. Finally, we explore the potential of trilepton signature in probing such a scenario at 14 TeV LHC and find that the region with $40\,\rm{GeV} \lesssim m_{\tilde{\chi}^0_1} \lesssim 60\,\rm {GeV}$ and $160 \rm {GeV}\,\lesssim m_{\tilde{\chi}^0_{2,3}} \lesssim 300\,\rm{GeV}$ can be covered at $3\sigma$ level with luminosity ${\cal L}=300$ fb$^{-1}$.