In the semi-constrained NMSSM (scNMSSM, or NMSSM with non-universal Higgs mass) under current constraints, we consider a scenario where $h_2$ is the SM-like Higgs, $\tilde��^0_1$ is singlino-dominated LSP, $\tilde��^{\pm}_1$ and $\tilde��^0_{2,3}$ are mass-degenerated, light and higgsino-dominated NLSPs (next-to-lightest supersymmetric particles). We investigate the constraints to these NLSPs from searching for SUSY particles at the LHC Run-I and Run-II, discuss the possibility of discovering these NLSPs in the future, and come to the following conclusions: (i) With all data of Run I and up to 36 $\rm fb^{-1}$ data of Run II at the LHC, the search results by ATLAS and CMS can still not exclude the higgsino-dominated NLSPs of $100\sim200$ GeV. (ii) When the mass difference with $\tilde��^0_{1}$ is smaller than $m_{h_2}$, $\tilde��^0_{2}$ and $\tilde��^0_{3}$ have opposite preference on decaying to $Z/Z^*$ or $h_1$. (iii) When the mass difference between NLSP and LSP is larger than $m_Z$, most of the samples can be checked at $5��$ level with future 300 $\rm fb^{-1}$ data at the LHC. While with 3000 $\rm fb^{-1}$ data at the High Luminosity LHC (HL-LHC), nearly all of the samples can be checked at $5��$ level even if the mass difference is insufficient. (iv) The $a_1$ funnel and the $h_2/Z$ funnel mechanisms for the singlino-dominated LSP annihilating can not be distinguished by searching for NLSPs.

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