An indirect probe of the higgsino world at the CEPC.

The higgsino world is one of the popular natural SUSY scenarios, in which $$|\mu | \ll M_{\mathrm{gauginos}} \ll M_{\mathrm{scalars}}$$ . As such, searching for light degenerate higgsinos becomes an essential task of testing naturalness in supersymmetry (SUSY). In this work, we study the indirect effects of light higgsinos in the process $$e^+e^- \rightarrow W^+W^-$$ at future Higgs factories, such as the Circular Electron Positron Collider (CEPC) in China. We find that the higgsino mass parameter $$\mu \lesssim 210 \, \hbox {GeV}$$ favored by naturalness can be covered if the accuracy of the measurement of $$W^+W^-$$ production can reach 0.1% at 240 GeV CEPC. [ABSTRACT FROM AUTHOR]