Higgsino asymmetry and direct-detection constraints of light dark matter in the NMSSM with non-universal Higgs masses

In this study, we analyze the direct-detection constraints of light dark matter in the next-to minimal supersymmetric standard model（NMSSM） with non-universal Higgs masses（NUHM）; we specially focus on the correlation between higgsino asymmetry and spin-dependent（SD） cross section. We draw the following conclusions.（i）The SD cross section is proportional to the square of higgsino asymmetry in dark matter ■in the NMSSM-NUHM,and hence, it is small for highly singlino-dominated dark matter.（ii） The higgsino-mass parameter μeff is smaller than approximately 335 GeV in the NMSSM-NUHM due to the current muon g-2 constraint, but our scenario with light dark matter can still be alive under current constraints including the direct detection of dark matter in the spindependent channel.（iii） With a sizeable higgsino component in the light dark matter, the higgsino asymmetry and SD cross section can also be sizeable, but dark matter relic density is always small; thus, it can escape the direct detections.（iv） Light dark matter in the h2-and Z-funnel annihilation channels with sufficient relic density can be covered by future LUX-ZEPLIN（LZ） 7-ton in SD detections.（v） The spin-independent（SI） cross section is dominated by h1-and h2-exchanging channels, which can even cancel each other in some samples, leaving an SI cross section smaller by a few orders of magnitude than that of one individual channel.