  The LHC inverse problem is infamously challenging when neutralinos and
charginos are heavy and pure and other superparticles are decoupled. This limit
is becoming more relevant to particle physics nowadays. Fortunately, in this
limit, Higgsinos produce a distinctive signature if they are the LSPs or NLSPs.
The identifying signature is the presence of equal numbers of Z bosons and
Higgs bosons in NLSP productions and subsequent decays at hadron colliders. The
signature is derived from the Goldstone equivalence theorem by which partial
widths into Z and Higgs bosons are inherently related and from the fact that
Higgsinos consist of two indistinguishable neutralinos. Thus it is valid in
general for many supersymmetry models; exceptions may happen when Higgsino
NLSPs decay to weakly coupled LSPs such as axinos or gravitinos.
