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The observed excesses in the search for neutralinos and charginos by ATLAS and CMS can be fitted simultaneously in the minimal supersymmetric standard model (MSSM) assuming a light higgsino mass, of magnitude less than about 250 GeV, and a…
We investigate the prospects of probing weak-scale higgsinos through electroweak precision measurements at a future $e^+ e^-$ collider. In the Minimal Supersymmetric Standard Model, higgsinos mix with winos and binos after electroweak…
It is shown how the fundamental gaugino and higgsino parameters of the chargino and neutralino system in the MSSM can completely be determined in high--precision experiments at e+e- linear colliders even if in their initial phase only the…
Supersymmetric models with nearly-degenerate light higgsinos provide a consistent solution to the naturalness problem under rigorous constraints from current experimental searches for sparticles. However, it is challenging to probe the…
We discuss neutralino dark matter arising from supersymmetric models with extra inert Higgsinos and singlinos, where inert means that their scalar partners do not get vacuum expectation values. As an example, we consider the extended…
A highly bino-like Dark Matter (DM), which is the Lightest Supersymmetric Particle (LSP), could be motivated by the stringent upper bounds on the DM direct detection rates. This is especially so when its mass is around or below 100 GeV for…
Results are presented from a search for long-lived neutralinos decaying into a photon and an invisible particle, a signature associated with gauge-mediated supersymmetry breaking in supersymmetric models. The analysis is based on a 4.9…
As any $e^+e^-$ scattering process can be accompanied by a hard photon emission from the initial state radiation, the analysis of the energy spectrum and angular distributions of those photons can be used to search for hard processes with…
Neutralinos with a large singlino component may appear in extended supersymmetric models with additional singlet Higgs fields. Since singlinos do not couple to (s)fermions and gauge bosons, the cross sections for the production of singlino…
We point out that the extra neutralinos and charginos generically appearing in a large class of $E_6$ inspired models lead to distinctive signatures from gluino cascade decays in comparison to those from the Minimal Supersymmetric Standard…
We consider the production of neutralino, chargino, and charged Higgs boson pairs in the MSSM framework at future $e^+e^-$ colliders. We show that, for c.m. energies in the one TeV range and in a ``moderately'' light SUSY scenario, a…
We analyse new signals of Dark Matter (DM) at the Large Hadron Collider (LHC) in a 3-Higgs Doublet Model (3HDM) where only one doublet acquires a Vacuum Expectation Value (VEV), preserving a parity $Z_2$. The other two doublets are inert…
We discuss a new variant of the E6 inspired supersymmetric standard model (E6SSM) in which the two inert singlinos are exactly massless and the dark matter candidate has a dominant bino component. A successful relic density is achieved via…
In supersymmetric extensions of the Standard Model with a very light gravitino, the effective theory at the weak scale should contain not only the goldstino G, but also its supersymmetric partners, the sgoldstinos. In the simplest case, the…
We study the associated production of a very light pseudoscalar Higgs boson with a pair of charginos. The novel signature involves a pair of charged leptons from chargino decays and a pair of photons from the pseudoscalar Higgs boson decay,…
It is one of the most challenging tasks at the Large Hadron Collider and at a future Linear Collider not only to observe physics beyond the Standard Model, but to clearly identify the underlying new physics model. In this paper we…
A search for a chargino$-$neutralino pair decaying via the 125 GeV Higgs boson into photons is presented. The study is based on the data collected between 2015 and 2018 with the ATLAS detector at the LHC, corresponding to an integrated…
Given the recent constraints from the dark matter (DM) direct detections, we examine a light GeV-scale (2-30 GeV) neutralino DM in the alignment limit of the Minimal Supersymmetric Standard Model (MSSM). In this limit without decoupling,…
We study the possibility of a light Dark Matter (DM) within a constrained Minimal Supersymmetric Standard Model (cMSSM) framework augmented by a SM singlet-pair sector to account for the non-zero neutrino masses by inverse seesaw mechanism.…
An interesting feature of the next-to-minimal supersymmetric standard model (NMSSM) is that one or more Higgs bosons may be comparably light (M_{H_i}<M_Z) without being in conflict with current experimental bounds. Due to a large singlet…