Related papers: Neutralino decay in the $\mu$-problem solvable ext…
We consider a singlino dominated neutralino in supersymmetric models with an extra U(1). In case both the $\mu$ term and also the $Z^\prime$ mass are generated by the vacuum expectation value of the scalar component of the same singlet…
We analyze the decays of charginos, neutralinos, gluinos and the first/second generation squarks in the Minimal Supersymmetric extension of the Standard Model, focusing on the three-body decays in scenarios where the ratio $\tan \beta$ of…
Grand unified theories can lead to non-universal boundary conditions for the gaugino masses at the unification scale. We consider the implications of such non-universal boundary conditions for the composition of the lightest neutralino as…
The neutralino sector in E_6 inspired supersymmetric models with extra neutral gauge bosons and singlet Higgs fields contains additional gaugino and singlino states compared to the MSSM. We discuss the neutralino mixing in rank 5 and rank 6…
The radiative decay of the next-to-lightest neutralino into a lightest neutralino and a photon is analyzed in the MSSM. We find that significant regions of the supersymmetric parameter space with large radiative BR's (up to about 100%) do…
Consecutively to the chargino system, $\tilde{chi}^pm$, in which the SU(2) gaugino parameter $M_2$, the higgsino mass parameter $\mu$ and $\tan\beta$ can be determined, the remaining fundamental supersymmetry parameter, the U(1) gaugino…
I investigate production and decay of heavy neutral gauge bosons Z' in GUT-inspired U(1)' groups and in the Sequential Standard Model. In particular, decays into supersymmetric particles, such as slepton, chargino and neutralino pairs, as…
We analyze the prospects for light neutralino dark matter in the minimal supersymmetric model extended by a $U(1)$ gauge group. We allow the neutralino to be an arbitrary admixture of singlet and doublet higgsinos, as well as of the three…
Decays of the lightest neutralino are studied in $R_p$-violating models, with operators $\lambda^\prime L Q D^c$ and $\lambda L L E^c$ involving third-generation matter fields and with dominant $\lambda^\prime$ and $\lambda$ couplings.…
In supersymmetric models with non-universal gaugino masses, it is possible to have opposite-sign SU(2) and U(1) gaugino mass terms. In these models, the gaugino eigenstates experience little mixing so that the lightest SUSY particle remains…
We study supersymmetric scenarios where the dark matter is the gaugino of an unbroken hidden U(1) which interacts with the visible world only via a small kinetic mixing with the hypercharge. Strong constraints on the parameter space can be…
Among the possible decay modes of Higgs particles into supersymmetric states, neutralino and chargino decays play a prominent r\^ole. The experimental opportunities of observing such decay modes at LEP2 and at future e+e- linear colliders…
Motivated by results from short-baseline neutrino oscillation data, we study neutrino masses and mixing in U(1)' supersymmetric models with R-parity breaking. Whether R-parity is broken spontaneous or through (effective) bilinear terms in…
In supersymmetric models extended with an anomalous $U(1)_H$ different R-parity violating couplings can yield an unstable neutralino. We show that in this context astrophysical and cosmological constraints on neutralino decaying dark matter…
In the scenario recently proposed by Arkani-Hamed and Dimopoulos, the supersymmetric scalar particles are all very heavy, at least of the order of $10^9$ GeV but the gauginos, higgsino, and one of the CP-even neutral Higgs bosons remain…
The possible solution of dark matter problem with neutralinos of supersymmetric models within the supergravity framework is reviewed. A novel correlation between the neutralino relic abundance $\Omega_\chi$ and the soft supersymmetry…
Extending the Higgs sector of the MSSM by the addition of a gauge singlet scalar field can remedy the mu problem. We explore the implications of extended models for both the spectrum of the neutralinos and the cascade decays of the…
We study the low scale predictions of supersymmetric standard model extended by $U(1)_{B-L}\times U(1)_{R}$ symmetry, obtained from $SO(10)$ breaking via a left-right supersymmetric model, imposing universal boundary conditions. Two singlet…
Once supersymmetric neutralinos $\tilde{\chi}^0$ are produced copiously at $e^+e^-$ linear colliders, their characteristics can be measured with high precision. In particular, the fundamental parameters in the gaugino/higgsino sector of the…
We consider the neutralino mass matrix in a supersymmetric theory based on SU(2) $\times$ U(1) gauge group with arbitrary number of singlet, doublet and triplet Higgs superfields. We derive an upper bound on the mass of the lightest…