Related papers: Neutralino decay in the $\mu$-problem solvable ext…
If the sneutrino mass is below the chargino mass, the dominant decay mode of the lightest chargino is via a two-body decay channel $\chi^{\pm}_1 \ra \tilde{\nu} + l^{\pm}$. Sneutrinos are invisible in $R$-parity conserving supersymmetric…
We study the decay of a standard model-like Higgs boson into a gravitino and a neutralino, which subsequently decays promptly into another gravitino and a photon. Such a decay can be important in scenarios where the supersymmetry breaking…
The $U(1)_X$ extension of the minimal supersymmetric standard model(MSSM) is called as $U(1)_X$SSM with the local gauge group $SU(3)_C\times SU(2)_L \times U(1)_Y \times U(1)_X$. $U(1)_X$SSM has three singlet Higgs superfields beyond MSSM.…
Radiative symmetry breaking is studied in a superstring-inspired supersymmetric model which is extended with a low energy extra $U(1)$ symmetry. In this model the $\mu$-problem is radiatively solved in an automatic way. The right-handed…
The cosmological significance of the neutralino sector is studied for a class of models in which electroweak symmetry breaking is seeded by a gauge singlet. Extensive use is made of the renormalisation group equations to significantly…
In supersymmetric theories, the top quark can decay into its scalar partner plus a neutralino, with an appreciable rate. We calculate the $O(\alpha_s)$ QCD corrections to this decay mode in the minimal supersymmetric extension of the…
The atmospheric and solar neutrino problems can be explained in a supersymmetric scenario where R-parity is broken bilinearly. Within this context we explore the decays of the top squark. We find that the Rp violating decay $\tilde t_1 -> b…
If supersymmetry is discovered at the LHC, the next question will be the determination of the underlying model. While this may be challenging or even intractable, a more optimistic question is whether we can understand the main contours of…
We make a detailed analysis on the nucleon decay in the minimal supersymmetric $SU(5)$ grand unified model. We find that a requirement of the unification of three gauge coupling constants leads to a constraint on a mass $M_{H_C}$ of…
In the MSSM, the assumptions of a common sfermion mass parameter m_0 and a common gaugino mass parameter m_1/2, along with the requirements from radiative electroweak symmetry breaking, lead to relatively large values of the Higgs mixing…
We present a detailed study of the decays of the neutral Higgs bosons $H^0$ and $A^0$ within the Minimal Supersymmetric Standard Model. We find that the supersymmetric modes ${\tilde{t}}\bar{\tilde{t}}$ and ${\tilde{b}}\bar{\tilde{b}}$ can…
We investigate SU(5) and SO(10) GUTs with vanishing scalar masses and trilinear scalar couplings at a scale higher than the unification scale. The parameter space of the models, further constrained by b-\tau Yukawa coupling unification,…
It is pointed out that there is a strong correlation between the neutralino dark matter scattering cross section $\sigma_{\tilde{\chi} p}$ and the branching ratio for $B_s \to \mu^+ \mu^-$ within minimal supergravity (mSUGRA) and its…
SUSY/SUGRA models with naturalness defined via small $\mu$ are constrained due to experiment on the relic density and the experimental limits on the WIMP-proton cross-section and WIMP annihilation cross-section from indirect detection…
We study polarization and spin correlation effects in the MSSM and in extended supersymmetric models at an e^+e^- linear collider with polarized beams. The production of light neutralinos e^+ e^- --> \tilde\chi^0_1 \tilde\chi^0_2 and the…
We study the production of the lightest neutralinos in the radiative process $e^+e^- \to \tilde\chi^0_1 \tilde\chi^0_1\gamma$ in low energy supersymmetric models for the International Linear Collider energies. This includes the minimal…
The parameters of the Minimal Supersymmetric Standard Model appear to require uncomfortably precise adjustment in order to reconcile the electroweak symmetry breaking scale with the lower mass limits on a neutral Higgs scalar boson. This…
We extend the recently proposed gluino axion model to include neutrino masses. We discuss how the canonical seesaw model and the Higgs triplet model may be realized in this framework. In the former case, the heavy singlet neutrinos are…
We study the production of the lightest neutralinos in the radiative process $e^+e^- \to \tilde\chi^0_1 \tilde\chi^0_1\gamma$ in supersymmetric models with grand unification. We consider models wherein the standard model gauge group…
The totality of neutrino-oscillation phenomena appears to require the existence of a light singlet neutrino. As pointed out recently, this can be naturally accommodated with a specific extra U(1) factor contained in the superstring-inspired…