Related papers: Constraining Supergravity Scenarios through the $b…
The gluino contributions to the $C'_{7,8}$ Wilson coefficients for b->s\gamma are calculated within the unconstrained MSSM. New stringent bounds on the \dRLbs and \dRRbs mass insertion parameters are obtained in the limit in which the SM…
We discuss several phenomenological aspects of the fully constrained version of the next-to-minimal supersymmetric extension of the standard model (cNMSSM). Assuming universal boundary conditions at a high energy scale for the soft…
We study the constraints on the parameter space of the supersymmetric standard model extended by a gauge singlet, which arise from the absence of global minima of the effective potential with slepton or squark vevs. Particular attention is…
We analyze uncertainties in the theoretical prediction for the inclusive branching ratio $BR[B \rightarrow X_s \gamma]$. We find that the dominant uncertainty in the leading order expression comes from its $\mu$-dependence. We discuss a…
I review the phenomenological and cosmological constraints on the parameter space associated with the Constrained Minimal Supersymmetric Standard Model (CMSSM). The effect of the recent WMAP determination of the cold dark matter density…
Using the recent CLEO measurement of $Br(b\to s \gamma)$, we find that the branching ratio of $b\to s g$ cannot be larger than $10\%$ in two Higgs doublet models. The small experimental value of $Br(b\to e\bar{\nu}X)$ can no longer be…
We propose a solution to the $\mu$-problem due to the non-universal soft supersymmetry breaking in a class of supersymmetric extensions of the SM with an extra U(1) and the NMSSM. Our scenario resembles an earlier one which has been…
We investigate the constraints on Supersymmetry arising from available precision measurements using a global fit approach. When interpreted within minimal supergravity (mSUGRA), the data provide significant constraints on the masses of…
We update the standard model predictions for the branching ratios of the decays B -> (K,K*,Xs) l^+ l^-, with l=e,mu. Using the measurements of BR(B -> Xs gamma) and BR(B -> K l^+ l^-) as well as the upper limits on BR(B -> (K*,Xs) l^+…
We study B_s --> mu+ mu- in the context of the R-parity violating minimal supergravity in the high tan beta regime. We find that the lowest value of the branching ratio can go well below the present LHCb sensitivity and hence B_s --> mu+…
Recent re-evaluations of the Standard Model (SM) contribution to ${\mathcal Br(b\to s\gamma)$ hint at a positive correction from new physics. Since a charged Higgs boson exchange always gives a positive contribution to this branching ratio,…
Within the Minimal Supersymmetric Grand Unified Theory (MSGUT) masses of the predicted supersymmetric particles are constrained by the world averaged values of the electroweak and strong coupling constants, the lower limits on the proton…
If all strongly interacting sparticles (the squarks and the gluinos) in an unconstrained minimal supersymmetric standard model (MSSM) are heavier than the corresponding mass lower limits in the minimal supergravity (mSUGRA) model, obtained…
We revisit the constraints on the parameter space of the Minimal Supersymmetric Standard Model (MSSM), from charge and color breaking minima in the light of information on the Higgs from the LHC so far. We study the behavior of the scalar…
We study the structure of soft breaking terms in the context of a gaugino condensation scenario. Assuming that the Supergravity Lagrangian is the correct quantum field theory limit, at some momentum scale $\mu_{UV}$, of a more fundamental…
The purely leptonic rare decay Bs -> mu+mu- is very sensitive to supersymmetric contributions which are free from the helicity suppression of its Standard Model diagrams. The recent observation of the decay by the LHCb experiment and the…
The requirement that the supersymmetric scalar potential be stable in the minimal supergravity (mSUGRA) model imposes an upper bound on the universal gaugino mass $m_{1/2}$ as function of the common scalar mass $m_0$. Combining this with…
When solving renormalisation group equations in a quantum field theory, one often specifies the boundary conditions at multiple renormalisation scales, such as the weak and grand-unified scales in a theory beyond the standard model. A point…
New limits on the Higgs mass from LEP and new calculations on the radiative (penguin) decay of the b->s gamma branching ratio restrict the parameter space of the Constrained Minimal Supersymmetric Standard Model (CMSSM). We find that for…
In the Minimal Supersymmetric Standard Model (MSSM), there are numerous sources of flavour-violation in addition to the usual Kobayashi-Maskawa mixing matrix of the Standard Model. We reexamine the renormalisation group equations (RGEs)…