Related papers: Light Stop and the $b\rightarrow s\gamma$ Process
The flavour-changing neutral current transition b \to s can serve as a sensitive probe of WIMP dark matter models, if the WIMP mass is under 2 GeV. In this work we extend our earlier analysis to a generic class of models where the…
Light neutralino dark matter can be achieved in the Minimal Supersymmetric Standard Model if staus are rather light, with mass around 100 GeV. We perform a detailed analysis of the relevant supersymmetric parameter space, including also the…
Taking a bottom-up point of view and focussing on the lack of signals so far in the Higgs and in the flavour sectors, we argue in favour of giving consideration to supersymmetric extensions of the Standard Model where the lightest Higgs…
The recent discovery of a light CP-even Higgs in a region of masses consistent with the predictions of models with low energy supersymmetry have intensified the discussion of naturalness in these situations. The focus point solution…
We consider regions of the parameter space of the Minimal Supersymmetric Standard Model (MSSM) with bino-like neutralino dark matter in which a large fraction of the total dark matter annihilation cross section in the present era arises…
We examine the Constrained Minimal Supersymmetric Standard Model (CMSSM) with an additional requirement of strict b - tau unification in the region of small tan(beta). We find that the parameter space becomes completely limited below about…
We derive new limits on light stops from diboson resonance searches in the $\gamma\gamma$, $Z \gamma$, $ZZ$, $WW$ and $hh$ channels from the first run of the LHC. If the two-body decays of the light stop are mildly suppressed or…
Supersymmetric extensions of the Standard Model generally give a theoretical upper limit on the lightest Higgs boson mass which may be uncomfortably close to the current experimental lower bound of $m_h$ > 114 GeV. Here we show ways in…
We show that the present limit from CLEO on the inclusive decay $b\to s\gamma$ provides strong constraints on the parameters of the charged Higgs sector in two-Higgs-Doublet-Models. Only a slight improvement in the experimental bound will…
The recent observation by the CLEO Collaboration of the inclusive decay $b\to s\gamma$ with a branching fraction consistent with the expectations of the Standard Model is used to constrain the parameter space of the Left-Right Symmetric…
The Minimal Supersymmetric Standard Model opens the possibility of electroweak baryogenesis provided that the light scalar top quark (stop) is lighter than the top quark. In addition, the lightest neutralino is an ideal candidate to explain…
A light supersymmetric top quark partner (stop) with a mass nearly degenerate with that of the Standard Model (SM) top quark can evade direct searches. The precise measurement of SM top properties such as the cross-section has been…
The restrictions on the lightest Higgs boson mass in the minimal supersymmetric models are briefly reviewed. The particle spectrum is considered in the framework of the simplest modification of NMSSM that allows to avoid the domain wall…
In the Higgs sector of the Minimal Supersymmetric Standard Model, the mass of the pseudoscalar $A$ is an independent parameter together with $\tan \beta \equiv v_2/v_1$. If $m_A$ is small, then the process $e^+ e^- \to h + A$ is…
We investigate the phenomenological viability of a very light bottom squark, with a mass less than half of the Z boson mass. The decays of the Z and Higgs bosons to light sbottom pairs are, in a fairly model independent manner, strongly…
We study both the branching ratio for $b \to s \gamma$ decay and the muon anomalous magnetic moment, $a_{\mu} \equiv (g-2)_{\mu} /2$, in the minimal supersymmetric standard model with gauge-mediated supersymmetry breaking. Combining new…
Supersymmetric models are typically taken to have $\mu$ parameter and all soft supersymmetry breaking parameters at or near the weak scale. We point out that a small window of allowed values exists in which $\mu$ and the electroweak gaugino…
Motivated by the absence, so far, of any direct signal of conventional low-energy supersymmetry, we explore the consequences of making the lightest Higgs boson in supersymmetry relatively heavy, up to about 300 GeV, in the most…
Bounds of the neutral current sector parameters of the left-right symmetric model are investigated taking into account the low-energy data, LEP-data and CDF-result for the top mass $m_t=174\pm 10^{+13}_{-12}$. It is found that in the case…
New NLO b->sgamma calculations have become available. We observe that at large tanbeta the dominant NLO term of the chargino amplitude, which is proportional to mu.tanbeta^2, changes the sign of this amplitude in a large region of the CMSSM…