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M. G. Paucar

Publications and source records attributed to M. G. Paucar.

4 recordsLinked to original sources

Long-lived Charginos in the Focus-point Region of the MSSM Parameter Space

We analyse the possibility to get light long-lived charginos within the framework of the MSSM with gravity mediated SUSY breaking. We find out that this possibility can be realized in the so-called focus-point region of parameter space. The mass degeneracy of higgsino-like chargino and two higgsino-like neutralinos is the necessary condition for a long lifetime. It requires the fine-tuning of parameters, but being a single additional constraint in the whole parameter space it can be fulfilled in the Constrained MSSM along the border line where radiative electroweak symmetry breaking fails. In a narrow band close to the border line the charginos are long-lived particles. The cross-sections of their production and co-production at the LHC via electroweak interaction reach a few tenth of pb.

hep-ph

Long-living superpartners in the MSSM

The parameter space of the Constrained Minimal supersymmetric Standard Model is considered. It is shown that for the particular choice of parameters there are some regions where long-living charged superparticles exist. Two regions of interest are the co-annihilation region with light staus, and the region with large negative trilinear scalar coupling A distinguished by light stops. The phenomenology of long-living superparticles is briefly discussed.

hep-ph

Light stops in the MSSM parameter space

We consider the regions of the MSSM parameter space where the top squarks become light and even may be the LSP. This happens when the triple scalar coupling A becomes very big compared to m_0. We show that in this case the requirement that the LSP is neutral imposes noticeable constraint on the parameter space excluding low m_0 and m_{1/2} similar to constraint from the Higgs mass limit. In some cases these constraints overlap. This picture takes place in a wide region of \tanβ. In a narrow band close to the border line the stops are long-lived particles and decay into quarks and neutralino (chargino). The cross-section of their production at LHC via gluon fusion mechanism in this region may reach a few pb.

hep-ph

Production of Long-Lived Sleptons at LHC

We analyse the MSSM parameter space and discuss the narrow band near the so-called co-annihilation region where sleptons may be long-lived particles. This region is consistent with the WMAP restrictions on the Dark matter and depends on the value of $\tanβ$. In this region staus are long-lived and may go through the detector. Due to a relatively small mass (150 $÷$ 850 GeV) their production cross-section at LHC may reach a few % pb.

hep-ph