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Marta Losada

Publications and source records attributed to Marta Losada.

41 records · Page 3Linked to original sources
arXiv1998

The Electroweak Phase Transition in the MSSM

The construction of an effective 3D theory at high temperatures for the MSSM as a model of electroweak baryogenesis is discussed. The analysis for a single light scalar field shows, that given the experimental constraints, there is no value of the Higgs mass for which a sufficiently first-order phase transition is obtained. A precise determination of the 3D parameters of the effective theory for the case of a light right-handed stop allows us to obtain an upper bound on the masses of the lightest Higgs and right-handed stop using the two-loop effective potential. A two-stage phase transition persists for a small range of values of $m_{\tilde{t}_{R}}$.

hep-ph↗
arXiv1998

The Two-Loop Finite-Temperature Effective Potential of the MSSM and Baryogenesis

We construct an effective three dimensional theory for the MSSM at high temperatures in the limit of large-$m_{A}$. We analyse the two-loop effective potential of the 3D theory for the case of a light right handed stop to determine the precise region in the $m_{h}$-$m_{\tilde{t}_{R}}$ plane for which the sphaleron constraint for preservation of the baryon asymmetry is satisfied. We also compare with results previously obtained usind 3D and 4D calculations of the effective potential. A two-stage phase transition still persists for a small range of values of $m_{\tilde{t}_{R}}$. The allowed region requires a value of $m_{\tilde{t}_{R}} \lsi m_{t}$ and $m_{h} \lsi 100$ (110) GeV for $m_{Q} = 300$ GeV (1 TeV).

hep-ph↗
arXiv1996

The Electroweak Phase Transition in the Minimal Supersymmetric Standard Model

Using dimensional reduction we construct an effective 3D theory of the Minimal Supersymmetric Standard Model at finite temperature. The final effective theory is obtained after three successive stages of integration out of massive particles. We obtain the full 1-loop relation between the couplings of the reduced theory and the underlying 4D couplings and masses. The procedure is also applied to a general two Higgs doublet model and the Next to Minimal Supersymmetric Standard Model. We analyze the effective 3D theory constructed for the MSSM to determine the regions of parameter space for which electroweak baryogenesis is possible. We find that the inclusion of all supersymmetric scalars has the effect of enhancing the strength of the phase transition. The requirement of a very light stop is not necessary for baryogenesis. The phase transition is sufficiently first order if the lightest Higgs mass, $m_{h} ~< 70$ GeV. We note the existence of potentially interesting regions of parameter space for which existing analysis techniques are inadequate to decide the question.

hep-ph↗
arXiv1996

SUSY and the Electroweak Phase Transition

We analyze the effective 3 dimensional theory previously constructed for the MSSM and multi-Higgs models to determine the regions of parameter space in which the electroweak phase transition is sufficiently strong for a $B+L$ asymmetry to survive in the low temperature phase. We find that the inclusion of all supersymmetric scalars and all 1-loop corrections has the effect of enhancing the strength of the phase transition. Without a light stop or extension of the MSSM the phase transition is sufficiently first order only if the lightest Higgs mass $M_{h}\lsi 70$ GeV and $tanβ\lsi 1.75$.

hep-ph↗
arXiv1996

High Temperature Dimensional Reduction of the MSSM and other Multi-Scalar Models

Using dimensional reduction we construct an effective 3D theory of the Minimal Supersymmetric Standard Model at finite temperature. The final effective theory is obtained after three successive stages of integration out of massive particles. We obtain the full 1-loop relation between the couplings of the reduced theory and the underlying 4D couplings and masses. The procedure is also applied to a general two Higgs doublet model and the Next to Minimal Supersymmetric Standard Model.

hep-ph↗