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New source for electroweak baryogenesis in the minimal supersymmetric standard model
1Physics Department, McGill University, 3600 University Street, Montréal, Québec, Canada H3A 2T8.
Physical Review Letters
|January 3, 2001
Summary
The origin of the universe's baryon asymmetry may stem from the electroweak phase transition. A larger Higgsino field current, H1+H2, enhances baryogenesis efficiency but still requires significant CP-violating angles.
Area of Science:
- Cosmology
- Particle Physics
- Supersymmetry
Background:
- The baryon asymmetry of the Universe (BAU) is a fundamental puzzle in cosmology.
- The minimal supersymmetric standard model (MSSM) offers a framework for electroweak baryogenesis.
- Previous studies focused on the H1-H2 Higgsino current for BAU generation.
Purpose of the Study:
- To investigate the role of the orthogonal Higgsino field current (H1+H2) in electroweak baryogenesis.
- To determine the conditions necessary for generating sufficient BAU within the MSSM.
Main Methods:
- Analysis of electroweak phase transition dynamics within the MSSM.
- Calculation of sphaleron biasing efficiency using different Higgsino field currents.
Main Results:
- The H1+H2 Higgsino current is several orders of magnitude larger than H1-H2.
- This larger current significantly increases the efficiency of electroweak baryogenesis.
- However, large CP-violating angles (≥ 0.15) are still necessary to achieve the observed BAU.
Conclusions:
- The H1+H2 current provides a more efficient mechanism for electroweak baryogenesis.
- The MSSM can potentially explain BAU, but requires substantial CP violation.
- Further experimental and theoretical work is needed to constrain these parameters.