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Setting Limits on Supersymmetry Using Simplified Models
Published on: November 15, 2013
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Indications for a Nonzero Lepton Asymmetry from Extremely Metal-Poor Galaxies
Anne-Katherine Burns1, Tim M P Tait1, Mauro Valli2
1Department of Physics and Astronomy, University of California, Irvine, California 92697, USA.
Physical Review Letters
|April 17, 2023
Summary
New Subaru Survey data on helium-4 in early galaxies, combined with deuterium measurements, suggest a non-zero lepton asymmetry. This finding hints at new physics beyond the standard Lambda Cold Dark Matter model.
Area of Science:
- Cosmology
- Early Universe Physics
- Big Bang Nucleosynthesis
Background:
- Recent Subaru Survey measurements of helium-4 in extremely metal-poor galaxies present a potential puzzle for early Universe models.
- Precise measurements of primordial deuterium provide complementary data for cosmological studies.
Purpose of the Study:
- To investigate indications of a non-zero lepton asymmetry during Big Bang Nucleosynthesis (BBN).
- To assess the impact of uncertainties in nuclear reaction networks on BBN calculations.
- To explore potential new physics beyond the standard Lambda Cold Dark Matter (ΛCDM) model.
Main Methods:
- Utilizing recent helium-4 measurements from extremely metal-poor galaxies.
- Incorporating percent-level precision data for primordial deuterium.
- Employing a Bayesian analysis framework, integrating data from cosmic microwave background observations.
Main Results:
- A non-zero lepton asymmetry is suggested at approximately the 2σ significance level.
- The analysis highlights the crucial role of nuclear reaction network uncertainties.
- The findings provide a hint for cosmological models extending beyond ΛCDM.
Conclusions:
- The study provides evidence for a non-zero lepton asymmetry in the early Universe.
- This asymmetry could be consistently realized under specific conditions in the early Universe.
- The results encourage further investigation into physics beyond the standard cosmological model.
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