One Geometric Principle Governs Multiple Mysteries (Image Credits: Pixabay)
Tiruchirappalli, India – Physicists introduced a pioneering model that connects neutrino masses, dark matter characteristics, and the universe’s matter-antimatter imbalance through modular S4 symmetry and a type-III seesaw mechanism.[1][2]
One Geometric Principle Governs Multiple Mysteries
A single complex modulus, known as τ, dictates all Yukawa couplings and CP-violating phases in this framework. Researchers Abhishek and V. Suryanarayana Mummidi from the National Institute of Technology, Tiruchirappalli, along with colleagues, demonstrated how this parameter shapes both visible and dark sectors.
The modular S4 symmetry provides the geometric foundation. It links flavor structures in neutrinos to broader cosmic phenomena. “The geometry of the modular symmetry intrinsically links the origin of flavor, CP violation, and the cosmic matter asymmetry,” the team noted in their study.[1] This approach eliminates the need for multiple ad hoc parameters. Instead, resonant leptogenesis emerges naturally, tying together disparate puzzles in particle physics and cosmology.
Precise Predictions for Neutrino Properties
The model generates an effective light-neutrino mass matrix via the type-III seesaw formula: Mν ≃ −MTDM−1ΣMD. Heavy SU(2)L triplets with zero hypercharge operate at a relatively low scale of about 107 GeV.
It aligns with NuFIT 5.2 data for normal ordering. Key forecasts include a CP-violating phase δCP ≃ ±(150°–180°), neutrino mass sum Σmν ≃ (0.06–0.08) eV, and effective Majorana mass mββ ≃ (8–18) × 10−3 eV. Mixing parameters feature sin2θ23 ≃ 0.56 or 0.59, signaling nearly maximal atmospheric mixing. Majorana phases cluster discretely near (0, π) and (±π/2), offering distinct signatures.
Dark Matter Emerges Without Extra Tuning
The framework yields the observed dark matter relic density, Ωχh2 ≃ 0.12, through asymmetric dark matter dynamics. Boltzmann equation analyses confirmed viable parameter spaces.
Dark matter mass predictions cluster around 83 GeV, 37 GeV, or 0.1–2 GeV ranges. These values match cosmological observations and evade direct detection limits. A correlated baryon-dark matter co-genesis fixes abundances predictively.[1]
- 83 GeV candidate aligns with collider constraints.
- 37 GeV option fits indirect detection bounds.
- Low-mass regime (0.1–2 GeV) suits emerging experiments.
Resonant Leptogenesis Fuels Baryogenesis
Nearly degenerate heavy triplet states amplify CP asymmetries to εL,χ ∼ 10−9–10−6. This enhancement, by factors of 102–3, produces the baryon asymmetry ηB ≃ 6 × 10−10 despite small Yukawas ∼10−3.
The imaginary part of τ serves as the unique CP source. Scattering processes in the early universe sustain these asymmetries, linking leptogenesis to visible matter dominance.
Clear Paths for Experimental Tests
Future neutrinoless double-beta decay searches like nEXO and LEGEND-1000 will probe mββ. Collider experiments could detect type-III seesaw triplets at 107 GeV.
Direct detection and cosmology further constrain the 83 GeV dark matter signal. For full details, see the study on arXiv:2602.03384.[1]
This model promises a cohesive view of fundamental physics. It challenges researchers to hunt for these interconnected signatures.
Key Takeaways
- Modular S4 symmetry and type-III seesaw unify neutrinos, dark matter, and baryogenesis via one modulus τ.
- Forecasts 83 GeV dark matter mass and specific neutrino parameters testable soon.
- Resonant leptogenesis explains matter’s prevalence without fine-tuning.
Physicists now eye upcoming data to validate this elegant synthesis. What implications do you see for beyond-Standard-Model physics? Share in the comments.
