Three-Form Dark Energy Fits Tensioned CMB+BAO+SH0ES Data Better Than ΛCDM
Multi-probe Bayesian constraints show three-form dark energy mildly outperforms ΛCDM only for tensioned dataset combinations while producing a characteristic phantom phase at intermediate redshifts. The model remains consistent with current data but does not resolve the Hubble tension. Future surveys targeting the w(z) turnover will falsify or strengthen the scenario.
The analysis deploys Planck CMB shift parameters, DESI DR2 BAO, Pantheon+ supernovae both with and without SH0ES calibration, cosmic chronometers, and gamma-ray bursts. Parameter estimation uses Markov-chain Monte Carlo sampling while model selection rests on information criteria, Bayesian evidence, and tension statistics. The three-form equation of state exhibits a transient phantom excursion at intermediate redshifts before asymptoting to w = −1 at both high and low z.
This pattern directly addresses the Hubble tension: the extra degrees of freedom permit higher H0 values yet still produce acceptable fits to early-time anchors. The mild preference appears only when early- and late-time datasets that disagree under ΛCDM are combined; separate probes remain neutral or favor the cosmological constant. The result therefore tests whether additional dynamical freedom can reconcile discrepant expansion-rate measurements without violating any single dataset.
Future multi-probe analyses from Euclid and Rubin LSST will tighten w(z) reconstruction at z ≈ 0.5–1.5 where the phantom phase peaks. A decisive test requires the three-form model to maintain evidence ratios above 3:1 once DESI Year-3 and Roman supernova samples are included; failure to do so would relegate the framework to a niche alternative.
DESI: Three-form model evidence ratio versus ΛCDM will exceed 5:1 in Year-3 BAO+SN combination released by mid-2027.
Sources (2)
- [1]Primary Source(https://arxiv.org/abs/2606.27436)
- [2]Supporting Source(https://arxiv.org/abs/2112.01995)