Thursday, August 13, 2026

Hadronic B Decay Anomalies

The anomaly of the day is an anomaly in a certain kind of B meson decay. I'm very skeptical and think it will go away and is probably due to poor modeling of the Standard Model prediction, but I'll note its existence in this post for further analysis.

The decays B→PP, where the pseudoscalar P is a π or K, have been studied under the assumption of flavour SU(3) symmetry [SU(3)F]. The global fit shows a 3.6σ discrepancy with the Standard Model (SM). 
Separate fits for ΔS=0 and ΔS=1 decays find parameter sets that differ by a factor of 10, suggesting 1000% SU(3)F breaking, significantly larger than the ∼ 30% breaking expected in the SM. This study has been extended to include final states with η and η′ mesons. The resulting global fit, once again under the assumption of SU(3)F symmetry, is worse, with a 4.1σ deviation from the SM. When theoretical constraints |C˜/T˜| = 0.2 or A˜ = 0 are imposed, the fits worsen, with the discrepancy approaching 5σ. These results hint at new-physics contributions to these decays.
Marianne Bouchard, David London, "Anomalies in Hadronic B Decays" arXiv:2608.11298 (August 11, 2026) (Contribution to the Proceedings of the XVI International Conference on Beauty, Charm, Hyperons in Hadronic Interactions (BEACH 2026), 7-12 June 2026, Firenze, Italy).

Another Alternative To Particle Dark Matter

A Covarying Coupling Constant theory performs similarly to, but not better than MOND. Both are much better at explaining galaxy rotation dynamics than a Cold Dark Matter theory using an NFW dark matter distribution (which is theoretically necessary for truly sterile dark matter particles).

The Covarying Coupling Constants (CCC) framework, developed to account for high-redshift JWST observations, contains a mechanism -- a covarying-constant effective mass field keyed to local density -- that modifies galactic dynamics without particle dark matter. 
We test it against the full Spitzer Photometry and Accurate Rotation Curves (SPARC) sample of 175 disc galaxies, extending an earlier study of a few objects. Working in an inverse formulation, in which each model predicts the baryonic rotation curve from the observed one, we compare CCC against Modified Newtonian Dynamics (MOND) and one- and two-parameter Navarro-Frenk-White (NFW) haloes on identical footing, using the reduced χ2ν. We show that the published sharp density turn-off in the earlier study is unphysical and replace it with a smooth transition -- the density-space analogue of the MOND interpolating function, introducing no new parameter. One-parameter smooth-CCC then performs comparably to galaxy-by-galaxy fitted MOND (the lower χ(ν)^2 in 56 per cent of galaxies, mean χ(ν)^2 of 2.58 versus 2.65; the paired difference is not significant), while two-parameter NFW shows a substantially broader fit-quality distribution and a larger tail of poor or boundary-limited fits (mean χ(ν)^2≈7). The CCC turn-off density is not universal (scatter 0.82 dex) and correlates with galaxy size, qualitatively consistent with a spherical reconstruction applied to flattened disc systems. Recast as an acceleration, however, a(t) = V(flat)^2/R(t) has scatter 0.33 dex (on the 91-galaxy resolved subset) -- matching the MOND scale a0 (0.34 dex) -- and comparable magnitude of order 2×10^−10 m/s^2, with its size correlation removed. Though not designed for galactic dynamics, CCC describes rotation curves as well as galaxy-by-galaxy fitted MOND.
Rajendra P. Gupta, Nikolaos Samaras "Testing Covarying Coupling Constants (CCC) against the full SPARC rotation-curve sample: a like-for-like comparison with MOND and NFW" arXiv:2608.11575 (August 12, 2026).

Tuesday, August 11, 2026

Denisovan Remains May Be Younger Than First Believed

Not long ago, we were finally able to find decent sized bones that proteins provided proteomic evidence (rather than DNA evidence which was not available) were able to match to Denisovans, which were found on the coast of the main island of Taiwan, finally putting a body together with the ghost population implied by DNA evidence. Two more leg bones were recently found.

Earlier dating had suggested an age for the Taiwanese Denisovan remains of about 160,000 years ago, long before modern humans arrived in the region and overlapping with Homo erectus. Analysis of the new leg bones by a more reliable and credible method, however, reveals that they are actually just 45,000 years old, contemporaneous with a modern human presence in the region.

At one level this isn't a surprise. Modern humans in Southeast and East Asia and Oceania have genetic admixture from Denisovans, so they had to overlap at some point. But it is surprising that the two different dating methods differed from each other by a factor of four.

The chemical analysis also suggests that these Denisovans, like Neanderthals, had a diet heavy in meat from large mammals.

My link is to a blog post by John Hawks who cites his sources:

* Chang, Chun-Hsiang, et al., "The first archaic Homo from Taiwan." 6 Nature Communications 6037 (2015). doi:10.1038/ncomms7037

* Grün, R. & Stringer, C., "Direct dating of human fossils and the ever-changing story of human evolution." 322 Quaternary Science Reviews 108379 (2023). https://doi.org/10.1016/j.quascirev.2023.108379

* Kaifu, Y., Chang, et al., "Denisovan leg bones from Taiwan reveal large body size." bioRxiv (2026). https://doi.org/10.64898/2026.08.07.743438

* Tsutaya, et al., "A male Denisovan mandible from Pleistocene Taiwan." 388(6743) Science 176–180 (2025). https://doi.org/10.1126/science.ads3888

* Yoneda, et al., "Habitat and feeding ecology of a Denisovan from Late Pleistocene Taiwan." bioRxiv (2026). https://doi.org/10.64898/2026.08.07.743455

* Zhang, D., et al., "Denisovan DNA in Late Pleistocene sediments from Baishiya Karst Cave on the Tibetan Plateau." 370(6516) Science 584–587 (2020). https://doi.org/10.1126/science.abb6320

Systemic Deviations From The Radial Acceleration Relation?

There is weak evidence that the radial acceleration relation, which is implied by Milgrom's toy-model MOND theory of weak field gravity, requires a single parameter correction is correlated with the compactness of the galaxies measured, primarily in dwarf galaxies.

Query if this could be due to the external field effect or due to gravitationally bound systems that are not in equilibrium? It could also be due to underestimated systemic error in estimating gas fractions, which is much harder to determine that stellar mass.
We ask whether any one-parameter structural correction to the radial acceleration relation (RAR) can be uniquely recovered from SPARC rotation curves, and answer with an identifiability audit: each candidate is benchmarked against per-galaxy nuisance freedom, with predictive scoring against mass-only and data-quality baselines. 
In the full sample (N = 126) the answer is no: a hybrid compactness term improves the fit, but zero-point freedom absorbs the gain, and in cross-validation the model fails to out-predict a mass-only baseline and loses to a quality-flag baseline. 
One regime retains structural information: in gas-dominated, low-acceleration disks -- where MOND's strict locality and ΛCDM feedback models diverge most sharply -- the RAR residual correlates with compactness (r = 0.46, p = 1.3×10^−4), remains significant under hierarchical partial pooling (β = 0.23, p = 1.7×10^−5; N = 63), and survives canonical joint control for quality, sampling, mass, inclination error, and first-order pressure support (r = 0.30, p = 0.02). All significant results pass a Benjamini-Hochberg correction over the declared 27-test family. 
Three limits temper that survival: it is not significant under rank-based control over the widest proxy set; it resides in faint dwarfs independent surveys do not reach; and after mass control it is shared across the mass-size manifold. Pressure support brackets the interpretation -- isotropic drift correction absorbs a quarter of the amplitude, while a Jeans treatment overcorrects resolved cases -- leaving the physical origin undetermined. The audit's product is the extraction limit: claimed corrections must clear the 0.106 dex per-galaxy nuisance floor, a mass-only baseline, and data-quality stratification.
Lukas A. Sosna, "An Identifiability Audit of One-Parameter Structural Corrections to the Radial Acceleration Relation in SPARC" arXiv:2608.08945 (August 9, 2026).