Wednesday, March 20, 2019

Anatolian Farmers Emerged From Local Hunter-Gatherers

This is completely consistent with the paradigm, but paradigm confirming research has its place too. 

The nuances are also notable. Mesolithic Europeans arose from populations that overlapped with those of the first farmers of the Fertile Crescent. And, in Anatolia, at least, Iranian/Caucasian first farmers predated Levantine first farmers.

Anatolia was home to some of the earliest farming communities. It has been long debated whether a migration of farming groups introduced agriculture to central Anatolia. Here, we report the first genome-wide data from a 15,000 year-old Anatolian hunter-gatherer and from seven Anatolian and Levantine early farmers. We find high genetic continuity between the hunter-gatherer and early farmers of Anatolia and detect two distinct incoming ancestries: an early Iranian/Caucasus related one and a later one linked to the ancient Levant. Finally, we observe a genetic link between southern Europe and the Near East predating 15,000 years ago that extends to central Europe during the post-last-glacial maximum period. Our results suggest a limited role of human migration in the emergence of agriculture in central Anatolia.
Michal Feldman, et al., "Late Pleistocene human genome suggests a local origin for the first farmers of central Anatolia." Nature Communications, 2019 DOI: 10.1038/s41467-019-09209-7

Tuesday, March 19, 2019

Progress In Estimating Hadron Masses

The scalar and axial-vector meson results are particularly an improvement over past work. Top quarks, of course, do not hadronize, so five valence quark types is appropriate. It is also worth noting that the fundamental parameters of QCD are only known to about 0.5% to 1% significance (or worse), so given the multiple parameters at issue, the 2.4%-2.9% errors are not much different from doing first principles calculations using these fundamental parameters.
Using a confining, symmetry-preserving regularisation of a vector×vector contact interaction, we compute the spectra of ground-state pseudoscalar and vector (fg¯) mesons, scalar and axial-vector (fg) diquarks, and JP=1/2+,3/2+ (fgh) baryons, where f,g,h{u,d,s,c,b}. The diquark correlations are essentially dynamical and play a key role in formulating and solving the three-valence-quark baryon problems. The baryon spectrum obtained from this largely-algebraic approach reproduces the 22 known experimental masses with an accuracy of 2.9(2.4)   %. It also possesses the richness of states typical of constituent-quark models, predicting many heavy-quark baryons not yet observed. This study indicates that diquark correlations are an important component of all baryons; and owing to the dynamical character of the diquarks, it is typically the lightest allowed diquark correlation which defines the most important component of a baryon's Faddeev amplitude.
Pei-Lin Yin, Chen Chen, Gastao Krein, Craig D. Roberts, Jorge Segovia, Shu-Sheng Xu "Masses of ground-state mesons and baryons, including those with heavy quarks" (March 1, 2019).

Details results appear below the fold.

META NOTE: This is the 1600th post at this blog.