Thursday, May 4, 2023

Measuring CKM Matrix Parameters In A Novel Way

The figure is via the Particle Data Group.

One test of the Standard Model is whether the unitary triangle, which should be possible to derive from the CKM matrix, is consistent with experiment. If the unitary triangle is consistent with experiments to high precision, this is another global test that the Standard Model is complete and is not missing any particles that interact via W boson interactions with Standard Model quarks.

Evaluating the unitary triangle's fit to experimental data currently hinges on difficult to measure bottom quark to charm and up quark transition probabilities in the CKM matrix. But, the author proposes a different way to measure this is more tractable to measure.
During the last three decades the determination of the Unitarity Triangle (UT) was dominated by the measurements of its sides R(b) and R(t) through tree-level B decays and the ΔM(d)/ΔM(s) ratio, respectively, with some participation of the measurements of the angle β through the mixing induced CP-asymmetries like S(ψK(S)) and ε(K). 
However, as pointed out already in 2002 by Fabrizio Parodi, Achille Stocchi and the present author, the most efficient strategy for a precise determination of the apex of the UT, that is (ϱ¯,η¯), is to use the measurements of the angles β and γ. The second best strategy would be the measurements of R(b) and γ. However, in view of the tensions between different determinations of |V(ub)| and |V(cb)|, that enter R(b), the (β,γ) strategy should be a clear winner once LHCb and Belle II will improve the measurements of these two angles. 
In this note we recall our finding of 2002 which should be finally realized in this decade through precise measurements of both angles by these collaborations. In this context we present two very simple formulae for ϱ¯ and η¯ in terms of β and γ which could be derived by high-school students, but to my knowledge never appeared in the literature on the UT, not even in our 2002 paper. 
We also emphasize the importance of precise measurements of both angles that would allow to perform powerful tests of the SM through numerous |V(cb)|-independent correlations between K and B decay branching ratios R(i)(β,γ) recently derived by Elena Venturini and the present author. The simple findings presented here will appear in a subsection of a much longer contribution to the proceedings of KM50 later this year. I exhibited them here so that they are not lost in the latter.
Andrzej J. Buras, "Waiting for Precise Measurements of β and γ" arXiv:2305.00021 (April 28, 2023).

12 comments:

DDeden said...

OT
Was Java man a Denisovan? New video by Steven Milo on new paper.
https://www.youtube.com/watch?v=NNusMHoSdss

andrew said...


Without watching the video itself, Java Man is the type fossil for Asian Homo Erectus, so almost by definition, he should not be a Denisovan.

Java Man is also dated to ca. 1.8 mya, which is long before genetic estimates of TMRCA of modern humans, Denisovans, and Neanderthals, respectively.

andrew said...

John Hawks states in a Tweet:

"Now, we have learned a few things from DNA and ancient proteins. H. antecessor is a sister of the Neandertal-Denisovan-modern clade. Neandertals, today's humans, and Denisovans share common ancestors around 700,000 years ago. Neandertals and Denisovans were related."

Wikipedia on Java Man:

"Java Man (Homo erectus erectus, formerly also Anthropopithecus erectus, Pithecanthropus erectus) is an early human fossil discovered in 1891 and 1892 on the island of Java (Dutch East Indies, now part of Indonesia). Estimated to be between 700,000 and 1,490,000 years old, it was, at the time of its discovery, the oldest hominid fossil ever found, and it remains the type specimen for Homo erectus.

Led by Eugène Dubois, the excavation team uncovered a tooth, a skullcap, and a thighbone at Trinil on the banks of the Solo River in East Java. Arguing that the fossils represented the "missing link" between apes and humans, Dubois gave the species the scientific name Anthropopithecus erectus, then later renamed it Pithecanthropus erectus. The fossil aroused much controversy. Within a decade of the discovery almost eighty books or articles had been published on Dubois's finds. Despite Dubois's argument, few accepted that Java Man was a transitional form between apes and humans.[1] Some dismissed the fossils as apes and others as modern humans, whereas many scientists considered Java Man as a primitive side branch of evolution not related to modern humans at all. In the 1930s Dubois made the claim that Pithecanthropus was built like a "giant gibbon", a much misinterpreted attempt by Dubois to prove that it was the "missing link".

Eventually, similarities between Pithecanthropus erectus (Java Man) and Sinanthropus pekinensis (Peking Man) led Ernst Mayr to rename both Homo erectus in 1950, placing them directly in the human evolutionary tree.

To distinguish Java Man from other Homo erectus populations, some scientists began to regard it as a subspecies, Homo erectus erectus, in the 1970s. Other fossils found in the first half of the twentieth century in Java at Sangiran and Mojokerto, all older than those found by Dubois, are also considered part of the species Homo erectus. The fossils of Java Man have been housed at the Rijksmuseum van Geologie en Mineralogie and later Naturalis in the Netherlands since 1900."

andrew said...

More from the same article:

"Other fossils attest to the even earlier presence of H. erectus in Java. Sangiran 2 (named after its discovery site) may be as old as 1.66 Ma (million years). The controversial Mojokerto child, which Carl C. Swisher and Garniss Curtis once dated to 1.81 ± 0.04 Ma, has now been convincingly re-dated to a maximum age of 1.49 ± 0.13 Ma, that is, 1.49 million years with a margin of error of plus or minus 130,000 years.

Type specimen

The fossils found in Java are considered the type specimen for H. erectus. Because the fossils of Java Man were found "scattered in an alluvial deposit" – they had been laid there by the flow of a river – detractors doubted that they belonged to the same species, let alone the same individual. German pathologist Rudolf Virchow, for instance, argued in 1895 that the femur was that of a gibbon. Dubois had difficulty convincing his critics, because he had not attended the excavation, and could not explain specifically enough the exact location of the bones. Because the Trinil thighbone looks very much like that of a modern human, it might have been a "reworked fossil", that is, a relatively young fossil that was deposited into an older layer after its own layer had been eroded. For this reason, there is still dissent about whether all the Trinil fossils represent the same species."

DDeden said...

Actually, Milo (& Joao) seemed to favor the 12 Ngandong fossils ~125ka(?) more than the older fossils. I agree.

DDeden said...

The gibbon-like thighbone is the one thing that kept me from wholly subscribing to the "everything out of Africa" scenarios. Now I think that Danuvius (Bavaria forest, 11.6ma) is on our lineage, that modern African arboreal apes got to Africa via the Black Sea area, while Homo stayed there but expanded east (Dmanisi 1.7ma), south (Java, ~1.6ma) and west (African Rift). Sahelanthropus was a knucklewalker (ulna paper), probably a chimp ancestor.

neo said...

maybe Denisovans are all Asian Homo Erectus

andrew said...

@neo

Almost certainly not. Too close genetically to modern humans and to Neanderthals.

neo said...

@andrew

Almost certainly not. Too close genetically to modern humans and to Neanderthals.


However, they had larger molars which are reminiscent of Middle to Late Pleistocene archaic humans and australopithecines.

robust molars which are more similar to those of Middle to Late Pleistocene archaic humans. The third molar is outside the range of any Homo species except H. habilis and H. rudolfensis, and is more like those of australopithecines. The second molar is larger than those of modern humans and Neanderthals, and is more similar to those of H. erectus and H. habilis.[20] Like Neanderthals, the mandible had a gap behind the molars, and the front teeth were flattened; but Denisovans lacked a high mandibular body, and the mandibular symphysis at the midline of the jaw was more receding.[12][18] The parietal is reminiscent of that of H. erectus.[39]


Callaway, E. (2019). "Siberia's ancient ghost clan starts to surrender its secrets". Nature News. 566 (7745): 444–446. Bibcode:2019Natur.566..444C. doi:10.1038/d41586-019-00672-2. PMID 30814723.

Chen, F.; Welker, F.; Shen, C.-C.; et al. (2019). "A late Middle Pleistocene Denisovan mandible from the Tibetan Plateau" (PDF). Nature. 569 (7756): 409–412. Bibcode:2019Natur.569..409C. doi:10.1038/s41586-019-1139-x. PMID 31043746. S2CID 141503768. Archived (PDF) from the original on 13 December 2019. Retrieved 7 December 2019.

Warren, M. (2019). "Biggest Denisovan fossil yet spills ancient human's secrets". Nature News. 569 (7754): 16–17. Bibcode:2019Natur.569...16W. doi:10.1038/d41586-019-01395-0. PMID 31043736.

Green, R. E.; Kircher, M.; et al. (2010). "Genetic history of an archaic hominin group from Denisova Cave in Siberia" (PDF). Nature. 468 (7327): 1053–60. Bibcode:2010Natur.468.1053R. doi:10.1038/nature09710. hdl:10230/25596. PMC 4306417. PMID 21179161. Archived from the original on 17 May 2020. Retrieved 29 July 2018.

DDeden said...

I would suggest that the Ngandong fossils represent southernmost Denisovans.

neo said...

the Ngandong fossils represent southernmost Denisovans.

the Ngandong fossils are Homo Erectus

DDeden said...

Yes, a later vintage. Article on mtDNA routes from No. China coast to New World & Japan: https://www.eurekalert.org/news-releases/988195#.ZFqAU6ckdsc.twitter