A 7.9 Sigma Tension In Measuring V(cb) Of The CKM Matrix

In February 2020, a post at this blog reviewed the values of nine CKM matrix elements (which in turn can be derived from not more than four parameters, which are experimentally determined in the Standard Model).

The square of the absolute value of each element is equal to the probability of the transition described in the element to the second type of quark in the subscript taking place, given that a W+ boson has been emitted by a quark of the type of the first type of quark shown in the subscript.

One of those nine elements is V(cb) which has a global best fit value of:

(41.47 ± 0.70) *10^-3

Unitarity constraints (since the sum of the probabilities of all possible transitions from a single quark should equal 100%) suggest that V(cb) may be a bit high.

A new study, limited to fits to decays of neutral B mesons to a negatively charged vector D meson (D∗− (2010), which has as valence quarks an anti-charm quark and a d quark) together with a positively charged lepton (i.e. a positron, anti-muon, or anti-tau lepton) and a neutrino corresponding to it, using new methods, comes up with a lower value for element V(cb) at quite high precision. The result from this study is:

 (35.10 ± 0.41) * 10^-3.

This is a 7.9 sigma tension between this measurement and the global average which is a serious tension.

There could be a methodological error or an error in estimating the margin of error in the new measurement, but given the stark difference, this tension deserves further study.

[Submitted on 21 Aug 2020]

Revisiting fits to B0→D∗−ℓ+νℓ to measure |Vcb| with novel methods and preliminary LQCD data at non-zero recoil

Daniel Ferlewicz, Phillip Urquijo, Eiasha Waheed

We present a study of fits to exclusive B0→D∗−ℓ+νℓ measurements for the determination of the Cabbibo-Kobayashi-Maskawa matrix element magnitude |Vcb|, based on the most recent Belle untagged measurement. Results are obtained with the Caprini-Lellouch-Neubert (CLN) and Boyd-Grinstein-Lebed (BGL) form factor parameterisations, with and without the inclusion of preliminary Lattice QCD measurements of form factors at non-zero hadronic recoil from the JLQCD collaboration. The CLN and BGL fits are also studied in different scenarios with reduced theoretical assumptions, and at higher order expansions respectively. To avoid bias from high systematic uncertainty correlations we use a toy MC approach with a Cholesky decomposition of the covariance matrix. We find that (1)ηEW|Vcb|=(35.2±0.2±0.8)×10−3 for CLN and (34.9±0.3±1.0)×10−3 for BGL(1,0,2) without input from Lattice QCD. The errors quoted correspond to statistical and systematic uncertainties, respectively. We find no evidence to support lepton flavour dependence on the measurement of |Vcb| but find some tension in the results associated with the ratio of form factors R1. We show how input from JLQCD allows for well defined fit results with reduced model dependence in CLN and BGL. The results obtained using preliminary values are consistent between different orders of parameterisations, ultimately providing a method for a model-independent exclusive measurement of |Vcb|. Using preliminary inputs from the JLQCD collaboration, (1)ηEW|Vcb| is found to be approximately (35.1±0.07±0.4)×10−3 in BGL(2,2,2).

Aztec Astronomy

We have some historical records of pre-Columbian Aztec astronomy demonstrated by the following pre-print:

[Submitted on 20 Aug 2020]

Eclipses in the Aztec Codices

Emil Khalisi

This paper centers on the collection of accounts on solar eclipses from the era of the Aztecs in Mesoamerica, about 1300 to 1550 AD. We present a list of all eclipse events complying with the topological visibility from the capital Tenochtitlan. Forty records of 23 eclipses entered the various Aztec manuscripts (codices), usually those of large magnitude. Each event is discussed with regard to its historical context, as we try to comprehend the importance the Aztecs gave to the phenomenon. It seems that this culture paid noticeably less attention to eclipses than the civilisations in the "Old World". People did not understand the cause of it and did not care as much about astronomy as in Babylonia and ancient China. Furthermore, we discuss the legend on the comet of Moctezuma II. It turns out that the post-conquest writers misconceived what the sighting was meant to be.

Comments:	15 pages, 10 figs, 2 tabs, 25 refs
Subjects:	History and Philosophy of Physics (physics.hist-ph); Earth and Planetary Astrophysics (astro-ph.EP)
Journal reference:	Habilitation at the University of Heidelberg, Germany, February 2020
Cite as:	arXiv:2008.08982 [physics.hist-ph]
	(or arXiv:2008.08982v1 [physics.hist-ph] for this version)

Roanoke Mystery Solved

One of the early posts at sister blog Wash Park Prophet was about Roanoke. At the time, I opened up the broader reflection on failed first steps with this summary of the story:

In 1587, the English founded a colony at Roanoke Island, in Virginia. Three years later, only ruins remained. All 117 settlers were gone. 

As everyone knows, this didn't stop the English from colonizing North America. Twenty years later, in 1607, they founded Jamestown, and while that colony struggled at first, with the majority of its settlers dying in the hard winter of 1609-1610 until only 60 lived, Jamestown survived and the rest is history.

Roanoke's mystery, however, has pretty much been solved now.

The "Lost Colony" on Roanoke Island merged their community with a friendly Indian tribe called the Croatoans on Hatteras Island sometime after 1587 and before 1590. The descendants of the merged  communities continues together for generations afterwards, because this very early American colony wasn't making it on its own and faced hostility from another tribe in the region who had enslaved the Croatoans until the Roanoke colonists freed them.

BUXTON, N.C. — The English colonists who settled the so-called Lost Colony before disappearing from history simply went to live with their native friends — the Croatoans of Hatteras, according to a new book. 

“They were never lost,” said Scott Dawson, who has researched records and dug up artifacts where the colonists lived with the Indians in the 16th century. “It was made up. The mystery is over.” 

Dawson has written a book, published in June, that details his research. It is called “The Lost Colony and Hatteras Island,” and echos many of the sentiments he has voiced for years. A team of archaeologists, historians, botanists, geologists and others have conducted digs on small plots in Buxton and Frisco for 11 years. Dawson and his wife, Maggie, formed the Croatoan Archaeological Society when the digs began. Mark Horton, a professor and archaeologist from England’s University of Bristol leads the project. Henry Wright, professor of anthropology at the University of Michigan, is an expert on native history. Teams have found thousands of artifacts 4-6 feet below the surface that show a mix of English and Indian life. Parts of swords and guns are in the same layer of soil as Indian pottery and arrowheads. The excavated earth looks like layer cake as the centuries pass. 

“In a spot the size of two parking spaces, we could find 10,000 pieces,” he said. 

Pieces found during the project are on display at the Hatteras Library. The rest are in storage. Dawson’s book draws from research into original writings of John White, Thomas Harriot and others. Most of their writings were compiled at the time by English historian Richard Hakluyt. Records from Jamestown also helped Dawson understand more about the tribes’ political structure. 

The evidence shows the colony left Roanoke Island with the friendly Croatoans to settle on Hatteras Island. They thrived, ate well, had mixed families and endured for generations. More than a century later, explorer John Lawson found natives with blue eyes who recounted they had ancestors who could “speak out of a book,” Lawson wrote. The two cultures adapted English earrings into fishhooks and gun barrels into sharp-ended tubes to tap tar from trees. 

The Lost Colony stemmed from an 1587 expedition. Just weeks after arriving, White had to leave the group of settlers — including his daughter, Eleanor Dare, and newborn granddaughter, Virginia — to get more supplies from England. White was not able to return for three years. When he arrived at Roanoke Island in 1590 he found “CROATOAN” carved on a post and “cro” on a tree. He found no distress marks. They literally made a sign. It was expected the colonists would go with their friends, the Croatoans and tribe member, Manteo, Dawson said. Manteo had traveled to England with earlier expeditions and was baptized a Christian on Roanoke Island. 

White later wrote of finding the writing on the post, “I greatly joyed that I had found a certain token of their being at Croatoan where Manteo was born ....”  A bad storm and a near mutiny kept White from reaching Hatteras. He returned to England without ever seeing his colony again. Archaeologists found a flower-shaped clothing clasp belonging to a woman with the other items. Sir Walter Raleigh sent three expeditions to the New World in 1584, 1585 and in 1587. The first two had more military purposes and did not include women. The 1587 group brought 16 women with it, Dawson said. They also found round post holes where Indians built their long houses 25 feet to 60 feet long and they uncovered square post holes made by English during the same period. 

“They were in the Indian village surrounded by long houses,” Dawson said. Bones of turtle, wildfowl and deer bones indicate good eating. Pigs teeth turn up for generations. 

“They never had to eat the last pig,” Dawson said. 

Any skeletons uncovered during the digs were left untouched out of respect, Dawson said. One artifact could depict a recorded event. A lead tablet and lead pencil found at the dig could have belonged to White himself, Dawson said. White also was part of the 1585 group, working as an artist who drew natives and wildlife. The British Museum has the originals. He likely used the newly discovered tablet or a similar one to draw the miniature pictures. The uncovered tablet has an impression of an Englishman shooting a native in the back. The paper drawing has never been found. 

Wingina, chief of the Secotans, was shot twice in the back by an Englishman in 1586 at a village near what is now Manns Harbor, Dawson said. The Croatoans assisted the English in the ambush, Dawson said. The Secotans and the Croatoans hated each other, Dawson said. Secotans enslaved Croatoans just a few years before the English arrived. The English had burned a Secotan village in 1585. The Croatoans befriended the English as powerful friends with guns and armor. White’s colony welcomed their friendship, especially after one of their members, George Howe, was killed by the Secotans. White was concerned about the danger posed by the Secotans when he left for England. The Croatoans saved the colonists by taking them away from Roanoke Island to their Hatteras Island village, Dawson said.

“You’re robbing an entire nation of people of their history by pretending Croatoan is a mystery on a tree,” he said. “These were a people that mattered a lot.”

From here.

Sudan's Many Ancient Names

Of all the ancient historical names for the country we now know as Sudan, I can't say that Sudan was a good choice. 

The land south of Egypt, beyond the first cataract of the Nile, was known to the ancient world by many names: Ta-Seti, or Land of the Bow, so named because the inhabitants were expert archers; Ta-Nehesi, or Land of Copper; Ethiopia, or Land of Burnt Faces, from the Greek; Nubia, possibly derived from an ancient Egyptian word for gold, which was plentiful; and Kush, the kingdom that dominated the region between roughly 2500 B.C. and A.D. 300. In some religious traditions, Kush was linked to the biblical Cush, son of Ham and grandson of Noah, whose descendants inhabited northeast Africa.

From the Smithsonian Magazine.