Thursday, January 27, 2022

About The CKM Matrix

A new preprint makes two notable observations about the CKM matrix. 

One of them is that only one of the four parameters of the CKM matrix in the Wolfenstein parameterization (see below for background), specifically "A", runs significant with energy scale.  The body text notes that:
The running of A has been calculated before, but there is an apparent disagreement in the literature about its running in the SM: Ref. [8] reports an increase in A of about 13% from the weak scale to the GUT scale, while in Fig. 2 of Ref. [9] A increases by about 25%. We resolve this discrepancy. As we explain in § II, we find that recomputing the running of A using the methods of Ref. [9] gives a result which, in fact, agrees with Ref. [8]. Thus, we take the results of both Ref. [8] and Ref. [9] (except for their Fig. 2) to be correct.
Roughly speaking, this parameter quantifies the extent to which the probability of a first or second generation quark becoming a third generation quark, or visa versa, differs in a way that is not a function of the other parameters, from other possible quark generation transitions. 

It also notes that below the top quark mass energy scale, the CKM matrix is basically constant and does not meaningfully run with energy scale.

In the low energy scale limit, the measured value of A, whose best fit global average value is 0.814, is consistent with these transitions occurring with two-thirds of the probability derived from consideration of the other terms.

The body text explains why this is the case:
The CKM elements run due to the fact that the Yukawa couplings run. Furthermore, the running of the CKM matrix is related to the fact that the running of the Yukawa couplings is not universal. If all the Yukawa couplings ran in the same way, the matrices that diagonalize them would not run. Thus, it is the nonuniversality of the Yukawa coupling running that results in CKM running. 
Since only the Yukawa coupling of the top quark is large, that is, O(1), to a good approximation we can neglect all the other Yukawa couplings. There are three consequences of this approximation: 
1. The CKM matrix elements do not run below m(t). 
2. The quark mass ratios are constant except for those that involve m(t). 
3. The only Wolfenstein parameter that runs is A. 
The first two results above are easy to understand, while the third one requires some explanation. A is the parameter that appears in the mixing of the third generation with the first two generations, and thus is sensitive to the running of the top Yukawa coupling. λ mainly encodes 1–2 mixing — that is, between the first and second generations — and is therefore insensitive to the top quark. The last two parameters, η and ρ, separate the 1–3 and 2–3 mixing. Thus they are effectively just a 1–2 mixing on top of the 2–3 mixing that is generated by A. We see that, to a good approximation, it is only A that connects the third generation to the first and second, and thus it is the only one that runs.
The other is that it looks for numerical coincidences that could conjecturally suggest a deeper structure for the CKM matrix, on a brute force basis, comprehensively for at all energy scales up to the Planck energy scale and finds 19 of them, one of which it deems worthy of setting forth in its abstract. With respect to this relation, the body text notes that:
We find one particularly intriguing relation, 
|V(td)V(us)| = |V^2(cb)|,     (1.3) 
that holds in the SM between 10^9 and 10^15 GeV, overlapping the scale where the Higgs quartic vanishes and the GUT scale. In terms of Wolfenstein parameters, this relation can be written as 
A^2 = (1 − ρ)^2 + η^2 . (1.4) 
Ideally we would like to find a UV model that generates this relation without tuning.
The paper and its abstract are as follows:
We look for relations among CKM matrix elements that are not consequences of the Wolfenstein parametrization. In particular, we search for products of CKM elements raised to integer powers that approximately equal 1. We study the running of the CKM matrix elements and resolve an apparent discrepancy in the literature. 

To a good approximation only A runs, among the Wolfenstein parameters. 

Using the Standard Model renormalization group we look for CKM relations at energy scales ranging from the electroweak scale to the Planck scale, and we find 19 such relations. These relations could point to structure in the UV, or be numerical accidents. 
For example, we find that |VtdVus|=|V2cb|, within 2% accuracy, in the 109-1015 GeV range. 

We discuss the implications of this CKM relation for a Yukawa texture in the UV.
Yuval Grossman, Ameen Ismail, Joshua T. Ruderman, Tien-Hsueh Tsai, "CKM substructure from the weak to the Planck scale" arXiv:2201.10561 (January 25, 2022).


In the Standard Model of Particle Physics, W+ bosons can be emitted by up-type quarks to give rise to any of the three down-type quarks (mass-energy conservation in the end states permitting), and W- bosons can be emitted by down-type quarks to give rise to any of the three up-type quarks (mass-energy conservation permitting). The probability of a quark emitting a W boson is quantified with the weak force coupling constant.

The Cabibbo–Kobayashi–Maskawa matrix a.k.a. CKM matrix summarizes the experimentally measured physical constants that quantify the probability that a W boson emission from a particular type of quark will result in a particular type of quark being produced when mass-energy conservation in the end states does not constrain the available options. There are nine components to the CKM matrix (which are complex valued), the absolute value of which when squared equals the probability that an emission of a W boson from a particular kind of quark will produce a particular kind of quark.

Illustration from Wikipedia. The magnitude of the element combines the real and imaginary components of each element (basically it is the square root of the absolute value of the square of  each entry), discarding any purely complex residual after doing so.

These entries are complex valued because these probabilities are not CP-symmetric. The CP conservation violations quantified by the CKM matrix reflect the fact that the probabilities are not quite the same for matter and antimatter (although CP violation in the CKM matrix is quite small).

The CKM matrix can also be illustrated geometrically as opposed to algebraically as shown below in a Wikipedia illustration:

While the CKM matrix has nine complex valued entries, it can be fully described with four parameters, although there are multiple ways that this parameterization can be done. It is possible to have a parameterization with as few as one complex valued parameter and three real number valued parameters.

Like all of the experimentally measured Standard Model physical constants, the values of  the CKM matrix "run" with energy scale according to a "beta function" that can be determined without experimental input from the equations of the Standard Model.

One of the two main parameterization of the CKM matrix is the Wolfenstein parameterization, which is attractive relative to the "standard parameterization" because it is suggestive of a particular underlying structure in the CKM matrix.

Illustration from Wikipedia.

The Black Plague Was Present In Bronze Age Britain

The Bell Beaker people brought the plague to Britain, and presumably, they also brought it to much of the rest of Western Europe as well (consistent with its probable original origins in East Eurasia).

Pooja Swali and colleagues have just published a paper titled: Yersinia pestis genomes reveal plague in Britain 4,000 years ago. They identified the genome of the bacterium Yersinia pestis in the genome of two skeletons (C10091 and C10098) from the disarticulated remains of more than 40 individuals disposed in a natural well at Charterhouse Warren Farm in Somerset, England:

These individuals show signs of fatal perimortem trauma. They are accompanied by objects belonging to the Bell Beaker culture. The two individuals with the plague are two children aged 10 and 12. One of them has been directly radiocarbon dated between 4145 and 3910 years old. The presence of mortal wounds on the skeletons of this well makes it improbable that this well was used as a burial following a plague epidemic.

From Bernard's blog (Google translated from the original French). 

Notably, for the first time, Google translate correctly translated the phrase "Bell Beaker culture", rather than translating the French word literally, which isn't similar to the English language term at all.

A phylogenetic analysis of the Bronze Age British plague genome samples also illustrates that there were distinct Neolithic, Bronze Age, and Medieval waves of the Black Plague in Europe, each with distinct common ancestors. 

Since we don't have written historical accounts clearly associated with the plague prior to the Justinian plague (which raged from 541-549 CE in the Eastern Roman Empire), it is hard to know if the earlier variants of it were as catastrophically deadly as the Medieval variants that killed a third of the people in many parts of Europe.

Wednesday, January 26, 2022

Superfluid Dark Matter Has Some Issues

A recent pre-print, with two of my favorite physicist physics bloggers (McGaugh and Hossenfelder) collaborating as co-authors, examines the fit of Mistele and Hossenfelder's superfluid dark matter hypothesis to a large sample of galactic rotation curves, compares its performance to Modified Newtonian Dynamics (MOND) and finds it wanting.
We make rotation curve fits to test the superfluid dark matter model. Our aim is to investigate whether superfluid dark matter provides satisfactory fits to galactic rotation curves with reasonable stellar mass-to-light ratios. We fitted the superfluid dark matter model to the rotation curves of 169 galaxies in the SPARC sample. We found that the mass-to-light ratios obtained with superfluid dark matter are generally acceptable in terms of stellar populations. However, the best fit mass-to-light ratios have an unnatural dependence on the size of the galaxy in that giant galaxies have systematically lower mass-to-light ratios than dwarf galaxies. A second finding is that the superfluid often fits the rotation curves best when the superfluid's force does not closely resemble that of Modified Newtonian Dynamics (MOND). In that case, we can no longer expect superfluid dark matter to reproduce the phenomenologically observed scaling-relations that make MOND appealing. If, on the other hand, we consider only solutions whose force approximates MOND well, then the total mass of the superfluid is in tension with gravitational lensing data. We conclude that even the best fits with superfluid dark matter are still unsatisfactory.
Tobias Mistele, Stacy McGaugh, Sabine Hossenfelder "Galactic Mass-to-Light Ratios With Superfluid Dark Matter" arXiv:2201.07282 (January 18, 2022).

String Theory Is Still Vaporware

Woit explains convincingly that even string theorists know that string theory has no foreseeable observational basis, and that the theoretical arguments currently being advanced are wanting as well. 

Friday, January 21, 2022

What Is The Weak Gravity Conjecture?

The review article is 120 pages long, but the abstract and introduction alone are very helpful in providing a grounding in what the weak gravity conjecture is, and why it matters.

The Weak Gravity Conjecture holds that in a theory of quantum gravity, any gauge force must mediate interactions stronger than gravity for some particles. 
This statement has surprisingly deep and extensive connections to many different areas of physics and mathematics. Several variations on the basic conjecture have been proposed, including statements that are much stronger but are nonetheless satisfied by all known consistent quantum gravity theories. 
We review these related conjectures and the evidence for their validity in the string theory landscape. 
We also review a variety of arguments for these conjectures, which tend to fall into two categories: qualitative arguments which claim the conjecture is plausible based on general principles, and quantitative arguments for various special cases or analogues of the conjecture. 
We also outline the implications of these conjectures for particle physics, cosmology, general relativity, and mathematics. 
Finally, we highlight important directions for future research.
Daniel Harlow, Ben Heidenreich, Matthew Reece, Tom Rudelius, "The Weak Gravity Conjecture: A Review" arXiv:2201.08380 (January 20, 2022) (invited review, submitted to Reviews of Modern Physics).

Wednesday, January 19, 2022

Do We See The Expansion Of The Universe In Titan's Orbit?

Saturn's moon Titan's orbit gets about a four and  a half inches a year further from Saturn each year, plus or minus an inch or so, according to an ultra-precise measurement by the Cassini probe. 

There are all sorts of factors that could account for this, so assuming that the overall expansion of the Universe, which is such a tiny consideration at this distance scale, could account for this effect seems like a long shot. On the other hand, a back of napkin calculation suggests that the observed effect is of the right order of magnitude to be explained by it. 

So, while this is interesting enough observation to make note of for future reference, I don't necessarily take it too seriously.

Recently it was found from Cassini data that the mean recession speed of Titan from Saturn is v=11.3±2.0 cm/yr which corresponds to a tidal quality factor of Saturn Q≅100 while the standard estimate yields Q≥6⋅10^4. It was assumed that such a large speed v is due to a resonance locking mechanism of five inner mid-sized moons of Saturn. 
In this paper, we show that an essential part of v may come from a local Hubble expansion, where the Hubble-Lemaıtre constant H(0) recalculated to the Saturn-Titan distance D is 8.15 cm/(yr D). Our hypothesis is based on many other observations showing a slight expansion of the Solar system and also of our Galaxy at a rate comparable with H(0). We demonstrate that the large disproportion in estimating the Q factor can be just caused by the local expansion effect.
Michal Křížek, Vesselin G. Gueorguiev, André Maeder, "An alternative explanation of the orbital expansion of Titan and other bodies in the Solar system" arXiv:2201.05311 (January 14, 2022).

Cycles Of Activity In The Sun Support The Existence Of Planet 9

A new paper makes a fascinating argument for the existence of a Planet 9 that is largely independent of prior arguments in favor of it, based upon solar activity cycles. The underlying theory it relies upon is controversial and is one of several that has been proposed to explain observed solar activity cycles.

But, if Planet 9 turns out to be where it is supposed to be under this theory with the predicted parameters, this theory of what is driving solar activity is boosted tremendously.
Planet 9 is currently a hypothetical planet the orbital parameters of which are based on anomalous orbits of Kuiper Belt objects. 
The orbital parameters are such that, if Planet 9 exists, the theory of solar barycentric dynamics would be profoundly altered. We show that, with Planet 9 included in the solar system, barycentric theory is a much more effective predictor of solar activity on the decadal, centennial and millennium time scales. In particular the most elementary quantity of barycentric theory, the Sun to planet barycentre distance, is more coherent with decadal solar activity cycles and grand solar activity minima than barycentric distance without Planet 9 included. Further, barycentric theory including Planet 9 contains strong components at periods corresponding to the Hallstaatt and Gleissberg cycles whereas barycentric theory without Planet 9 shows no evidence of these cycles. 
A challenge that emerged during this study was the absence of the strongest component in barycentric theory, the Jose component at ~ 178 year period, from the spectra of millennium scale solar activity. This conundrum was solved by demonstrating that, during the transformation from solar motion to solar activity, the Jose component in solar motion was, in the spectrum of solar activity, split into multiple sidebands due to phase modulation by lower frequency cycles. 
The excellent fit to solar activity at multiple time scales by barycentric theory with Planet 9 included is itself supporting evidence for the existence of Planet 9, specifically by providing an estimate of the current heliographic longitudinal location and orbital period.
Ian R. Edmonds, "The Sun to planetary center of mass distance is coherent with solar activity on the decade, centennial and millennium time scales when Planet 9 is included in the solar system" arXiv:2201.06745 (January 18, 2022).

Wednesday, January 12, 2022

Old Modern Human Remains Older Than Previously Believed

Genetic and archaeological evidence is converging on the time frame in which modern humans emerged as a new species in Africa.
A partial H. sapiens skull and associated skeletal parts found in 1967 in the Kibish rock formation along Ethiopia’s Omo River date to at least around 233,000 years ago, pushing back the age of the fossils by 36,000 years or more. An age well exceeding 200,000 years for the Ethiopian fossils, known as Omo 1, fits with recent fossil discoveries suggesting that H. sapiens evolved across Africa starting roughly 300,000 years ago.
From Science News citing C.M. Vidal, et al., "Age of the oldest known Homo sapiens from eastern AfricaNature (January 12, 2022). doi: 10.1038/s41586-021-04275-8.

Why Is Galaxy AGC 114905 Weird?

This Galaxy Seems To Have No Apparent Dark Matter Phenomena For No Good Reason When Galaxies Like This Usually Are Usually "Dark Matter Dominated"

Galaxy AGC 114905, which is discussed in a December 2021 paper published the scientific journal MNRAS, seems to be a small "low surface brightness"/"ultra-diffuse" galaxy, isolated from any other nearby galaxies that could give rise to tidal stripping of dark matter or an "external field effect" in a modified gravity theory like MOND, that could explain why its apparent rotation curve looks like it has almost no dark matter. I previously discussed this paper in a less complete "quick hit" post at this blog.

The overwhelmingly majority of galaxies of this type, as predicted by MOND before observations were made of them in the early 1980s, have rotation curves that seems to have a particularly large proportion of dark matter to ordinary matter, in a dark matter hypothesis, and are deep in the MOND-regime of very weak gravitational fields in a modified gravity approach. 

Neither dark matter theory, nor MOND, provides a ready explanation for why an outlier case like this should happen.

Stacy McGaugh, at his blog Triton Station, examines this outlier caseThe chart below showing galaxies relative to the line indicating the Tully-Fischer relationship, from this blog post, illustrates how much of an outlier this result is (with AGC 114905 in orange):

The Inclination Angle Of The Disk Is Easy To Get Wrong And Material. An Error Here Is Probably At Least A Partial Reason For This Outlier Result.

McGaugh's primary conclusion is that the factor that the paper itself identifies that the most likely source of systemic error in its estimated rotation curve identified by the authors themselves, an inaccuracy in the determination of the angle at which we are seeing the basically disk shaped galaxy with our telescopes, called the inclination angle, is the most likely culprit. He states:
The authors do the right thing and worry about the inclination, checking to see what it would take to be consistent with either LCDM or MOND, which is about i=11º in stead of the 30º indicated by the shape of the outer isophote.

they “find it unlikely that we are severely overestimating the inclination of our UDG, although this remains the largest source of uncertainty in our analysis.” I certainly agree with the latter phrase, but not the former. I think it is quite likely that they are overestimating the inclination. I wouldn’t even call it a severe overestimation; more like par for the course with this kind of object. . . .

So the bottom line is that I am not convinced that the uncertainty in the inclination is anywhere near as small as the adopted ±3º.

He places this analysis in the context of a long career of analyzing these issues in these kinds of galaxies, demonstrating first, that even modest inclination issues do indeed have a material effect, and secondly, that the magnitude of typically measurement errors in determining the correct inclination are often quite large.

Along the way, he also points to two other potential problems that are not entirely unrelated.

Is A Model Assuming A Thin Axisymmetric Disk Sound?

One is that the modeling is based upon an axisymmetric thin disk galaxy which is a spherical cow model in a case like this one with a highly irregular shape (see the image below from the 2021 paper), that doesn't  work very accurately in a galaxy like this one that is outside the model's range of applicability.

McGaugh notes that:
This messy morphology is typical of very low surface brightness galaxies – hence their frequent classification as Irregular galaxies. Though messier, it shares some morphological traits with the LSB galaxies shown above. The central light distribution is elongated with a major axis that is not aligned with that of the gas. The gas is raggedy as all get out. The contours are somewhat boxy; this is a hint that something hinky is going on beyond circular motion in a tilted axisymmetric disk.

Is This Galaxy Out Of Equilibrium? 

Another plausible possibility that McGaugh suggests for this outlier is that it may be out of equilibrium, while models used to relate dynamical rotation curve to inferred dark matter fraction, with only rare exceptions not utilized in this case, assume that the body they are modeling is in a state of equilibrium. 

The fact that AGC 114905 is currently isolated from other large galaxies makes it less likely that a near miss from a massive object took it out of equilibrium, but some kinds of objects (e.g. an intermediate sized black hole or a very dim proto-galaxy) could have an impact on the dynamics of a small galaxy, while not providing any indication that it was nearby in the time frame necessary for a fairly unstable small galaxy to come into equilibrium. This isn't the first hypothesis one would leap to, but outlier phenomena often have outlier causes.

How Important Is The Thickness Of The Disk Or The Fact That The Galaxy Is Gas-Rich?

Another point raised by McGaugh is one I also see in a new light that he does not suggest in the context of Deur's approaches. McGaugh states, continuing his discussion of the limitations of the models used that:
The modeling exercise is good, but it assumes “razor-thin axisymmetric discs.” That’s a reasonable thing to do when building such a model, but we have to bear in mind that real disks are neither. The thickness of the disk probably doesn’t matter too much for a nearly face-on case like this, but the assumption of axisymmetry is extraordinarily dubious for an Irregular galaxy. That’s how they got the name.

In the context of Deur's approach, the three dimensional shape of a mass distribution is critical to causing the gravitational effects that make the toy-model MOND theory work. 

In a spherically symmetric mass distribution, a system will have no inferred dark matter and no MOND-like gravitational effects. 

In an axisymmetric thin disk, he concludes that the self-interaction of the gravitational field gives rise to a MOND-like second order effect that declines as 1/r instead of 1/r^2 with radius, which becomes material when the first order 1/r^2 Newtonian term gets small in very weak gravitational fields.

As applied to this situation, what Deur's approach implies is that if AGC 114905 is a quite thick disk relative to its radius, compared to the theoretical ideal of an axisymmetric thin disk that produces MOND-like behavior, that the non-1/r^2 second order gravitational effects should be weaker, and that the dark matter proportion that one would expect to infer when trying to fit AGC 114905 into a dark matter particle model would be smaller. So, the thickness of the disk may be more important to the accuracy of the analysis than McGaugh, working from a MOND-like frame of reference, would expect.

From the 2021 Paper

Another way that an analysis along the lines of Deur's approach could impact the result is that if AGC 114905 has a high proportion of gas and other interstellar media relative to stars, and if the interstellar medium within AGC 114905 is quite close to spherically symmetric, even if the stars are aligned in more of a disk-like arrangement, this could be a big deal. 

This would reduce the inferred dark matter proportion that would be expected, since the second order gravitational effect would arise only as to the proportion of the mass in the galaxy that is in stars, rather than all of the matter in the galaxy, and it might even weaken the second order effects between the stars, effectively diluting them. This kind of scenario doesn't seem implausible in the case of this particular galaxy.

Now, the effect of the disk thickness, interstellar gas proportion, and interstellar gas distribution shape in a Deur style analysis still wouldn't be sufficient to bring AGC 114905 to the point of having no inferred dark matter proportion, that the article concludes that it has. 

However thick and gas dominated it may be, and whatever the distribution of the gas in the galaxy might be, AGC 114905 still isn't actually spherically symmetric, so there should be, a priori, some inferred dark matter proportion. 

But this Deur style analysis might make it possible to support a gravitational theory based explanation of AGC 114905 with a significantly smaller error in inclination angle than would be possible without this contributing factor to the analysis, allowing for a much less dramatic underestimation of the inclination angle error than would be necessary otherwise to explain this outlier case.

Tuesday, January 11, 2022

Is Ainu Part Of A Larger "Austric" Language Family?


I mention this hypothesis set forth in a 2009 linguistics paper for completeness, but don't give it that much credit. 

I am inclined to favor the majority view that Ainu is a language isolate, with linguistic family connections too remote in time to be discernible through linguistic analysis of modern or historically attested languages. 

Still, it is credible enough and corroborated enough by other evidence that it shouldn't be dismissed out of hand either.

The Genetic And Archaeological Evidence

The genetic data (through no fault of the authors of this 2009 piece which had much less genetic evidence at its disposal) and related physical anthropology data referenced in the paper needs to be pretty much ignored in favor of better quality and more recent data  and anthropological work (e.g. in 20122013 and 2021). My linked analysis of a state of the art 2021 paper's findings notes that:
A TreeMix analysis places the Jomon as an offshoot of the Hoabinhian people (a Mesolithic wave of people in Southeast Asia and Southern China ca. 12,000 to 10,000 BCE), with the Kusunda people (who are hunter-gathers in Western Nepal who historically spoke a language that is an isolate and were animistic religiously) as an intermediate population.

Y-DNA haplogroup D has a cryptic distribution found in isolated pockets across Asia including Siberia and Tibet that tends to favor a Northern route origin.

The mtDNA haplogroups N9b and M7a also tell story so deep in history (both are very basal in the Eurasian mtDNA tree and derived from African mtDNA haplogroup L3) that it is hard to reconstruct. Both mtDNA M and mtDNA N show distributions that tend to favor a Southeast Asian route to Japan, but perhaps this is because the northern bearers of this haplogroup went extinct, and were then almost fully replaced in the Last Glacial Maximum.

More up to date genetic data certainly favors the Austric hypothesis of this paper over an Altaic hypothesis, that the paper's authors reject on linguistic grounds. 

But the genetic data is really agnostic between the possibility that the Ainu language is a language isolate, and the hypothesis that it could have a common source proto-language with the Austroasiatic and Austronesian languages that have "homelands" in Southeast Asia and Southern China. 

The genetically and archaeologically supported time frame in which the Jomon people were isolated from mainland East Asia tends to favor, instead, the language isolate hypothesis, because the common language family connection of an "Austric" language family that would be consistent with the archaeological and genetic evidence would be deeper in the past than the common protolanguages shared by any other linguistically reconstructible language families. 

If the word lists are as solid as claimed by the authors of this paper, the common ancestor of the Austric languages should have started to break up into the predecessors of the modern language families something like 3,000 to 6,000 years ago, or so (a time depth comparable to the one separating the most distinct of the Indo-European languages from each other, for example), rather than the at least 15,000 years of isolation suggested by genetic data and paleoclimate data (about the time depth probably uniting the pre-Columbian Native American languages of the Americas other than the language families that include the Na-Dene and Inuit languages, i.e. AmerInd, that are impossible to unite in their modern forms with linguistic information alone by any common linguistic characteristics). 

On the other hand, as fishermen who had some outposts of their civilization as distant as the Ryukyu Islands, it is conceivable that they could have had maritime trade with East Asia that could have resulted in language shift, although the genetic data for the Jomon and Ainu people while supporting some links to Northeast Asia, do not support significant cultural or population genetic ties to Southern China and beyond from about 15,000 years ago to about 3,000 years ago).

Linguistic Evidence

The heart of the piece are the 88 suggested correspondences with Ainu or Proto-Ainu words that they identify, including eight pronouns, the numbers one through four (in five variations), and seventy-five other core vocabulary words. 

Also, the correspondences listed also tend to support a coherent "Austric" grouping including Austroasiatic, Austronesian, and Thai-Kadai (at least). Other linguistic and genetic evidence favors the Austroasiatic and Hmong-Mien grouping.

These are respectable sized word lists, although I lack the expertise to critically evaluate the credibility of the "solid" and "doubtful" cognates on the list, which is where my doubt about the credibility of the authors is implicated. 

The Russian school of linguistics, of which Blazek is a member and the journal this article comes from is a part, is notorious for lumping together languages into language families, like Nostratic, without solid evidence to back up the classification. And, the Sante Fe Institute, which is Bengtson's academic affiliation, also has a track record of low quality linguistic scholarship. 

The Word List Details

All but one of the thirteen pronouns and numbers have solid suggested word-list correspondences from the Austroasiatic Mon-Khmer language (the comparison for the number 3 is doubtful), as do forty of the seventy-five other core words (with another nine more doubtful correspondences). Of the words that do not have a solid Mon-Khmer cognate, they identify another five core vocabulary words have an Austroasiatic Munda correspondence (usually accompanying a more doubtful Mon-Khmer cognate). In all there are 57 Ainu-Austroasiatic correspondences identified with another ten doubtful correspondences. The eight corresponding pronouns, as especially core words, would suggest a closer relationship between Ainu and Austroasiatic than with Austronesian, despite a slightly higher solid correspondence count for Austronesian.

They identify solid Austronesian, or Austronesian Asli correspondence for eight of the thirteen numbers and pronouns (half of the pronouns and the number four are absent), and another fifty-three core vocabulary words, including twenty-nine without a solid Austroasiatic cognate.  In all there are 61 solid Ainu-Austronesian correspondences identified and another three doubtful correspondences (including one pronoun).

There are thirty-two correspondence present in both Austroasiatic and Austronesian, a roughly fifty-percent overlap.

There are 35 of eighty-eight words that have solid Thai-Kadai cognates (including eight of thirteen pronouns and numbers), but just five core words (or no numbers or pronouns) that have solid Thai-Kadai cognates but not solid Austroasiatic or Austronesian cognates ("evening", "rain", "river", "stone" (one of two Ainu words with this meaning), and "year"), with "evening" and "river" having doubtful Mon-Khmer correspondences.

They identify no solid cognates for words that do not have a solid Mon-Khmer, Munda, Austronesian, or Thai-Kadai correspondence on their word-list. 

None of their correspondences are exclusively Hmong-Mien or Nihali

There are 17 of eighty-eight words that have solid Hmong-Mien correspondences (including three of eight pronouns, and just one number (one of two forms of 2) and thirteen other core words ("child", "die", "earth", "egg", one of three forms of "eye"/"eyebrow", "fire", "lake"/"deep water", "mouth", "five"/"palm of hand", "rain", one of two forms of "stone", "vulva" and (fresh) water"). Of these seventeen words, just six lack a Mon-Khmer counterpart ("die", "egg", "lake"/"deep water", "rain", "stone" and "vulva").

The are only 3 solid Nihali correspondences ("fire", "tooth", and one of three variants associated with "eye"), each of which also have solid Mon-Khmer correspondences. This suggests that Nihali is a weak candidate for an overall "Austric" family grouping, as proposed tangentially in this paper, although it is a special case as the Wikipedia article on it that is linked above explains that its superficial dissimilarity from other Austroasiatic languages may be a deliberate ruse:
Franciscus Kuiper was the first to suggest that Nihali may be unrelated to any other Indian language, with the non-Korku, non-Dravidian core vocabulary being the remnant of an earlier population in India. However, he did not rule out that it may be a Munda language, like Korku. Kuiper suggested that Nihali may differ from neighbouring languages, such as Korku, mostly in its function as an argot, such as a thieves' cant. Kuiper's assertions stem, in part, from the fact that many oppressed groups within India have used secret languages to prevent outsiders from understanding them.

Linguist Norman Zide describes the recent history of the language as follows: "Nihali's borrowings are far more massive than in such textbook examples of heavy outside acquisition as Albanian." In this respect, says Zide, modern Nihali seems comparable to hybridised dialects of Romani spoken in Western Europe. Zide claims that this is a result of a historical process that began with a massacre of Nihalis in the early 19th century, organised by one of the rulers of the area, supposedly in response to "marauding". Zide alleges that, afterwards, the Nihalis "decimated in size", have "functioned largely as raiders and thieves ... who [have] disposed of ... stolen goods" through "outside associates". Zide adds that Nihali society has "long been multilingual, and uses Nihali as a more or less secret language which is not ordinarily revealed to outsiders" and that early researchers "attempting to learn the language were, apparently, deliberately rebuffed or misled".
The paper
There have been several attempts to solve the question of the genetic affiliation of the Ainu language of Hokkaido, formerly spoken also in Sakhalin and the Kuril islands. Apart from some inadequate or unlikely proposals there are two principal serious hypotheses: (1) Altaic, or more inclusively ‘Euroasiatic’ (Nostratic), as advocated for instance by Ramstedt, Koppelmann, Street, Patrie, Krippes, and Greenberg (with Ruhlen); and (2) Austronesian and Austroasiatic (plus Thai-Kadai and Miao-Yao, together Austric): e.g., Gjerdman, Sternberg, Murayama, and Vovin. Physical anthropology has been ambiguous on this question, in some aspects favoring a Northeast Asian, in others a Southeast Asian origin of the Ainu. The authors of the present article prefer (2), the Austric hypothesis, assuming an internal structure of the Austric macro-phylum consisting of Austro-Thai (Austronesian + Kadai), Miao-Austroasiatic (Hmong-Mien + Austroasiatic), and the peripheral remnants Nihali (in India) and Ainu. This article contains eighty-eight etymologies that the authors believe are strong evidence for the Austric affinity of the Ainu language. The lexical material includes personal pronouns, lower numerals, and other core basic vocabulary. Most importantly, this article is intended to stimulate discussion of the position of Ainu in genetic classification.
John D. Bengtson and Vaclav Blazek, "Ainu and Austric: Evidence of a Genetic Relationship" 2 Journal of Language Relationship 1-24 (2009).

From the body text at pages 1-3 and 19:

The Ainu language is known from Hokkaido, Sakhalin and the Kuril islands (where it is now extinct). According to toponymy, Ainu was also formerly spoken on Honshu (Hudson 1994, 242–44), and apparently on other islands of the Japanese archipelago, probably even as far as the Ryukyu Islands, where, for example, place-names of the type Pira correlate with Ainu pira “rock” (Kagami 1962; Beleňkaja 1964). There are surprising biological similarities between Ainu and the Ryukyans, especially visible on new-born children (Levin 1971, 197; Hudson 1994, 247), supported by evidence of molecular genetics (Cavalli-Sforza et al. 1994, 232). 

[Ed. History attests that a language in the Ainu language family was probably spoken in the Northern part of Honshu, the main Japanese island, until about 1000 CE, and modern Japanese people have a significant minority component of Ainu-like, Jomon-like ancestry arising from an admixture event ca. 1000 BCE with a Manchurian-like Yayoi population from Korea.]

There have been several attempts to solve the question of the genetic affiliation of the Ainu language. Aside from some attempts at comparison which are rather romantic (with Hebrew [!] by Batchelor), or give quite unsystematic results, e.g. with Indo-European by Naert (1958, 1961), Lindquist (1960) or Van Windekens (1961) — see critical reviews of Benveniste (1960), Dolgopolsky (1963), Tailleur (1961), Refsing [ed.] (1998); or with ‘Palaeo-Eurasian’, i.e. ‘Caucasian’, Basque, Yenisseian, Burushaski, plus some Amerindian languages, by Tailleur (1963, 1968), there are two main competing hypotheses:

(1) Altaic: first mentioned by Ramstedt; further defended e.g. by Street, Language 38[1962], 92–99; Patrie 1982 (critically reviewed e.g. by Helimski 1984); and more extensively in the ‘Euroasiatic’ concept including Altaic, Nivkh, Uralic, Indo-European etc.: Koppelmann1928, 1933; Ruhlen 1987, 131–32 and 1994, 16–20; Krippes, Ural-Altaische Jahrbücher 61 [1989],149–51; Greenberg 2000–2002;

(2) Austronesian and Austroasiatic (plus Thai-Kadai and Miao-Yao, together Austric): 1926, 1960; Sternberg 1929, 1933; Murayama 1992a, 1992b, 1993; Vovin 1993 (cf. thereview of Sidwell 1996).

Our research supports the Austric hypothesis. . . .

Ainu (and Nihali, in India) may represent peripheral remnants of this Austric macro-phylum (see Bengtson 1996, Blažek 1996). The following scheme depicts their mutual relations: In physical anthropology the Ainu type has generally been included in the Mongoloid subspecies. On the basis of DNA evidence, the genetic taxonomy of Cavalli-Sforza et al. (1988,6003; 1992, 5621; 1994, 231–32) postulates a ‘Northeast Asian’ branch, comprising the Ainu, Japanese, and Koreans, along with Tibetans, North Chinese, and others. Similar results were obtained by classical methods of physical anthropology (Alekseev & Trubnikova 1984, 88). On the other hand, some undoubtedly very archaic features, such as the Ainus’ profuse body hair, and characteristic Sundadont dentition, point to relations with Southeast Asia (Alekseev & Trubnikova 1984, 94–96; Turner 1989). We might also mention the remarkable closeness of gene frequencies between the Ainu people and the aborigines of Taiwan, for example IGKC,KM (1&1,2), P1(1) or RH, haplotype cDE (Cavalli-Sforza et al. 1994, 385–86, 425–26). The connection of the ancestors of the Ainu people with Southeast Asia was thoroughly argued by Sternberg (1929).

The earliest known presence of modern man in the Japanese archipelago is estimated at 30,000 years BP (e.g., Utanobori on Hokkaido, or Osinovka on Sakhalin: see Golubev & Lavrov1988, 206, 220). At 11.000 years BP the first ceramic artifacts appear (Cavalli-Sforza et al. 1994, 202, have this as early as 12.700 BP; in any case, it is the world’s first appearance of ceramics).The style of pottery changed ca. 10.000 BP, which is thought to indicate the advent of the Jômon culture (remarkably, on Sakhalin this technology was delayed by 2.000 years, comparedwith Hokkaido — see Golubev & Lavrov 1988, 225). The contemporary Ainu people are very probably the descendants of the creators of the Jômon culture (cf. Hudson 1994, 244; Cavalli-Sforza et al. 1994, 203, 232). About 400 BC a new population came to Kyushu from the Korean peninsula, the bearers of the culture called Yayoi. They brought a developed rice agriculture and an Altaic language (Proto-Japanese). The closest relative of Old Japanese was the language of the old Korean kingdom, Koguryŏ (cf. Hudson 1994, 246–47). 
. . .

Following the great specialist in Austronesian (and African) languages, Otto Dempwolff, we assume that the preceding list of lexical parallels between Ainu and the Austric languages represents the first step in the inductive phase of the demonstration of genetic relationship (really a continuation of the first steps taken by Gjerdman, et al.). The following step (already begun, for example, by Norquest, 1998) consists of the formulation of regular phonetic correspondences, which should be verified during the deductive phase. We believe that future progress in comparative and historical Austric linguistics will lead to the complete demonstration of the membership of Ainu within the Austric macro-phylum (along with Austronesian, Thai-Kadai, Miao-Yao, Austroasiatic, and probably also Nihali). If our article helps to stimulate discussion of the position of Ainu in genetic classification, it has served its purpose.