Wednesday, September 29, 2021

GR v. Newtonian Gravity

Another paper (alas, poorly written due to ESL issues), by an independent author examines the difference between General Relativity and Newtonian gravity in the case of two massive bodies rather than one massive body and a test particle of negligible mass.

The result, analytically determined, confirms Deur's analysis that the distinction is not immaterial in some circumstances, and that this could be the underlying mechanism of modified Newtonian dynamics.

The metric tensor in the four dimensional flat space-time is represented as the matrix form and then the transformation is performed for successive Lorentz boost. After extending or more generalizations the transformation of metric is derived for the curved space-time, manifested after the synergy of different sources of mass. The transformed metric in linear perturbation interestingly reveals a shift from Newtonian gravity for two or more than two body system.
Shubhen Biswas, "The metric transformations and modified Newtonian gravity" arXiv:2109.13515 (September 28, 2021).

Tuesday, September 28, 2021

Quick Miscellaneous Physics Results

Neutrino Physics 

A new paper from the Neutrino-4 experiment makes the case of a sterile neutrino and also estimates the neutrino masses. It also predicts very high neutrino masses compared to other experiments. With an electron neutrino mass of 0.8 eV, a muon neutrino mass of 0.4 eV, a tau neutrino mass of less than 0.6 eV, and a sterile neutrino mass of 2.7 eV. I am highly skeptical of the result, not least because the mass predictions are also out of line with other results. This is a screenshot of the abstract in the paper itself which is used to preserve the fussy formatting:

* Another new review of the sterile neutrino question can be found here (the updated added September 29, 2021):
Two anomalies at nuclear reactors, one related to the absolute antineutrino flux, one related to the antineutrino spectral shape, have drawn special attention to the field of reactor neutrino physics during the past decade. Numerous experimental efforts have been launched to investigate the reliability of flux models and to explore whether sterile neutrino oscillations are at the base of the experimental findings. This review aims to provide an overview on the status of experimental searches at reactors for sterile neutrino oscillations and measurements of the antineutrino spectral shape in mid-2021. 
The individual experimental approaches and results are reviewed. Moreover, global and joint oscillation and spectral shape analyses are discussed. 
Many experiments allow setting constraints on sterile oscillation parameters, but cannot yet cover the entire relevant parameter space. Others find evidence in favour of certain parameter space regions. In contrast, findings on the spectral shape appear to give an overall consistent picture across experiments and allow narrowing down contributions of certain isotopes.

* Neutrino-nucleon collision models still have kinks to be worked out in the low energy, forward muon angle regime where models fail to adequately account for the extent to which events in this part of the parameter space are suppressed. The authors speculate on what might be missing from the models but aren't really sure why the discrepancy arises.

* Neutrino data from experiments and neutrino data from cosmic ray observations are reasonably consistent with each other.

Other Physics

* The charge radius of the proton is measured to be 0.840(4) fm (with conservative rounding assumptions), consistent with prior experimental measurements from muonic hydrogen of 0.840 87(39) fm, and with the better recent measurements using ordinary hydrogen such as a 2019 measurement that found a radius of 0.833(10) fm. 

In 2014, the CODATA average measurement had stated that the charge radius of the proton was  0.8751(61) fm, which has subsequently been determined to be too large due to reliance on older, less accurate experiments with ordinary hydrogen, and less correct theoretical analysis of their results. Correctly theoretically analyzing the old data would have produced a result of 0.844(7) fm.

* Non-perturbative and perturbative QCD models need to be used together to get more precise determinations of the QCD coupling constant. Perturbative QCD methods alone have hit their limits.

* Someone argues for a better way to do renormalization (really a better way to apply existing methods) in QCD.

* Someone makes a more accurate prediction of how many Higgs bosons the LHC should produce at its highest energies. This still has more than a 5% uncertainty, however.

* The Paul Scherrer Institute in Switzerland does mesoscale particle physics experiments at lower energies than the LHC. It has a nice brief review of the relevant Standard Model Physics of the interactions it studies and potential beyond the Standard Model tweaks to it in this regime that it is studying using lower energies but greater precision to study more practically relevant parts of the Standard Model. The abstract of the article is useless, so I quote from the introduction.

These experiments either lead to precise determinations of physical parameters required as input for other experiments (e.g., muon life time, pion mass), or search for physics beyond the Standard Model (BSM). The BSM searches proceed along different frontiers. 

One way to search for new physics is to consider physical observables whose Standard Model (SM) contributions either vanish or are too small to be experimentally accessible. In other words, they are identical to zero for practical purposes. Examples are charged lepton-flavor violating (cLFV) muon decays or a permanent neutron electric dipole moment (EDM). To put constraints on the branching ratios of BSM decays, one has to observe a large number of decays. This is, thus, called a search at the intensity frontier. 

Another way to search for new physics is to consider precision observables and search for deviations from the SM expectations. Prominent examples are the precision QED tests with muonium, as well as the precision laser spectroscopy experiments with muonic atoms. These are, thus, called searches at the precision frontier. The low-energy experiments at PSI are complementary to the experiments at LHC, which sit at the energy frontier.

After a general overview of the theoretical methods applied to describe the processes and bound states in Table 5.1, we will, in turn, consider the muon, the proton, nucleons and nuclei, the free neutron, and the pions.

* The significance of the 151 GeV anomaly at the LHC is overstated.

* Experimental evidence continues to disfavor the existence of a light pseudoscalar Higgs boson "A", which is a generic prediction of models like supersymmetric with multiple Higgs doublets.

* A group of scientists try to explain the charged and neutrino mass hierarchies, muon g-2, electron g-2, leptogenesis, and dark matter with a inverse seesaw model, which is usually only used to attempt to explain neutrino masses and sometimes dark matter. The effort is notable for its breadth, although I very much doubt that it is a correct explanation. A similar model is proposed here.

* Someone proposes a non-SUSY E6 GUT to explain various outstanding physics anomalies consistent with experimental constraints. It is probably wrong.

* Experimental constraints on the proton lifetime (which the Standard Model assumes is stable) are close to ruling out the simplest supersymmetric SU(5) GUT theory.

Friday, September 24, 2021

Reminder That XENON1T Was A Fail

A new study, led by researchers at the University of Cambridge and reported in the journal Physical Review D, suggests that some unexplained results from the XENON1T experiment in Italy may have been caused by dark energy, and not the dark matter the experiment was designed to detect.
From here.

This post is a friendly reminder that any "New Physics" findings based upon the anomalous results from the XENON1T experiment should not be taken seriously. 

It is known that there were material sources of background noise that were ignored in the XENON1T data analysis that could have impacted the result. And, the experimental apparatus was dismantled before it was possible to analyze it in order to determine if those ignored background sources were creating false positives that looked like New Physics.

Its results remain reliable to the extent that it ruled out New Physics (since those results would merely be weakened by false positives). But, some or all of its results that have been attributed to beyond the Standard Model physics were almost surely false positives. So, it is useless for purpose of proving the existence of New Physics.

The Legacy Of Herding

The Legacy Of Herding

Historical food productions practices influence culture and morality long after those food production practices are long gone.
According to the widely known ‘culture of honor’ hypothesis from social psychology, traditional herding practices are believed to have generated a value system that is conducive to revenge-taking and violence. 
We test this idea at a global scale using a combination of ethnographic records, historical folklore information, global data on contemporary conflict events, and large-scale surveys. 
The data show systematic links between traditional herding practices and a culture of honor. First, the culture of pre-industrial societies that relied on animal herding emphasizes violence, punishment, and revenge-taking. Second, contemporary ethnolinguistic groups that historically subsisted more strongly on herding have more frequent and severe conflict today. Third, the contemporary descendants of herders report being more willing to take revenge and punish unfair behavior in the globally representative Global Preferences Survey. In all, the evidence supports the idea that this form of economic subsistence generated a functional psychology that has persisted until today and plays a role in shaping conflict across the globe.
Yiming Cao, et al., "Herding, Warfare, and a Culture of Honor" NBER (September 2021).

Another paper fleshes out the concept a bit more (and has a nice literature review), although its description of the southern United States as historically a herding culture is doubtful. Appalachia was indeed settled by Scotch-Irish herders and does have a culture of honor, but, the lowlands of the American South (which also has a culture of honor), where plantation farming became predominant, was settled by lesser English gentry farmers, not by descendants of herders.
A key element of cultures of honor is that men in these cultures are prepared to protect with violence the reputation for strength and toughness. Such cultures are likely to develop where (1) a man's resources can be thieved in full by other men and (2) the governing body is weak and thus cannot prevent or punish theft. 
Todd K. Shackelford, "An Evolutionary Psychological Perspective on Cultures of Honor" Evolutionary Psychology (January 1, 2005) (open access). DOI:

The example of the Southern United States suggests that a weak state may be as important a factor in the development of a culture of honor as a herding economy.

The Legacy Of Plough v. Hoe Farming

Parallel hypotheses from the same disciplines associate ancestral heavy plough farming with strongly patriarchal societies with strong differentiation in gender roles, and ancestral hoe farming with less patriarchal and sometimes even matrilineal societies.

The Legacy Of Clan Based Societies

It has also become common in modern political theory to associate weak government approaching anarchy with clan based societies in which women are forced into highly subordinated roles, somewhat in the tradition of Thomas Hobbes ("nasty, brutish and short") as opposed to those who idealize an Eden-like "state of nature." See, e.g., Valerie M. Hudson, et al., "Clan Governance and State Stability: The Relationship between Female Subordination and Political Order" 109(3) American Political Science Review 535-555 (August 2015).

The Legacy Of Cousin Marriage

Also along the same lines, cousin marriage (often common in clan based societies and also among feudal aristocrats) tends to be a practice the undermines democratic government:

Image from here.
How might consanguinity affect democracy? 
Cousin marriages create extended families that are much more closely related than is the case where such marriages are not practiced. To illustrate, if a man’s daughter marries his brother’s son, the latter is then not only his nephew but also his son-in-law, and any children born of that union are more genetically similar to the two grandfathers than would be the case with non-consanguineous marriages. Following the principles of kin selection (Hamilton, 1964) and genetic similarity theory (Rushton, 1989, 2005), the high level of genetic similarity creates extended families with exceptionally close bonds. Kurtz succinctly illustrates this idea in his description of Middle Eastern educational practices:

If, for example, a child shows a special aptitude in school, his siblings might willingly sacrifice their personal chances for advancement simply to support his education. Yet once that child becomes a professional, his income will help to support his siblings, while his prestige will enhance their marriage prospects. (Kurtz, 2002, p. 37).

Such kin groupings may be extremely nepotistic and distrusting of non-family members in the larger society. In this context, non-democratic regimes emerge as a consequence of individuals turning to reliable kinship groupings for support rather than to the state or the free market. It has been found, for example, that societies having high levels of familism tend to have low levels of generalized trust and civic engagement (Realo, Allik, & Greenfield, 2008), two important correlates of democracy. Moreover, to people in closely related kin groups, individualism and the recognition of individual rights, which are part of the cultural idiom of democracy, are perceived as strange and counterintuitive ideological abstractions (Sailer, 2004).

From the body text of the following article whose abstract is also set forth below: 

This article examines the hypothesis that although the level of democracy in a society is a complex phenomenon involving many antecedents, consanguinity (marriage and subsequent mating between second cousins or closer relatives) is an important though often overlooked predictor of it. Measures of the two variables correlate substantially in a sample of 70 nations (r = −0.632, p < 0.001), and consanguinity remains a significant predictor of democracy in multiple regression and path analyses involving several additional independent variables
The data suggest that where consanguineous kinship networks are numerically predominant and have been made to share a common statehood, democracy is unlikely to develop
Possible explanations for these findings include the idea that restricted gene flow arising from consanguineous marriage facilitates a rigid collectivism that is inimical to individualism and the recognition of individual rights, which are key elements of the democratic ethos. Furthermore, high levels of within-group genetic similarity may discourage cooperation between different large-scale kin groupings sharing the same nation, inhibiting democracy. Finally, genetic similarity stemming from consanguinity may encourage resource predation by members of socially elite kinship networks as an inclusive fitness enhancing behavior.
Michael A. Woodley, Edward Bell, "Consanguinity as a Major Predictor of Levels of Democracy: A Study of 70 Nations" 44(2) Journal of Cross-Cultural Psychology (2013). 

Thursday, September 23, 2021

Another Problem With LambdaCDM

The latest issue with the standard LambdaCDM cosmology is a subtle one, relating to the location and character of the galaxies in parts of the universe that are mostly void. But, it is notable because it is largely independent of our problems identified with LambdaCDM and because it involves the large scale cosmology scale where LambdaCDM has historically been seen as being more successful.

We extract void catalogs from the Sloan Digital Sky Survey Data Release 16 (SDSS DR16) survey and also from the Millennium simulation. We focus our comparison on distribution of galaxies brighter than M(r)<−18 inside voids and study the mean separation of void galaxies, distance from the void center, and the radial density profile.  
We find that mean separation of void galaxies depends on void size, as bigger voids have lower mean separation in both samples. However, void galaxies in the observation sample seem to have generally larger mean-distance than simulated ones at any given void size. In addition, observed void galaxies tend to reside closer to the void center than those in the simulation. This discrepancy is also shown in the density profile of voids. Regardless of the void size, the central densities of real void profiles are higher than the ones in the predicted simulated catalog.
Saeed Tavasoli, "Void Galaxy Distribution: A Challenge for ΛCDM" arXiv:2109.10369 (September 21, 2021) (Accepted in ApJ Letter) DOI: 10.3847/2041-8213/ac1357.

Wednesday, September 22, 2021

A Grab Bag Paper On East Asian Historical Genetics

In the course of looking into the three component story of the formation of the Japanese people that I posted yesterday, I came across a gem of a preprint from March 25, 2020 covering all manner of only vaguely related subjects. I may have previously blogged some of its findings, but it really is all over the place and could have legitimately spawned five distinct articles.
The deep population history of East Asia remains poorly understood due to a lack of ancient DNA data and sparse sampling of present-day people. We report genome-wide data from 191 individuals from Mongolia, northern China, Taiwan, the Amur River Basin and Japan dating to 6000 BCE – 1000 CE, many from contexts never previously analyzed with ancient DNA. We also report 383 present-day individuals from 46 groups mostly from the Tibetan Plateau and southern China. 
We document how 6000-3600 BCE people of Mongolia and the Amur River Basin were from populations that expanded over Northeast Asia, likely dispersing the ancestors of Mongolic and Tungusic languages. 
In a time transect of 89 Mongolians, we reveal how Yamnaya steppe pastoralist spread from the west by 3300-2900 BCE in association with the Afanasievo culture, although we also document a boy buried in an Afanasievo barrow with ancestry entirely from local Mongolian hunter-gatherers, representing a unique case of someone of entirely non-Yamnaya ancestry interred in this way. The second spread of Yamnaya-derived ancestry came via groups that harbored about a third of their ancestry from European farmers, which nearly completely displaced unmixed Yamnaya-related lineages in Mongolia in the second millennium BCE, but did not replace Afanasievo lineages in western China where Afanasievo ancestry persisted, plausibly acting as the source of the early-splitting Tocharian branch of Indo-European languages. 
Analyzing 20 Yellow River Basin farmers dating to ∼3000 BCE, we document a population that was a plausible vector for the spread of Sino-Tibetan languages both to the Tibetan Plateau and to the central plain where they mixed with southern agriculturalists to form the ancestors of Han Chinese. 
We show that the individuals in a time transect of 52 ancient Taiwan individuals spanning at least 1400 BCE to 600 CE were consistent with being nearly direct descendants of Yangtze Valley first farmers who likely spread Austronesian, Tai-Kadai and Austroasiatic languages across Southeast and South Asia and mixing with the people they encountered, contributing to a four-fold reduction of genetic differentiation during the emergence of complex societies. 
We finally report data from Jomon hunter-gatherers from Japan who harbored one of the earliest splitting branches of East Eurasian variation, and show an affinity among Jomon, Amur River Basin, ancient Taiwan, and Austronesian-speakers, as expected for ancestry if they all had contributions from a Late Pleistocene coastal route migration to East Asia.

Tuesday, September 21, 2021

Penrose's Model For Gravitational Collapse Of Quantum Superpositions Doesn't Work

The way that an observer making an observation triggers a collapse of a quantum physical wave function is a longstanding unsolved problem in physics. 

A recent experimental effort to see if quantum gravity effects triggered this in a theory promoted by Roger Penrose, but first proposed by Lajos Diósi, turns out not to be the answer to this question, which remains unsolved.

Roger Penrose proposed that a spatial quantum superposition collapses as a back-reaction from spacetime, which is curved in different ways by each branch of the superposition. In this sense, one speaks of gravity-related wave function collapse. He also provided a heuristic formula to compute the decay time of the superposition—similar to that suggested earlier by Lajos Diósi, hence the name Diósi–Penrose model. The collapse depends on the effective size of the mass density of particles in the superposition, and is random: this randomness shows up as a diffusion of the particles’ motion, resulting, if charged, in the emission of radiation. Here, we compute the radiation emission rate, which is faint but detectable. We then report the results of a dedicated experiment at the Gran Sasso underground laboratory to measure this radiation emission rate. Our result sets a lower bound on the effective size of the mass density of nuclei, which is about three orders of magnitude larger than previous bounds. This rules out the natural parameter-free version of the Diósi–Penrose model.

From Nature Physics via which explains the results as follows:

It's one of the oddest tenets of quantum theory: a particle can be in two places at once—yet we only ever see it here or there. Textbooks state that the act of observing the particle "collapses" it, such that it appears at random in only one of its two locations. But physicists quarrel over why that would happen, if indeed it does. Now, one of the most plausible mechanisms for quantum collapse—gravity—has suffered a setback.

The gravity hypothesis traces its origins to Hungarian physicists Károlyházy Frigyes in the 1960s and Lajos Diósi in the 1980s. The basic idea is that the gravitational field of any object stands outside quantum theory. It resists being placed into awkward combinations, or "superpositions," of different states. So if a particle is made to be both here and there, its gravitational field tries to do the same—but the field cannot endure the tension for long; it collapses and takes the particle with it.

Renowned University of Oxford mathematician Roger Penrose championed the hypothesis in the late 1980s because, he says, it removes the anthropocentric notion that the measurement itself somehow causes the collapse. "It takes place in the physics, and it's not because somebody comes and looks at it." . . . 

In the new study, Diósi and other scientists looked for one of the many ways, whether by gravity or some other mechanism, that a quantum collapse would reveal itself: A particle that collapses would swerve randomly, heating up the system of which it is part. "It is as if you gave a kick to a particle," says co-author Sandro Donadi of the Frankfurt Institute for Advanced Studies.

If the particle is charged, it will emit a photon of radiation as it swerves. And multiple particles subject to the same gravitational lurch will emit in unison. "You have an amplified effect," says co-author Cătălina Curceanu of National Institute for Nuclear Physics in Rome.

To test this idea, the researchers built a detector out of a crystal of germanium the size of a coffee cup. They looked for excess x-ray and gamma ray emissions from protons in the germanium nuclei, which create electrical pulses in the material. The scientists chose this portion of the spectrum to maximize the amplification. They then wrapped the crystal in lead and placed it 1.4 kilometers underground in the Gran Sasso National Laboratory in central Italy to shield it from other radiation sources. Over 2 months in 2014 and 2015, they saw 576 photons, close to the 506 expected from naturally occurring radioactivity, they report today in Nature Physics.

By comparison, Penrose's model predicted 70,000 such photons. "You should see some collapse effect in the germanium experiment, but we don't," Curceanu says. That suggests gravity is not, in fact, shaking particles out of their quantum superpositions. (The experiment also constrained, though did not rule out, collapse mechanisms that do not involve gravity.)

Why The Sterile Neutrino Anomaly Isn't A Big Deal

Sabine Hoffenfelder's latest blog post talks about the sterile neutrino anomaly seen at the Liquid Scintillator Neutrino Detector, LSND for short, which ran from 1993 to 98 and again at the Mini Booster Neutrino Experiment experiment at Fermilab since 2003 seeming to show a six sigma anomaly by 2018. She wonders why it isn't a big deal now.

While it is common to talk about a five sigma threshold for discovery of new physics, there are really two more parts of that test: the result needs to be replicated rather than being contradicted by other experiments, and there has to be a plausible physics based theory to explain the result. 

Usually, Sabine is a voice of reason and spot on (I bought her book "Lost in Math" and agree with almost everything that she says in it). But on this score, I don't agree with her.  She states that:
15 years ago, I worked on neutrino mixing for a while, and in my impression back then most physicists thought the LSND data was just wrong and it’d not be reproduced.
But, most physicists still think that the LSND/MiniBooNE data is wrong, and it wasn't reproduced by other experiments. Instead, multiple experiments and astronomy observations using different methods that make their results robust contradict the LSND/MiniBooNE result. 

Equally important, several independent important sources of systemic error were identified with the LSND data and its successor MiniBooNE experiment's data. Basically, these experiments failed to consider the mix of fuels in the nuclear reactors they were modeling, used a wrong oscillation parameter, and failed to correlate their near and far detector results in ways that overestimated the number of neutrinos that should appear which made it look like there were more neutrinos disappearing than there actually were.

Thus, there is very strong evidence that the LSND/MiniBooNE apparent detection of a sterile neutrino was wrong. 

Instead, there is strong evidence that there are no sterile neutrinos that oscillate with ordinary neutrinos that have masses of under 10 eV. 

For what it is worth, searches for non-standard neutrino interactions (other than CP violation) have also come up empty so far and severely constrained that possibility. See, e.g., a paper from IceCube, a paper from ANTARES, an analysis of data from Daya Bay, and a summary of results from six other experiments.

Furthermore, there are no beyond the Standard Model active neutrinos with masses of under 10 TeV. This is also an important part of the argument that there are also no fourth generation quarks or charged leptons, because, for reasons of theoretical consistency, each generation of Standard Model fundamental fermions must be complete.

Other Experiments Contradict LSND/MiniBooNE And There Are Plausible Sources Of Systemic Error

The big problem with the reactor anomaly is that these two sets of results rather than being replicated, were repeatedly contradicted, and instead a plausible physics based explanation for why it was wrong was established.

Three different recent experiments (STEREO, PROSPECT and DANSS) have contradicted the LSND/MiniBooNE result. And, the anomalies seen at LSND/MiniBooNE were determined to most likely be due to a failure to model the mix of reactor fuels between Uranium-235 and Plutonium-239 properly, resulting in an error in the predicted number of neutrino events that the actual detections were compared to in determining that there was a deficit of neutrinos that could be explained by an oscillation to one or more sterile neutrino flavors. See Matthieu Licciardi "Results of STEREO and PROSPECT, and status of sterile neutrino searches" (May 28, 2021) (Contribution to the 2021 EW session of the 55th Rencontres de Moriond). See also additional analysis of the fuel mix issue, additional results from Moriond 2021 (including IceCube), and the results from the MINOS, MINOS+, Daya Bay, and Bugey-3 Experiments (these may be the same experiments mentioned above with different names) which found in a preprint that was subsequently published in a peer reviewed journal:
Searches for electron antineutrino, muon neutrino, and muon antineutrino disappearance driven by sterile neutrino mixing have been carried out by the Daya Bay and MINOS+ collaborations. This Letter presents the combined results of these searches, along with exclusion results from the Bugey-3 reactor experiment, framed in a minimally extended four-neutrino scenario. Significantly improved constraints on the θμe mixing angle are derived that constitute the most stringent limits to date over five orders of magnitude in the sterile mass-squared splitting Δm241, excluding the 90% C.L. sterile-neutrino parameter space allowed by the LSND and MiniBooNE observations at 90% CLs for Δm241<5eV^2. Furthermore, the LSND and MiniBooNE 99% C.L. allowed regions are excluded at 99% CLs for Δm241 < 1.2 eV^2.

A similar conclusion was reached using overlapping data but also data from the Planck cosmic microwave background observations here.

In addition to these issues, an analysis back in 2014 already noticed data contradicting the sterile neutrino hypothesis at the ICARUS and OPERA, and observed that some of the parameters used to make the estimates were off and that using the right ones greatly reduced the statistical significance of the anomaly. See Boris Kayser "Are There Sterile Neutrinos" (February 13, 2014). MINOS and Daya Bay had already contradicted the reactor anomaly back in 2014 as well. More recent analysis has likewise downgraded the statistical significance of the anomalies previously reported, although it has not entirely eliminated it.

Cosmology Data Strongly Disfavors Sterile Neutrinos

Cosmology measures also place a cap on neutrino mass including the sum of the neutrino masses of about 0.087 eV or less, in a manner indifferent between sterile neutrinos of less than about 10 eV, and active neutrinos, which doesn't leave room for a reactor anomaly sterile neutrino. See Eleonora Di Valentino, Stefano Gariazzo, Olga Mena "On the most constraining cosmological neutrino mass bounds" arXiv:2106.16267 (June 29, 2021).

A far heavier sterile neutrino would not be discernible as a neutrino from cosmology data and instead would look like a type of dark matter particle. But, the LSND/MiniBooNE result was pointing to a sterile neutrino with a mass of under 5 eV, so it would be subject to the cosmology bounds.

Also, there are strict direct detection exclusions on heavier dark matter particles as well, although none of those would bar a truly sterile neutrino with no interactions with ordinary matter other than oscillations with active neutrinos.

The main criticism of reliance on cosmology data is that it is highly model dependent, even though this particular conclusion is quite robust to different cosmology models.

Limits On Active Neutrinos

We can also be comfortable that there are no active neutrinos (e.g. a fourth generation neutrino otherwise identical to the three Standard Model neutrinos) with masses of less than about 10 TeV, when direct measurements paired with oscillation data limit the most massive of the three Standard Model neutrino masses to not more than 0.9 eV, and cosmology data limits the most massive of the three Standard Model neutrino masses to not more than 0.09 eV.

Data from W and Z boson decays likewise tightly constrain the number of active neutrinos with masses of less than 45,000,000,000,000 meV/c^2 to exactly three.

Dark dark matter detection experiments have ruled out particles that make up most of hypothetical dark matter particles having weak force interaction coupling constants equal to Standard Model neutrinos at masses of up to about 10 TeV (i.e. 10,000 GeV). In the chart below, that cross section is the blue dotted line marked "Z portal C(x)=1" by a factor of 1,000,000. So, even if the flux of 45 GeV+ Standard Model neutrinos were a million times smaller than the hypothetical flux of dark matter particles through Earth, they would be ruled out by the direct detection experiments up to about 10 TeV.

Direct measurement of the lightest neutrino mass from the Katrin experiment of about 0.8 eV, which means that all of the active neutrino masses have to be less than about 0.9 eV based upon the oscillation data. This means that the sterile neutrino mass predicted by the LSND/MiniBooNE result relative to the active neutrino masses still couldn't have been so massive that it would have evaded cosmology bounds.

Neutrinoless double beta decay results rule out Majorana mass neutrinos above about 180 meV (according to the body text of the linked paper). The same experiments will soon be able to confirm or rule out the scenario of sterile neutrinos heavier than 10 eV that cosmology tools cannot constrain.

Japanese Ethnogenesis Arose From Three Components Not Two


The conventional story of Japanese ethnogenesis is that the Jomon hunter-gatherer-fishing culture arrived in Japan in the Upper Paleolithic era, a few thousand years after the Last Glacial Maximum, until around 1000 BCE when the Yayoi wet rice farming, cavalry warrior people arrived from Korea and conquered the Jomon, receiving substantial genetic admixture from them but little linguistic or cultural influence. The admixture event was notable particularly for having more male admixture into Yayoi society than female admixture, which is the opposite of the usually pattern when one people conquer another.

The Main Findings Of A New Paper

While this story pieced together from archaeology, linguistics and ancient and modern population genetic analysis isn't wrong, it misses two key points which a new paper studying a small but representative set of ancient DNA samples with state of the art methods and large comparison data sets reveal.

The big point is that after the Yayoi conquered the Jomon and admixed with them ca. 1000 BCE, there was a second wave of migration to Japan during the Kofun period of Japanese history, ca. 300 CE to 538 CE, by a population similar to the modern Han Chinese people that has the source of more than 60% of the resulting populations autosomal DNA. Since that second migration event, there has been only some modest introgression of additional Han Chinese-like admixture into the Japanese gene pool.

As Wikipedia explains at the link above:
The Kofun period (古墳時代, Kofun jidai) is an era in the history of Japan from about 300 to 538 AD (the date of the introduction of Buddhism), following the Yayoi period. The Kofun and the subsequent Asuka periods are sometimes collectively called the Yamato period. This period is the earliest era of recorded history in Japan, but studies depend heavily on archaeology since the chronology of historical sources tends to be distorted.

It was a period of cultural import. Continuing from the Yayoi period, the Kofun period is characterized by a strong influence from the Korean Peninsula; archaeologists consider it a shared culture across the southern Korean Peninsula, Kyūshū and Honshū.  
The word kofun is Japanese for the type of burial mound dating from this era, and archaeology indicates that the mound tombs and material culture of the elite were similar throughout the region. 
From China, Buddhism and the Chinese writing system were introduced near the end of the period. The Kofun period recorded Japan's earliest political centralization, when the Yamato clan rose to power in southwestern Japan, established the Imperial House, and helped control trade routes across the region.
Incidentally, this influx of East Asians into Japan started at fall of Han dynasty (three kingdoms) during a chaotic time of northern barbarian uprisings/invasions when dynasties were being formed in the north and the south (in addition to the Yamato dynasty of Japan).

The second point is relatively minor. The Yayoi people had a Northeast Asian genetic affinity akin, for example, to Manchurians, rather than to Han Chinese people. This insight emerges from the big discovery that the non-Jomon component of Japanese population genetics can be broken down into two distinct waves of migrations, which, when separated, are clearly derived from genetically distinct populations.

The timing of the waves of migration is supported by genetic admixture data estimates. As the body text of the new paper explains:
[W]e find support for a two-pulse model from our dating of the admixture in the Kofun individuals by DATES.

A single admixture event with the intermediate population (i.e., YR_LBIA) is estimated to have occurred 1840 ± 213 years before the present (B.P.), which is much later than the onset of the Yayoi period (~3 ka ago).

In contrast, if two separate admixture events with two distinct sources are assumed, the resulting estimates reasonably fit the timings consistent with the beginning of the Yayoi and Kofun periods (3448 ± 825 years B.P. for the admixture between Jomon and Northeast Asian ancestry and 1748 ± 175 years B.P. for Jomon and East Asian ancestry). These genetic findings are further supported by both the archaeological evidence and the historical records, which document the arrival of new people from the continent during the period.
Historical Context

The background material in the introduction, is, as is often the case, very helpful:
The Japanese archipelago has been occupied by humans for at least 38,000 years. However, its most radical cultural transformations have only occurred within the past 3000 years, during which time its inhabitants quickly transitioned from foraging to widespread rice farming to a technologically advanced imperial state. These rapid changes, coupled with geographical isolation from continental Eurasia, make Japan a unique microcosm in which to study the migratory patterns that accompanied agricultural spread and economic intensification in Asia. Before the arrival of farming cultures, the archipelago was occupied by diverse hunter-gatherer-fisher groups belonging to the Jomon culture, characterized by their use of pottery. The Jomon period began during the Oldest Dryas that followed the Last Glacial Maximum (LGM), with the earliest pottery shards dating to ~16,500 years ago (ka ago), making these populations some of the oldest users of ceramics in the world. Jomon subsistence strategies varied and population densities fluctuated through space and time, with trends toward sedentism. This culture continued until the beginning of the Yayoi period (~3 ka ago), when the arrival of paddy field rice cultivation led to an agricultural revolution in the archipelago. This was followed by the Kofun period, starting ~1.7 ka ago, which saw the emergence of political centralization and the imperial reign that came to define the region. 
An enduring hypothesis on the origin of modern Japanese populations proposes a dual-structure model, in which Japanese populations are the admixed descendants of the indigenous Jomon and later arrivals from the East Eurasian continent during the Yayoi period. This hypothesis was originally proposed on the basis of morphological data but has been widely tested and evaluated across disciplines. Genetic studies have identified population stratifications within present-day Japanese populations, supporting at least two waves of migrations to the Japanese archipelago. Previous ancient DNA studies have also illustrated the genetic affinity of Jomon and Yayoi individuals to Japanese populations today. Still, the demographic origins and impact of the agricultural transition and later state formation phase are largely unknown. From a historical linguistic standpoint, the arrival of proto-Japonic language is theorized to map to the development of Yayoi culture and the spread of wet rice cultivation. However, archaeological contexts and their continental affiliations are distinct between the Yayoi and Kofun periods; whether the spread of knowledge and technology was accompanied by major genetic exchange remains elusive.


The mechanism of this paper does a lot to explain why the Jomon weren't simply crushed demographically the way hunter-gatherers in other parts of the world were upon encountering farming societies. 

More generally, knowing that there were sequential Manchurian and Chinese contributions to the formation of the Japanese People, and their order and distance from each other in time, also helps in reconstructing puzzles about how Japanese culture came to be the way that it is now. 

The paper demonstrates that the current population genetic mix in Japan is very recent, on the order of 1600 years old. In contrast, the population genetic mix of Europe was largely fixed by the end of the Bronze Age about 3200 years ago.

This paper sheds far more specific light on the context in which the Japanese language arose which strengthens the Altaic hypothesis and more generally favors some theories about historical Japanese linguistics while disfavoring others.

The paper calls attention to a larger Tungusic linguistic and cultural area that was a social and political and military reality and peaked at a time on the boundary between history and prehistory, that is now almost forgotten.

The paper's findings regarding the relative homogeneity of Jomon genetics over thousands of years and the entire expanse of Japanese territory supports a hypothesis that the Jomon may have shared a single language family, presumably one close to Ainu, while disfavoring deep schisms adding structure that divides this population.

The Paper

The paper and its abstract are:
Prehistoric Japan underwent rapid transformations in the past 3000 years, first from foraging to wet rice farming and then to state formation. A long-standing hypothesis posits that mainland Japanese populations derive dual ancestry from indigenous Jomon hunter-gatherer-fishers and succeeding Yayoi farmers. However, the genomic impact of agricultural migration and subsequent sociocultural changes remains unclear. We report 12 ancient Japanese genomes from pre- and postfarming periods. Our analysis finds that the Jomon maintained a small effective population size of ~1000 over several millennia, with a deep divergence from continental populations dated to 20,000 to 15,000 years ago, a period that saw the insularization of Japan through rising sea levels. Rice cultivation was introduced by people with Northeast Asian ancestry. Unexpectedly, we identify a later influx of East Asian ancestry during the imperial Kofun period. These three ancestral components continue to characterize present-day populations, supporting a tripartite model of Japanese genomic origins.
Niall P. Cooke, et al., "Ancient genomics reveals tripartite origins of Japanese populations" 7(38) Science Advances (September 17, 2021) DOI: 10.1126/sciadv.abh2419

Genetic Details

The genetic data was summarized as follows in the body text with uniparental genetic haplogroups considered:
Mitochondrial haplogroups for all Jomon individuals belong to the N9b or M7a clades, which are strongly associated with this population and rare outside of Japan today. The three Jomon males belong to the Y chromosome haplogroup D1b1, which is present in modern Japanese populations but almost absent in other East Asians. 

In contrast, the Kofun individuals all belong to mitochondrial haplogroups that are common in present-day East Asians, while the single Kofun male has the O3a2c Y chromosome haplogroup, which is also found throughout East Asia, particularly in mainland China.

Further Analysis Of Each Of The Three Components

The discussion section of the paper spells out a narrative and clarifies the geographic origin and timing of each population genetic wave of migration to Japan.

The Jomon
The lineage ancestral to Jomon is proposed to have originated in Southeast Asia with a deep divergence from other ancient and present-day East Asians. The timing of this divergence was previously estimated to be between 18 and 38 ka ago; our modeling with the ROH profile of the 8.8-ka-old Jomon individual narrows this date to a lower limit within the range of 20 to 15 ka ago. The Japanese archipelago had become accessible through the Korean Peninsula at the beginning of the LGM (28 ka ago), enabling population movements between the continent and archipelago. The subsequent widening of the Korea Strait 17 to 16 ka ago due to rising sea levels may have led to the isolation of the Jomon lineage from the rest of the continent and also coincides with the oldest evidence of Jomon pottery production. Our ROH modeling also shows that the Jomon maintained a small effective population size of ~1000 during the Initial Jomon period, and we observe very little changes to their genomic profile in subsequent periods or across the different islands of the archipelago.

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. 

See also this paper on Jomon and Ainu mtDNA, noting that by the Edo period, 29/94 of Ainu people in Hokkaido had characteristically Jomon mtDNA i.e. mtDNA N9b1, M7a2, G1b*; 33/94 has Okhotsk mtDNA (a NE Asian population with Y1 and C5a2b); 6/94 had Siberian mtDNA (D4o1, G1b1 and Z1a), and 26/94 has "mainland" Japan mtDNA (D4xD4o1, M7b1a1a1, F1b1a, N9a, M7a1a7, A5a, and A5c) (a classification I'm not inclined to fully agree with).

The Yayoi 

The Yayoi described as a distinct wave tends to support the hypothesis that Japanese is part of an Altaic macro-language family, with the Korean and Japanese languages probably having the most close affinity to the Tungusic languages of Eastern Siberia and Manchuria (shown in red below) prior to heavy borrowing from Chinese (each of the three maps below are from Wikipedia). As the Altaic language link above explains:

With fewer speakers than Mongolic or Turkic languages, Tungusic languages are distributed across most of Eastern Siberia (including the Sakhalin Island), northern Manchuria and extending into some parts of Xinjiang and Mongolia. Some Tungusic languages are extinct or endangered languages as a consequence of language shift to Chinese and Russian. In China, where the Tungusic population is over 10 million, just 46,000 still retain knowledge of their ethnic languages.

Scholars have yet to reach agreement on how to classify the Tungusic languages but two subfamilies have been proposed: South Tungusic (or Manchu) and North Tungusic (Tungus). Jurchen (now extinct; Da Jin 大金), Manchu (critically endangered; Da Qing 大清), Sibe (Xibo 锡伯) and other minor languages comprise the Manchu group.

The Northern Tungusic languages can be reclassified even further into the Siberian Tungusic languages (Evenki, Lamut, Solon and Negidal) and the Lower Amur Tungusic languages (Nanai, Ulcha, Orok to name a few).

Significant disagreements remain, not only about the linguistic sub-classifications but also some controversy around the Chinese names of some ethnic groups, like the use of Hezhe (赫哲) for the Nanai people.

The spread of agriculture is often marked by population replacement, as documented in the Neolithic transition throughout most of Europe, with only minimal contributions from hunter-gatherer populations observed in many regions. However, we find genetic evidence that the agricultural transition in prehistoric Japan involved the process of assimilation, rather than replacement, with almost equal genetic contributions from the indigenous Jomon and new immigrants at the Kyushu site. This implies that at least some parts of the archipelago supported a Jomon population of comparable size to the agricultural immigrants at the beginning of the Yayoi period, as it is reflected in the high degree of sedentism practiced by some Jomon communities. 
The continental component inherited by the Yayoi is best represented in our dataset by the Middle Neolithic and Bronze Age individuals from the West Liao River basin with a high level of Amur River ancestry (i.e., WRL_BA_o and HMMH_MN). Populations from this region are genetically heterogeneous in time and space. The Middle-to-Late Neolithic transition (i.e., between 6.5 and 3.5 ka ago) is characterized with an increase in Yellow River ancestry from 25 to 92% but a decrease in Amur River ancestry from 75 to 8% over time, which can be linked to an intensification of millet farming. However, the population structure changes again in the Bronze Age, which started around 3.5 ka ago, due to an apparent influx of people from the Amur River basin. This coincides with the beginning of intensive language borrowing between Transeurasian and Sinitic linguistic subgroups. Excess affinity to the Yayoi is observable in the individuals who are genetically close to ancient Amur River populations or present-day Tunguisic-speaking populations. Our findings imply that wet rice farming was introduced to the archipelago by people who lived somewhere around the Liaodong Peninsula but who derive a major component of their ancestry from populations further north, although the spread of rice agriculture originated south of the West Liao River basin. 

Further linguistic analysis can be found in another recent paper referenced in this one, which argues that the original macro-Altaic homeland was an early Neolithic one in the West Liao River basin.

The Kofun

The Kofun wave of migration was Han Chinese-like and from the Southern Korean peninsula. 

The most noticeable archaeological characteristic of Kofun culture is the custom of burying the elite in keyhole-shaped mounds, the size of which reflect hierarchical rank and political power. The three Kofun individuals sequenced in this study were not buried in those tumuli, which suggests that they were lower-ranking people. Their genomes document the arrival of people with majority East Asian ancestry to Japan and their admixture with the Yayoi population. This additional ancestry is best represented in our analysis by Han, who have multiple ancestral components. A recent study has reported that people became morphologically homogeneous in the continent from the Neolithic onward, which implies that migrants during the Kofun period were already highly admixed. 
Several lines of archaeological evidence support the introduction of new large settlements to Japan, most likely from the southern Korean peninsula, during the Yayoi-Kofun transition. Strong cultural and political affinity between Japan, Korea, and China is also observable from several imports, including Chinese mirrors and coins, Korean raw materials for iron production, and Chinese characters inscribed on metal implements (e.g., swords). Access to these resources from overseas brought about intensive competition between communities within the archipelago; this facilitated political contact with polities in the continent, such as the Yellow Sea coast, for dominance. Therefore, continuous migration and continental impacts are evident throughout the Kofun period. Our findings provide strong support for the genetic exchange involved in the appearance of new social, cultural, and political traits in this state formation phase.
The Ancient DNA Samples Used

The paper looks at nine new Jomon ancient DNA samples in addition to three old Jomon ancient DNA samples (in all four men and eight women from ca. 6819 BCE to 569 BCE), two old Yayoi ancient DNA samples (a man from ca. 44 CE and a woman), and three new Kofun ancient DNA samples (a man and two women from ca. 622 CE to 675 CE) (although the dating would suggest that they are actually from the Asuka era).

The paper further explains its samples as follows:

Here, we report 12 newly sequenced ancient Japanese genomes spanning 8000 years of the archipelago’s pre- and protohistory. To our knowledge, this is the largest set of time-stamped genomes from the archipelago, including the oldest Jomon individual and the first genomic data from the imperial Kofun period. We also include five published prehistoric Japanese genomes in our analysis: three Jomon individuals (F5 and F23 from the Late Jomon period and IK002 from the Final Jomon period), as well as two 2000-year-old individuals associated with the Yayoi culture from the northwestern part of Kyushu Island, where skeletal remains exhibit Jomon-like characters rather than immigrant types but other archaeological materials clearly support their association with the Yayoi culture. Despite this morphological assessment, these two Yayoi individuals show an increased genetic affinity to present-day Japanese populations compared with the Jomon, implying that admixture with continental groups was already advanced by the Late Yayoi period.

The paper later notes that:

Our kinship analysis confirms that all pairs of individuals are unrelated. 

The conclusion of the paper notes that the main limitation of its findings is the small size of its ancient DNA samples for each period which may not reflect geographic diversity and population structure in each time period (especially the Yayoi and Kofun periods).

Monday, September 20, 2021

Another Voice In the Gravity And Tully-Fischer Conversation (And More)

None of this is unfamiliar to me, but it is nice to see more people having this epiphany. Of course, the next step that this author needs to take after this initial baby step is to imagine what kind of physics would be necessary to produce this kind of structure.
The flattening of spiral-galaxy rotation curves is unnatural in view of the expectations from Kepler's third law and a central mass. It is interesting, however, that the radius-independence velocity is what one expects in one less dimension. In our three-dimensional space, the rotation curve is natural if, outside the galaxy's center, the gravitational potential corresponds to that of a very prolate ellipsoid, filament, string, or otherwise cylindrical structure perpendicular to the galactic plane. While there is observational evidence (and numerical simulations) for filamentary structure at large scales, this has not been discussed at scales commensurable with galactic sizes. If, nevertheless, the hypothesis is tentatively adopted, the scaling exponent of the baryonic Tully--Fisher relation due to accretion of visible matter by the halo comes out to reasonably be 4. At a minimum, this analytical limit would suggest that simulations yielding prolate haloes would provide a better overall fit to small-scale galaxy data.

UPDATE September 21, 2021

A couple more articles in the same vein. 

The first is very akin to Deur's effort to infer dark sector phenomena from an analysis of General Relativity that grapples with the removal of simplifying assumptions often used to make it possible to obtain a clean analytic solution, although this approach is inspired by statistical mechanics rather than by quantum chromodynamics.
Inspired by the statistical mechanics of an ensemble of interacting particles (BBGKY hierarchy), we propose to account for small-scale inhomogeneities in self-gravitating astrophysical fluids by deriving a non-ideal Virial theorem and non-ideal NavierStokes equations. These equations involve the pair radial distribution function (similar to the two-point correlation function used to characterize the large-scale structures of the Universe), similarly to the interaction energy and equation of state in liquids. Within this framework, small-scale correlations lead to a non-ideal amplification of the gravitational interaction energy, whose omission leads to a missing mass problem, e.g., in galaxies and galaxy clusters. 
We propose to use a decomposition of the gravitational potential into a near- and far-field component in order to account for the gravitational force and correlations in the thermodynamics properties of the fluid. Based on the non-ideal Virial theorem, we also propose an extension of the Friedmann equations in the non-ideal regime and use numerical simulations to constrain the contribution of these correlations to the expansion and acceleration of the Universe. 
We estimate the non-ideal amplification factor of the gravitational interaction energy of the baryons to lie between 5 and 20, potentially explaining the observed value of the Hubble parameter (since the uncorrelated energy account for ∼ 5%). Within this framework, the acceleration of the expansion emerges naturally because of the increasing number of sub-structures induced by gravitational collapse, which increases their contribution to the total gravitational energy. A simple estimate predicts a non-ideal deceleration parameter qni ' -1; this is potentially the first determination of the observed value based on an intuitively physical argument. We show that another consequence of the small-scale gravitational interactions in bound structures (spiral arms or local clustering) yields a transition to a viscous regime that can lead to flat rotation curves. This transition can also explain the dichotomy between (Keplerian) LSB elliptical galaxy and (non-Keplerian) spiral galaxy rotation profiles. Overall, our results demonstrate that non-ideal effects induced by inhomogeneities must be taken into account, potentially with our formalism, in order to properly determine the gravitational dynamics of galaxies and the larger scale universe. 
P. Tremblin, et al., "Non-ideal self-gravity and cosmology: the importance of correlations in the dynamics of the large-scale structures of the Universe" arXiv:2109.09087 (September 19, 2021) (submitted to A&A, original version submitted in 2019).

The second generalized modified gravity approaches to explaining dark matter in galaxies in the traditional geometric paradigm.
We obtain more straightforwardly some features of dark matter distribution in the halos of galaxies by considering the spherically symmetric space-time, which satisfies the flat rotational curve condition, and the geometric equation of state resulting from the modified gravity theory. In order to measure the equation of state for dark matter in the galactic halo, we provide a general formalism taking into account the modified f(X) gravity theories. Here, f(X) is a general function of X∈{R,,T}, where R, and T are the Ricci scalar, the Gauss-Bonnet scalar and the torsion scalar, respectively. These theories yield that the flat rotation curves appear as a consequence of the additional geometric structure accommodated by those of modified gravity theories. Constructing a geometric equation of state wX≡pX/ρX and inspiring by some values of the equation of state for the ordinary matter, we infer some properties of dark matter in galactic halos of galaxies.
Ugur Camci, "On Dark Matter As A Geometric Effect in the Galactic HaloarXiv:2109.09466 366 Astrophys. Space. Sci. 91 (September 17, 2021) DOI: 10.1007/s10509-021-03997-5

While not in the same vein, so it doesn't get lost in the shuffle, I also note a new paper which identifies a potential source of systemic error that could help explain the discrepancy in the Hubble constant measurements at high z and low z. 

While papers with new physics explanations for the Hubble constant anomaly abound, given the history of prior Hubble constant anomalies, and prior anomalies in fundamental physics generally, papers identifying potential sources of systemic error deserve outsized attention, because most anomalies in fundamental physics are resolved by discovering them.
The bias in the determination of the Hubble parameter and the Hubble constant in the modern Universe is discussed. It could appear due to statistical processing of data on galaxies redshifts and estimated distances based on some statistical relations with limited accuracy. This causes a number of effects leading to either underestimation or overestimation of the Hubble parameter when using any methods of statistical processing, primarily the least squares method (LSM). The value of the Hubble constant is underestimated when processing a whole sample; when the sample is constrained by distance, especially when constrained from above, it is significantly overestimated due to data selection. The bias significantly exceeds the values of the error the Hubble constant calculated by the LSM formulae.

These effects are demonstrated both analytically and using Monte Carlo simulations, which introduce deviations in both velocities and estimated distances to the original dataset described by the Hubble law. The characteristics of the deviations are similar to real observations. Errors in estimated distances are up to 20%. They lead to the fact that when processing the same mock sample using LSM, it is possible to obtain an estimate of the Hubble constant from 96% of the true value when processing the entire sample to 110% when processing the subsample with distances limited from above.

The impact of these effects can lead to a bias in the Hubble constant obtained from real data and an overestimation of the accuracy of determining this value. This may call into question the accuracy of determining the Hubble constant and significantly reduce the tension between the values obtained from the observations in the early and modern Universe, which were actively discussed during the last year.
S.L.Parnovsky "Bias of the Hubble constant value caused by errors in galactic distance indicatorsarXiv:2109.09645 (September 20, 2021) (Accepted for publication at Ukr. J. Phys).