A "No Hype" Science Journalism Stand-Out

Science journalism aimed at the educated (or not so educated) layman in the general public is prone to sensationalism and claims of new discoveries that aren't supported by the body text, or at least, aren't supported by the source and the general scientific community. But there are exceptions. 

One stand out is an article from Phys.org which is a source that often offends in this regard but doesn't this time. Its headline accurately states:

Theoretical physicists find Higgs boson does not seem to contain any harbingers of new physics

The headline conclusion, reached after twelve years of study since its discovery was announced on July 4, 2012, is familiar to readers of this blog, but deserves recognition for resisting sensationalism and restating the scientific consensus.  See, e.g., noting decays to a Z boson and a photon and here (summarizing the data to date). 

The article used as its touchstone has the following abstract and citation (and isn't itself, the headline suggests, a broad review article, and is instead one more mundane article confirming that the experimental study of the Higgs boson confirms the theoretical expectations for it):

We evaluate the top-bottom interference contribution to the fully inclusive Higgs production cross section at next-to-next-to-leading order in QCD. Although bottom-quark-mass effects are power suppressed, the accuracy of state-of-the-art theory predictions makes an exact determination of this effect indispensable. The total effect of the interference at 13 TeV is −1.99⁢(1)+0.30−0.15  pb, while the pure 𝒪⁡(𝛼4𝑠) correction is 0.43 pb. With this result, we address one of the leading theory uncertainties of the cross section.

Michał Czakon et al, "Top-Bottom Interference Contribution to Fully Inclusive Higgs Production", Physical Review Letters (2024). DOI: 10.1103/PhysRevLett.132.211902

As additional context, Peter Higgs after whom the Higgs boson  is named, died in April of this year.

There is actually a slight Higgs boson anomaly, that is barely statistically significant locally (2.2 sigma), which would probably lose its statistical significance after considering look elsewhere effects, involving lower than expected Higgs boson decays to fermions (but the expected number of decays to bosons).

There are also a couple of low significance resonance "bumps" that have been touted as possible additional electromagnetically neutral Higgs bosons that have not been confirmed, one a bit below the Higgs boson mass of about 125 GeV, at about 96 GeV, and one or two a bit above it. Even if these "bumps" were confirmed to be real particles, there is no a priori reason to have any  confidence that they have anything to do with the Higgs boson.

Early Neolithic Arabia

 

Archaeologists in Saudi Arabia have excavated eight ancient "standing stone circles" that they say were used as homes. About 345 of these structures were identified through aerial surveys across the Harrat 'Uwayrid, a lava field near the city of AlUla in northwestern Saudi Arabia, the team reported July 2 in the journal Levant. The circles range from 13 to 26 feet (4 to 8 meters) in diameter and have at least one standing stone at the center. The circles date back around 7,000 years and have the remains of stone walls and at least one doorway. They would have had roofs made of either stone or organic materials, the team wrote. . . . 

Around 7,000 years ago, the environment in northern Saudi Arabia was much wetter than it is today, but farming had not yet come into use. "There's no evidence of farming domesticated species of plants like wheat and barley, but gathering wild plants likely took place, and perhaps manipulating the landscape to increase the likelihood and yield of wild species," McMahon said.

When these standing stone circles were in use, another form of stone structure, known today as a mustatil (Arabic for "rectangle"), was being built as well. Excavations at the mustatils suggest they had a ritual purpose that may have included the sacrifice of cattle. The contemporaneous use of the mustatils and standing stone circles indicates that it is "likely that these two megalithic structure types are aspects of a single cultural entity," the team wrote.

Gary Rollefson, a professor emeritus of anthropology at Whitman College and San Diego State University who was not involved in the research but has conducted extensive archaeological work in the region, said he thinks the people who built the standing stone circles and mustatils are descended from people who lived in Jordan and Syria about 500 years earlier.

He told Live Science that the architecture of the standing stone circles is similar to that of structures found in Jordan dating to about 500 years earlier, and the people who built the structures in Jordan also herded sheep, goats and cattle. The migration may have been spurred by an increase in population brought about by new hunting technologies, such as the "kite," a series of stone walls used to force wild animals into a kill zone. These hunting advances dramatically increased the supply of food, which, in turn, led to an increase in the human population in the Jordan/Syria area.

"They were building up a large population in eastern Jordan and [parts of] Syria," Rollefson said, and they needed to find new hunting grounds, which would have led them to gradually go south, into what is now Saudi Arabia.

Via Live Science.

The paper indicates that there were post-Neolithic early herders, rather than primarily being hunter-gatherers.

The paper and its abstract are as follows:

Recent archaeological investigations in AlUla County have provided the first detailed chrono-cultural evidence for long-term Neolithic domestic occupation in this archaeologically unknown region of north-west Arabia. 

This paper presents the preliminary findings drawn from multi-scalar datasets collected through extensive aerial and ground surveys, and the excavations of ‘monumental’ architectural installations, named in this study as ‘Standing Stone Circles’. These structures were individual dwellings, constructed in concentrations of varying numbers with associated domestic installations, such as hearths. The Standing Stone Cicle sites presented in this paper demonstrate a scale of Neolithic occupation not previously recognized in Saudi Arabia. These structures provide evidence of ongoing occupation throughout the 6th and 5th millennia BCE, concurrent with a general florescence of human activity across north-west Arabia. The faunal remains indicate a mixed subsistence economy, dominated by domesticates but supplemented by wild species. 

Broader considerations of the Neolithic economy, and models of pastoralism and mobility, are made possible on the basis of this, and the associated assemblages of stone artefacts and small finds. The data provided in this article offers a general picture of the Neolithic period in AlUla, addressing the significant geographical and temporal gaps within the archaeological knowledge of north-west Arabia. The identification of diagnostic Late Neolithic Levantine projectile point types, in conjunction with architectural parallels with the Levant, provides further insight into the origins of neolithization in north-west Arabia.

Jane McMahon, et al., "New evidence for Neolithic occupation in north-west Arabia: Standing Stone Circles on the Harrat ‘Uwayrid'" Levant (July 2, 2024) (open access).

Archaic Hominin News

The flow of genes in multiple episodes between Neanderthals and modern humans is now better understood, and we have a new Denisovan genome from 200,000 years ago with better quality than any previous Denisovan genome. Via Razib:

Recurrent gene flow between Neanderthals and modern humans over the past 200,000 years:

Our understanding of admixture between humans and Neanderthals has changed dramatically over the past decade and a half. Once thought not to have occurred at all, there is now ample evidence for gene flow from Neanderthals to humans and vice versa. Li et al. used a new framework to model the increasingly complex dynamics of introgression between humans and Neanderthals and the ramifications for both populations. They identified regions of human ancestry in Neanderthals, estimated population sizes for Neanderthals were about 20% lower than previously thought, and proposed the possibility of two pulses of gene flow from humans to Neanderthals. This study comprehensively synthesizes our current knowledge of hominin admixture. —Corinne N. Simonti.

The most ancient human genome yet has been sequenced—and it’s a Denisovan’s. 24x, high quality, 200,000 years ago.

From the Denisovan link:

“I’m pleased to tell you about a new Denisovan genome from a 200,000-year-old male,” said [Stéphane] Peyrégne, a postdoc at the Max Planck Institute for Evolutionary Anthropology.

The genetic sequence he unveiled is the oldest high-quality human genome yet—80,000 years older than the previous record holder: a Neanderthal that lived about 120,000 years ago. The new results come after more than a decade of effort to find fossilized bones and a second genome of a Denisovan, the mysterious archaic human discovered through its DNA 14 years ago. That first Denisovan genome came from a girl’s pinkie finger bone dated between 60,000 to 80,000 years ago. The genomes of both Denisovans and the ancient Neanderthal all came from the same cold, fossil-rich site: Denisova Cave in the Altai Mountains of Siberia.

According to the analysis by Peyrégne and colleagues, the newly sequenced male comes from a distinct population of early Denisovans that interbred multiple times with a group of Neanderthals whose population had not been detected in DNA before. . . . 

Denisovans are primarily known from their DNA. Researchers have the genome of the girl, as well as bits of nuclear and mitochondrial DNA from fragmentary fossils—teeth, a toe bone—of seven additional individuals, all also from Denisova Cave. Scientists have also identified some Denisovan DNA in living humans, including in Papuans and Han Chinese people, acquired from past interbreeding. DNA in sediments showed that Denisovans were first in the cave 300,000 years ago, and later lived in a cave on the Tibetan Plateau. The scanty fossils reveal this archaic human had larger molars than did the Neanderthals and a robust lower face, known from a jawbone in China. . . . archaeologist Maxim Kozlikin of the Russian Academy of Sciences (RAS) found a molar in a deep layer dated to 200,000 years ago, Peyrégne reported in his talk. The RAS team sent the molar to Max Planck, where evolutionary geneticists extracted enough DNA to provide 24-fold coverage of the genome. . . .

the male Denisovan had inherited 5% of his genome from an ancient, previously unknown population of Neanderthals. The male, labeled Denisova 25, came from a separate population of Denisovans from the girl, known as Denisova 3, and from the other Denisovans in the cave. The girl’s DNA is more closely related to the Denisovan sequences in living modern humans, who got them from at least two Denisovan populations.

All this suggests the older male’s population was replaced in the cave by later Denisovans. . . . the male Denisovan’s ancestors interbred multiple times with Neanderthals. Denisovans were apparently replaced in the cave by Neanderthals for a period, based on the Neanderthal fossil dated to about 120,000 years ago. By about 60,000 years ago, though, the Denisovans had moved back in. The two groups may even have met in the cave—DNA from a bone fragment from a female who was more than 50,000 years old shows her mother was a Neanderthal and her father a Denisovan. Later, both DNA and fossils indicate modern humans occupied the cave and Denisovans and Neanderthals disappear. . . .  

Although Denisovans and Neanderthals apparently interbred repeatedly, their lineages are distinct: They diverged from a common ancestor at least 400,000 years ago. The ancestors of Neanderthals settled in Europe and the Middle East, whereas Denisovans headed farther east into Asia where they evolved separately, acquiring roughly 300,000 genetic changes that differentiate them from Neanderthals, according to the new genome. “Neanderthals and Denisovans remain in separate groups,” and mixed at the edges of their geographic ranges. . . . 

an audience member asked whether the male’s genome also had DNA from an even older, unidentified type of human–perhaps Homo erectus—whose DNA has been spotted in the Denisovan girl’s genome. “If there is any Denisova superarchaic ancestry, it’s also present in this genome,” Peyrégne responded. “[That DNA] is shared between Denisova 3 and Denisova 25.”

See also speculations on the Yeti myth is an oral history recollection of Denisovans in Tibet at the Old European Culture Blog, and John Hawks post about large brained archaic hominin Julurens in China, who could be cousins of Neanderthals and Denisovans.

The Lightest Neutron Star

The maximum neutron star mass is an open question in physics that receives more attention than the minimum neutron star mass. But the range of neutron star masses is quite narrow, with roughly a factor of two separating the least massive ones from the most massive ones, and there are theoretical efforts to establish why this is the case.

Supernova theory has struggled to explain the lightest known neutron star candidate with an accurate mass determination, the 1.174M⊙ companion in the eccentric compact binary system J0453+1559. 

To improve the theoretical lower limit for neutron star birth masses, we perform 3D supernova simulations for five stellar models close to the minimum mass for iron core collapse. We obtain a record-low neutron star mass of 1.192M⊙ and a substantial kick of ∼100kms^−1. Given residual uncertainties in stellar evolution, a neutron star origin for the 1.174M⊙ object remains plausible.

Bernhard Müller, Alexander Heger, Jade Powell, "The minimum neutron star mass in neutrino-driven supernova explosions" arXiv:2407.08407 (July 11, 2024).

Neutron Star Properties

Neutron stars are hard to model from first principles because they involve a regime where general relativity and Standard Model physics intersect with vast numbers of particles condensed in highly dense matter rather than in the small number of particles at time seen in particle colliders where high energy physics is usually done, even though they are, in principle, still rather simple systems. 

But astronomy observations can constrain their properties and provide us with insights about the underlying high energy physics in a domain that otherwise would be inaccessible to solar system bound physics experiments. This requires a mix of physics motivated models of neutron stars and carefully processed and analyzed astronomy data.

This data is homing in on a nearly universal neutron star to be pretty universally close to a 12 kilometer radius, and a maximum neutron star mass of modestly more than two solar masses. 

This maximum neutron star mass is low relative to other data that is more direct, but not by a lot. As I noted in a June 26, 2020 blog post (which later notes that two independent papers think that the 2.5-2.64 solar mass object observed with a gravitational wave detector is much more likely to be a black hole than a neutron star).

Gravitational wave detectors have observed what appears to be an intermediate sized black hole (26 times the mass of the Sun) collide with a "compact object" with a mass of 2.6 (2.5 to 2.64 at a 90% confidence interval) times the mass of the Sun.

Beyond a certain cutoff mass at a given radius, compact masses like neutron stars, collapse and form black holes. But, calculating the cutoff isn't a clean and simple calculation, because you have to model how tightly protons and neutrons can be squeezed together by gravity as nuclear forces push back against being squeezed too tightly, and those are complex systems involving vast numbers of protons and neutrons that can't be modeled exactly.

The most dense, large compact objects in the universe that are not black holes are neutron stars. Neutron stars are just massive, extremely dense, ordinary stars on the continuum of ordinary star behavior.

But black holes are qualitatively different. In classical General Relativity they are mathematical singularities. In theories of quantum gravity, black holes are "almost" singularities (from which nothing can escape) but leak slightly in a theoretically described phenomena called "Hawking Radiation" which is too slight to be observed over the noise of cosmic background radiation with current means.

This compact object is potentially more massive than any previously observed neutron star (it has a higher minimum mass within experimental uncertainties than any previously observed neutron star), but it is lighter than the lightest known black hole (see here), subject to outliers near the boundary with large error margins in their mass estimates.

The least massive black hole ever observed has a mass of 2.72-2.82 solar masses (in a 95% confidence range). The most massive previously observed neutron stars have masses of 2.32-3.15, 1.9-3.00, 2.15-2.70 and 2.16-2.64 solar masses (in a 95% confidence range). So, the cutoff has to be somewhere in the range of 2.32 solar masses to 2.82 solar masses. This object is squarely in the middle of that range.

Another recent study which I blogged on April 30, 2024, puts a 95% confidence interval maximum neutron star mass at 2.38 solar masses and a maximum radius of 12.0 km. 

A new study, whose abstract and citation appear below, puts the most massive possible neutron star at 2.43 solar masses at a 95% confidence interval by one method, and 2.64 solar masses at a 95% confidence interval by another, with best fit maximum neutron star masses of 2.15 solar masses by one method and 2.08 solar masses by another. 

A cutoff maximum neutron star mass of 2.32 to 2.38 solar masses would best harmonize the available information from the newest studies and observations.

The narrowing in of the maximum mass of a neutron star and its radius also fixes a quite narrow range for the highest observed mass per volume of any object at any scale observed in Nature. Maybe I'll calculate that as an exercise at some point in light of the updated data.

Pulse profile modeling of X-ray data from NICER is now enabling precision inference of neutron star mass and radius. Combined with nuclear physics constraints from chiral effective field theory (χEFT), and masses and tidal deformabilities inferred from gravitational wave detections of binary neutron star mergers, this has lead to a steady improvement in our understanding of the dense matter equation of state (EOS). 

Here we consider the impact of several new results: the radius measurement for the 1.42M⊙ pulsar PSR J0437−4715 presented by Choudhury et al. (2024), updates to the masses and radii of PSR J0740+6620 and PSR J0030+0451, and new χEFT results for neutron star matter up to 1.5 times nuclear saturation density. Using two different high-density EOS extensions -- a piecewise-polytropic (PP) model and a model based on the speed of sound in a neutron star (CS) -- 

we find the radius of a 1.4M⊙ (2.0M⊙) neutron star to be constrained to the 95% credible ranges 12.28+0.50−0.76 km (12.33+0.70−1.34 km) for the PP model and 12.01+0.56−0.75 km (11.55+0.94−1.09 km) for the CS model. The maximum neutron star mass is predicted to be 2.15+0.14−0.16 M⊙ and 2.08+0.28−0.16 M⊙ for the PP and CS model, respectively. 

We explore the sensitivity of our results to different orders and different densities up to which χEFT is used, and show how the astrophysical observations provide constraints for the pressure at intermediate densities. Moreover, we investigate the difference R2.0−R1.4 of the radius of 2M⊙ and 1.4M⊙ neutron stars within our EOS inference.

Nathan Rutherford, et al., "Constraining the dense matter equation of state with new NICER mass-radius measurements and new chiral effective field theory inputs" arXiv:2407.06790 (July 9, 2024).

Why Do People Still Try To Build Preon Theories?

Preon theories try to explain the particles and properties of the Standard Model of Particle Physics from few components than its six quarks, six leptons, and three kinds of massive fundamental bosons, and three kinds of massless fundamental bosons with a smaller set of more basic particles, in much the same way that atoms simplified molecules and crystals, in much the same way that protons and neutrons and electrons simplified the periodic table of the elements, and in much the same way that the Standard Model simplified the "particle zoo" of myriad possible hadrons.

Experimental tests of compositeness for the Standard Model particles, however, show no sign of them to the point where they would have to be more massive than the particles that are supposed to be made up out of them. The best and the brightest of the scientific profession has been trying to use this approach for half a century with no viable results.

So, why do people still build preon (preons as actual particles) theories?

It is so very tempting though.

Our very terminology points huge arrows in this direction by decomposing fundamental particles in the Standard Model into a bunch of discrete properties that are assigned numbers, which exist in some combinations but not others.

The list I've screen shotted doesn't even include QCD color charge, or whether both left and right, or only left or right parity is available, and particle v. antiparticle distinctions.

A b quark looks like a -1/3 charge preon, plus a single color charge preon, plus a spin-1/2 preon, plus a 1/3 baryon number preon, plus a bottomness preon, plus some composite hypercharge and weak hypercharge particles.

It looks like every other puzzle that science has ever presented to us without actually requiring multi-variable calculus and complex analysis to fathom.

It screams at you that there must be a simpler way! All of our other scientific and life experiences tell us that it feels like there should be some clever way to make it flow from something simpler and deeper.

If it worked for myriad molecules and crystals we encounter in everyday life, it worked for the periodic table of the elements, and it worked for the particle zoo of hadrons, then surely there must be a better way to simplify the 104 possible combinations of color charge, mass, electromagnetic charge, weak interaction charge, spin, parity, and particle-antiparticle combinations (including the graviton, and excluding continuous properties like photon frequency and kinetic energy):

* 3 quark generations x 2 quark EM charges x 3 colors each x 2 parity possibilities x particle/antiparticles for each = 72 discrete quark variants;

* 3 charged lepton generations x 2 parity possibilities x particle/antiparticles for each = 12 discrete charged lepton variants; and

* 3 neutrino generations x 1 parity possibility x particle/antiparticle for each = 6 discrete neutrino variants

for 90 discrete fundamental fermion variants.

The eight color combinations of gluons, the W+ and W- bosons, one Z boson, the Higgs boson, the photon and the (hypothetical graviton) for 14 discrete fundamental bosons variants.

104 discrete fundamental particle variants in all.

How can 104 discrete variations of anything be fundamental, our intuition screams?

And there is a prize out there to claim: Reducing the number of experimentally determined constants in the Standard Model.

15 masses, 4 CKM parameters, 4 PMNS parameters, 3 coupling constants particular to the Standard Model, G and the cosmological constant in GR, and the speed of light (it was measured before it was defined, which is why it isn't a round number in meters) and Plank's constant for good measure.

Surely there must be a way to trim down the 30 fundamental constants (really a few less, since a few are not independent of each other due to electroweak unification)!

And, it isn't as if the 104 discrete variants of particle types and 30 fundamental constants show no patterns! 

There are mass hierarchies and textures and alternative parameterizations. There are correlations between the masses and the mixing angles. There are combinations of properties that are allowed, and combinations of properties that aren't. 

We already have formulas connecting a couple of the coupling constants to a couple of the masses. So, why shouldn't there be more formulas like that?

Even if your preon model cuts down the number of fundamental particles only minimally, if it can provide a way to calculate many more of those 30 experimentally determined physical constants from first principles, that's a huge win that can provide more precision without more experimental measurements!

And, for those who believe that dark matter particles are a thing and that dark energy has substance, or that SUSY is real, or that there might be inflatons or other motley BSM particles, it offers the reward of a path to identify what those BSM particles could be before we discover them experimentally. Indeed, in light of the fact that we may never actually be able to observe them experimentally because the experiments are too hard, at least to complete in our lifetime, theorizing them may be the best that we can do. Mr. Higgs had to wait 40 years and was lucky to see his prediction bear fruit!

The same incentives, with more sophistication, drive GUT models, theories of everything, and string theory, which are basically preon theories for grown ups.

We already know things sufficiently fundamental to know what we need to know to apply the Standard Model and GR to all sorts of absurdly hard problems that are at the very limits of our technological abilities with absurd precision, but it is still so unsatisfying and clunky!

So that's "why" people keep working on preon models.

Is it time well spent?

Probably not.

Using the same methods that we used to discovery protons, neutrons and quarks, it takes huge contortions for preons to be real without some sort of Higgs field/gravitational field shielding or something similar to hide hugely massive particles as components of much less massive particles.

But there is also a deep sense that this clunky complexity can't be all that there is to know. The data we have is so organized and structured and fits together so well. It looks like a preon problem! And, preon theories are very inexpensive to research using data collected for other purposes. And, highly respected HEP scientists have tried in the past and published their whimsies, before giving up, so it is respectable, up to a point (even if the numerology monster lurks behind every corner and the experimental constraints get tighter every time we review them anew).

As a result, people keep trying that approach, the same way that they try to climb Mount Everest despite the long line of dead bodies that they have to pass by on the way and knowing that their particular quest isn't likely to change the world in any meaningful way. The data is sitting there, staring us in the face, taunting us!

Preon theory, GUT theory, TOE theory, string theory, and lots of other BSM theorizing is ultimately driven by an unwillingness to accept that what we know now is as good as it gets. Preon theories are just the entry level version of the larger quest. So, we'll keep seeing them until we have better answers from one source or another.

Minotaur Labyrinth May Be Been Discovered In Crete.

A 4,000-year-old circular structure resembling Minoan tomb architecture was unearthed near Kastelli, Crete, suggesting it could be the legendary labyrinth of King Minos.

From the Jerusalem Post.

A Different Take On Neutrino Oscillation

This paper suggests an attractive alternative interpretation of neutrino oscillation.

To account for neutrino oscillations, it is postulated that the neutrino has nonvanishing mass and each flavor eigenstate is formed by three distinct mass eigenstates, whose probability amplitudes interfere with each other during its propagation. 

However, I find that the energy conservation law requires these mass eigenstates, if they exist, to be entangled with distinct joint energy eigenstates of the other particles produced by the same weak interaction as the neutrino. This entanglement destroys the quantum coherence among the neutrino's mass eigenstates, which are responsible for flavor oscillations under the aforementioned postulation. 

I reveal that the neutrino oscillations actually originate from virtual excitation of the Z bosonic field diffusing over the space. During the propagation, the neutrino can continually excite and then immediately re-absorb a virtual Z boson. This virtual bosonic excitation produces a backaction on the neutrino, enabling it to oscillate among three flavors. When the neutrino propagates in matter, its behavior is determined by the competition between the coherent flavor transformation and decoherence effect resulting from scatterings.

Shi-Biao Zheng, "Neutrino oscillations originate from virtual excitation of Z bosons" arXiv:2407.00954 (July 1, 2024).

The Spread Of Austronesian Languages To Vietnam

Why do the people in the highlands of Vietnam speak Austronesian languages, which diffused mostly through maritime contact?

There seems to be a core of matrilineal Austronesians in Austronesian language speaking populations in Vietnam, but mostly, this appears to be a product of language shift.

This case is particularly notable in historical linguistics because so often, the origins of a language in a place are hidden deep in the depths of prehistory, while in this case, there are historical records of what was going on that genetic evidence is merely corroborating and refining. We know that Austronesian languages, which arrived only around 2500 years ago and probably suffered a great blow around 600 years ago, are the more recent linguistic layer in Vietnam than Austroasiatic languages, and can even name particular individuals and historical events that were pivotal in that process.

We also have parallel historical accounts (mostly Chinese) of the arrivals of Sino-Tibetan (i.e. Chinese, who ruled Vietnam for a thousand years starting around 111 BCE but with a Chinese kingdom in some of its territory ca. 180 BCE), Tai-Kadai (see also here noting an arrival in the 400s to 1000s CE after first mentions of their existence in Southern China ca. 500 BCE),  and Hmong-Mien languages (in the 1600s CE) in mainland Southeast Asia, in each case from what is now China.

Austronesian (AN) is the second-largest language family in the world, particularly widespread in Island Southeast Asia (ISEA) and Oceania. In Mainland Southeast Asia (MSEA), groups speaking these languages are concentrated in the highlands of Vietnam. However, our knowledge of the spread of AN-speaking populations in MSEA remains limited; in particular, it is not clear if AN languages were spread by demic or cultural diffusion. 

In this study, we present and analyze new data consisting of complete mitogenomes from 369 individuals and 847 Y-chromosomal single nucleotide polymorphisms (SNPs) from 170 individuals from all five Vietnamese Austronesian groups (VN-AN) and five neighboring Vietnamese Austroasiatic groups (VN-AA). 

We found genetic signals consistent with matrilocality in some, but not all, of the VN-AN groups. Population affinity analyses indicated connections between the AN-speaking Giarai and certain Taiwanese AN groups (Rukai, Paiwan, and Bunun). However, overall, there were closer genetic affinities between VN-AN groups and neighboring VN-AA groups, suggesting language shifts. Our study provides insights into the genetic structure of AN-speaking communities in MSEA, characterized by some contact with Taiwan and language shift in neighboring groups, indicating that the expansion of AN speakers in MSEA was a combination of cultural and demic diffusion.

Dinh Huong Thao, et al., "Investigating demic versus cultural diffusion and sex bias in the spread of Austronesian languages in Vietnam" PLOS One (June 17, 2024).

The body text of the introduction to the new article provides useful context that ties into the available linguistic and historical evidence (the link is mine):

The Austronesian language family (AN), encompassing 1256 languages spoken by approximately 360 million people, stretches from Madagascar to Hainan, Southeast Asia, Taiwan, and Near and Remote Oceania. The ancestors of Austronesian-speaking peoples are thought to have originated in the Yangtze River Delta 9–6 thousand years ago (kya) and then spread to Taiwan. Nine out of ten AN primary sub-branches are exclusive to Taiwan, while all AN languages outside of Taiwan belong to just a single primary sub-branch (Malayo-Polynesian, consisting of more than 1200 languages), strongly suggesting that Taiwan was the source of the Austronesian expansion.

AN-speaking groups in Island Southeast Asia (ISEA) have been extensively examined from cultural and biological perspectives, contributing valuable data for elucidating the history of this region. However, ethnic groups in Mainland Southeast Asia (MSEA) that speak AN languages have not yet received the same attention. In MSEA, AN-speaking groups are found in Vietnam, Thailand, and Cambodia but account for only a small proportion of the population (e.g., about 1.32% % of ~100 million people in Vietnam). 

A crucial question concerning the spread of AN-speaking groups in MSEA is the extent to which this was a process of demic diffusion (i.e., migration of AN-speaking groups from elsewhere spreading both their languages and their genes) vs. cultural diffusion (i.e., existing MSEA groups adopting an AN language with little genetic mixing with AN-speaking groups from elsewhere). 

Historical records point to the appearance of AN speakers along the coast of Indochina and the Gulf of Thailand around the 5th century BCE; the close relationship of the AN languages of Vietnam with the Malayic branch of the family points to northwest Borneo as the source of this migration. However, whether the nature of the subsequent diffusion of AN languages was demic or cultural continues to be an open question. 

Here, we address this question, and potential sex bias in the spread of AN ancestry, by analyzing mtDNA and Y chromosome variation in AN-speaking groups from Vietnam.

Vietnam (VN), with its long coastline, occupies a key geographical position in MSEA and is home to 54 ethnic groups speaking languages classified into five language families: Austroasiastic (AA), Tai-Kadai (TK; also known as Kra-Dai), Hmong-Mien (HM), Sino Tibetan (ST) and Austronesian (AN). There are five recognized AN-speaking groups in Vietnam: Cham, Churu, Ede, Giarai, and Raglay, together accounting for ~1.32% of the national census size. It is thought that the first AN-speaking group to arrive in Vietnam were the ancestors of the Cham on the South Central Coast in 500 BCE, who probably originated in Borneo. From there, the Cham rapidly extended their territory and established the Champa kingdom. In the process, their languages underwent profound contact-induced changes due to the language shift of the autochthonous populations who were politically subordinate to the Cham. Modern Austronesian-speaking communities in Vietnam (VN-AN) mainly occupy the mountainous Central Highlands and the South Central coastline. Their social customs, traditions, and family dynamics are related to the ancient Champa and comparable to their counterparts in ISEA. To date, the maternal genetic ancestry of the Vietnamese Cham was described based only on the mtDNA HVS region, which provides limited resolution, while complete mtDNA genome sequences are available for two groups of Cham from Cambodia. Recent studies examined both uniparental markers and genome-wide data for two AN-speaking groups, Ede and Giarai. These findings were compared with other neighboring populations from different language families but not with other AN-speaking ethnicities on the mainland due to data scarcity, hindering attempts to trace the dispersal of the AN languages in MSEA.

The Wikipedia link explains that:

The Chams descended from seafaring settlers who reached the Southeast Asian mainland from Borneo about the time of the Sa Huỳnh culture between 1000 BCE and 200 CE, the predecessor of the Cham kingdom. The Cham language is part of the Austronesian family. According to one study, Cham is related most closely to modern Acehnese in northern Sumatra.

The Sa Huỳnh culture was an Austronesian seafaring culture that centered around present-day Central Vietnam coastal region. During its heyday, the culture distributed across the Central Vietnam coast and had commercial links across the South China Sea with the Philippine archipelago and even with Taiwan (through Maritime Jade Road, Sa Huynh-Kalanay Interaction Sphere), which now most archaeologists and scholars have consentient [sic] determined and are no longer hesitant in linking with the ancestors of the Austronesian Cham and Chamic-speaking peoples.

The Champa Kingdom mostly died in 1471 CE, although it limped along as a semi-autonomous region for almost four more centuries:

In the Cham–Vietnamese War (1471), Champa suffered serious defeats at the hands of the Vietnamese, in which 120,000 people were either captured or killed. 50 members of the Cham royal family and some 20–30,000 were taken prisoners and deported, including the king of Champa Tra Toan, who died along his way to the north in captivity. Contemporary reports from China record a Cham envoy telling to the Chinese court: "Annam destroyed our country" with additional notes of massive burning and looting, in which 40 to 60,000 people were slaughtered. The kingdom was reduced to a small enclave near Nha Trang and Phan Rang with many Chams fleeing to Cambodia.

Champa was reduced to the principalities of Panduranga and Kauthara at the beginning of the 16th century. Kauthara was annexed by the Vietnamese in 1653. From 1799 to 1832, Panduranga lost its hereditary monarchy status, with kings selected and appointed by the Vietnamese court in Huế.

The last remaining principality of Champa, Panduranga, survived until August 1832, when Minh Mang of Vietnam began his purge against rival Le Van Duyet's faction, and accused the Cham leaders of supporting Duyet. Minh Mang ordered the last Cham king Po Phaok The and the vice-king Po Dhar Kaok to be arrested in Hue, while incorporating the last remnants of Champa into what are the Ninh Thuan and Binh Thuan provinces.

To enforce his finger grip, Minh Mang appointed Vietnamese bureaucrats from Hue to govern the Cham directly in phủ Ninh Thuan while removing the traditional Cham customary laws. Administratively, Panduranga was integrated into Vietnam proper with harsh measures. These reforms were known as cải thổ quy lưu ("replacing thổ [aboriginal] chieftains by circulating bureaucratic system"). Speaking Vietnamese and following Vietnamese customs became strictly mandatory for the Cham subjects. Cham culture and Cham identity were rapidly, systematically destroyed. Vietnamese settlers seized most of Cham farmlands and commodity productions, pushing the Cham to far-inland arid highlands, and the Cham were subjected to heavy taxations and mandated conscriptions. Two widespread Cham revolts against Minh Mang's oppression arose in 1833–1835, the latter led by khatib Ja Thak Wa - a Cham Bani cleric – which was more successful and even briefly reestablished a Cham state for a short period of time, before being crushed by Minh Mang's forces.

The unfortunate defeat of the people of Panduranga in their struggle against Vietnamese oppression also sealed their and remnant of Champa's fate. A large chunk of the Cham in Panduranga were subjected to forced assimilation by the Vietnamese, while many Cham, including indigenous highland peoples, were indiscriminately killed by the Vietnamese in massacres, particularly from 1832 to 1836, during the Sumat and Ja Thak Wa uprisings. Bani mosques were razed the ground. Temples were set on fire. Cham villages and their aquatic livelihoods were annihilated. By that time, the Cham totally lost their ancestors' seafaring and shipbuilding traditions.

MOND-Like Behavior Applies To All Galaxies

As explained in a Triton Station blog post, the MOND-like behavior of galaxies called the "radial acceleration relation" holds true for galaxies of all sizes and shapes. 

The post notes that "an apparent offset between early type galaxies (ETGs, aka ellipticals) and late type galaxies (LTGs, aka spirals)" turns out to be a statistical artifact of analyzing the samples in an inconsistent manner.

Figure 3 from Mistele et al. (2024). The baryonic Tully–Fisher relation implied by weak lensing for the entire sample (yellow symbols, left column) and for ETGs and LTGs separately (red and blue symbols, right column). The Vflat values are weighted averages of the Vc values shown in Figure 1 for 50 kpc < R < 300 kpc (first row) and 50 kpc < R < 1000 kpc (second row). Vertical error bars represent a 0.1 dex systematic uncertainty on M*/L. For comparison, we also show the best fit to the kinematic data from Lelli et al. (2019; solid gray line) and the corresponding binned kinematic data (white diamonds).

We combine kinematic and gravitational lensing data to construct the Radial Acceleration Relation (RAR) of galaxies over a large dynamic range. 

We improve on previous weak-lensing studies in two ways. First, we compute stellar masses using the same stellar population model as for the kinematic data. Second, we introduce a new method for converting excess surface density profiles to radial accelerations. This method is based on a new deprojection formula which is exact, computationally efficient, and gives smaller systematic uncertainties than previous methods. 

We find that the RAR inferred from weak-lensing data smoothly continues that inferred from kinematic data by about 2.5 dex in acceleration. Contrary to previous studies, we find that early- and late-type galaxies lie on the same joint RAR when a sufficiently strict isolation criterion is adopted and their stellar and gas masses are estimated consistently with the kinematic RAR.

T. Mistele, S. McGaugh, F. Lelli, J. Schombert and P. Li, "Radial acceleration relation of galaxies with joint kinematic and weak-lensing data" Journal of Cosmology and Astroparticle Physics (April 4, 2024) (open access). DOI 10.1088/1475-7516/2024/04/020.

Other papers also establish that these dynamics are present in galaxies are early as they can be detected with the James Webb Space Telescope (JWST), which has an ability to see faint, highly redshifted objects that is unparalleled. This is true even in galaxies that are visible before the LambdaCDM model says that they should exist at all.

Bottom Quark Mass And The LP & C Relation

The pole masses of the top quark, Higgs boson, Z boson, W boson, tau lepton, muon, and electron are relatively straight forward to measure directly, and are known to decent to excellent relative precision.

In contrast, the bottom, charm, strange, down, and up quarks are always confined in a hadron. This means that their masses can't be measured directly and instead have to be reverse engineered from hadron properties according to some self-consistent scheme, one in which the pole masses of isolated particles is not even necessarily well defined.

The most common scheme for determining the masses of the five less massive quarks is the MS-bar mass a.ka. the modified minimal subtraction scheme. But this isn't the only scheme for determining their masses. Another one is the "on-shell mass" of bottom and charm quarks which can be determined more or less exactly and to almost the same precision as the MS-bar mass upon which a lot of good data has been assembled. And, it more fundamental, and hence more appropriate to use for theoretical purposes (although the "on-shell" mass of the three lightest quarks is ill-defined). As explained in the introduction of the linked paper:

In perturbative QCD (pQCD) theory, two schemes are frequently adopted for renormalizing the quark masses, e.g. the on-shell (OS) scheme and the modified minimal subtraction (MS) scheme. 

The OS mass, also known as the pole mass, offers the advantage of being grounded in a physical definition which is gauge-parameter independent and scheme independent. It ensures that the inverse heavy-quark propagator exhibits a zero at the location of the pole mass to any order in the perturbative expansion. 

On the other hand, the MS scheme focuses solely on removing the subtraction term 1/ǫ+ln(4π)−γE from the quantum corrections to the quark two-point function. And by combining this with the bare mass, one can derive the expression for the renormalized MS mass.

In high-energy processes, the MS mass is preferred for its lack of intrinsic uncertainties. It has been found that for the high-energy processes involving the bottom quark, such as the B meson decays, when their typical scales are lower than the bottom quark mass, the using of MS mass becomes less suitable and the OS mass is usually adopted. 

Practically, the perturbative series using the OS mass is plagued by renormalon ambiguities, resulting in a perturbative series with poor convergence. Thus for precision tests of the Standard Model, accurate determination of the OS mass is important. 

It is noted that the OS mass can be related to the MS mass by using the perturbative relation between the bare quark mass (mq,0) and the renormalized mass in either the OS or MS scheme, where q denotes the heavy charm, bottom, and top quark, respectively.

The MS-bar mass of the bottom quark is 4.18 + 0.03 - 0.02 GeV. A new paper determines that this is equivalent to an on-shell mass of the bottom quark of 5.36 + 0.10 - 0.07 GeV. The new preprint that makes this conversion and its abstract are as follows:

Shun-Yue Ma, Xu-Dong Huang, Xu-Chang Zheng, Xing-Gang Wu, "Precise determination of the bottom-quark on-shell mass using its four-loop relation to the MS bar scheme running mass" arXiv:2406.18025 (June 26, 2024).

The on-shell mass of the charm quark (calculated somewhat less precisely) is 2.486 + 0.126 - 0.109 GeV.

Why care which definition of quark mass is used?

One reason is that this is relevant to a hypothesized relationship between the masses of the Standard Model fundamental particles and the Higgs vacuum expectation value (Higgs vev) known as the LP & C relation. 

This hypothesis holds that the sum of the square of the fundamental particle masses is equal to the square of the Higgs vev. This is equivalent to saying that the Higgs field Yukawas of the fundamental particles in the Standard Model add up to exactly one.

Putting best fit measurements into this formula comes up just a little short in a way that is principally due to the top quark mass being too light, when MS-bar scheme running masses are used for the other five quarks.

The current best fit measurement of the top quark mass is 172.690 ± 0.3 GeV.

But, to make the LP & C relation work with the best fit masses of all of the other fundamental particles, the preferred value is 173.615 GeV, which is about a 3.1 sigma tension.

If the on-shell mass of the bottom quark is used instead, however, this eases up these tensions somewhat. 

For example, fitting the top quark mass alone requires a top quark mass of 173.583 GeV when using the on-shell mass of the bottom quark, which is a little bit less than a 3.0 sigma tension. Using the on-shell masses of the charm quark as well would require a top quark mass of 173.570 GeV, which is a bit more than a 2.9 sigma tension.

Another way to make the numbers fit while reducing the tensions for the mass measurements of individual particles is to use top quark masses and Higgs boson masses. In the case of the Higgs boson, the current world average mass is 125.25 ± 0.17 GeV.

If both the top quark mass and Higgs boson mass are increased above their best fit measurements by equal numbers of standard deviations, which reduces the tension to about 2.6 sigma, and that could be reduced to a tension of about 2.5 sigma or less for both the top quark and the Higgs boson, using on-shell masses, which is significantly more mild than a 3.1 sigma tension in the top quark mass.

With all three adjustments, the LP & C relation could fit with a top quark mass of 173.44 GeV and the Higgs boson mass of 125.675 GeV, neither of which is a huge stretch, which means that the LP & C relation is still a viable theory, even though it is not perfectly consistent with the latest mass measurements.

Using the MS-bar mass rather than the on-shell masses of the three light quarks turns out to be immaterial in evaluating the LP & C relation, in which the uncertainties are dominated by the uncertainties in the largest absolute fundamental particle masses.

Alternatively, the LP & C relation could hold because the list of Standard Model fundamental particles is not complete, in which case it estimates the sum of the square of the masses of the missing fundamental particles, subject to the relative uncertainties in the known fundamental particle masses, in a global test of the completeness of the Standard Model.

The best fit to this gap, if concentrated in a single particle, would be a particle with a mass of about 17.5 GeV, but with a great uncertainty, mostly due to the uncertainties in the top quark and Higgs boson masses, and to a lesser extent the W boson mass uncertainty.

The trouble is, of course, that this mass range is well-explored, has produced no fundamental particles in this mass range, and would wildly throw off the observed branching fractions of the Higgs boson, Z boson, and W boson if it did exist, so it probably doesn't.

On-shell masses also make sense to use when exploring generalizations of Koide's rule to quark masses.

McGaugh On Structure Formation

McGaugh reminds the world that the early structure formation seen in the James Webb Space Telescope (JWST) was predicted long ago by MOND and is inconsistent with the ΛCDM model.

Galaxies in the early universe appear to have grown too big too fast, assembling into massive, monolithic objects more rapidly than anticipated in the hierarchical ΛCDM structure formation paradigm. 

The available data are consistent with there being a population of massive galaxies that form early (z≳10) and follow an approximately exponential star formation history with a short (≲1 Gyr) e-folding timescale on the way to becoming massive (M∗≈10¹¹M⊙) galaxies by z=0, consistent with the traditional picture for the evolution of giant elliptical galaxies. Observations of the kinematics of spiral galaxies as a function of redshift similarly show that massive disks and their scaling relations were in place at early times, indicating a genuine effect in mass that cannot be explained as a quirk of luminosity evolution. 

That massive galaxies could form by z=10 was explicitly predicted in advance by MOND. We discuss some further predictions of MOND, such as the early emergence of clusters of galaxies and the cosmic web.

Stacy S. McGaugh, James M. Schombert, Federico Lelli, Jay Franck, "Accelerated Structure Formation: the Early Emergence of Massive Galaxies and Clusters of Galaxies" arXiv:2406.17930 (June 25, 2024) (submitted to Apj).

A Good Reason To Like The Mirror Universe Scenario

 

A mirror universe scenario overcomes this meme. 

Deur's approach (whether or not it modifies general relativity) also solves the conservation of mass-energy issue associated with "dark energy" using the same mechanism that he used to explain dark matter phenomena, and explains the "cosmic coincidence" problem as a bonus prize.

NFW And Einasto DM Halos Don't Work

Neither of the leading models for dark matter particle distributions in dark matter halos can accommodate the observed reality that galaxies have an inner core, rather than an inner cusp. 

[A]n ideal spherically symmetric stellar system with isotropic velocities and an inner core cannot reside in a Navarro, Frenk, and White (NFW) gravitational potential. . . . stellar cores are also inconsistent with Einasto potentials. This result may have implications to constrain the nature of DM through interpreting the stellar cores often observed in dwarf galaxies.

From  Jorge Sanchez Almeida, "Einasto gravitational potentials have difficulty to hold spherically symmetric stellar systems with cores" arXiv:2406.13613 (June 19, 2024) (RNAAS complementing our previous paper Sanchez Almeida et al. (2023, ApJ, 954, 153; doi: https://doi.org/10.3847/1538-4357/ace534)).

Absolute Neutrino Mass Bound Tightened

The old KATRIN bound on the lightest neutrino mass was 0.8 eV. Now it is down to 0.45 eV. This pushes the limit on the sum of the three neutrino masses to 1.41 eV in a normal hierarchy and 1.46 eV in an inverted hierarchy. 

After a full run of data collection, KATRIN is expected to lower that bound to 0.2 eV. This would push the limit on the sum of the three neutrino masses to 0.66 eV in a normal hierarchy and 0.71 eV in an inverted hierarchy. 

This is about six times less tight a bound on the neutrino masses than the cosmology based neutrino mass bounds, which approach 0.12 eV or less for the sum of the three neutrino masses, but this is a much less model dependent limit than cosmology based limit.

The fact that neutrinos carry a non-vanishing rest mass is evidence of physics beyond the Standard Model of elementary particles. Their absolute mass bears important relevance from particle physics to cosmology. In this work, we report on the search for the effective electron antineutrino mass with the KATRIN experiment. KATRIN performs precision spectroscopy of the tritium β-decay close to the kinematic endpoint. Based on the first five neutrino-mass measurement campaigns, we derive a best-fit value of m^2(ν)=−0.14+0.13−0.15 eV^2, resulting in an upper limit of mν < 0.45 eV at 90 % confidence level. With six times the statistics of previous data sets, amounting to 36 million electrons collected in 259 measurement days, a substantial reduction of the background level and improved systematic uncertainties, this result tightens KATRIN's previous bound by a factor of almost two.

M. Aker, et al., "Direct neutrino-mass measurement based on 259 days of KATRIN data" arXiv:2406.13516 (June 19, 2024).

The best fit value for the electron neutrino mass is slightly below zero, when in reality, it can't have a value of less than zero. So, the probability density is heavily concentrated around a value indistinguishable from zero (a bit more than 74% in a Gaussian probability distribution which clearly isn't the true appropriate probability distribution).

So, while the limits of the experiment probably can't rule out of mass of more than 0.2 eV at a 90% confidence interval with a full run of KATRIN experiment, the best fit value after the full run is still likely to be indistinguishable or almost indistinguishable from zero. 

This would imply a best fit value for the sum of the three neutrino masses of about 0.06 eV in a normal hierarchy and 0.11 eV in an inverted hierarchy. And, almost every available observational dataset favors a normal hierarchy over an inverted hierarchy, although not truly decisively.

Measuring The Mean Lifetime Of A Short Lived Particle

The LHCb experiment has measured the mean lifetime of a particle called the bottom xi or cascade B baryon, a spin 1/2 baryon with a down quark, a strange quark, and a bottom quark as valence quarks, with a mass of 5,797.0 ± 0.6 MeV (between the mass of a helium atom and a lithium atom), which is the eighth most massive baryon ever observed (the most massive is the bottom omega baryon with a mass of 6,046.1 ± 1.7 MeV, which is a spin-1/2 baryon with two strange quarks and a bottom quark as valence quarks). 

Its mean lifetime is: 1.578 ± 0.018 ± 0.010 ± 0.011 ps which with a combined uncertainty is 1.578 ± 0.023 ps. A picosecond is 10^-12 seconds (i.e. a trillionth of a second). As the linked article's abstract explains:

This measurement improves the precision of the current world average of the Ξ_b^- lifetime by about a factor of two, and is in good agreement with the most recent theoretical predictions.

It is astounding that we can measure such a tiny span of time to better than 2% precision. The uncertainty in its lifetime is on the order of 40 trillionths of second. 

The measured value is about 0.2% less than the best theoretical prediction to date, and the theoretical prediction also has an uncertainty of about 2%, so the measured value is basically a perfect match to the theoretically predicted value.

There are at least fifteen possible decays of bottom xi baryons whose branching fractions are summarized by the particle data group. This history of this particle's discovery can be found here. The first experimental observation of this particle, which took place at Fermilab, was announced just over seventeen years ago, on June 12, 2007.

There are baryons which decay a trillion times faster, as little as 5.63 ± 0.14 x 10^-24 seconds, usually to a pion and either a proton or a neutron, for the four kinds of spin-3/2 delta baryons which have only up and down quarks as valence quarks and masses of 1232 ± 2 MeV. 

There is nothing terribly notable about this most recent measurement of the mean lifetime of the bottom xi except that it was first publicly announced today in a preprint on arXiv.

Sterile Neutrinos Largely Ruled Out Up To 3eV

A reactor neutrino study has largely ruled out sterile neutrinos up to 3 eV, and possibly up to 4.5 eV. This rules out the Gallium anomaly (explained here), which already has many explanations that do not require new physics.

The preprint and its abstract are as follows:

The PROSPECT experiment is designed to perform precise searches for antineutrino disappearance at short distances (7-9 ~m) from compact nuclear reactor cores. This Letter reports results from a new neutrino oscillation analysis performed using the complete data sample from the PROSPECT-I detector operated at the High Flux Isotope Reactor in 2018. 

The analysis uses a multi-period selection of inverse beta decay neutrino interactions with reduced backgrounds and enhanced statistical power to set limits on electron-flavor disappearance caused by mixing with sterile neutrinos with 0.2-20 eV^2 mass splittings. 

Inverse beta decay positron energy spectra from six different reactor-detector distance ranges are found to be statistically consistent with one another, as would be expected in the absence of sterile neutrino oscillations. The data excludes at 95% confidence level the existence of sterile neutrinos in regions above 3~eV^2 previously unexplored by terrestrial experiments, including all space below 10~eV^2 suggested by the recently strengthened Gallium Anomaly. The best-fit point of the Neutrino-4 reactor experiment's claimed observation of short-baseline oscillation is ruled out at more than five standard deviations.

M. Andriamirado, et al., "Final Search for Short-Baseline Neutrino Oscillations with the PROSPECT-I Detector at HFIR" arXiv:2406.10408 (June 14, 2024).

Neutrino-less double beta decay has also been further constrained: 

We present a search for neutrinoless double-beta (0νββ) decay of 136Xe using the full KamLAND-Zen 800 dataset with 745 kg of enriched xenon, corresponding to an exposure of 2.097 ton yr of 136Xe. This updated search benefits from a more than twofold increase in exposure, recovery of photo-sensor gain, and reduced background from muon-induced spallation of xenon. 

Combining with the search in the previous KamLAND-Zen phase, we obtain a lower limit for the 0νββ decay half-life of T(0ν1/2) > 3.8×10^26 yr at 90% C.L., a factor of 1.7 improvement over the previous limit. The corresponding upper limits on the effective Majorana neutrino mass are in the range 28-122 meV using phenomenological nuclear matrix element calculations.

S. Abe, et al., "Search for Majorana Neutrinos with the Complete KamLAND-Zen Dataset" arXiv:2406.11438 (June 17, 2024).

Analysis 

This is still a long way from ruling out neutrinos with purely Majorana mass in either the inverted hierarchy (which requires a half-life about 1000 times as long), or the normal hierarchy. (which requires a half-life 100,000 to 1,000,000 times as long).

This upper bound on Majorana mass implies a maximum sum of the three neutrino masses, if neutrinos have purely Majorana mass and an inverted hierarchy, of about 0.5 eV.

The upper bound on the sum of the three neutrino masses due to direct measurements of the lightest neutrino mass at Katrin of 0.8 eV is currently about 2.51 eV. When Katrin runs its course, this should fall to a lightest neutrino mass of less than 0.2 eV  and a sum of the three neutrino masses of less than 0.71 eV.

The lower bound on the sum of the neutrino masses based upon neutrino oscillation data is about 0.059 eV in the normal hierarchy and 0.109 eV in the inverted hierarchy.

Cosmology bounds on the sum of the three neutrino masses are much tighter, but with the DESI data set, the bounds on the sum of the three neutrino masses from all sources are on the verge of being over constrained (i.e. the cosmology bounds favor a sum of the three neutrino masses under 0.059 eV), which suggests that the cosmology model used to set these bound may be flawed.