LambdaCDM Fails Again

LambdaCDM again fails to reproduce what we observe. 

This paper suggests that self-interacting dark matter could solve this particular problem, but numerous prior papers demonstrate that SIDM has multiple serious problems of its own. See, e.g., posts on March 19, 2025, July 25, 2023, December 1, 2022, February 2, 2022, August 11, 2020, February 20, 2020, November 23, 2018, October 23, 2017, July 5, 2017, December 6, 2016, and December 20, 2015.

The galaxy correlation function serves as a fundamental tool for studying cosmology, galaxy formation, and the nature of dark matter. It is well established that more massive, redder and more compact galaxies tend to have stronger clustering in space. These results can be understood in terms of galaxy formation in Cold Dark Matter (CDM) halos of different mass and assembly history. 

Here, we report an unexpectedly strong large-scale clustering for isolated, diffuse and blue dwarf galaxies, comparable to that seen for massive galaxy groups but much stronger than that expected from their halo mass. Our analysis indicates that the strong clustering aligns with the halo assembly bias seen in simulations with the standard ΛCDM cosmology only if more diffuse dwarfs formed in low-mass halos of older ages. This pattern is not reproduced by existing models of galaxy evolution in a ΛCDM framework, and our finding provides new clues for the search of more viable models. 

Our results can be explained well by assuming self-interacting dark matter, suggesting that such a scenario should be considered seriously.

Ziwen Zhang, et al., "Unexpected clustering pattern in dwarf galaxies challenges formation models" arXiv:2504.03305 (April 7, 2025) (Accepted for publication in Nature).

Sabine On Naturalness

No, Matt, this is no crisis

This is a comment on a recent video by Matt O'Dowd.

I find it extremely distressing that we are still discussing this even though it's abundantly clear that naturalness arguments have historically worked extremely badly. It's a pseudo-scientific method that physicists need to stop using.

Sabine Hossenfelder reiterates the correct observation that the physics community has wasted vast efforts on the utterly bullshit concept of "naturalness." 

A New Koide's Rule Extension Paper

A. C. Kleppe has uploaded a preprint entitled  "Quark mass matrices inspired by a numerical relation" that explores how Koide's rule for charged lepton masses can be extended to quarks. This conference paper presentation is Kleppe's first paper on arXiv and it isn't clear that the author has a university affiliation.

The abstract, after stating Koide's 1981 charged lepton mass rule (which still holds to high precision as the inputs have become more accurate over the last 44 years) states that:

Inspired by this relation, we introduce tentative mass matrices, using numerical values, and find matrices that display an underlying democratic texture.

I have discussed other attempts to make this extension and my own thoughts on it, in several previous posts at this blog. The paper does not, however, meaningfully engage with (or even mention) most of the prior literature in this area.

The statement in the paper that:

It should be noted that for the square roots of the running charged lepton masses at MZ around 91 GeV, the results no longer give the exact Koide formula.

is particularly concerning when it comes to understanding, because Koide's rule is a rule about the pole masses of particles and not about the running mass of those particles at a consistent energy scale. And, Koide's rule is, in fact, exquisitely confirmed when applied to pole masses.  

This distinction matters because the proper definition of mass to use for light quarks when extending Koide's rule is not self-evident.

The conclusion, which I have screenshotted rather than cut and paste from to preserve the integrity of the notation, states:

McGaugh On MOND Cosmology

Stacy McGaugh explores cosmology in MOND in a recent post at his blog. 

MOND struggles to fit to an expansion history of the universe, since it is just a toy model and not a full fledged relativistic theory, although it gets some things just right even without dark matter. The question of MOND cosmologies is a work in progress.

Today's Notable arXiv Papers

Astrophysicists were playful this year. HEP physicists weren't feeling the love. 

Since their domestication at the dawn of civilization, cats have been known for their uncanny ability to seemingly defy gravity. We conjecture that this innate ability of cats is real: uniquely in the animal kingdom, felis catus, possibly along with a few closely related species, are indeed capable of manipulating their passive gravitational mass. We explore this idea in the context of both general relativity and quantum physics. We reach the intriguing conclusion that a close study of the behavior of cats in a gravitational field might shed light not only on the mechanism of neutrino mass mixing but perhaps even on the most fundamental question in theoretical physics: a satisfactory unification of the theory of gravitation and quantum field theory.

Viktor T. Toth, "Feline gravity manipulation" arXiv:2503.22919 (April 1, 2025).

In the big data era of Astrophysics, the improvement of visualization techniques can greatly enhance the ability to identify and interpret key features in complex datasets. This aspect of data analysis will become even more relevant in the near future, with the expected growth of data volumes. With our studies, we aim to drive progress in this field and inspire further research. We present the second release of pastamarkers, a Python-based matplotlib package that we initially presented last year. In this new release we focus on big data visualization and update the content of our first release. We find that analyzing complex problems and mining large data sets becomes significantly more intuitive and engaging when using the familiar and appetizing colors of pasta sauces instead of traditional colormaps

PASTA Collaboration, "pastamarkers 2: pasta sauce colormaps for your flavorful results" arXiv:2503.23126 (April 1, 2025).

Any permutation-invariant function of data points r⃗ i can be written in the form ρ(∑iϕ(r⃗ i)) for suitable functions ρ and ϕ. This form - known in the machine-learning literature as Deep Sets - also generates a map-reduce algorithm. The area of a triangle is a permutation-invariant function of the locations r⃗ i of the three corners 1≤i≤3. We find the polynomial formula for the area of a triangle that is explicitly in Deep Sets form. This project was motivated by questions about the fundamental computational complexity of n-point statistics in cosmology; that said, no insights of any kind were gained from these results.

Connor Hainje, David W. Hogg, "A formula for the area of a triangle: Useless, but explicitly in Deep Sets form" arXiv:2503.22786 (April 1, 2025).

Johannes Kepler's attempt to explain the arrangement of the six innermost planets of the Solar System using his Platonic Solid Model-which postulates that planetary orbits are nested within the five Platonic solids-was ultimately unsuccessful. However, while his model failed to describe our own planetary system, Kepler was remarkably prescient in hypothesizing the existence of exoplanetary systems that might conform to this geometric framework. In this study, we analyze all known multiple exoplanet systems containing three to six planets and identify those that best match the Keplerian Platonic model. Using a semi-major-axis (SMA) ratio metric defined as the sum of squared differences between observed and theoretical semi-major-axis ratios, we find that the most well-matched three-, four-, five-, and six-planet exoplanetary systems exhibit significantly lower discrepancy values (4.38×10−6,1.05×10−2,8.21×10−2, and 2.43×10−1, respectively) compared to the inner six planets of the Solar System at 12.68. These results demonstrate that Kepler's Platonic Model is applicable to certain exoplanetary systems, suggesting that while the Solar System does not adhere to this idealized structure, other planetary systems may be governed by underlying geometric and mathematical principles akin to Kepler's vision. This study highlights the special nature of these exoplanetary systems and their potential alignment with the Platonic five-element framework.

Ji Wang, "Kepler's Platonic Model and Its Application to Exoplanetary Systems" arXiv:2503.22793 (April 1, 2025).

This paper explores an unexpected yet compelling parallel between the evolution of the universe, as described by cosmological eras, and the artistic evolution of Taylor Swift, delineated by her distinct album eras. By mapping key characteristics and transitions in the universe's history to corresponding themes and milestones in Swift's career, I offer a novel perspective on both. I culminate with predictions for Swift's future work and dare to ask a question of cosmic importance: Could Taylor Swift's thirteenth album hold the secret to the universe's ultimate destiny?

Jane C. Bright, "The Eras Tour: Mapping the Eras of Taylor Swift to the Cosmological Eras of the Universe" arXiv:2503.22795 (April 1, 2025).

Understanding our place in the universe is an eternal quest. Through the analysis of the 3D structures of 66 nearby open clusters using Gaia DR3 data, we discovered an intriguing pattern: most clusters show their elongation directions pointing at the Sun, suggesting that the Solar System might just be the universe's favorite spot, a cosmic feng shui hotspot! This surprising result hints at a subtle blend of geometry and geomancy.

Lu Li, Zhengyi Shao, "On the structure of open clusters: geometric vs geomantic" arXiv:2503.22800 (April 1, 2025).

We present a novel and somewhat whimsical approach to pulsar hotspot modeling by drawing inspiration from the iconic one-eyed monster, Mike Wazowski, from Monsters, Inc. Utilizing X-ray high-quality timing data from NICER, we apply a Bayesian inference framework to model the X-ray pulse profile of PSR J0437--4715. Our analysis employs a Wazowski Configuration (WC) in which the conventional hotspot parametrization is replaced with a predefined image template, whose redness and size are adjusted to mimic temperature variations. The results reveal a configuration where two hotspots--one brighter and smaller in the north represents the energetic ``University time Wazowski", and one larger yet cooler in the south represents the ``Monster, Inc. time Wazowski"--combine to produce the observed X-ray pulse profile. These findings not only demonstrate the sensitivity of pulse profile modeling to hotspot morphology but also open up the intriguing possibility that the X-ray emission of some pulsars may be interpreted as a cosmic homage to our favorite animated character.

Chun Huang, "The Cosmic One-Eyed Smile: Revealing the Hidden Face of Mike Wazowski" arXiv:2503.22914 (April 1, 2025) (Submitting to Monster University Journal).

Cookies are enjoyed best when they are both crispy and soft. I investigate in which proportion the cookies are crispy and soft, and disentangle whether it makes them biscuits, cakes, or none of the above. I baked cookies for colleagues at KTH, Stockholm, and University of Geneva, Switzerland, adopting my mum's mum's mum's etc. recipe. I created a dedicated survey for my colleagues with three well-selected questions to answer while eating one cookie. The weighted-average mean of the crispiness and softness, weighted by the respective enjoyment of the cookie, over the whole population amount to 7.0 +/- 1.1 and 5.3 +/- 1.4, respectively. The enjoyment of the cookies amounts to 9.1 +/- 2.3. People like (my) cookies, and cookies are neither cakes, nor biscuits, they are just... cookies!

Sophie Rosu, "All about Cookies: The perfect compromise between softness and crispiness" arXiv:2503.23114 (April 1, 2025).

Catsteroseismology, or asterocatsmology, is an unexplored area of observational and theoretical research that proposes to use purr-mode oscillations to study the much-beloved but poorly-understood species Felis catus. In this work, we conduct a survey to measure fundamental purrameters of cats and relate them to their purr-modes. Relations between these fundamental cat purrameters, which include physical (eg. size, cuddliness) and personality (eg. aggression, intelligence) traits, and purr-modes can help probe their inner lives and emotions. We find that while purr characteristics tentatively trend with several physical and personality traits, more data is required to better constrain these relationships and infer the direct predictive power of personality on purr-modes, or vice versa.

Rae Holcomb, Christopher Lam, "Catsteroseismology: Survey-based Analysis of Purr-mode Oscillations Suggests Inner Lives of Cats are Unknowable" arXiv:2503.23560 (April 1, 2025).

We report the detection of whisky in the atmosphere of the extrasolar super-Earth planet GJ 1132b from transmission spectroscopic data. It is seen both in atmospheric absorption as well as in chromospheric emission, the latter probably due to the intense heating of the co-rotating planet's day-side surface. This detection cannot be explained using natural sources of alcohol, implying that there must be a technically advanced civilisation -- possibly originating from the neighboring habitable planet GJ 1132c -- that is engaged in massive distilling operations accompanied by high levels of industrial pollution. The reason for the necessarily vast scale of production is either to produce rocket fuel for an interplanetary economy or, more likely, for an unusually high level of personal consumption. The latter hypothesis suggests a novel explanation for the Fermi Paradox (the lack of indirect or direct contact with extraterrestrials): a technically versed civilisation would be incapable of achieving the higher technical levels necessary for the development of a detectable radio signature -- much less interstellar travel -- at the suggested rates of consumption.

Frederic V. Hessman, Andrew Collier Cameron, Keith Horne, "Detection of an extraterrestrial technical civilisation on the extrasolar planet GJ 1132b" arXiv:2503.23788 (April 1, 2025).

High angular resolution holds the key to extending our knowledge in several domains of astronomical research. In addition to the development of new instruments, advancements in post-processing algorithms can enhance the performances attainable in an observation, turning archival observations into a treasure. We developed a machine-learning tool, named zoom-in, that is able to improve the angular resolution of an astronomical image by a factor of ∼100 by optimally recombining short-cadence sequences of images. After training our model on real-life photographs, we tested our method on archival images of the Moon taken through ESO instruments. We were able to achieve a remarkable spatial resolution of ∼1 m of the lunar surface. While analyzing one of the fields from the sample, we discovered structures of clear anthropic origin inside the Aristarchus crater. The features appear to be consistent with ancient ruins of cities and castles. A thorough analysis of the relevant literature allowed us to conclude that this valley corresponds to the one described in Ludovico Ariosto's "Orlando Furioso": a place where all the items lost by humans gather and pile up. Analyses of the surface brightness from our images, indicating an abnormally high albedo of ∼0.25, further corroborate this idea suggesting a conspicuous presence of glass. We infer the presence of >1 billion flasks of human wits on the lunar surface, whose origin we investigate in detail. We urge for a dedicated mission, astolfo, to be carried out by Artemis astronauts in order to recover human wits and bring them back to the Earth.

Vito Squicciarini, Irina Mirova, Francis D. Anderson, Zhiyuan He, Wahman al-Khwarizmi, "Orlando's flask: detection of a lost-and-found valley on the Moon" arXiv:2503.24242 (April 1, 2025) (Submitted for publication on 1st April 2025 to the prestigious journal Acta Prima Aprilia).

The cosmological principle posits that the universe does not exhibit any specific preference for position or direction. However, it remains unclear whether the universe has a distinct preference for parity: whether certain properties are more likely to be classified as even or odd. In this study, we analyze the largest available galaxy group catalogs to explore this hypothesis: specifically, whether the number of galaxies within a galaxy group or cluster is more likely to be odd or even. Our findings convincingly indicate that the universe indeed favors odd numbers, with results achieving a significance level well above the 4.1−σ threshold.

Shiyin Shen, Nan Li, "The Universe is Odd" arXiv:2503.22839 (April 1, 2025) (This manuscript is deliberately announced on an odd-numbered date).

For generations, people have complained that things used to be better in the past. In this paper, we investigate this change by specifically looking at creativity in astronomy. To do this, we explore if older constellations reflected a greater sense of creativity on the part of those designing them than more modern constellations do. We find that things really have become simplistic and less original over time.

Michael B. Lund, "Astronomers Getting Less Creative Over Time Is Why This Title Isn't Better" arXiv:2503.23614 (April 1, 2025) (submitted to Acta Prima Aprilia).

We all love the ecstasy that comes with submitting papers to journals or arXiv. Some have described it as yeeting their back-breaking products of labor into the void, wishing they could never deal with them ever again. The very act of yeeting papers onto arXiv contributes to the expansion of the arXiverse; however, we have yet to quantify our contribution to the cause. In this work, I investigate the expansion of the arXiverse using the arXiv astro-ph submission data from 1992 to date. I coin the term "the arXiverse constant", a0, to quantify the rate of expansion of the arXiverse. I find that astro-ph as a whole has a positive a0, but this does not always hold true for the six subcategories of astro-ph. I then investigate the temporal changes in a0 for the astro-ph subcategories and astro-ph as a whole, from which I infer the fate of the arXiverse.

Joanne Tan, "Written in the Stars: How your (pens and) papers decide the fate of the arXiverse" arXiv:2503.23957 (April 1, 2025) (Published in the 2024 issue of Acta Prima Aprila. An arXiv resubmission after a year).

I report the discovery of jacquetium (0Jq), the first naturally occurring element found since more than 80 years.

Emmanuel Jacquet, "Jacquetium, a new, naturally-occurring chemical element" arXiv:2503.24030 (April 1, 2025) (Submitted to the Journal of Improbable Science, 2025 yearly (April 1) issue).

The field of astronomy evolves rapidly, and it is essential to keep up with these changes in order to effectively communicate with the broader community. However, communication itself also changes as new words, phrases, and slang terms enter the common vernacular. This is especially true for the current youngest generations, who are capable of efficiently communicating via the Internet. In order to maintain effective communication, we explore the possibility of expanding the language used in scientific communication to include recently coined slang. This attempt at outreach, while potentially very difficult, could provide a means to expand the field and capture the attention of early-career scientists, improving retention within the field. However, our results indicate that, while possible, this method of communication is, like, probably not really worth it, no cap.

Anne E Blackwell, David L Moutard, Jake A Miller, "The Rizzeta Stone: Adopting Gen-α Colloquial Language to Improve Scientific Paper Rizz and Aura from a Skibidi Perspective" arXiv:2504.00073 (April 1, 2025).

The spherical cow approximation is widely used in the literature, but is rarely justified. Here, I propose several schemes for extending the spherical cow approximation to a full multipole expansion, in which the spherical cow is simply the first term. This allows for the computation of bovine potentials and interactions beyond spherical symmetry, and also provides a scheme for defining the geometry of the cow itself at higher multipole moments. This is especially important for the treatment of physical processes that are suppressed by spherical symmetry, such as the spindown of a rotating cow due to the emission of gravitational waves. I demonstrate the computation of multipole coefficients for a benchmark cow, and illustrate the applicability of the multipolar cow to several important problems.

Benjamin V. Lehmann, "Higher multipoles of the cow" arXiv:2504.00506 (April 1, 2025) (No cows were harmed).

We present the first--ever example of a macroscopic system in a quantum superposition. The system in question is a Siamese cat known as Lola; however, on a time scale of about 12 hours it oscillates into a different state that we refer to as "Mola". In the "Lola" state, the system is sweet and friendly and allows to cuddle itself, but in the "Mola" state, it is malevolent and witchy. When the probability of the system being in the "Mola" state is high, decoherence is strongly discouraged!

Harman Deep Kaur, Mariagrazia Trapanese, Kirill Zatrimaylov, "Macroscopic "Lola/Mola" Cat State" arXiv:2503.23433 (April 1, 2025).

Voyager 1

 

Big Bang Nucleosynthesis and Neutrino Physics

A clever new paper uses the observational evidence from astronomy supporting Big Bang Nucleosynthesis to constrain the hypotheses of sterile neutrinos or non-standard neutrino interactions to almost the level reached from Earth bound experiments and other cosmology observations. 

Their findings tend to reinforce the Standard Model view that there are only three flavors of neutrinos and that they have only the interactions allowed by the Standard Model (i.e. weak force interactions and neutrino oscillations according to the PMNS matrix).

In this work we investigate the impact of two phenomenological Beyond the Standard Model (BSM) scenarios concerning the role of neutrinos in the early universe: non-standard neutrino interactions (NSI) and non-unitary three-neutrino mixing. 

We evaluate the impact of these frameworks on two key cosmological observables: the effective number of relativistic neutrino species (Neff), related to neutrino decoupling, and the abundances of light elements produced at Big Bang Nucleosynthesis (BBN). For the first time, neutrino CC-NSI with quarks and non-unitary three-neutrino mixing are studied in the context of BBN, and the constraints on such interactions are found to be remarkably competitive with terrestrial experiments. In the case of non-unitarity, the combination between neutrino decoupling and BBN imposes stringent constraints that can either mildly favour the existence of New Physics (NP), or reinforce the SM, depending on the choice of the experimental nuclear rates involved in the BBN calculation.

Gabriela Barenboim, Stefano Gariazzo, Alberto Sánchez-Vargas, "Big Bang Nucleosynthesis as a probe of non-standard neutrino interactions and non-unitary three-neutrino mixing" arXiv:2503.21998 (March 27, 2025).

Did Homo Sapiens Arise As A Hybrid?

In addition to being highly model dependent and unsupported by ancient DNA data, and hence somewhat speculative, this is really a less revolutionary proposal than it seems. 

Modern humans still arise in Africa (including a hypothetical admixture event that gives rise to the new species ca. 290,000 years ago). Basically, it is just proposing that in addition to the Neanderthal admixture shared by all non-Africans, and the Denisovan admixture that took place in the first generation of modern humans to reach Asia, there was an 20% admixture event from Homo erectus involving all modern humans associated with the emergence of the new species.

In their model, the 80% source, probably Homo heidelbergensis is also ancestral to Neanderthals and Denisovans, evolves from from Homo erectus about 1,500,000 years ago and suffers a severe bottleneck period, while the 20% Homo erectus ancestry was exclusive to Homo sapiens and was probably initially a larger percentage as a result of an admixture event in Africa about 290,000 years ago. The Homo erectus ancestry percentage was reduced in percentage over time due to its inferior selective fitness in most parts of the Homo erectus genome that have an impact on phenotypes (i.e. that have any actual discernible effect).

The evolutionary path leading to the rise of modern humans is full of twists and turns, and the latest surprise reveals that our species likely sprung forth from two ancient intermingling populations. A new study has confirmed that these groups first diverged from each other around 1.5 million years ago and later merged back together 300,000 years ago, initiating a genetic mixing event that culminated with the birth of modern humans.

The study, published in Nature Genetics, completely rewrites the story of humans. Scientists have long believed that Homo sapiens first appeared in Africa somewhere between 200,000 years and 300,000 years ago, having descended from a single ancestral lineage. The idea of genetic admixture flips the script, however, showing that human origins are much more complex than previously thought.

The researchers . . . tapped into modern human DNA from the 1000 Genomes Project, an international catalog filled with human genomes from a variety of populations. The research team created a computational algorithm called cobraa, which was designed to represent the event of an ancestral population splitting and rejoining. . . . 

With this method, they were able to produce a structured model that displayed two ancestral populations breaking apart in ancient times. In the years after this divergence, one of the populations experienced major fluctuations in size.

“Immediately after the two ancestral populations split, we see a severe bottleneck in one of them — suggesting it shrank to a very small size before slowly growing over a period of one million years,” said co-author Aylwyn Scally from the University of Cambridge’s Department of Genetics, in a statement. “This population would later contribute about 80 percent of the genetic material of modern humans and also seems to have been the ancestral population from which Neanderthals and Denisovans diverged.”

The second population, meanwhile, contributed 20 percent to the genetic makeup of modern humans. The researchers found that many of the genes this group passed along to humans were not located near regions of the genome corresponding to gene functions; this could reflect a concept called purifying selection, which is the process of natural selection filtering out harmful mutations. However, the researchers believe that some of the genes from the second population may have still been integral to brain development in modern humans.  . . .

An element of mystery still surrounds the identity of these ancestral populations. The researchers point to Homo erectus and Homo heidelbergensis as potential answers since they were present in Africa around the time of the genetic admixture, but further research is needed to match genetic ancestors with fossil groups.

Nature Genetics. A structured coalescent model reveals deep ancestral structure shared by all modern humans

From Discover Magazine. The abstract of the open access paper states:

Understanding the history of admixture events and population size changes leading to modern humans is central to human evolutionary genetics. Here we introduce a coalescence-based hidden Markov model, cobraa, that explicitly represents an ancestral population split and rejoin, and demonstrate its application on simulated and real data across multiple species. 

Using cobraa, we present evidence for an extended period of structure in the history of all modern humans, in which two ancestral populations that diverged ~1.5 million years ago came together in an admixture event ~300 thousand years ago, in a ratio of ~80:20%. Immediately after their divergence, we detect a strong bottleneck in the major ancestral population. 

We inferred regions of the present-day genome derived from each ancestral population, finding that material from the minority correlates strongly with distance to coding sequence, suggesting it was deleterious against the majority background. Moreover, we found a strong correlation between regions of majority ancestry and human–Neanderthal or human–Denisovan divergence, suggesting the majority population was also ancestral to those archaic humans.

A Grab Bag Of Astrophysics and High Energy Physics Papers

Astrophysics Papers

Black hole physicists are skeptical of leading cosmology paradigms.

The cosmological constant, cosmological inflation, and string theory, all lack majority support among black hole physicists. Also, a majority of them take the position that the Big Bang means that "the universe evolved from a hot dense state", not "an absolute beginning time" which is the weaker of the two possible definitions of what the Big Bang theory means.

The purpose of this survey is to take a snapshot of the attitudes of physicists, which may be useful to sociologists and historians of science. A total of 85 completed surveys were returned out of 151 registered participants of the "Black holes Inside and out" conference, held in Copenhagen in 2024. The survey asked questions about the nature of black holes and some of the most contentious issues in fundamental physics. A number of surprising results were found. 

For example, some of the leading frameworks, such the cosmological constant, cosmic inflation, or string theory, while most popular, gain less than majority of votes from the participants. The only statement that gains majority approval (by 68% of participants) was that the Big Bang means that "the universe evolved from a hot dense state", not "an absolute beginning time". 

This provides reasons for caution in describing ideas as consensus in the scientific community when a more nuanced view may be justified.

From here.

MOND still works.

Meanwhile, MOND still works to explain early galaxies, while LamdaCDM theory does not:

We investigate the shape and morphology of early-type galaxies (ETGs) within the framework of Modified Newtonian Dynamics (MOND). 

Building on our previous studies, which demonstrated that the monolithic collapse of primordial gas clouds in MOND produces galaxies (noted throughout as 'model relics' in the context of this work) with short star formation timescales and a downsizing effect as observationally found, we present new analyses on the resulting structural and morphological properties of these systems. Initially, the monolithically formed galaxies display disk-like structures. 

In this study, we further analyze the transformations that occur when these galaxies merge, observing that the resulting systems (noted throughout as 'merged galaxies' in the context of this work) take on elliptical-like shapes, with the (V_rot/V_sigma) - ellipticity relations closely matching observational data across various projections. We extend this analysis by examining the isophotal shapes and rotational parameter (lambda_R) of both individual relics and merged galaxies. 

The results indicate that ETGs may originate in pairs in dense environments, with mergers subsequently producing elliptical structures that align well with observed kinematic and morphological characteristics. Finally, we compare both the model relics and merged galaxies with the fundamental plane and Kormendy relation of observed ETGs, finding close agreement. Together, these findings suggest that MOND provides a viable physical framework for the rapid formation and morphological evolution of ETGs.

Robin Eappen, Pavel Kroupa, "Scaling relations of early-type galaxies in MOND" arXiv:2503.15600 (March 19, 2025) (published in Galaxies 2025, 13, 22).

Primordial black hole dark matter still doesn't work.

New strict bounds on primordial black holes as dark matter that don't share systemic errors with other comparably strictly bounding observations have been found. This is consistent with a mountain of evidence strongly disfavoring primordial black holes as a significant source of dark matter phenomena.

High Energy Physics Papers

Heavy neutrinos have not been found.

There is no evidence from the LHC for a "heavy neutral lepton" (basically a heavy neutrino) up to masses of 14.5 GeV. This is not all that huge of a finding as W and Z boson decays largely rule out neutrinos beyond the three Standard Model active neutrinos with masses of less than about 45 GeV.

Hints of up to two kinds of possible heavy Higgs bosons.

Finally, there are resonances that could be arguably interpreted at a 152 GeV Higgs boson S, and another heavy Higgs boson H that decays to two S bosons at the LHC. 

Note the while the observational evidence of the neutral scalar S boson resonance, conceptualized as an intermediate mass Higgs boson (relative to the Standard Model Higgs boson which is an electromagnetically neutral, spin-0, even parity, 125 GeV particle with couplings proportional to the Standard Model fundamental particle masses) is very strong, the evidence of a heavy neutral H boson resonance that is a heavy Higgs boson isn't a part of the simplified model examined that is as definitively established. It would have to have a mass of at least about 302 GeV, but even its mass does not seem to have been definitively pinned down. 

Despite the high statistical significance of the resonance, I wouldn't consider it established yet for reasons including a lack of replication so far, and a lack of a full exploration of the implications of the hypothesized two new fundamental bosons. I personally also need to take some time to figure out what couplings and other properties it is proposed to have, and more generally, to better understand the theory behind it. This latest paper is also not peer reviewed or published yet, although there is no good reason to think that this won't happen.

Aside from popping into existence in high energy physics experiments and decaying, ultimately, into W bosons and b quarks and an invisible decay mode, it isn't clear what phenomenological impact these heavy Higgs bosons would have, or what the apparent invisible decay mode of the S boson would be (the default assumption, without more Standard Model physics, would be neutrinos). 

It also isn't clear to me at this time if alternative explanations for this resonance that do not involve new physics have been considered or proposed. But both the H boson and the S boson seem to be much more massive than any hadron with two to six valence quarks. The S boson, at least, is also too light and apparently too long lived, to have a top quark component. Could the H and S bosons be simply excited resonances of the 125 GeV Standard Model Higgs boson? I've seen proposals along those lines before in the literature (prior to the discovery of these resonances).

But, these proposed new particles are more credible than, for example, the X17 boson hypothesis.

The Higgs boson discovery at the Large Hadron Collider (LHC) at CERN confirmed the existence of the last missing particle of the Standard Model (SM). The existence of new fundamental constituents of matter beyond the SM is of great importance for our understanding of Nature. 

In this context, indirect (non-resonant) indications for new scalar bosons were found in the data from the first run of the LHC, taken between 2010 and 2012 at CERN: an excess in the invariant mass of muon-electron pairs, consistent with a new Higgs boson (S) with a mass of 150±5 GeV. Other processes with multiple leptons in the final state, moderate missing energy, and possibly (bottom quark) jets exhibit deviations from the SM predictions. These anomalies can be explained within a simplified model in which a new heavy Higgs boson H decays into two lighter Higgses S. This lighter Higgs S subsequently decays to W bosons, bottom quarks and has also an invisible decay mode.

Here, we demonstrate that using this model we can identify narrow excesses in di-photon and Z-photon spectra around 152 GeV. By incorporating the latest measurements of di-photons in association with leptons, we obtain a combined global significance of 5.4σ. 

This represents the highest significance ever reported for an excess consistent with a narrow resonance beyond the SM (BSM) in high-energy proton-proton collision data at the LHC. Such findings have the potential to usher in a new era in particle physics - the BSM epoch - offering crucial insights into unresolved puzzles of nature.

Srimoy Bhattacharya, et al., "Emerging Excess Consistent with a Narrow Resonance at 152 GeV in High-Energy Proton-Proton Collisions" arXiv:2503.16245 (March 20, 2025).

Incidentally, the paper also cites the two main papers that predicted the existence of the Standard Model Higgs boson, which I reproduce below for future reference:

* Higgs, P.W.: Broken symmetries, massless particles and gauge fields. Phys. Lett. 12, 132–133 (1964) https://doi.org/10.1016/0031-9163(64)91136-9

* Englert, F., Brout, R.: Broken Symmetry and the Mass of Gauge Vector Mesons. Phys. Rev. Lett. 13, 321–323 (1964) https://doi.org/10.1103/PhysRevLett.13. 321