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
6 comments:
Re: MOND, I thought the idea that galaxies might form in pairs interesting. But when I searched the paper, it doesn't look like there is a justification for galaxies forming in pairs. Rather, they explained that the simulations started as pairs so that they could test the outcome of 2 galaxies merging, which possibly supports a theory of elliptical-galaxy formation. To my surface understanding, it seems like a leaped-to conclusion.
Did you notice any additional info there about *why* galaxies might form in pairs?
This gist of the analysis is that at the time that the first galaxies are forming, the observable universe is much smaller in radius than it is today, and that slight inhomogenities lead to clouds of stuff to collapse into galaxies, with random momentum. This is happening in parallel all over the universe. Knowing how the range of big each early collapse formed galaxy is, you can use statistical mechanics like equations to estimate how often they will collide into each other if you know that range and average of the velocity of each galaxy which is a parameter you can tune a little to fit the data in a way informed by theory. This tells you how many collisions you can expect, but then you need to consider a good sample of all of the different possible collision geometries that are possible, how likely each possibility is in a set of random gas-like collisions, and carefully analyze what happens in each different possibility in the collision. This produces a certain number of unmerged galaxies and a certain number of merged galaxies with characteristics that can be described with a weighted average of the different possibilities in your simulation since it depends primarily on the geometry of the collision. You then compare what the mix of galaxies looks like in your simulation to what is observed with Hubble and the JWST. If the mix and distribution of galaxies in your simulation at a given time since the Big Bang looks similar by statistical measures to what you really see, your model works. In fact, the simulated galaxies in the model show up a bit later than in actual observations, although still much earlier than in LambdaCDM, so they acknowledge that they have some minor kinks to work out.
One thing that their model doesn't consider, although it is probably a source of only a modest part of the discrepancy between the model and observation, is that you could, in theory, have more than two galaxies merge into each other at once (which is much harder to model) because they randomly end up sufficiently close to each other at the same time. This should be an order of magnitude less common, but it should happen sometimes and should speed up galaxy formation a little bit.
Mathematically, the problem is very similar to that problem of how single sun and binary solar systems form, except that in the case of galaxies, MOND effects matter, while in the case of solar systems, the gravitational fields involved are generally going to be stronger than the MOND threshold, so no MOND effects are present in solar system formation. This makes the math in the MOND case for galaxies much harder than the math in the solar system case, and generically, since the part of a galaxy with MOND gravitational effects is stronger than in LamdaCDM, galaxies are both more likely to form from collapses and more likely to form through mergers because the binding between them is stronger in near contact interactions. This is why galaxies form sooner in MOND than in LambdaCDM. And, while their model isn't a perfect fit, it is impressively close given that MOND has fewer free parameters once you fix Milgrom's constant a0 from unrelated astronomy data, and knowing that you are oversimplifying the situation somewhat in a very quantifiable way.
A few things are likely to contribute to the discrepancy that they do see. One is that they may not have the pace of star formation right (some observations suggest it happens quite a bit faster than conventional theory predicts). Another is that their model assumes that each galaxy formation is independent of each other galaxy formation, when in fact, the "cosmic web" of high and low mass density areas in the universe suggest that there are correlations involved in the initial single collapse formed galaxy process that leave some places with lots single collapse galaxies that are close to each other, and other places with few of them, causing mergers to be more likely than the model predicts in some places, and less likely in others. While the less dense places would lag a little, overall, this would increase the number of merged, larger galaxies more quickly than they would if they were fully independent, homogeneous, and random. One way to get to that inhomogenity, for example, would be to substitute Deur's theory which is more prone to that because geometry is more important in Deur's theory than in MOND, for MOND, both of which are very similar to each other in the case of the bulk of matter in single galaxies.
how would a 152 GeV Higgs boson S change your understanding of physics?
But, these proposed new particles are more credible than, for example, the X17 boson hypothesis.
FYI
sabine hossenfelder
Atomic Anomaly Confirmed! Evidence for a “dark force”?
https://www.youtube.com/watch?v=XCQN7g-2fag&t=289s
Phys. Rev. Lett. 134, 063002 – Published 11 February, 2025
https://journals.aps.org/prl/
Probing New Bosons and Nuclear Structure with Ytterbium Isotope Shifts
Menno Door1,2,*,†, Chih-Han Yeh3,*,‡, Matthias Heinz4,5,1,§, Fiona Kirk3,6, Chunhai Lyu1, Takayuki Miyagi4,5,1, Julian C. Berengut7, Jacek Bieroń8, Klaus Blaum1 et al.
"Additionally, we perform a King plot analysis to set bounds on a fifth force in the keV/𝑐2 to MeV/𝑐2 range coupling to electrons and neutrons."
reference source
DOI: https://doi.org/10.1103/PhysRevLett.134.063002
23 sigma for Mev mass new boson
based on MIT
Physical Review Letters
Evidence for Nonlinear Isotope Shift in Yb+ Search for New Boson
Ian Counts1,*, Joonseok Hur1,*, Diana P. L. Aude Craik1, Honggi Jeon2, Calvin Leung1, Julian C. Berengut3, Amy Geddes3, Akio Kawasaki4, Wonho Jhe2 et al.
Phys. Rev. Lett. 125, 123002 – Published 15 September, 2020
Hints of Dark Bosons
Published 15 September, 2020
"A signal predicted for a type of dark matter appears in the spectra of ytterbium isotopes."
reference source
DOI: https://doi.org/10.1103/PhysRevLett.125.123002
Hints of Dark Bosons
September 15, 2020• Physics 13, s115
A signal predicted for a type of dark matter appears in the spectra of ytterbium isotopes.
"In their experiments, both teams measured the so-called isotope shift—the change in atomic spectra exhibited by isotopes of the same element. A group led by Vladan Vuletić of the Massachusetts Institute of Technology measured this shift between five ytterbium istotopes..., could also indicate the existence of dark bosons."
reference source
https://physics.aps.org/articles/v13/s115
Ytterbium Isotope Shifts done by MIT and another group, 23 sigma
dark boson fifth force " MeV/𝑐2 range "coupling to electrons and neutrons" (but no strong coupling to protons).
sounds familiar?
I remember seeing somewhere a paper that extends the standard model with both vector X17 and a second Higgs with a mass around 150Gev and sterile neutrions.
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