Derived Properties In Particle Physics

It is customary to assume more properties of gauge theories than is necessary to produce all of their properties. Some of those assumptions can be derived, including CP invariance.

We revisit the emergence of a Yang-Mills symmetry in theories with massless spin 1 particles from fundamental physical properties of scattering amplitudes. In the standard proofs, some symmetry and reality properties of the coupling constants in three-point amplitudes are assumed. These properties cannot be justified using only three-point amplitudes but we show that they arise as consequences of the consistent factorization of four-particle amplitudes, for particular choices of the particle basis. This applies to self-interactions of massless spin 1 particles and also to their interactions with spin 0 and 1/2 particles. CP invariance is a derived property, not an additional assumption. The situation for gravity interactions is analogous and it is dealt with in the same fashion.

Renato M. Fonseca, Clara Hernandez-Garcia, Javier M. Lizana, Manuel Perez-Victoria, "Gauge theories from scattering amplitudes with minimal assumptions" arXiv:2511.21664 (November 26, 2025).

Two Tully-Fischer Relations Linked

 

The Baryonic Tully - Fisher relation (BTFR) links the baryonic mass of galaxies to their characteristic rotational velocity and has been shown to with remarkable precision across a wide mass range. 

Recent studies, however, indicate that galaxy clusters occupy a parallel but offset relation, raising questions about the universality of the BTFR. 

Here, we demonstrate that the offset between galaxies and clusters arises naturally from cosmic time evolution. Using the evolving BTFR derived from the Nexus Paradigm of quantum gravity, we show that the normalization of the relation evolves as an exponential function of cosmic time, while the slope remains fixed at ∼4. This provides a simple and predictive framework in which both galaxies and clusters obey the same universal scaling law, with their apparent offset reflecting their different formation epochs. Our results unify mass-velocity scaling across five orders of magnitude in baryonic mass, offering new insights into cosmic structure formation.

Stuart Marongwe, Stuart Kauffman, "The Evolving Baryonic Tully Fisher Relation: A Universal Law from Galaxies to Galactic Clusters" arXiv:2511.20188 (November 25, 2025).

There is a tight link between the amount of ordinary matter in a galaxy and its rotation speed over many orders of magnitude. This empirical relationship arises naturally from the phenomenological gravity modification known as MOND, without dark matter.

The same relationship holds true for galaxy clusters, but it is shifted from the relationship for galaxies.

The authors propose a theory that would unify both of these relationships. It works, but it isn't terribly convincing but there are a multitude of ways that galaxies and galaxy clusters differ which could give rise to the shift in the relationship that is observed.

Closely related issues are discussed at the latest post at Triton Station.

JUNO Hype And Reality

A new neutrino physics experiment published a preprint with new measurements of neutrino oscillation constants. The new equipment works to high precision and will help fine tune the exact values of some the least precisely known experimentally measured parameters in the Standard Model of Particle Physics. 

This is interesting to people who follow particle physics closely. It is also scientifically important. But honestly, it isn't that interesting to the average person with only a general interest in science.

But, Rory Harris at Live Science in a fit a yellow journalism in the science world, writes a story containing all sorts of nonsense about JUNO revealing beyond the Standard Model physics, as well as the usual, misleading blather about CP violation experimentation answering questions about the baryon asymmetry of the universe (which this experiment does not do).

How Long Do Animals Live?

 

From Quarks To Chemistry

Protons, neutrons, and hundreds of other much less stable hadrons  (i.e. systems of quarks and/or gluons bound by the strong force) are understood quite well with the Standard Model of Particle Physics, although there are challenges in understanding scalar mesons, axial vector mesons, and hadrons with four or more quarks, as well as in distinguishing true hadrons with four or more quarks from "hadron molecules", and predicting the full spectrum of hadrons from first principles.

Protons and neutrons in atomic nuclei are not bound together primarily by the strong force itself. Instead, the nuclear binding force between protons and neutrons in an atomic nucleus is the sum of the forces arising from the exchange of several kinds of light mesons (primarily pions but also other light mesons including kaons).

We are not quite there in terms of using Standard Model physics to explain the physics and chemistry of atomic nuclei, although we are getting closer to achieving this vertical integration of subatomic and atomic scale phenomena, and we making great progress on this front. Part of the hold up is the challenge of explaining "parton distribution functions" (PDFs), a property of hadrons that, in principle, can be worked out from first principles with Standard Model physics. But until the past few years, PDFs have actually been determined almost entirely from brute force raw data collection and organization from particle accelerator data.

We also mostly understand the way electrons interact with atomic nuclei, which is almost entirely an electromagnetic quantum electrodynamics (QED) phenomena.

The next layer above understanding atoms, is chemistry, which pertains mostly to how atoms interact with each other, much of which ultimately flow from the physics of atomic nuceli.

We extend the QCD Parton Model analysis by employing a factorized nuclear structure model that explicitly accounts for both individual nucleons and correlated nucleon pairs. This novel framework establishes a paradigm that directly links the nuclear physics description of matter (in terms of protons and neutrons) to the particle physics schema (in terms of quarks and gluons). 

Our analysis of high-energy data from lepton Deep-Inelastic Scattering, Drell-Yan, and W/Z production simultaneously extracts the universal effective distribution of quarks and gluons inside correlated nucleon pairs, and their nucleus-specific fractions. 

The successful extraction of these universal distributions marks a significant advance in our understanding of nuclear structure, as it directly connects nucleon-level and parton-level quantities.

Fredrick Olness, "Bridging the Gap: Connecting Atomic Nuclei to Their Quantum Foundations" arXiv:2511.15659 (November 19) ("Talk presented at the 32nd International Workshop on Deep Inelastic Scattering and Related Subjects (DIS 2025), Capetown, South Africa, 24-28 March 2025. To appear in the proceedings").

MOND From Loop Quantum Gravity

Another "Fundamond" (i.e. fundamental theory to explain MOND phenomenology) proposal tweaked to incorporate quantum gravity considerations. Spin connection foams are a subset of the loop quantum gravity program that seeks to quantize space-time.

Building upon previous work that derived an alternative to (galactic) dark matter in the form of Modified Newtonian Dynamics (MOND), with a specific theoretical interpolating function, from the motion of a non-relativistic test particle in the gravitational field of a point mass immersed in the non-relativistic static limit of the spin connection foam -- which represents the quantum analogue of Minkowski spacetime within precanonical quantum gravity -- we now show the consequences of using higher moments (third and fourth) of the corresponding geodesic equation with a random spin connection term. 

These higher moments lead to more general quantum modifications of the Newtonian potential (qMOND potentials expressed in terms of Gauss and Appell hypergeometric functions), more general (steeper) MOND interpolating functions, and a new modification of MOND at low accelerations (mMOND) that features an almost-flat asymptotic rotation curve ∝r−^1/18, which is expected to operate at approximately the same galactic scales as MOND.

M.E. Pietrzyk, V.A. Kholodnyi, I.V. Kanattšikov, J. Kozicki, "Modifications of Newtonian dynamics from higher moments of quantum spin connection in precanonical quantum gravity" arXiv:2511.15025 (November 18, 2025) ("To appear in the Special Issue "My Favourite Dark Matter Model'' of MPLA").

Inflation Without Inflaton

I'm agnostic but skeptical about cosmological inflation. This preprint (which is part of a series of articles) is a middle ground between conventional cosmological inflation theory and a true no inflation theory.

Rather than a new substance/particle, it relies upon the quantum nature of space-time itself for its conclusions.

We present a complete computation of the scalar power spectrum in the inflation without inflaton (IWI) framework, where the inflationary expansion is driven solely by a de~Sitter (dS) background and scalar fluctuations arise as second-order effects sourced by tensor perturbations. By explicitly deriving and numerically integrating the full second-order kernel of the Einstein equations, we obtain a scale-invariant scalar spectrum without invoking a fundamental scalar field. 

In this framework, the amplitude of the scalar fluctuations is directly linked to the scale of inflation. More precisely, we show that matching the observed level of scalar fluctuations, Δ2ϕ(k∗) ≈ 10^−9 at Cosmic Microwave Background (CMB) scales, fixes the inflationary energy scale H(inf) as a function of the number of observed e-folds N(obs). 

For N(obs) ≃ 30 − 60, we find Hinf≃5×10^13 GeV − 2 × 10^10 GeV, corresponding to a tensor-to-scalar ratio r≃ 0.01 − 5 × 10^−9. In particular, requiring consistency with instantaneous reheating, we predict a number of e-folds of order~(50) and an inflationary scale H(inf) ≃ 10^11GeV. We also incorporate in our framework the quantum break-time of the dS state and show that it imposes an upper bound on the number of particle species. Specifically, using laboratory constraints on the number of species limits the duration of inflation to N(obs) ≲ 126 e-folds. 

These results establish the IWI scenario as a predictive and falsifiable alternative to standard inflaton-driven models, linking the observed amplitude of primordial fluctuations directly to the quantum nature and finite lifetime of dS space.

Marisol Traforetti, et al., "Inflation without an Inflaton II: observational predictions" arXiv:2511.11808 (November 14, 2025).

C.N. Yang Dies At Age 103

Theoretical physicist C.N. Yang has died at the age of 103 years. 

He is the Yang in Yang-Mills theory, which he and his collaborators devised in 1953, which is a generic quantum field theory that is used by scientists to study amplitudes (i.e. vector probabilities) that are foundational in all Standard Model processes and most quantum gravity theories.

He also won a Nobel prize in 1957 for his work on CP violation.

The Case Against The External Field Effect And A Relativistic MOND Theory

A new paper provides a possible explanation for observational evidence of a MOND-like external field effect, without definitively ruling it out. I made a post about the paper that is being re-examined exactly five years ago today.

We examine the claimed observations of a gravitational external field effect (EFE) reported in Chae et al. 

We show that observations suggestive of the EFE can be interpreted without violating Einstein's equivalence principle, namely from known correlations between morphology, environment and dynamics of galaxies. 

While Chae et al's analysis provides a valuable attempt at a clear test of Modified Newtonian Dynamics, an evidently important topic, a re-analysis of the observational data does not permit us to confidently assess the presence of an EFE or to distinguish this interpretation from that proposed in this article.

Corey Sargent, William Clark, Antonia Seifert, Alicia Mand, Emerson Rogers, Adam Lane, Alexandre Deur, Balša Terzić, "On the Evidence for Violation of the Equivalence Principle in Disk Galaxies" arXiv:2511.03839 (November 5, 2025) (published in 8 Particles 65 (2025)).

Another promising MOND related preprint that uses entropy and temperature (which is associated intimately with entropy) to devise a relativistic gravitational theory that reproduced MOND phenomenology was also released today:

We derive a relativistic extension of Modified Newtonian Dynamics (MOND) within the framework of entropic gravity by introducing temperature-dependent corrections to the equipartition law on a holographic screen. 

Starting from a Debye-like modification of the surface degrees of freedom and employing the Unruh relation between acceleration and temperature, we obtain modified Einstein equations in which the geometric sector acquires explicit thermal corrections. Solving these equations for a static, spherically symmetric spacetime in the weak-field, low-temperature regime yields a corrected metric that smoothly approaches Minkowski space at large radii and naturally contains a characteristic acceleration scale.

In the very-low-acceleration regime, the model reproduces MOND-like deviations from Newtonian dynamics while providing a relativistic underpinning for that phenomenology. We confront the theory with rotation-curve data for NGC~3198 and perform a Bayesian parameter inference, comparing our relativistic MOND (RMOND) model with both a baryons-only Newtonian model and a dark-matter halo model. We find that RMOND and the dark-matter model both fit the data significantly better than the baryons-only Newtonian prediction, and that RMOND provides particularly improved agreement at r≳20kpc. These results suggest that temperature-corrected entropic gravity provides a viable relativistic framework for MOND phenomenology, motivating further observational tests, including gravitational lensing and extended galaxy samples.

A. Rostami, K. Rezazadeh, M. Rostampour, "Relativistic MOND Theory from Modified Entropic Gravity" arXiv:2511.05632 (November 7, 2025).

Why Does Cosmology Give Us A Negative Neutrino Mass As A Best Fit Value?

The apparent preference for a best fit value of the neutrino masses from cosmology measurements is probably a matter of some fine methodological adjustments that weren't made for gravitational lensing.

Recent analyses combining cosmic microwave background (CMB) and baryon acoustic oscillation (BAO) challenge particle physics constraints on the total neutrino mass, pointing to values smaller than the lower limit from neutrino oscillation experiments. To examine the impact of different CMB likelihoods from Planck, lensing potential measurements from Planck and ACT, and BAO data from DESI, we introduce an effective neutrino mass parameter (∑m̃ ν) which is allowed to take negative values. 

We investigate its correlation with two extra parameters capturing the impact of gravitational lensing on the CMB: one controlling the smoothing of the peaks of the temperature and polarization power spectra; one rescaling the lensing potential amplitude. In this configuration, we infer ∑m̃ ν=−0.018+0.085−0.089 eV (68% C.L.), which is fully consistent with the minimal value required by neutrino oscillation experiments. 

We attribute the apparent preference for negative neutrino masses to an excess of gravitational lensing detected by late-time cosmological probes compared to that inferred from Planck CMB angular power spectra. We discuss implications in light of the DESI BAO measurements and the CMB lensing anomaly.

Andrea Cozzumbo, et al., "A short blanket for cosmology: the CMB lensing anomaly behind the preference for a negative neutrino mass" arXiv:2511.01967 (November 3, 2025).

A Dark Energy Alternative

There are multiple possible alternatives to a cosmological constant. This is one of the better attempts.

In our local-to-global cosmological framework, cosmic acceleration arises from local dynamics in an inhomogeneous Einstein-de Sitter (iEdS) universe without invoking dark energy. 

An iEdS universe follows a quasilinear coasting evolution from an Einstein-de Sitter to a Milne state, as an effective negative curvature emerges from growing inhomogeneities without breaking spatial flatness. Acceleration can arise from structure formation amplifying this effect. 

We test two realizations, iEdS(1) and iEdS(2), with H(0) = {70.24,74.00} km s^−1 Mpc^−1 and Ω(m,0) = {0.290,0.261}, against CMB, BAO, and SN Ia data. 

iEdS(1) fits better than ΛCDM and alleviates the H0 tension, whereas iEdS(2) fully resolves it while remaining broadly consistent with the data. Both models yield t0≃13.64 Gyr, consistent with globular-cluster estimates.

Peter Raffai, et al., "A Case for an Inhomogeneous Einstein-de Sitter Universe" arXiv:2511.03288 (November 5, 2025).