Tuesday, November 26, 2024

The Lightest Neutron Star Ever? Or Something Else?

A new preprint argues that a newly observed object that looks lot like a neutron star, but is less massive than should have been possible theoretically, might be an exotic star.

But, since the observed mass, of 0.77 + 0.2 -0.17 solar masses, is still within two sigma of the theoretical minimum mass of a neutron star, which is 1.17 solar masses, I don't take the conclusion that it could be an exotic object (made up of color flavor locked quark matter), very seriously.

In other news, I have a dim opinion of any paper whose abstract begins:
The gauge singlet right-handed neutrinos are one of the essential fields in neutrino mass models that explain tiny masses of active neutrinos.

If you feel the need to create right handed neutrinos (with masses different from any of the three Standard Model active neutrinos) to explain anything, your model is probably wrong because you are too lazy to find a solution that doesn't need them, and there is no positive experimental evidence that they exist. This possibility has been a perennial source for a steady stream of dead end theoretical speculation for at least a decade or two. This paper is the work of dim bulbs in the physics community. Try harder until you come up with something better.

To be clear, I'm not saying that I'm a professional physicist coming up with something better myself. But you don't have to be a genius composer yourself to appreciate the difference between Mozart and a mediocre music theory student.

4 comments:

neo said...

arXiv:2411.17319 (hep-ph)
[Submitted on 26 Nov 2024]
Missing matter in galaxies as a neutrino mixing effect
Antonio Capolupo, Salvatore Capozziello, Gabriele Pisacane, Aniello Quaranta

We show that, in the framework of quantum field theory in curved spacetime, the semiclassical energy-momentum tensor of the neutrino flavor vacuum fulfills the equation of state of dust and cold dark matter. We consider spherically symmetric spacetimes, and we demonstrate that, within the weak field approximation, the flavor vacuum contributes as a Yukawa correction to the Newtonian potential. This corrected potential may account for the flat rotation curves of spiral galaxies. In this perspective, neutrino mixing could contribute to dark matter

Comments: 18 pages, 3 figures
Subjects: High Energy Physics - Phenomenology (hep-ph); Astrophysics of Galaxies (astro-ph.GA); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Theory (hep-th)
Cite as: arXiv:2411.17319 [hep-ph]

The above considerations, in particular the final result, can be applied to the dynamics of spiral galaxies. In
particular, we will show that both flat rotation curves and the baryonic Tully-Fisher relation can be achieved in this
frameworkVI. DISCUSSION AND CONCLUSIONS
Using QFT in curved space we have derived general results pertaining the flavor vacuum and its associated energy-
momentum tensor. We have shown that in most cases of interest the latter attains a perfect fluid form, characterized
by the dust and cold dark matter equation of state. We have then delved into the important case of static spherically
symmetric spacetimes, deriving an explicit expression for the energy density due to the flavor vacuum. In the weak
field approximation, we have solved the Poisson equation with the above mentioned source, and found that it is solved
by a Yukawa form of the potential. Borrowing from results in the recent literature pertaining Yukawa cosmology, we
have argued that such potential can explain the flatness of the rotation curves of spiral galaxies. In this way the flavor
vacuum plays the role of (part of?) the dark matter component. By leveraging on the theoretical Tully-Fisher relation
that emerges from the Yukawa potential, akin to the MOND result v4
F LAT = GMa0, we have fitted the experimental
baryonic Tully-Fisher relation for two important datasets, including gas rich galaxies. We have discussed two possible
scenarios, one for which the ultraviolet cutoff for the energy density is held constant and one for which the c

andrew said...

I bookmarked it, but didn't have time to read it. I'm pounding away like crazy to get some business contracts written before Thanksgiving with only brief physics breaks.

neo said...

happy Thanksgiving i may get kfc

Mitchell said...

How will you get Dirac masses for neutrinos without right-handed neutrinos?