Like every arguable experimental anomaly these days, the large number of high energy photons from GRB 221009A observed by LHAASO has given rise to many ambulance chasing papers purporting to explain these observations with "new physics" (which I do not dignify with citations at this blog).
But, as this paper explains, these astronomy observations can be explained without physics beyond the core theory of the Standard Model and General Relativity. These results are at most, a slightly more than two sigma statistical fluke in circumstances where the reduction for look elsewhere effects needs to be significant.
Papers like this one that work hard to find a plausible explanation for seeming anomalies with well-established and proven "old physics" should be encouraged and should weigh far more heavily in hiring and promotions than ambulance chasing papers (although the poor English grammar in the title written by non-native English speakers should be remedied prior to publication).
It is reported that the Large High Altitude Air Shower Observatory (LHAASO) observed thousands of very-high-energy photons up to ∼18 TeV from GRB 221009A. We study the survival rate of these photons by considering the fact that they are absorbed by the extragalactic background light.
By performing a set of 10^6 Monte-Carlo simulations, we explore the parameter space allowed by current observations and find that the probability of predicting that LHAASO observes at least one photons of 18 TeV from GRB 221009A within 2000 seconds is 4-5%.
Hence, it is still possible for the standard physics to interpret LHAASO's observation in the energy range of several TeV. Our method can be straightforwardly generalized to study more data sets of LHAASO and other experiments in the future.
Zhi-Chao Zhao, Yong Zhou, Sai Wang, "Standard physics is still capable to interpret ∼18 TeV photons from GRB~221009A" arXiv:2210.10778 (October 16, 2022).
3 comments:
you might like this Deur - i might post to pf
High Energy Physics - Theory
[Submitted on 8 Oct 2022]
Non-relativistic gravity theories in four spacetime dimensions
Patrick Concha, Evelyn RodrÃguez, Gustavo Rubio
In this work we present a non-relativistic gravity theory defined in four spacetime dimensions using the MacDowell-Mansouri geometrical formulation. We obtain a Newtonian gravity action which is constructed from the curvature of a Newton-Hooke version of the so-called Newtonian algebra. We show that the non-relativistic gravity theory presented here contains the Poisson equation in presence of a cosmological constant. Moreover we make contact with the Modified Newtonian Dynamics (MOND) approach for gravity by considering a particular ansatz for a given gauge field. We extend our results to a generalized non-relativistic MacDowell-Mansouri gravity theory by considering a generalized Newton-Hooke algebra.
Comments: 20 pages
Subjects: High Energy Physics - Theory (hep-th); General Relativity and Quantum Cosmology (gr-qc)
Cite as: arXiv:2210.04101 [hep-th]
General Relativity and Quantum Cosmology
[Submitted on 30 Nov 2006 (v1), last revised 15 May 2009 (this version, v2)]
MacDowell-Mansouri gravity and Cartan geometry
Derek K. Wise
The geometric content of the MacDowell-Mansouri formulation of general relativity is best understood in terms of Cartan geometry. In particular, Cartan geometry gives clear geometric meaning to the MacDowell-Mansouri trick of combining the Levi-Civita connection and coframe field, or soldering form, into a single physical field. The Cartan perspective allows us to view physical spacetime as tangentially approximated by an arbitrary homogeneous "model spacetime", including not only the flat Minkowski model, as is implicitly used in standard general relativity, but also de Sitter, anti de Sitter, or other models. A "Cartan connection" gives a prescription for parallel transport from one "tangent model spacetime" to another, along any path, giving a natural interpretation of the MacDowell-Mansouri connection as "rolling" the model spacetime along physical spacetime. I explain Cartan geometry, and "Cartan gauge theory", in which the gauge field is replaced by a Cartan connection. In particular, I discuss MacDowell-Mansouri gravity, as well as its more recent reformulation in terms of BF theory, in the context of Cartan geometry.
Comments: 34 pages, 5 figures. v2: many clarifications, typos corrected
Subjects: General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Theory (hep-th); Differential Geometry (math.DG)
Cite as: arXiv:gr-qc/0611154
Thanks. I'll take a look.
See also [Submitted on 22 Oct 2022]
An empirical analysis of the dynamics of both individual galaxies and gravitational lensing in galaxy clusters without dark matter
G.Pascoli
The existence of the flat rotation curves of galaxies is still perplexing. The dark matter paradigm was proposed long ago to solve this conundrum; however, this proposal is still under debate. In this paper, we search for universal relationships solely involving the baryonic density that incorporate both galactic dynamics and gravitational lensing in galaxy clusters without requiring dark matter. If this type of formula exists, we show that it is possible that it can clearly indicate that dark matter is either perfectly tailored to baryonic matter or, from a more radical point of view, even perhaps useless. If the latter situation is true, then we must give greater visibility to models such as modified inertia (MOND) or even modified gravity (MOG).
Comments: 19 pages 16 figures
Subjects: Astrophysics of Galaxies (astro-ph.GA)
Cite as: arXiv:2210.12380
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