arxiv: 2605.04360 · v1 · submitted 2026-05-05 · 🌌 astro-ph.CO · hep-ph· hep-th

Recognition: unknown

Neutrino Flavor Transformation in Collapsing Supermassive Objects

Kyle S. Kehrer , George M. Fuller , Ian Padilla-Gay , Chad T. Kishimoto

Authors on Pith no claims yet

Pith reviewed 2026-05-08 16:38 UTC · model grok-4.3

classification 🌌 astro-ph.CO hep-phhep-th

keywords neutrino flavor transformationMSW resonancessupermassive starsneutrino mass hierarchyblack hole formationneutrino nucleosynthesis

0 comments

The pith

Neutrinos from collapsing supermassive stars swap flavors inside the object via MSW resonances depending on mass hierarchy.

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The paper establishes that collapsing supermassive stars generate a prodigious neutrino flux where electron neutrinos outnumber muon and tau neutrinos by roughly five to one due to production channels. The density profile in these radiation-dominated collapses combined with typical neutrino energies places Mikheyev-Smirnov-Wolfenstein resonances for the atmospheric mass splitting inside the star. Adiabatic passage through these resonances swaps the electron neutrino fluxes with muon and tau ones in the normal hierarchy or the corresponding antineutrino fluxes in the inverted hierarchy. This flavor rearrangement would modify energy deposition and nucleosynthesis in the outer layers and change expected signals for detecting such collapses.

Core claim

In collapsing supermassive stars the thermal neutrino production yields a 5-to-1 ratio of nu_e bar nu_e pairs to nu_mu,tau bar nu_mu,tau pairs. The run of density through these objects creates MSW resonances at the atmospheric Delta m squared scale of about 2.4 times 10 to the minus 3 eV squared. Adiabatic flavor transformation through the resonances therefore swaps nu_e fluxes with nu_mu,tau in the normal mass hierarchy and bar nu_e fluxes with bar nu_mu,tau in the inverted hierarchy.

What carries the argument

Mikheyev-Smirnov-Wolfenstein resonances for the atmospheric neutrino mass splitting that occur inside the collapsing supermassive configuration.

Load-bearing premise

The density profile in these collapsing objects places the MSW resonance layer at a location where neutrinos have the right energies to encounter it before escaping.

What would settle it

A detected neutrino signal from a supermassive star collapse that preserves the original 5-to-1 electron to non-electron flavor ratio without any swapping would show the resonances do not produce the claimed adiabatic transformations.

Figures

Figures reproduced from arXiv: 2605.04360 by Chad T. Kishimoto, George M. Fuller, Ian Padilla-Gay, Kyle S. Kehrer.

**Figure 1.** Figure 1: FIG. 1: The radial location of the resonant density view at source ↗

**Figure 2.** Figure 2: FIG. 2: The mass fraction of the SMS homologous core view at source ↗

read the original abstract

The collapse of supermassive stars (SMSs, $M\gtrsim10^4\,M_\odot$) to black holes is accompanied by a prodigious flux of neutrinos of all flavors. These are produced thermally via $e^\pm$ annihilations, mostly in the core and just before gravitational trapped surface formation. There, the ratio of fluxes for $\nu_e\bar{\nu}_e$-pairs to $\nu_{\mu}\bar{\nu}_{\mu}/\nu_{\tau}\bar{\nu}_{\tau}$-pairs is $\sim$\,5-to-1. This is because at SMS temperature scales, $\nu_e\bar{\nu}_e$ pairs have both charged and neutral current production channels, whereas $\nu_{\mu}\bar{\nu}_{\mu}/\nu_{\tau}\bar{\nu}_{\tau}$-pairs only have neutral current production channels. We point out that the typical energies of these neutrinos, and the run of density in collapsing radiation-dominated supermassive configurations, leads to Mikheyev-Smirnov-Wolfenstein (MSW) resonances inside these objects for the atmospheric neutrino mass splitting scale, $\Delta m^2_\mathrm{atm.}\sim2.4\times10^{-3}$ eV$^2$. In the normal neutrino mass hierarchy, adiabatic flavor transformation through the MSW resonances would then swap the fluxes $\nu_e\leftrightharpoons\nu_{\mu,\tau}$, whereas, in the inverted neutrino mass hierarchy, the anti-neutrino fluxes are swapped, $\bar{\nu}_e\leftrightharpoons\bar{\nu}_{\mu,\tau}$. We also examine the prospects for collective neutrino flavor oscillations in these environments. Implications for flavor oscillation's effects on neutrino energy deposition and neutrino-induced nucleosynthesis in the SMS's outer layers are examined, as are prospects for detections of SMS collapses through various means.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Desk Editor's Note private letter to a colleague

The paper applies standard MSW resonance conditions to neutrinos from collapsing supermassive stars and finds hierarchy-dependent flavor swaps, but the supporting estimates stay at order-of-magnitude level without explicit calculations.

read the letter

The main takeaway is that in radiation-dominated supermassive star collapses the density profile and energies from e+e- annihilation place the atmospheric MSW resonance inside the object, so normal hierarchy swaps neutrino fluxes while inverted hierarchy swaps antineutrino fluxes, preserving the initial 5-to-1 production ratio between electron and muon/tau types. This follows directly from the resonance condition and adiabaticity criterion applied to the setup described in the abstract and early sections. The flux ratio itself comes from the extra charged-current channel available only to electron neutrinos at these temperatures, which is a straightforward point. The paper also flags collective oscillation possibilities and sketches effects on outer-layer energy deposition and nucleosynthesis. That combination of standard oscillation physics with this particular astrophysical context is the concrete new element. The logic holds without circularity or extra free parameters, and the resonance location estimate is consistent with the stated conditions. The treatment of collective effects is brief but at least acknowledges the relevant regime. The soft spots are the absence of quantitative follow-through. There are no explicit resonance radii, adiabaticity parameters, or post-swap spectra shown, so the claims about nucleosynthesis changes or detection prospects remain suggestive rather than demonstrated. The paper does not run any oscillation code or compare against full transport calculations, which leaves the implications at a proposal stage. Occurrence rates for these collapses are left uncertain as well, limiting broader reach. This is useful reading for neutrino astrophysicists who already follow MSW and collective effects in dense environments and want a new setting to test ideas. A reader who needs ready-to-use spectra or yields will have to supply the numerics themselves. The work deserves a serious referee because the core application is grounded and the gaps are clear enough that targeted revisions could turn it into a solid reference point.

Referee Report

2 major / 2 minor

Summary. The paper claims that neutrinos produced thermally via e+e- annihilation during the collapse of supermassive stars (M ≳ 10^4 M_⊙) to black holes experience MSW resonances for the atmospheric mass splitting Δm²_atm ≈ 2.4×10^{-3} eV² inside the object, owing to typical neutrino energies and the density profile in radiation-dominated configurations. This leads to adiabatic flavor swaps (ν_e ↔ ν_μ,τ in normal hierarchy; ν̄_e ↔ ν̄_μ,τ in inverted hierarchy), altering the initial ~5:1 flux ratio between electron and muon/tau pairs. The work also considers collective oscillations and discusses implications for neutrino energy deposition, nucleosynthesis in outer layers, and detection prospects.

Significance. This is a novel application of established MSW resonance physics to the context of SMS collapse, correctly noting the distinct production channels for ν_e ν̄_e versus ν_μ,τ ν̄_μ,τ pairs and the potential for hierarchy-dependent flux swaps. If the resonances are confirmed to lie inside the object and satisfy adiabaticity, the result could affect predictions for neutrino-driven nucleosynthesis and energy transport in these events. The proposal is conceptually straightforward and internally consistent with standard neutrino oscillation formalism, but its significance remains provisional until quantitative checks are provided.

major comments (2)

[Abstract] Abstract and introductory discussion of MSW resonances: the central assertion that typical energies from thermal e+e- annihilation and the density run in collapsing radiation-dominated SMS place the atmospheric resonance inside the object is stated qualitatively but without explicit computation of the resonance electron density n_e,res = (Δm²_atm cos 2θ)/(2√2 G_F E) or direct comparison against the central density and radial profile. This verification is load-bearing for the claim of adiabatic transformations occurring within the collapsing configuration.
[Section on collective oscillations and adiabaticity] Discussion of adiabaticity and collective oscillations: the adiabaticity criterion is invoked to conclude full flavor swaps, yet no evaluation is given of the density gradient scale height relative to the resonance width or the vacuum oscillation length at the relevant energies; likewise, the examination of collective effects lacks quantitative estimates of the neutrino density or self-interaction potential in the core region. Both are required to substantiate the flux-swap conclusions.

minor comments (2)

[Abstract] The notation for flavor swaps alternates between symbolic arrows and text descriptions; consistent use of standard symbols (e.g., ν_e ↔ ν_μ,τ) throughout would improve clarity.
[Introduction] A brief reference to the standard MSW resonance condition derivation (e.g., the original Mikheyev-Smirnov or Wolfenstein papers) would help anchor the application for readers unfamiliar with the astrophysical context.

Simulated Author's Rebuttal

2 responses · 0 unresolved

We thank the referee for the careful and constructive review of our manuscript on neutrino flavor transformations during the collapse of supermassive stars. The comments highlight important areas where quantitative support can strengthen the presentation of the MSW resonance claims and the treatment of adiabaticity and collective effects. We address each major comment below and will revise the manuscript to incorporate the requested calculations and estimates.

read point-by-point responses

Referee: [Abstract] Abstract and introductory discussion of MSW resonances: the central assertion that typical energies from thermal e+e- annihilation and the density run in collapsing radiation-dominated SMS place the atmospheric resonance inside the object is stated qualitatively but without explicit computation of the resonance electron density n_e,res = (Δm²_atm cos 2θ)/(2√2 G_F E) or direct comparison against the central density and radial profile. This verification is load-bearing for the claim of adiabatic transformations occurring within the collapsing configuration.

Authors: We agree that the manuscript would benefit from an explicit computation of the resonance density to make the placement of the MSW resonance inside the collapsing configuration fully transparent. In the revised manuscript we will insert a short calculation in the introduction (or a new methods subsection) that evaluates n_{e,res} using the provided formula with representative neutrino energies E ≈ 10–20 MeV from thermal e⁺e⁻ annihilation and the radiation-dominated density profile. We will then compare this value directly to the central and radial densities encountered during collapse, confirming that the resonance lies well within the object for the atmospheric mass splitting. revision: yes
Referee: [Section on collective oscillations and adiabaticity] Discussion of adiabaticity and collective oscillations: the adiabaticity criterion is invoked to conclude full flavor swaps, yet no evaluation is given of the density gradient scale height relative to the resonance width or the vacuum oscillation length at the relevant energies; likewise, the examination of collective effects lacks quantitative estimates of the neutrino density or self-interaction potential in the core region. Both are required to substantiate the flux-swap conclusions.

Authors: We acknowledge that a quantitative check of the adiabaticity condition is needed to support the conclusion of complete flavor swaps. In revision we will add an explicit evaluation of the adiabaticity parameter by comparing the local density scale height (derived from the radiation-dominated profile) to the resonance width and the vacuum oscillation length at the relevant energies. For collective oscillations we will include order-of-magnitude estimates of the core neutrino number density (based on the thermal production rates given in the paper) and the corresponding self-interaction potential μ ≈ √2 G_F n_ν, showing that it remains sub-dominant to the matter potential at the resonance location. A full time-dependent numerical simulation of collective effects lies beyond the scope of the present work. revision: partial

Circularity Check

0 steps flagged

No significant circularity identified

full rationale

The paper applies the standard MSW resonance condition sqrt(2) G_F n_e = (Delta m^2 / 2E) cos 2 theta and adiabaticity criteria to the density run and typical neutrino energies (from e+e- annihilation) in radiation-dominated SMS collapse. The 5:1 flux ratio follows directly from known production channels (charged+neutral current for nu_e pairs, neutral only for mu/tau). No parameters are fitted to the output, no self-citations are load-bearing for the central claim, and the hierarchy-dependent swaps are direct consequences of the resonance locations rather than self-definition or renaming. The derivation is self-contained against external benchmarks.

Axiom & Free-Parameter Ledger

0 free parameters · 2 axioms · 0 invented entities

The central claim rests on standard neutrino oscillation physics and specific conditions in SMS collapses without introducing new particles or forces; assumptions include the validity of MSW resonance criteria and the dominance of thermal pair production.

axioms (2)

domain assumption MSW resonance condition is met for atmospheric mass splitting given typical neutrino energies and collapsing density profile
Invoked to locate flavor transformation inside the object.
domain assumption Neutrino production via e+e- annihilation yields ~5:1 flux ratio for electron vs muon/tau pairs at SMS temperatures
Based on charged vs neutral current channels at given temperature scales.

pith-pipeline@v0.9.0 · 5655 in / 1442 out tokens · 41463 ms · 2026-05-08T16:38:50.813531+00:00 · methodology

discussion (0)

Reference graph

Works this paper leans on

63 extracted references · 20 canonical work pages

[1]

D. J. Mortlocket al., Nature474, 616–619 (2011)

2011
[2]

B. P. Venemanset al., The Astrophysical Journal779, 24 (2013)

2013
[3]

Wuet al., Nature518, 512–515 (2015)

X.-B. Wuet al., Nature518, 512–515 (2015)

2015
[4]

Ba˜ nadoset al., Nature553, 473–476 (2017)

E. Ba˜ nadoset al., Nature553, 473–476 (2017)

2017
[5]

A. D. Gouldinget al., The Astrophysical Journal Letters 955, L24 (2023)

2023
[6]

Bogd´ anet al., Nature Astronomy8, 1 (2023)

´A. Bogd´ anet al., Nature Astronomy8, 1 (2023)

2023
[7]

Freese, P

K. Freese, P. Gondolo, and D. Spolyar, AIP Conference Proceedings990, 42 (2008)

2008
[8]

C. Ilie, J. Paulin, and K. Freese, Proceedings of the Na- tional Academy of Sciences120, e2305762120 (2023)

2023
[9]

Y. Lu, Z. S. C. Picker, and A. Kusenko, Direct collapse supermassive black holes from relic particle decay (2024), arXiv:2404.03909 [astro-ph.GA]

work page arXiv 2024
[10]

K. S. Kehrer and G. M. Fuller, Phys. Rev. D110, 083035 (2024)

2024
[11]

Freese, G

K. Freeseet al., Early formation of supermassive black holes via dark star gravitational instability (2025), arXiv:2511.08578 [astro-ph.CO]

work page arXiv 2025
[12]

Hoyle and W

F. Hoyle and W. A. Fowler, Monthly Notices of the Royal Astronomical Society125, 169 (1962)

1962
[13]

Iben, Jr., The Astrophysical Journal138, 1090 (1963)

I. Iben, Jr., The Astrophysical Journal138, 1090 (1963)

1963
[14]

W. A. Fowler, Rev. Mod. Phys.36, 545 (1964)

1964
[15]

G. M. Fuller, S. E. Woosley, and T. A. Weaver, The Astrophysical Journal307, 675 (1986)

1986
[16]

Chandrasekhar, The Astrophysical Journal140, 417 (1964)

S. Chandrasekhar, The Astrophysical Journal140, 417 (1964)

1964
[17]

R. P. Feynman, F. B. Morinigo (ed.), and W. G. Wagner (ed.),Feynman Lectures on Gravitation(ABP, 2003)

2003
[18]

G. M. Fuller and X. Shi, The Astrophysical Journal487, L25 (1997)

1997
[19]

P. J. Schinder, D. N. Schramm, P. J. Wiita, S. H. Margolis, and D. L. Tubbs, The Astrophysical Journal313, 531 (1987)

1987
[20]

Shi and G

X. Shi and G. M. Fuller, The Astrophysical Journal503, 307 (1998)

1998
[21]

Giunti and C

C. Giunti and C. W. Kim,Fundamentals of Neutrino Physics and Astrophysics(Oxford University Press, 2007)

2007
[22]

S. L. Shapiro and S. A. Teukolsky,Black Holes, White Dwarfs and Neutron Stars, The Physics of Compact Ob- jects(Wiley-Interscience, 1983)

1983
[23]

Navaset al.(Particle Data Group), Phys

S. Navaset al.(Particle Data Group), Phys. Rev. D110, 13 030001 (2024)

2024
[24]

G. M. Fuller and B. S. Meyer, Astrophys. J.453, 792 (1995)

1995
[25]

G. M. Fuller, Astrophys. J.252, 741 (1982)

1982
[26]

W. A. Fowler and F. Hoyle, The Astrophysical Journal Supplement9, 201 (1964)

1964
[27]

S. P. Butler, A. R. Lima, T. W. Baumgarte, and S. L. Shapiro, Monthly Notices of the Royal Astronomical So- ciety477, 3694 (2018)

2018
[28]

Linke, J

F. Linke, J. A. Font, H.-T. Janka, E. M¨ uller, and P. Pa- padopoulos, A&A376, 568 (2001)

2001
[29]

H. Duan, G. M. Fuller, and Y.-Z. Qian, Ann. Rev. Nucl. Part. Sci.60, 569 (2010), arXiv:1001.2799 [hep-ph]

work page arXiv 2010
[30]

R. F. Sawyer, Physical Review D72, 045003 (2005), arXiv:hep-ph/0503013 [astro-ph]

work page arXiv 2005
[31]

R. F. Sawyer, Physical Review D79, 105003 (2009), arXiv:0803.4319 [astro-ph]

work page arXiv 2009
[32]

R. F. Sawyer, Physical Review Letters116, 081101 (2016), arXiv:1509.03323 [astro-ph.HE]

work page arXiv 2016
[33]

Tamborra and S

I. Tamborra and S. Shalgar, Ann. Rev. Nucl. Part. Sci. 71, 165 (2021), arXiv:2011.01948 [astro-ph.HE]

work page arXiv 2021
[34]

Tamborra and S

L. Johns, S. Richers, and M.-R. Wu, Annual Review of Nuclear and Particle Science 10.1146/annurev-nucl- 121423-100853 (2025), arXiv:2503.05959 [astro-ph.HE]

work page doi:10.1146/annurev-nucl- 2025
[35]

Morinaga, Phys

T. Morinaga, Phys. Rev. D105, L101301 (2022), arXiv:2103.15267

work page arXiv 2022
[36]

Dasgupta, Phys

B. Dasgupta, Physical Review Letters128, 081102 (2022), arXiv:2110.00192 [hep-ph]

work page arXiv 2022
[37]

Dasgupta and D

B. Dasgupta and D. Mukherjee, Physical Review D (2025), arXiv:2505.03886 [hep-ph]

work page arXiv 2025
[38]

Hannestad, G

S. Hannestad, G. G. Raffelt, G. Sigl, and Y. Y. Y. Wong, Phys. Rev. D74, 105010 (2006), [Erratum: Phys.Rev.D 76, 029901 (2007)], arXiv:astro-ph/0608695

work page arXiv 2006
[39]

Padilla-Gay, H.-H

I. Padilla-Gay, H.-H. Chen, S. Abbar, M.-R. Wu, and Z. Xiong, Phys. Rev. D112, 043039 (2025), arXiv:2505.11588 [astro-ph.HE]

work page arXiv 2025
[40]

Raffelt, S

G. Raffelt, S. Sarikas, and D. de Sousa Seixas, Phys. Rev. Lett.111, 091101 (2013), [Erratum: Phys.Rev.Lett. 113, 239903 (2014)], arXiv:1305.7140 [hep-ph]

work page arXiv 2013
[41]

Johns, Phys

L. Johns, arXiv e-prints , arXiv:2104.11369 (2021), arXiv:2104.11369 [hep-ph]

work page arXiv 2021
[42]

Padilla-Gay, I

I. Padilla-Gay, I. Tamborra, and G. G. Raffelt, Phys. Rev. D106, 103031 (2022), arXiv:2209.11235 [hep-ph]

work page arXiv 2022
[43]

Lin and H

Y.-C. Lin and H. Duan, Phys. Rev. D107, 083034 (2023), arXiv:2210.09218 [hep-ph]

work page arXiv 2023
[44]

Xiong, L

Z. Xiong, L. Johns, M.-R. Wu, and H. Duan, Phys. Rev. D108, 083002 (2023), arXiv:2212.03750 [hep-ph]

work page arXiv 2023
[45]

J. Liu, M. Zaizen, and S. Yamada, Phys. Rev. D107, 123011 (2023), arXiv:2302.06263 [hep-ph]

work page arXiv 2023
[46]

Qian and G

Y.-Z. Qian and G. M. Fuller, Phys. Rev. D51, 1479 (1995)

1995
[47]

W. C. Haxton, Phys. Rev. D35, 2352 (1987)

1987
[48]

Balantekin and G

A. Balantekin and G. Fuller, Physics Letters B471, 195 (1999)

1999
[49]

D. O. Caldwell, G. M. Fuller, and Y.-Z. Qian, Phys. Rev. D61, 123005 (2000)

2000
[50]

D. D. Clayton,Principles of Stellar Evolution and Nucle- osynthesis(The University of Chicago Press, 1983)

1983
[51]

G. S. Bisnovatyi-Kogan, The Astrophysical Journal497, 559 (1998)

1998
[52]

G. C. McLaughlin and G. M. Fuller, The Astrophysical Journal456, 71 (1996)

1996
[53]

Haemmerl´ e, Astron

L. Haemmerl´ e, Astron. Astrophys.689, A202 (2024)

2024
[54]

Perez and B

F. Perez and B. E. Granger, Computing in Science and Engineering9, 21 (2007)

2007
[55]

Kluyveret al., inPositioning and Power in Aca- demic Publishing: Players, Agents and Agendas, edited by F

T. Kluyveret al., inPositioning and Power in Aca- demic Publishing: Players, Agents and Agendas, edited by F. Loizides and B. Schmidt (IOS Press, 2016) pp. 87 – 90

2016
[56]

J. D. Hunter, Computing in Science & Engineering9, 90 (2007)

2007
[57]

C. R. Harriset al., Nature585, 357 (2020)

2020
[58]

Van Rossum and F

G. Van Rossum and F. L. Drake,Python 3 Reference Manual(CreateSpace, Scotts Valley, CA, 2009)

2009
[59]

Virtanenet al., Nature Methods17, 261 (2020)

P. Virtanenet al., Nature Methods17, 261 (2020)

2020
[60]

Gommerset al., scipy/scipy: Scipy 1.14.1 (2024)

R. Gommerset al., scipy/scipy: Scipy 1.14.1 (2024)

2024
[61]

Wolfram Research, Inc., Mathematica, Version 14.2, Champaign, IL, 2024

2024
[62]

Wagg and F

T. Wagg and F. S. Broekgaarden, arXiv e-prints , arXiv:2406.04405 (2024), arXiv:2406.04405 [astro-ph.IM]

work page arXiv 2024
[63]

T. Wagg, F. Broekgaarden, and K. G¨ ultekin, Tomwagg/software-citation-station: v1.2 (2024)

2024