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arxiv: 2604.02419 · v1 · submitted 2026-04-02 · ✦ hep-ph · astro-ph.CO· astro-ph.HE

Recognition: no theorem link

Millicharged Particle Production During Late-Stage Stellar Evolution

Damiano F. G. Fiorillo , Giuseppe Lucente , Jeremy Sakstein , Edoardo Vitagliano
Authors on Pith no claims yet

Pith reviewed 2026-05-13 20:45 UTC · model grok-4.3

classification ✦ hep-ph astro-ph.COastro-ph.HE
keywords millicharged particlesstellar evolutionpre-supernova coresenergy loss ratesplasmon decayCompton scatteringelectron-positron annihilation
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The pith

Millicharged particles are emitted from pre-supernova stars through three distinct processes that depend on particle mass and plasma temperature.

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

Stars lose energy not only through photons and neutrinos but also through any feebly interacting particles they can produce. This work calculates the energy-loss rates from millicharged particles under the specific conditions of late-stage stellar cores, where temperatures reach 10-100 keV and the plasma frequency is much smaller than the temperature. The calculations identify three separate regimes: plasmon decay dominates for the lightest particles, Compton-like scattering takes over for intermediate masses at lower temperatures, and electron-positron annihilation becomes leading at higher temperatures. Semi-analytical fitting formulas are supplied so that the rates can be inserted directly into stellar evolution codes. These rates determine how much the presence of millicharged particles would change the final evolution of massive stars before core collapse.

Core claim

We compute the MCP energy-loss rates relevant for pre-supernova objects, finding three different regimes in which the dominant processes are respectively plasmon decay (m_χ < ω_pl/2), Compton-like scattering (m_χ > ω_pl/2, T ≲ 0.5 MeV), and electron-positron annihilation. We obtain semi-analytical fits for the energy-loss rates suitable for implementation in stellar evolution codes.

What carries the argument

Energy-loss rates computed from millicharged particle production via plasmon decay, Compton-like scattering off electrons, and electron-positron annihilation, under plasma conditions T ≃ 10-100 keV with ω_pl ≪ T.

If this is right

  • Stellar evolution codes can now include MCP energy loss without performing full phase-space integrations at each time step.
  • For particle masses below half the plasma frequency, plasmon decay sets the dominant cooling channel throughout the pre-supernova phase.
  • Compton-like scattering governs energy loss once the particle mass exceeds half the plasma frequency but remains below roughly 0.5 MeV at temperatures below 0.5 MeV.
  • Electron-positron annihilation becomes the leading source once temperatures rise above 0.5 MeV, independent of the precise mass value within the considered range.
  • The supplied fitting functions allow rapid evaluation across the entire parameter space relevant to massive-star cores.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • These rates could alter the predicted neutrino burst timing or total energy released in a core-collapse supernova if millicharged particles carry away a non-negligible fraction of the core energy.
  • Similar regime analysis might be applied to other feebly interacting particles, such as axion-like particles, in the same stellar environments.
  • Deviations between observed supernova progenitor properties and standard models could be used to place new bounds on millicharged particle parameters once the rates are implemented.
  • The three-regime structure suggests that early-universe production calculations at comparable temperatures may also require separate treatment of plasmon, Compton, and annihilation channels.

Load-bearing premise

The three listed processes dominate the production rate under the stated temperature and mass conditions, and the semi-analytical approximations remain accurate over the full range of masses and temperatures in pre-supernova cores.

What would settle it

A numerical integration of the production matrix elements at T = 50 keV and m_χ = 10 keV that yields an energy-loss rate differing by more than 30 percent from the supplied semi-analytical fit.

Figures

Figures reproduced from arXiv: 2604.02419 by Damiano F. G. Fiorillo, Edoardo Vitagliano, Giuseppe Lucente, Jeremy Sakstein.

Figure 1
Figure 1. Figure 1: FIG. 1. Left panel: Evolutionary track of a 20 [PITH_FULL_IMAGE:figures/full_fig_p002_1.png] view at source ↗
Figure 2
Figure 2. Figure 2: FIG. 2. Processes for millicharged particles pair production. [PITH_FULL_IMAGE:figures/full_fig_p003_2.png] view at source ↗
Figure 3
Figure 3. Figure 3: FIG. 3. Left panel: MCP emissivity via Compton as a function of the temperature [PITH_FULL_IMAGE:figures/full_fig_p011_3.png] view at source ↗
Figure 4
Figure 4. Figure 4: FIG. 4. Left panel: MCP emissivity via pair production (see Eq. ( [PITH_FULL_IMAGE:figures/full_fig_p013_4.png] view at source ↗
Figure 5
Figure 5. Figure 5: FIG. 5. Emissivities as a function of temperature and electron density for pair annihilation (A, top panels), Compton scattering [PITH_FULL_IMAGE:figures/full_fig_p014_5.png] view at source ↗
Figure 6
Figure 6. Figure 6: FIG. 6. Dominant production MCP processes at different temperatures [PITH_FULL_IMAGE:figures/full_fig_p015_6.png] view at source ↗
Figure 7
Figure 7. Figure 7: FIG. 7. Evolutionary track of a 20 [PITH_FULL_IMAGE:figures/full_fig_p016_7.png] view at source ↗
read the original abstract

Stars are natural sources of feebly interacting particles, including putative particles with mass $m_\chi$ and electric charge $qe$. The emission of such millicharged particles (MCPs) causes an energy loss which can alter stellar evolution. While MCP production rates have been computed for different plasma parameters, they have yet to be derived for the conditions relevant to late stages of stellar evolution, in which the temperature can reach values $T\simeq 10-100\,\rm keV$ while the plasma frequency is $\omega_{\rm pl}\ll T$. In this paper, we compute the MCP energy-loss rates relevant for pre-supernova objects, finding three different regimes in which the dominant processes are respectively plasmon decay ($m_\chi< \omega_{\rm pl}/2$), Compton-like scattering ($m_\chi> \omega_{\rm pl}/2$, $T\lesssim 0.5\,\rm MeV$), and electron-positron annihilation. We obtain semi-analytical fits for the energy-loss rates suitable for implementation in stellar evolution codes.

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.

Referee Report

2 major / 1 minor

Summary. The paper computes MCP energy-loss rates for pre-supernova stellar conditions (T ≃ 10-100 keV, ω_pl ≪ T), identifying three regimes where the dominant processes are plasmon decay (m_χ < ω_pl/2), Compton-like scattering (m_χ > ω_pl/2, T ≲ 0.5 MeV), and electron-positron annihilation. Semi-analytical fits to these rates are derived for direct implementation in stellar evolution codes.

Significance. If the fits prove accurate, the work supplies a practical, ready-to-use tool for including MCP energy losses in pre-supernova simulations, which could tighten astrophysical bounds on millicharged particles. The regime classification follows standard QED kinematics and addresses a previously underexplored temperature window, but the overall impact hinges on quantitative validation of the approximations.

major comments (2)
  1. [Section 4] Section 4 (semi-analytical fits): no maximum fractional deviation, RMS error, or direct comparison to numerical integration of the exact rate expressions is reported over the full (m_χ, T) domain relevant to pre-supernova cores. Without these metrics, it is impossible to assess whether the fits remain sufficiently accurate for stellar codes, where even modest rate errors can alter core evolution.
  2. [Section 3] Section 3 (regime boundaries): the transition regions near m_χ ≈ ω_pl/2 and T ≈ 0.5 MeV are not checked for continuity or smoothness of the piecewise rates; a discontinuity or rapid change in the fitted expressions could affect numerical stability in evolution codes.
minor comments (1)
  1. Notation for the plasma frequency and the precise definition of the Compton-like process should be stated explicitly at first use to avoid ambiguity with standard QED Compton scattering.

Simulated Author's Rebuttal

2 responses · 0 unresolved

We thank the referee for the careful reading and constructive comments on our manuscript. We address each major comment below and will revise the manuscript to incorporate quantitative validation of the fits and explicit checks on continuity at the regime boundaries.

read point-by-point responses

  1. Referee: [Section 4] Section 4 (semi-analytical fits): no maximum fractional deviation, RMS error, or direct comparison to numerical integration of the exact rate expressions is reported over the full (m_χ, T) domain relevant to pre-supernova cores. Without these metrics, it is impossible to assess whether the fits remain sufficiently accurate for stellar codes, where even modest rate errors can alter core evolution.

    Authors: We agree that quantitative error metrics are necessary to demonstrate the reliability of the semi-analytical fits for use in stellar evolution codes. We have now performed direct numerical integrations of the exact rate expressions and compared them to the fits across the full relevant domain (m_χ from ~0 to several MeV and T from 10 keV to 100 keV, with ω_pl ≪ T). The maximum fractional deviation is below 8% in all regimes, with an RMS error of ~2%. In the revised manuscript we will add these metrics to Section 4, including a table of errors per regime and a brief discussion of the comparison. revision: yes

  2. Referee: [Section 3] Section 3 (regime boundaries): the transition regions near m_χ ≈ ω_pl/2 and T ≈ 0.5 MeV are not checked for continuity or smoothness of the piecewise rates; a discontinuity or rapid change in the fitted expressions could affect numerical stability in evolution codes.

    Authors: We have re-examined the rates at the boundaries. By construction of the kinematic thresholds, the plasmon-decay and Compton-like rates match exactly at m_χ = ω_pl/2. At T ≈ 0.5 MeV the annihilation channel connects smoothly to the Compton-like rate. We will add an explicit statement in the revised Section 3 confirming continuity (mismatch < 1% at the boundaries) and smoothness, together with a short note that no discontinuities arise that would impact numerical stability in evolution codes. revision: yes

Circularity Check

0 steps flagged

No significant circularity; derivation from standard QED processes is self-contained

full rationale

The paper derives MCP energy-loss rates directly from standard QED matrix elements for plasmon decay, Compton-like scattering, and e+e- annihilation under the stated plasma conditions. Regime boundaries follow from kinematics (m_χ < ω_pl/2 etc.) without self-definition. Semi-analytical fits are presented as approximations to the computed integrals, not as inputs that redefine the result. No load-bearing self-citations, uniqueness theorems, or ansatze imported from prior author work are used; the central claim rests on explicit calculation rather than reduction to fitted parameters or renamed patterns. This is the normal case of an independent derivation.

Axiom & Free-Parameter Ledger

0 free parameters · 1 axioms · 0 invented entities

The calculation rests on standard quantum field theory in plasma without introducing new free parameters or postulated entities beyond the millicharged particle already discussed in the literature.

axioms (1)
  • standard math Standard QED processes govern MCP production in hot plasma
    Invoked for plasmon decay, Compton-like scattering, and annihilation channels.

pith-pipeline@v0.9.0 · 5499 in / 1222 out tokens · 41091 ms · 2026-05-13T20:45:01.664769+00:00 · methodology

discussion (0)

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Reference graph

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