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arxiv: 2606.11310 · v1 · pith:VDDODY4Mnew · submitted 2026-06-09 · ✦ hep-ph · astro-ph.CO· astro-ph.HE· hep-ex· hep-th

Direct Detection of Millicharged Particles from Supernovae

Yanou Cui , Fengyi Li , Xiaolin Qi , Ian M. Shoemaker , Yu-Dai Tsai This is my paper

Pith reviewed 2026-06-27 12:23 UTC · model grok-4.3

classification ✦ hep-ph astro-ph.COastro-ph.HEhep-exhep-th
keywords millicharged particlessupernovaedirect detectiontime of flightelectron recoilneutrino burstXENONnTDUNE
0
0 comments X

The pith

Millicharged particles produced in supernovae can reach Earth and produce detectable electron recoils after the neutrino signal.

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

This paper shows that core-collapse supernovae can produce millicharged particles that escape to Earth and create signals in large detectors. The particles' mass causes a time delay relative to neutrinos, creating a search window after the neutrino burst passes. Calculations for several detectors indicate that for a millicharge of 10 to the minus 9 and masses in the sub-MeV to MeV range, more than 10 events could be seen per year. Such a detection would improve existing bounds from supernova cooling by up to an order of magnitude.

Core claim

Millicharged particles with charge fraction ε = 10^{-9} and masses between sub-MeV and MeV can be copiously produced in supernovae, escape, and induce more than 10 electron-recoil events per year at detectors including XENONnT, JUNO, DUNE, and Hyper-Kamiokande, with the signal separated by time-of-flight delay from the neutrino burst, thereby improving the supernova cooling bound on ε by up to an order of magnitude.

What carries the argument

Time-of-flight delay of millicharged particles relative to the supernova neutrino burst, which opens a clean temporal search window for electron-recoil signals.

If this is right

  • More than 10 events per year detectable at XENONnT, JUNO, DUNE, and Hyper-Kamiokande for the benchmark parameters.
  • The search improves the existing supernova cooling bound on the millicharge ε by up to an order of magnitude.
  • The method applies to sub-MeV to MeV-scale masses of the millicharged particles.
  • Distinct signals arise from electron recoils induced by the particles reaching terrestrial detectors.

Where Pith is reading between the lines

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

  • This approach could be combined with other direct detection methods to cross-check bounds on millicharged particles.
  • Non-observation in upcoming supernova events would constrain supernova production models for these particles.
  • Similar time-delay techniques might apply to searches for other feebly interacting particles from astrophysical sources.

Load-bearing premise

A sufficient number of millicharged particles are produced in the supernova core and escape the star to reach Earth without significant absorption.

What would settle it

Observing fewer than 10 events or no delayed signals in a year of data from a nearby supernova at one of the listed detectors for ε = 10^{-9} would indicate the production or escape fraction is lower than calculated.

Figures

Figures reproduced from arXiv: 2606.11310 by Fengyi Li, Ian M. Shoemaker, Xiaolin Qi, Yanou Cui, Yu-Dai Tsai.

Figure 1
Figure 1. Figure 1: FIG. 1. Projected discovery reach in the ( [PITH_FULL_IMAGE:figures/full_fig_p005_1.png] view at source ↗
Figure 2
Figure 2. Figure 2: FIG. 2. The left panel shows the mCP production rate in the SN core via the plasmon-decay channel (solid line) and the [PITH_FULL_IMAGE:figures/full_fig_p008_2.png] view at source ↗
Figure 3
Figure 3. Figure 3: FIG. 3. The time-integrated electron recoil spectra within the first year after the SN. Different experiments are considered for [PITH_FULL_IMAGE:figures/full_fig_p010_3.png] view at source ↗
Figure 4
Figure 4. Figure 4: FIG. 4. Electron recoil spectra at DUNE at different arrival times. Different panels represent different mCP masses. The solid [PITH_FULL_IMAGE:figures/full_fig_p011_4.png] view at source ↗
Figure 5
Figure 5. Figure 5: FIG. 5. Time profile of the mCP-induced electron recoil event rate at DUNE as a function of ToF delay ∆ [PITH_FULL_IMAGE:figures/full_fig_p011_5.png] view at source ↗
read the original abstract

This work proposes a new terrestrial probe for millicharged particles (mCPs) and demonstrates promising discovery prospects. mCPs can be copiously produced in core-collapse supernovae (SNe), and a fraction may escape, travel to Earth and yield distinct signals. The mCP mass induces a time-of-flight (ToF) delay relative to the SN neutrino burst, opening a clean search window after the neutrino signal has passed. We compute the mCP-induced electron-recoil signals at XENONnT, JUNO, DUNE, and Hyper-Kamiokande for benchmark SN scenarios, and find that for $\varepsilon = 10^{-9}$ and sub-MeV to MeV-scale masses, more than 10 events per year can be detected. This search can improve upon existing SN cooling bound on $\varepsilon$ by up to an order of magnitude.

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

1 major / 1 minor

Summary. The manuscript proposes using time-of-flight delayed electron-recoil signals from millicharged particles (mCPs) produced in core-collapse supernovae as a direct detection channel. For the benchmark millicharge ε = 10^{-9} and sub-MeV to MeV masses, the authors compute event rates exceeding 10 per year at XENONnT, JUNO, DUNE, and Hyper-Kamiokande. This is claimed to improve existing supernova cooling bounds on ε by up to an order of magnitude by exploiting the delay relative to the neutrino burst.

Significance. If the central rate calculations hold after uncertainty quantification, the work identifies a novel, clean search strategy for mCPs that leverages existing and near-future neutrino and dark-matter detectors. The time-of-flight separation from the neutrino signal is a concrete experimental advantage. The benchmark results suggest that current facilities could already probe parameter space beyond indirect cooling limits, providing a falsifiable prediction that could be tested with archival or upcoming data.

major comments (1)
  1. [Abstract and associated production/escape calculations] The headline claim of >10 events/year at ε=10^{-9} (Abstract) rests on mCP production (plasmon decay/bremsstrahlung) and escape fractions integrated over a single benchmark supernova core temperature/density profile. No variations over alternative SN simulations or ±20% shifts in core temperature are presented; a factor-of-3 reduction in escaping flux would drop the predicted counts below the stated threshold and remove the claimed order-of-magnitude improvement over the cooling bound. This uncertainty must be quantified for the central claim to be robust.
minor comments (1)
  1. [Abstract] The abstract refers to 'benchmark SN scenarios' without naming the specific temperature/density profile or reference simulation used; adding this citation would improve reproducibility.

Simulated Author's Rebuttal

1 responses · 0 unresolved

We thank the referee for their thoughtful review and for highlighting the need to assess robustness against supernova model variations. We address the single major comment below and will revise the manuscript accordingly.

read point-by-point responses

  1. Referee: [Abstract and associated production/escape calculations] The headline claim of >10 events/year at ε=10^{-9} (Abstract) rests on mCP production (plasmon decay/bremsstrahlung) and escape fractions integrated over a single benchmark supernova core temperature/density profile. No variations over alternative SN simulations or ±20% shifts in core temperature are presented; a factor-of-3 reduction in escaping flux would drop the predicted counts below the stated threshold and remove the claimed order-of-magnitude improvement over the cooling bound. This uncertainty must be quantified for the central claim to be robust.

    Authors: We agree that the central claim relies on a single benchmark supernova profile and that explicit quantification of sensitivity to core temperature and alternative simulations is required for robustness. The manuscript employs a standard benchmark profile drawn from the supernova neutrino literature, chosen for consistency with existing cooling-bound calculations. In the revised version we will add new calculations varying the core temperature by ±20% around the benchmark value and results from one alternative supernova simulation. These will be presented in an expanded Section on production/escape and in a supplementary figure showing the resulting range of event rates at the detectors. The abstract will be updated to report the benchmark result together with the range obtained under these variations, with appropriate caveats on the improvement over cooling bounds. This addresses the concern directly. revision: yes

Circularity Check

0 steps flagged

No circularity; event-rate calculations are explicit outputs from benchmark SN models and standard production cross-sections

full rationale

The paper computes mCP production via plasmon decay and bremsstrahlung, escape fractions, and detector event rates for chosen benchmark values of ε and mass using standard SN core profiles and particle-physics formulas. No equation reduces by construction to a fitted parameter renamed as a prediction, no self-citation supplies a load-bearing uniqueness theorem, and no ansatz is smuggled in. The >10 events/yr claim is an output of the integration over the chosen profiles, not a tautology. SN-model uncertainties affect the numerical result but do not create circularity under the stated criteria.

Axiom & Free-Parameter Ledger

1 free parameters · 2 axioms · 0 invented entities

Based solely on the abstract, the central claim rests on standard but unverified assumptions about particle production in supernovae and detector responses; no free parameters beyond the benchmark ε are listed.

free parameters (1)
  • benchmark millicharge ε
    Value 10^{-9} chosen to illustrate detectable event rates; not derived from data in the abstract.
axioms (2)
  • domain assumption Core-collapse supernovae produce millicharged particles at appreciable rates
    Invoked to justify the flux reaching Earth.
  • domain assumption A non-negligible fraction of produced mCPs escape the supernova
    Required for terrestrial detection.

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discussion (0)

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