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Constraints on millicharged particles from nuclear gamma-decays

T0 review · 2 major / 6 minor · reviewed 2026-08-06 · deepseek-v4-flash

Pith's one-line read Nuclear gamma cascades inside reactors produce millicharged particle pairs, letting existing low-threshold germanium data set the tightest millicharge limits for masses 0.7-2 MeV.

desk verdict Genuinely new reactor MCP limits from nuclear de-excitation gammas; the Eq. (6)-vs-Eq. (45) mismatch in the stress test does not hold up, but the TEXONO recast would benefit from an uncertainty budget. read the letter →

arxiv 2507.17955 v3 pith:FSCQHGM4 submitted 2025-07-23 hep-ph hep-exnucl-th

classification hep-phhep-exnucl-th
keywords millichargedparticlesinternalpairproductionnucleargammadecaysreactorsearcheselectronrecoildarkphotonsolarfluxMeV-scalesectors
verification ladder T0 review T1 audit T2 compute T3 formal

The pith

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

The reading

The paper argues that every nuclear gamma transition with energy ω can, in principle, emit a millicharged particle pair instead of a photon whenever 2mχ<ω, and that this internal pair-production channel is the dominant reactor source of millicharged particles for masses above roughly 0.5 MeV. Previous reactor analyses considered only Compton-like production e+γ→e+χχ̄, which cuts off near mχ~0.5 MeV; the gamma cascades from neutron capture, notably the 3.297 and 4.060 MeV E1 lines of 239U and the 2.223 MeV M1 line of 2H, extend the reach to about half the gamma energy. Matching the predicted electron-recoil rate to the measured spectrum of a 500 g germanium detector placed 28 m from a 2.9 GW reactor yields the strongest existing constraints on the millicharge ε in the mass interval 0.7-2 MeV, surpassing beam-dump and other reactor searches. The same machinery gives a solar millicharged flux and suggests that future low-threshold dark matter detectors could probe ε below $10^{-6}$.

What carries the argument

The load-bearing object is the internal pair-production ratio r = σ(n+N→N'+χχ̄)/σ(n+N→N'+γ), computed by multipole expansion of the nuclear matrix element under the recoil-less approximation. For E1 and M1 transitions the differential ratios give the millicharged energy spectrum from each gamma line, and the flux is summed over the 3.297 and 4.060 MeV lines of 239U and the 2.223 MeV line of 2H using neutron-capture yields. On the detection side, the Photo Absorption Ionization model converts the flux into electron-recoil spectra, which are matched to the measured spectrum of the low-threshold germanium experiment.

What would settle it

Measure the pair-production-to-photon ratio for the 3.297 and 4.060 MeV gamma lines of 239U by placing a low-threshold detector near a neutron beam on 238U; if the measured ratio falls several times below the E1 formula, the paper's ε constraints would weaken by roughly the fourth root of that deficit.

Watch

Extended reading notes

Core claim

For a fermion χ with charge εe, any nuclear gamma transition of energy ω can internally convert to a χχ̄ pair, and the pair-production rate relative to photon emission is controlled by the multipolarity of the transition, with the E1 channel dominating near the kinematic endpoint. Using neutron-capture yields simulated for a natural-water reactor and gamma line intensities from nuclear databases, the authors compute the millicharged flux from the 239U and 2H transitions and fold it with the photo-absorption ionization cross section to predict electron recoils in a low-threshold germanium detector. Matching this rate to the measured recoil spectrum gives ε exclusions that are strongest in the 0.7-2 MeV mass range, and the paper also derives a solar flux from positron annihilation and D(p,γ)3He, plus constraints on MeV-mass dark photons decaying to e+e-. The central claim is that reactor gamma cascades, not just photon-electron scattering, are the right production mechanism and substantially widen the mass range that near-reactor experiments can exclude.

Load-bearing premise

The argument rests on assuming that the nucleus emits a real photon and a millicharged pair with the same matrix element, so pair production follows the known gamma line intensities; if the virtual photon is suppressed, every derived limit weakens.

Editorial extensions

If this is right

  • The 0.7-2 MeV mass window for millicharged fermions is now excluded down to ε values that no previous experiment reached, with the limit curve set by reactor gamma cascades rather than beam dumps.
  • Reactor searches no longer lose sensitivity above mχ~0.5 MeV; the available energy of the (n,γ) lines sets a new kinematic ceiling near 2 MeV per particle.
  • Because the ionization cross section grows as 1/T at low recoil energy, detectors with thresholds below the current 300 eV will strengthen the same limits without any new source.
  • The gamma-line source also produces MeV-scale dark photons, giving the first near-reactor constraints on visibly decaying A' in the 1.1-4 MeV range, though these are weaker than existing limits.
  • The solar millicharged flux estimate gives a concrete target for low-threshold dark matter detectors: ε around 10^-6 and below could be probed once propagation through the Sun is modeled better.

Reading between the lines

Editorial extensions of the paper, not claims the author makes directly.

  • Beyond the paper, the same internal-pair-production argument applies to any intense gamma source, such as spallation neutron sources, medical isotope production, or fusion facilities, which could place comparable or better limits at different mass points.
  • Beyond the paper, the two 239U lines at 3.297 and 4.060 MeV should imprint a distinctive two-step structure in the recoil spectrum, so a shape analysis of the existing data could separate a millicharged signal from backgrounds even if the absolute flux is uncertain.
  • Beyond the paper, for mχ below the electron mass, hard reactor gammas convert to e+e- on uranium nuclei and the subsequent positron annihilation to χχ̄ scales as ε² rather than αε², so simulating photon conversion yields could improve sub-MeV limits beyond the range the paper stresses.
  • Beyond the paper, if future low-threshold detectors see a solar millicharged signal, disentangling it from neutrino coherent scattering will require independent knowledge of the solar millicharged energy distribution, which depends on thermalization in the Sun.
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Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, and a circularity audit.

Referee Report

2 major / 6 minor

Summary. This paper argues that nuclear γ-ray cascades from neutron capture in reactors — specifically the 3.297 and 4.060 MeV E1 lines of 239U from 238U(n,γ) and the 2.223 MeV M1 line of 2H from p(n,γ) — are an overlooked and powerful source of millicharged particles, since every nuclear γ transition with ω > 2mχ can internally convert into a χχ̄ pair. Using the multipole-expansion formalism of Pitrou and Pospelov, the authors derive the differential pair-production ratios for E1 and M1 in Sec. 2 (Eqs. 3–8), with E2/E3 generalized in Appendix A, construct the MCP flux at the TEXONO detector (Eqs. 9–10), convolve it with the PAI atomic-ionization cross section (Eq. 11), and match the predicted electron-recoil spectrum to the TEXONO measurement to set upper limits on the millicharge ε. The resulting limits are claimed to be the strongest laboratory constraints in the 0.7–2 MeV mass range, surpassing SLAC, CONNIE, and Atucha-II. Sections 4 and 5 extend the method to geo-radioactivity and solar fluxes and to MeV-scale dark photons, with candid statements about which of those results are not competitive.

Significance. The central significance is that the new production channel hardens the reactor MCP spectrum and extends the reachable mass range from ~0.5 MeV to ω/2 ≈ 2 MeV; if correct, the resulting 0.7–2 MeV limit would be the strongest laboratory exclusion to date. The paper's strengths are analytic: the multipole ratios are a parameter-free QED input, the appendix supplies the E2/E3 generalization, and the ε ∝ (rate)^{1/4} scaling makes the limits fairly robust to input-normalization errors. I independently checked the two E1 derivations and found them consistent: with A = EχEχ̄ + mχ², B = |pχ||pχ̄|, A²−B² = mχ²ω², I0 = 4B, I−1 = ln[(A+B)/(A−B)] and I−2 = B/(mχ²ω²), Eq. (45) gives (αε²/4πω³)[8B + 2(Eχ²+Eχ̄²) ln(...)], which equals Eq. (6) after prefactor conversion; the 12B discrepancy claimed in an internal stress-test is a prefactor-conversion artifact. The on/off-shell matrix-element assumption is the standard internal-conversion long-wavelength approximation and is safe here (kR ≲ 10⁻²).

major comments (2)
  1. [§3, Eq. (12), Fig. 3b] The limit-setting procedure is described only qualitatively: the limiting ε is found when the counting rate (12) is 'matched to the experimental rate in [30]', and the Fig. 3a caption adds that the predicted rate must not exceed the 2σ region of the TEXONO analysis. Because the central claim — the strongest constraints in the 0.7–2 MeV range — rests on the curve in Fig. 3b, and because a factor-of-2 shift in ε is comparable to the displayed margin over the other constraints at some masses, the procedure must be specified precisely for reproducibility: (i) the recoil-energy range and binning used; (ii) whether the curve is the envelope of per-bin 2σ upper limits or the result of a binned likelihood/χ² statistic; (iii) how the 2σ band of the background-subtracted TEXONO spectrum is defined (statistical only, or including systematic uncertainties); and (iv) how the mχ values are sampled. Please also state how the curve shifts if the comparison is done at the 1σ or 90% level.
  2. [§2, Eq. (9)] The input data that set the flux normalization are documented only loosely. The neutron-capture yields Y_n are taken from a 2005 simulation of the TEXONO reactor environment, justified only by a footnote, and the numerical values of Y_n(H), Y_n(238U), and the ENSDF line intensities I_γ for the three adopted transitions are not stated in the text. Although ε ∝ (Y_n)^{−1/4}, a factor-of-2–3 error in a yield moves ε by 20–30%, which is non-negligible relative to the claimed exclusion margins at some masses. Please provide a table of the adopted inputs, clarify the role of the symbol 'P_Yn' in Eq. (9), and either estimate the resulting uncertainty on ε or demonstrate that bracketed variations of the yields leave the limit curve essentially unchanged.
minor comments (6)
  1. [§4] Typo: '214Bo' should be '214Bi'; the 238U-chain gamma line above 1 MeV used in the text is from 214Bi.
  2. [§4, Eqs. (21)-(22)] There is a factor-of-2 inconsistency in the solar flux normalization: Eq. (22) at r = mχ/me → 0 gives ε²/2, while the text states the probability is 'just ε²' and writes the total flux as 2ε² times the pp neutrino flux, which fixes the prefactor of Eq. (21). Please clarify whether the probability counts pairs or individual MCPs and correct the prefactor if needed.
  3. [§4, Eq. (14)] Please double-check the prefactor 2/6 in Eq. (14): the 232Th chain has four beta decays (hence four geoneutrinos) per chain, and the 2.615 MeV line is emitted in the 36% 208Tl sub-branch, so one 208Pb de-excitation per six neutrino emissions appears to overestimate the geo-MCP flux by roughly a factor of two.
  4. [§3, Fig. 3b] The comparison plot shows only laboratory constraints. A sentence locating the new limits with respect to astrophysical bounds (for example, SN1987A energy-loss limits, which apply in a different, trapping-dependent ε window) would make the 'strongest constraint' claim unambiguous.
  5. [§3] Please justify the restriction to three transitions in the MCP flux sum; in particular, the 7.6 MeV 56Fe(n,γ) lines used in Sec. 5 are not included in the MCP flux, and the paper should state whether their contribution for the TEXONO geometry was checked.
  6. [§6] In the Discussion, 'loose sight' should read 'lose sight'.

Circularity Check

0 steps flagged · score 0.0 of 10

No significant circularity: the millicharge limits are outputs of a QED-based flux calculation normalized to external nuclear data; self-citations are supporting formalism only.

full rationale

The derivation chain is self-contained in the required sense. The MCP flux is constructed as the product of externally tabulated nuclear data (ENSDF gamma intensities and the TEXONO neutron-yield simulation of Ref. [38]) with a QED pair-production-to-photon ratio r (Eqs. (2)-(7), with further multipoles in Appendix A), evaluated under the explicitly stated off-shell matrix-element assumption. No quantity entering this flux is fitted to the TEXONO electron-recoil spectrum that is later used to set the limit; the limiting value of epsilon is obtained by equating the predicted differential rate (Eq. (12)) to the published TEXONO spectrum, so epsilon is the output of the comparison, not an input. The same holds for the solar flux, which is normalized to the standard solar pp-neutrino flux and an analytic annihilation ratio (Eqs. (21)-(22)). The self-citations to Ref. [36] (pair-emission formalism) and Ref. [18] (free-electron-approximation cross section) are supporting, parameter-free QED and empirical results whose assumptions do not include the target millicharge bounds; under the stated rules these count as independent evidence rather than load-bearing circularity. The alleged algebraic mismatch between Eq. (6) and Eq. (45) would be an internal-consistency or correctness issue if confirmed, not a demonstration that any result is assumed as its own input.

Assumptions & free parameters 1 free parameters · 6 assumptions · 0 invented entities

The central claim rests on standard QED for a fermionic millicharge, the equivalence of on-shell and off-shell nuclear matrix elements, the recoil-less approximation, external nuclear data (ENSDF, TEXONO neutron capture simulation), and the PAI model for detection. The only hand-chosen numeric input is the 1% iron-capture fraction used for the subdominant KamLAND dark photon estimate. No new entities are introduced beyond the pre-existing MCP and dark photon hypotheses.

free parameters (1)
  • Iron neutron-capture fraction for KamLAND estimate = 1% (0.01)
    Rough hand estimate for the fraction of reactor neutrons captured on iron in reactor walls, used only for the subdominant KamLAND dark photon sensitivity estimate (Eq. 27, Sec. 5), not for the central MCP limits.
assumptions (6)
  • domain assumption A fermionic millicharged particle χ with charge εe << e exists and interacts only electromagnetically (plus assumed dark sector couplings).
    The target model stated in the introduction; standard in the MCP literature, not introduced by this paper.
  • domain assumption Nuclear matrix elements for photon emission are unchanged when the photon is off-shell, so the pair-production ratio is obtained by kinematic factors (long-wavelength multipole expansion).
    Stated as the key assumption in Sec. 2 before Eq. (3); motivated by nuclear size small compared to MeV photon wavelengths.
  • domain assumption Recoil of the final nucleus can be neglected (leading-order 1/M expansion).
    Invoked in Sec. 2 for Eqs. (3)-(8); for p(n,γ)d the recoil is about 2.6 keV, small compared with ω.
  • domain assumption Neutron-capture yields per fission from the TEXONO simulation [38] are representative for the Kuo-Sheng and similar natural-water reactors.
    Footnote 4 in Sec. 2 acknowledges the yields are from the TEXONO environment but treats them as a plausible generic estimate.
  • domain assumption The PAI (photo absorption ionization) model describes the MCP-atom ionization cross section at the relevant energy transfers.
    Adopted in Sec. 3, Eq. (11); comparison with FEA and EPA is shown in Fig. 2, but no validation against MCP-specific measurements exists.
  • domain assumption Solar MCPs produced in the core emerge as a steady-state flux whose total rate equals the production rate, with thermalization only affecting their energy spectrum.
    Assumed in Sec. 4 around Eq. (21); the paper flags that a better slow-down calculation is needed and that for ε above about 10^-6 particles thermalize.

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Pith. "Pith review of Constraints on millicharged particles from nuclear gamma-decays." pith.science (2026). https://pith.science/paper/FSCQHGM4

@misc{pith2026250717955,
  author       = {Pith},
  title        = {Pith review of: Constraints on millicharged particles from nuclear gamma-decays},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/FSCQHGM4}},
  note         = {Machine review of arXiv:2507.17955}
}
abstract

We consider nuclear gamma decays and $\gamma$-emitting reactions that can be an efficient source of hypothetical millicharged particles ($\chi$). In particular, we revisit the production of millicharged particles in nuclear reactor environment, pointing out that $\gamma$ cascades from $^{239}$U is an overlooked yet a powerful source of $\chi\bar\chi$ pairs. This leads to an increased flux compared to previous studies. We then apply new estimates of the flux to derive novel limits on the value of millicharge, $\varepsilon = Q_\chi/e$, from the electron recoil searched for in a variety of experiments placed in proximity to the reactor cores. The derived limits on $\varepsilon$ are the strongest in the interval of masses $\sim 0.7-2$ MeV. We also derive the MCP flux from the Sun and point out potential sensitivity of the low-threshold dark matter search experiments.

Figures

Figures reproduced from arXiv: 2507.17955 by the authors.

Figure 1
Figure 1. Differential ratios for E1 (1a) and M1(1b) transitions with ε = 1 for different values of mχ/ω. Quantities with a bar on top are normalized by ω for universality: ¯mχ = mχ/ω, E¯χ = Eχ/ω. Notice that when mχ ≪ ω/2, the E1 and M1 yields of MCP are similar, while for heavier MCP (relative to ω/2), the M1 yields are more suppressed, as expected. where the factor of 2 comes from counting both χ and ¯χ, and D is the dista… view at source ↗
Figure 2
Figure 2. Atomic ionization differential cross sections for germanium crystal under Photo Absorption Ionization model [PITH_FULL_IMAGE:figures/full_fig_p006_2.png] view at source ↗
Figure 3
Figure 3. (3a): An example of the comparison between the analysis from TEXONO (blue dots) and this work (purple line) with mχ = 1MeV, ε = 2.7 × 10−5 . The constraint on the millicharge is obtained by requiring that the differential counting rate does not exceed the 2σ region of the TEXONO analysis. Near T = 1.4 keV, the energy transfer becomes enough to ionize electrons in the L shell of Ge (as documented in [42]) and thus pr… view at source ↗
Figures from the paper (2 more)
Figure 4
Figure 4. Figure 4: Relative production of solar MCPs due to different reactions. For [PITH_FULL_IMAGE:figures/full_fig_p010_4.png]
Figure 5
Figure 5. Figure 5: Excluded region for dark photon from this work and the SLAC E137 experiment [ [PITH_FULL_IMAGE:figures/full_fig_p011_5.png]

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Forward citations

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Reference graph

Works this paper leans on

72 extracted references · 18 canonical work pages · cited by 3 Pith papers

  1. [30]

    Constraints on millicharged particles with low threshold germanium detectors at Kuo-Sheng Reactor Neutrino Laboratory,

    TEXONO Collaboration, L. Singh et al., “Constraints on millicharged particles with low threshold germanium detectors at Kuo-Sheng Reactor Neutrino Laboratory,” Phys. Rev. D99 no. 3, (2019) 032009, arXiv:1808.02719 [hep-ph]

  2. [1]

    The Search for Feebly Interacting Particles,

    G. Lanfranchi, M. Pospelov, and P. Schuster, “The Search for Feebly Interacting Particles,” Ann. Rev. Nucl. Part. Sci.71 (2021) 279–313, arXiv:2011.02157 [hep-ph]

  3. [2]

    Physics Beyond Colliders at CERN: Beyond the Standard Model Working Group Report,

    J. Beacham et al., “Physics Beyond Colliders at CERN: Beyond the Standard Model Working Group Report,” J. Phys. G47 no. 1, (2020) 010501, arXiv:1901.09966 [hep-ex]

  4. [3]

    Two U(1)’s and Epsilon Charge Shifts,

    B. Holdom, “Two U(1)’s and Epsilon Charge Shifts,” Phys. Lett. B166 (1986) 196–198

  5. [4]

    Updated bounds on millicharged particles,

    S. Davidson, S. Hannestad, and G. Raffelt, “Updated bounds on millicharged particles,” JHEP 05 (2000) 003, arXiv:hep-ph/0001179

  6. [5]

    Dark Radiation constraints on minicharged particles in models with a hidden photon,

    H. Vogel and J. Redondo, “Dark Radiation constraints on minicharged particles in models with a hidden photon,” JCAP 02 (2014) 029, arXiv:1311.2600 [hep-ph]. 15

  7. [6]

    Constraints on millicharged particles from Planck data,

    A. D. Dolgov, S. L. Dubovsky, G. I. Rubtsov, and I. I. Tkachev, “Constraints on millicharged particles from Planck data,” Phys. Rev. D88 no. 11, (2013) 117701, arXiv:1310.2376 [hep-ph]

  8. [7]

    Supernova 1987A Constraints on Sub-GeV Dark Sectors, Millicharged Particles, the QCD Axion, and an Axion-like Particle,

    J. H. Chang, R. Essig, and S. D. McDermott, “Supernova 1987A Constraints on Sub-GeV Dark Sectors, Millicharged Particles, the QCD Axion, and an Axion-like Particle,” JHEP 09 (2018) 051, arXiv:1803.00993 [hep-ph]

Show all 72 references
  1. [8]

    CHAMP Cosmic Rays,

    D. Dunsky, L. J. Hall, and K. Harigaya, “CHAMP Cosmic Rays,” JCAP 07 (2019) 015, arXiv:1812.11116 [astro-ph.HE]

  2. [9]

    Self-Interacting Dark Sectors in Supernovae Can Behave as a Relativistic Fluid,

    D. F. G. Fiorillo and E. Vitagliano, “Self-Interacting Dark Sectors in Supernovae Can Behave as a Relativistic Fluid,” Phys. Rev. Lett.133 no. 25, (2024) 251004, arXiv:2404.07714 [hep-ph]

  3. [10]

    Earth-bound millicharge relics,

    M. Pospelov and H. Ramani, “Earth-bound millicharge relics,” Phys. Rev. D103 no. 11, (2021) 115031, arXiv:2012.03957 [hep-ph]

  4. [11]

    Terrestrial density of strongly-coupled relics,

    A. Berlin, H. Liu, M. Pospelov, and H. Ramani, “Terrestrial density of strongly-coupled relics,” Phys. Rev. D 109 no. 7, (2024) 075027, arXiv:2302.06619 [hep-ph]

  5. [12]

    An absorption profile centred at 78 megahertz in the sky-averaged spectrum,

    J. D. Bowman, A. E. E. Rogers, R. A. Monsalve, T. J. Mozdzen, and N. Mahesh, “An absorption profile centred at 78 megahertz in the sky-averaged spectrum,” Nature 555 no. 7694, (2018) 67–70, arXiv:1810.05912 [astro-ph.CO]

  6. [13]

    Strong constraints on light dark matter interpretation of the EDGES signal,

    R. Barkana, N. J. Outmezguine, D. Redigolo, and T. Volansky, “Strong constraints on light dark matter interpretation of the EDGES signal,” Phys. Rev. D98 no. 10, (2018) 103005, arXiv:1803.03091 [hep-ph]

  7. [14]

    Tighter limits on dark matter explanations of the anomalous EDGES 21 cm signal,

    E. D. Kovetz, V. Poulin, V. Gluscevic, K. K. Boddy, R. Barkana, and M. Kamionkowski, “Tighter limits on dark matter explanations of the anomalous EDGES 21 cm signal,” Phys. Rev. D98 no. 10, (2018) 103529, arXiv:1807.11482 [astro-ph.CO]

  8. [15]

    Reviving Millicharged Dark Matter for 21-cm Cosmology,

    H. Liu, N. J. Outmezguine, D. Redigolo, and T. Volansky, “Reviving Millicharged Dark Matter for 21-cm Cosmology,” Phys. Rev. D100 no. 12, (2019) 123011, arXiv:1908.06986 [hep-ph]

  9. [16]

    Dark Matter, Millicharges, Axion and Scalar Particles, Gauge Bosons, and Other New Physics with LDMX,

    A. Berlin, N. Blinov, G. Krnjaic, P. Schuster, and N. Toro, “Dark Matter, Millicharges, Axion and Scalar Particles, Gauge Bosons, and Other New Physics with LDMX,” Phys. Rev. D99 no. 7, (2019) 075001, arXiv:1807.01730 [hep-ph]

  10. [17]

    Search for millicharged particles at SLAC,

    A. A. Prinz et al., “Search for millicharged particles at SLAC,” Phys. Rev. Lett.81 (1998) 1175–1178, arXiv:hep-ex/9804008

  11. [18]

    Millicharged particles in neutrino experiments,

    G. Magill, R. Plestid, M. Pospelov, and Y.-D. Tsai, “Millicharged particles in neutrino experiments,” Phys. Rev. Lett.122 no. 7, (2019) 071801, arXiv:1806.03310 [hep-ph]

  12. [19]

    Proton fixed-target scintillation experiment to search for millicharged dark matter,

    K. J. Kelly and Y.-D. Tsai, “Proton fixed-target scintillation experiment to search for millicharged dark matter,” Phys. Rev. D100 no. 1, (2019) 015043, arXiv:1812.03998 [hep-ph]

  13. [20]

    Millicharged Particles in Liquid Argon Neutrino Experiments,

    R. Harnik, Z. Liu, and O. Palamara, “Millicharged Particles in Liquid Argon Neutrino Experiments,” JHEP 07 (2019) 170, arXiv:1902.03246 [hep-ph]

  14. [21]

    Improved Limits on Millicharged Particles Using the ArgoNeuT Experiment at Fermilab,

    ArgoNeuT Collaboration, R. Acciarri et al., “Improved Limits on Millicharged Particles Using the ArgoNeuT Experiment at Fermilab,” Phys. Rev. Lett.124 no. 13, (2020) 131801, arXiv:1911.07996 [hep-ex]

  15. [22]

    FLArE up dark sectors with EM form factors at the LHC forward physics facility,

    F. Kling, J.-L. Kuo, S. Trojanowski, and Y.-D. Tsai, “FLArE up dark sectors with EM form factors at the LHC forward physics facility,” Nucl. Phys. B987 (2023) 116103, arXiv:2205.09137 [hep-ph]

  16. [23]

    Search by the SENSEI Experiment for Millicharged Particles Produced in the NuMI Beam,

    SENSEI Collaboration, L. Barak et al., “Search by the SENSEI Experiment for Millicharged Particles Produced in the NuMI Beam,” Phys. Rev. Lett.133 no. 7, (2024) 071801, arXiv:2305.04964 [hep-ex]

  17. [24]

    LANSCE-mQ: Dedicated search for milli/fractionally charged particles at LANL,

    Y.-D. Tsai, I. Hwang, R. Schmitz, M. Citron, K. Gunthoti, J. Steenis, H. Jeong, H. Moon, J. H. Yoo, and M. X. Liu, “LANSCE-mQ: Dedicated search for milli/fractionally charged particles at LANL,” arXiv:2407.07142 [hep-ph]. 16

  18. [25]

    Probing millicharged particles at an electron beam dump with ultralow-threshold sensors,

    R. Essig, P. Li, Z. Liu, M. McDuffie, R. Plestid, and H. Xu, “Probing millicharged particles at an electron beam dump with ultralow-threshold sensors,” JHEP 04 (2025) 057, arXiv:2412.09652 [hep-ph]

  19. [26]

    New Constraints on Millicharged Particles from Cosmic-ray Production,

    R. Plestid, V. Takhistov, Y.-D. Tsai, T. Bringmann, A. Kusenko, and M. Pospelov, “New Constraints on Millicharged Particles from Cosmic-ray Production,” Phys. Rev. D102 (2020) 115032, arXiv:2002.11732 [hep-ph]

  20. [27]

    Millicharged cosmic rays and low recoil detectors,

    R. Harnik, R. Plestid, M. Pospelov, and H. Ramani, “Millicharged cosmic rays and low recoil detectors,” Phys. Rev. D103 no. 7, (2021) 075029, arXiv:2010.11190 [hep-ph]

  21. [28]

    Millicharged particles from proton bremsstrahlung in the atmosphere,

    M. Du, R. Fang, and Z. Liu, “Millicharged particles from proton bremsstrahlung in the atmosphere,” JHEP 08 (2024) 174, arXiv:2211.11469 [hep-ph]

  22. [29]

    Searching for heavy millicharged particles from the atmosphere,

    H. Wu, E. Hardy, and N. Song, “Searching for heavy millicharged particles from the atmosphere,” Phys. Rev. D110 no. 11, (2024) 115037, arXiv:2406.01668 [hep-ph]

  23. [31]

    Search for reactor-produced millicharged particles with Skipper-CCDs at the CONNIE and Atucha-II experiments,

    CONNIE, Atucha-IICollaboration, A. A. Aguilar-Arevalo et al., “Search for reactor-produced millicharged particles with Skipper-CCDs at the CONNIE and Atucha-II experiments,” arXiv:2405.16316 [hep-ex]

  24. [32]

    Search of axions at the Kuo-Sheng nuclear power station with a high-purity germanium detector,

    TEXONO Collaboration, H. M. Chang et al., “Search of axions at the Kuo-Sheng nuclear power station with a high-purity germanium detector,” Phys. Rev. D75 (2007) 052004, arXiv:hep-ex/0609001

  25. [33]

    New Directions for Axion Searches via Scattering at Reactor Neutrino Experiments,

    J. B. Dent, B. Dutta, D. Kim, S. Liao, R. Mahapatra, K. Sinha, and A. Thompson, “New Directions for Axion Searches via Scattering at Reactor Neutrino Experiments,” Phys. Rev. Lett.124 no. 21, (2020) 211804, arXiv:1912.05733 [hep-ph]

  26. [34]

    Axionlike particles searches in reactor experiments,

    D. Aristizabal Sierra, V. De Romeri, L. J. Flores, and D. K. Papoulias, “Axionlike particles searches in reactor experiments,” JHEP 03 (2021) 294, arXiv:2010.15712 [hep-ph]

  27. [35]

    Internal pair production associated with the emission of high-energy gamma rays,

    N. M. Kroll and W. Wada, “Internal pair production associated with the emission of high-energy gamma rays,” Phys. Rev.98 (1955) 1355–1359

  28. [36]

    QED corrections to Big-Bang nucleosynthesis reaction rates,

    C. Pitrou and M. Pospelov, “QED corrections to Big-Bang nucleosynthesis reaction rates,” Phys. Rev. C 102 no. 1, (2020) 015803, arXiv:1904.07795 [astro-ph.CO]

  29. [37]

    Talou and R

    P. Talou and R. Vogt, Nuclear Fission: Theories, Experiments and Applications. Springer Nature, 2023

  30. [38]

    Production of electron neutrinos at nuclear power reactors and the prospects for neutrino physics,

    TEXONO Collaboration, B. Xin et al., “Production of electron neutrinos at nuclear power reactors and the prospects for neutrino physics,” Phys. Rev. D72 (2005) 012006, arXiv:hep-ex/0502001

  31. [39]

    Version available at http://www.nndc.bnl.gov/ensarchivals/

    From ENSDF database as of December 14, 2024. Version available at http://www.nndc.bnl.gov/ensarchivals/

  32. [40]

    First search for atmospheric millicharged particles with the LUX-ZEPLIN experiment,

    LZ Collaboration, J. Aalbers et al., “First search for atmospheric millicharged particles with the LUX-ZEPLIN experiment,” arXiv:2412.04854 [hep-ex]

  33. [41]

    Relativistic Charged Particle Identification by Energy Loss,

    W. W. M. Allison and J. H. Cobb, “Relativistic Charged Particle Identification by Energy Loss,” Ann. Rev. Nucl. Part. Sci.30 (1980) 253–298

  34. [42]

    X-Ray Interactions: Photoabsorption, Scattering, Transmission, and Reflection at E = 50-30,000 eV, Z = 1-92,

    B. L. Henke, E. M. Gullikson, and J. C. Davis, “X-Ray Interactions: Photoabsorption, Scattering, Transmission, and Reflection at E = 50-30,000 eV, Z = 1-92,” Atom. Data Nucl. Data Tabl.54 no. 2, (1993) 181–342

  35. [43]

    Final results on the neutrino magnetic moment from the MUNU experiment,

    MUNU Collaboration, Z. Daraktchieva et al., “Final results on the neutrino magnetic moment from the MUNU experiment,” Phys. Lett. B615 (2005) 153–159, arXiv:hep-ex/0502037

  36. [44]

    Measurement of Nu(e)-bar -Electron Scattering Cross-Section with a CsI(Tl) Scintillating Crystal Array at the Kuo-Sheng Nuclear Power Reactor,

    TEXONO Collaboration, M. Deniz et al., “Measurement of Nu(e)-bar -Electron Scattering Cross-Section with a CsI(Tl) Scintillating Crystal Array at the Kuo-Sheng Nuclear Power Reactor,” Phys. Rev. D81 (2010) 072001, arXiv:0911.1597 [hep-ex]. 17

  37. [45]

    First observation of reactor antineutrinos by coherent scattering,

    N. Ackermann et al., “First observation of reactor antineutrinos by coherent scattering,” arXiv:2501.05206 [hep-ex]

  38. [46]

    First Simultaneous Precision Spectroscopy of pp, 7Be, and pep Solar Neutrinos with Borexino Phase-II,

    Borexino Collaboration, M. Agostini et al., “First Simultaneous Precision Spectroscopy of pp, 7Be, and pep Solar Neutrinos with Borexino Phase-II,” Phys. Rev. D100 no. 8, (2019) 082004, arXiv:1707.09279 [hep-ex]

  39. [47]

    Search for New Physics in Electronic Recoil Data from XENONnT,

    XENON Collaboration, E. Aprile et al., “Search for New Physics in Electronic Recoil Data from XENONnT,” Phys. Rev. Lett.129 no. 16, (2022) 161805, arXiv:2207.11330 [hep-ex]

  40. [48]

    Search for new physics in low-energy electron recoils from the first LZ exposure,

    LZ Collaboration, J. Aalbers et al., “Search for new physics in low-energy electron recoils from the first LZ exposure,” Phys. Rev. D108 no. 7, (2023) 072006, arXiv:2307.15753 [hep-ex]

  41. [49]

    Exploring New Physics with PandaX-4T Low Energy Electronic Recoil Data,

    PandaX Collaboration, X. Zeng et al., “Exploring New Physics with PandaX-4T Low Energy Electronic Recoil Data,” Phys. Rev. Lett.134 no. 4, (2025) 041001, arXiv:2408.07641 [hep-ex]

  42. [50]

    A reference earth model for the heat-producing elements and associated geoneutrino flux,

    Y. Huang, V. Chubakov, F. Mantovani, R. L. Rudnick, and W. F. McDonough, “A reference earth model for the heat-producing elements and associated geoneutrino flux,” Geochemistry, Geophysics, Geosystems 14 no. 6, (2013) 2003–2029

  43. [51]

    Spectroscopy of geoneutrinos from 2056 days of Borexino data,

    Borexino Collaboration, M. Agostini et al., “Spectroscopy of geoneutrinos from 2056 days of Borexino data,” Phys. Rev. D92 no. 3, (2015) 031101, arXiv:1506.04610 [hep-ex]

  44. [52]

    Review of particle physics,

    Particle Data GroupCollaboration, S. Navas et al., “Review of particle physics,” Phys. Rev. D110 no. 3, (2024) 030001

  45. [53]

    Energy levels of light nuclei A = 13-15,

    F. Ajzenberg-Selove, “Energy levels of light nuclei A = 13-15,” Nucl. Phys. A523 (1991) 1–196

  46. [54]

    Implication of the proton-deuteron radiative capture for Big Bang Nucleosynthesis,

    L. E. Marcucci, G. Mangano, A. Kievsky, and M. Viviani, “Implication of the proton-deuteron radiative capture for Big Bang Nucleosynthesis,” Phys. Rev. Lett.116 no. 10, (2016) 102501, arXiv:1510.07877 [nucl-th]. [Erratum: Phys.Rev.Lett. 117, 049901 (2016)]

  47. [55]

    Terrestrial detection of hidden vectors produced by solar nuclear reactions,

    F. D’Eramo, G. Lucente, N. Nath, and S. Yun, “Terrestrial detection of hidden vectors produced by solar nuclear reactions,” JHEP 12 (2023) 091, arXiv:2305.14420 [hep-ph]

  48. [56]

    Searching for millicharged particles with 1 kg of Skipper-CCDs using the NuMI beam at Fermilab,

    Oscura Collaboration, S. Perez et al., “Searching for millicharged particles with 1 kg of Skipper-CCDs using the NuMI beam at Fermilab,” JHEP 02 (2024) 072, arXiv:2304.08625 [hep-ex]

  49. [57]

    Probing Benchmark Models of Hidden-Sector Dark Matter with DAMIC-M,

    DAMIC-M Collaboration, K. Aggarwal et al., “Probing Benchmark Models of Hidden-Sector Dark Matter with DAMIC-M,” arXiv:2503.14617 [hep-ex]

  50. [58]

    Experimental search for the neutrino decay neutrino (3) — > j-neutrino + e+ + e- and limits on neutrino mixing,

    C. Hagner, M. Altmann, F. von Feilitzsch, L. Oberauer, Y. Declais, and E. Kajfasz, “Experimental search for the neutrino decay neutrino (3) — > j-neutrino + e+ + e- and limits on neutrino mixing,” Phys. Rev. D 52 (1995) 1343–1352

  51. [59]

    Search for Neutral Metastable Penetrating Particles Produced in the SLAC Beam Dump,

    J. D. Bjorken, S. Ecklund, W. R. Nelson, A. Abashian, C. Church, B. Lu, L. W. Mo, T. A. Nunamaker, and P. Rassmann, “Search for Neutral Metastable Penetrating Particles Produced in the SLAC Beam Dump,” Phys. Rev. D38 (1988) 3375

  52. [60]

    New Limits on Hidden Photons from Past Electron Beam Dumps,

    S. Andreas, C. Niebuhr, and A. Ringwald, “New Limits on Hidden Photons from Past Electron Beam Dumps,” Phys. Rev. D86 (2012) 095019, arXiv:1209.6083 [hep-ph]

  53. [61]

    Dark photon production through positron annihilation in beam-dump experiments,

    L. Marsicano, M. Battaglieri, M. Bondi’, C. D. R. Carvajal, A. Celentano, M. De Napoli, R. De Vita, E. Nardi, M. Raggi, and P. Valente, “Dark photon production through positron annihilation in beam-dump experiments,” Phys. Rev. D98 no. 1, (2018) 015031, arXiv:1802.03794 [hep-ex]

  54. [62]

    Revisiting Supernova 1987A Constraints on Dark Photons,

    J. H. Chang, R. Essig, and S. D. McDermott, “Revisiting Supernova 1987A Constraints on Dark Photons,” JHEP 01 (2017) 107, arXiv:1611.03864 [hep-ph]

  55. [63]

    Measurement of the 8B Solar Neutrino Flux with the KamLAND Liquid Scintillator Detector,

    KamLAND Collaboration, S. Abe et al., “Measurement of the 8B Solar Neutrino Flux with the KamLAND Liquid Scintillator Detector,” Phys. Rev. C84 (2011) 035804, arXiv:1106.0861 [hep-ex]. 18

  56. [64]

    Thermal neutron capture cross section for Fe56(n, γ),

    R. B. Firestone, T. Belgya, M. Krtiˇ cka, F. Beˇ cv´ aˇ r, L. Szentmiklo·si, and I. Tomandl, “Thermal neutron capture cross section for Fe56(n, γ),” Phys. Rev. C95 no. 1, (2017) 014328

  57. [65]

    Axionlike particle production at beam dump experiments with distinct nuclear excitation lines,

    L. Waites, A. Thompson, A. Bungau, J. M. Conrad, B. Dutta, W.-C. Huang, D. Kim, M. Shaevitz, and J. Spitz, “Axionlike particle production at beam dump experiments with distinct nuclear excitation lines,” Phys. Rev. D107 no. 9, (2023) 095010, arXiv:2207.13659 [hep-ph]

  58. [66]

    Neutrino Physics with JUNO,

    JUNO Collaboration, F. An et al., “Neutrino Physics with JUNO,” J. Phys. G43 no. 3, (2016) 030401, arXiv:1507.05613 [physics.ins-det]

  59. [67]

    Bosonic super-WIMPs as keV-scale dark matter,

    M. Pospelov, A. Ritz, and M. B. Voloshin, “Bosonic super-WIMPs as keV-scale dark matter,” Phys. Rev. D 78 (2008) 115012, arXiv:0807.3279 [hep-ph]

  60. [68]

    Dark Photon Decay Beyond The Euler-Heisenberg Limit,

    S. D. McDermott, H. H. Patel, and H. Ramani, “Dark Photon Decay Beyond The Euler-Heisenberg Limit,” Phys. Rev. D97 no. 7, (2018) 073005, arXiv:1705.00619 [hep-ph]

  61. [69]

    Light scalars and dark photons in Borexino and LSND experiments,

    M. Pospelov and Y.-D. Tsai, “Light scalars and dark photons in Borexino and LSND experiments,” Phys. Lett. B785 (2018) 288–295, arXiv:1706.00424 [hep-ph]

  62. [70]

    Axionlike Particles at Future Neutrino Experiments: Closing the Cosmological Triangle,

    V. Brdar, B. Dutta, W. Jang, D. Kim, I. M. Shoemaker, Z. Tabrizi, A. Thompson, and J. Yu, “Axionlike Particles at Future Neutrino Experiments: Closing the Cosmological Triangle,” Phys. Rev. Lett.126 no. 20, (2021) 201801, arXiv:2011.07054 [hep-ph]

  63. [71]

    New Constraints on Axionlike Particles with the NEON Detector at a Nuclear Reactor,

    NEON Collaboration, B. J. Park et al., “New Constraints on Axionlike Particles with the NEON Detector at a Nuclear Reactor,” Phys. Rev. Lett.134 no. 20, (2025) 201002, arXiv:2406.06117 [hep-ex]

  64. [72]

    Constraints on hidden photons produced in nuclear reactors,

    M. Danilov, S. Demidov, and D. Gorbunov, “Constraints on hidden photons produced in nuclear reactors,” Phys. Rev. Lett.122 no. 4, (2019) 041801, arXiv:1804.10777 [hep-ph]. 19

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Reviewed August 6, 2026 · model on record in the stance chip above.