Gravitational Positivity Bounds on Higgs-Portal Dark Matter
Pith reviewed 2026-05-22 18:46 UTC · model grok-4.3
The pith
Gravitational positivity bounds require new physics below 10^10 GeV for light Higgs-portal dark matter or high masses for GUT-scale cutoffs.
A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.
Core claim
Gravitational positivity bounds on the Higgs-portal scalar dark matter model, derived from forward scattering of dark matter particles, imply that without a dark matter self-coupling new physics must appear below 10^10 GeV if the dark matter mass is below the Higgs mass. With both the portal and self-coupling present, a cutoff at the grand unified theory scale generally requires a dark matter mass of order 10^10 to 10^11 GeV, allowing the observed relic abundance to be reproduced via freeze-in with a Higgs-portal coupling smaller than or equal to 3.5 times 10 to the minus 11 while constraining the reheating temperature to be at most 10^14 GeV.
What carries the argument
Gravitational positivity bounds applied to the forward scattering amplitude of two dark matter scalars in the presence of a massless graviton.
If this is right
- Without a self-coupling, any Higgs-portal dark matter lighter than the Higgs boson forces new physics below 10^10 GeV.
- With the self-coupling, dark matter masses of order 10^10 to 10^11 GeV are needed to reach a grand unified theory scale cutoff.
- Such heavy dark matter reproduces the observed relic density through freeze-in with a portal coupling at most 3.5 times 10 to the minus 11.
- The positivity bounds limit the reheating temperature to no more than 10^14 GeV.
Where Pith is reading between the lines
- Light Higgs-portal models become viable only if additional new physics enters at scales well below the grand unified theory.
- These constraints link ultraviolet gravity requirements directly to the cosmology of dark matter production and reheating.
- Similar positivity analyses could be applied to other scalar portal models to restrict their viable mass and coupling ranges.
Load-bearing premise
The gravitational theory is ultraviolet-completed by a perturbative string theory that justifies applying positivity bounds to the low-energy effective model.
What would settle it
Observation of scalar dark matter with mass below the Higgs mass, negligible self-coupling, and no new physics appearing below 10^10 GeV would contradict the derived bounds.
Figures
read the original abstract
Gravitational positivity bounds are constraints on a renormalizable theory in the presence of a massless graviton, under the assumption that the gravitational theory is ultraviolet-completed by a perturbative string theory. We derive these bounds for the Higgs-portal scalar dark matter model using the forward scattering process $\phi \phi \to \phi \phi$. We find that, in the absence of a dark matter self-coupling, new physics beyond the Higgs-portal dark matter interaction must appear below an energy scale of $10^{10}$ GeV if the dark matter mass is smaller than the Higgs boson mass. We further find that, in the presence of both interactions, achieving a cutoff scale at the grand unified theory scale generally requires a dark matter mass of order $10^{10}$-$10^{11}$ GeV (or above), with larger values favored when the four-point self-coupling plays a significant role. For such heavy Higgs-portal dark matter, the observed relic abundance of dark matter in the Universe can be successfully reproduced via the freeze-in mechanism with a tiny Higgs-portal coupling, $\lambda_{h\phi} \lesssim 3.5 \times 10^{-11}$. The reheating temperature is then constrained to be $T_{\mathrm{reh}} \lesssim 10^{14}$ GeV by the positivity bounds on the dark matter mass.
Editorial analysis
A structured set of objections, weighed in public.
Referee Report
Summary. The paper claims to derive gravitational positivity bounds for the Higgs-portal scalar dark matter model from the forward φφ → φφ scattering amplitude, assuming a perturbative string theory UV completion of gravity. In the absence of a dark matter self-coupling, it concludes that new physics must appear below 10^{10} GeV when the dark matter mass is below the Higgs mass. With the self-coupling included, a GUT-scale cutoff generally requires dark matter masses of order 10^{10}-10^{11} GeV, allowing the observed relic density to be achieved via freeze-in with a small portal coupling λ_{hφ} ≲ 3.5 × 10^{-11}, and constraining the reheating temperature to T_reh ≲ 10^{14} GeV.
Significance. If valid, these results offer a new way to constrain Higgs-portal dark matter using high-energy theoretical consistency conditions from gravity. The link to the freeze-in mechanism and specific numerical scales for the cutoff and reheating temperature provide concrete, testable implications for cosmology and particle physics. The approach highlights how positivity bounds can restrict renormalizable models when gravity is included.
major comments (2)
- [§2] The central claims depend on the assumption that the gravitational theory admits a perturbative string theory completion to justify the positivity bounds on the dimension-4 operators in the Higgs-portal model. While the assumption is stated, the manuscript does not provide an independent verification or discuss the sensitivity of the 10^{10} GeV scale to this choice versus weaker conditions like causality and unitarity.
- [§3.2] The quantitative bounds, such as the energy scale of 10^{10} GeV and the dark matter mass range of 10^{10}-10^{11} GeV, are presented without visible step-by-step derivation, error analysis, or checks against post-hoc parameter choices in the forward scattering calculation. Explicit expressions for the amplitude and the resulting positivity inequality would allow verification of these scales.
minor comments (2)
- Consider adding a table summarizing the key bounds for different cases (with/without self-coupling) for clarity.
- [Abstract] The abstract mentions 'generally requires' for the mass range; a more precise statement on the conditions would improve readability.
Simulated Author's Rebuttal
We thank the referee for their careful reading of the manuscript and for the constructive comments, which help clarify the presentation and assumptions. We address each major comment below and outline the revisions we will make.
read point-by-point responses
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Referee: [§2] The central claims depend on the assumption that the gravitational theory admits a perturbative string theory completion to justify the positivity bounds on the dimension-4 operators in the Higgs-portal model. While the assumption is stated, the manuscript does not provide an independent verification or discuss the sensitivity of the 10^{10} GeV scale to this choice versus weaker conditions like causality and unitarity.
Authors: The gravitational positivity bounds applied here follow the standard framework in the literature, which requires a perturbative string theory UV completion to constrain the dimension-4 operators via the forward scattering amplitude. An independent verification of such a completion for the specific Higgs-portal model would necessitate a full string-theoretic construction, which is outside the scope of this phenomenological study. We agree that a discussion of the sensitivity to weaker assumptions (such as causality and unitarity alone) would be valuable, as the bounds could relax under those conditions. We will add a dedicated paragraph in the introduction and/or conclusions to explicitly state the assumption, reference the relevant literature, and comment on the potential impact of alternative UV assumptions on the derived scale of 10^{10} GeV. revision: partial
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Referee: [§3.2] The quantitative bounds, such as the energy scale of 10^{10} GeV and the dark matter mass range of 10^{10}-10^{11} GeV, are presented without visible step-by-step derivation, error analysis, or checks against post-hoc parameter choices in the forward scattering calculation. Explicit expressions for the amplitude and the resulting positivity inequality would allow verification of these scales.
Authors: We apologize if the derivation steps were not sufficiently transparent. The bounds originate from the forward limit of the φφ → φφ amplitude in the effective theory, where the gravitational contribution and the portal/self-coupling terms are included. The positivity condition requires the coefficient of s² in the low-energy expansion to be non-negative, yielding the quoted scales after imposing the cutoff. We will revise Section 3.2 (and add an appendix if needed) to include the explicit analytic expression for the amplitude, the step-by-step derivation of the positivity inequality, and a clear mapping from the inequality to the numerical values of 10^{10} GeV and 10^{10}–10^{11} GeV for the dark matter mass. As these are theoretical consistency bounds rather than fits to data, a statistical error analysis does not apply; however, we will explicitly verify the results for representative parameter choices to confirm robustness. revision: yes
- Independent verification of a perturbative string theory UV completion for the Higgs-portal model, which lies beyond the scope of this work.
Circularity Check
Minor external assumption on string UV completion; derivation applies bounds independently via forward scattering
full rationale
The paper states the assumption of perturbative string theory UV completion explicitly to justify gravitational positivity bounds on the renormalizable EFT. It then computes the constraints for the Higgs-portal model by analyzing the forward φφ→φφ amplitude, yielding the reported scales (10^10 GeV etc.) and relic abundance statements. No quoted step reduces these outputs to fitted parameters from the same data, self-definitional loops, or a load-bearing self-citation chain that forces the result by construction. The forward-scattering calculation supplies independent content once the (external) assumption is granted. This qualifies as low circularity per the guidelines.
Axiom & Free-Parameter Ledger
axioms (1)
- domain assumption The gravitational theory is ultraviolet-completed by a perturbative string theory
Lean theorems connected to this paper
-
IndisputableMonolith/Foundation/RealityFromDistinction.leanreality_from_one_distinction unclear?
unclearRelation between the paper passage and the cited Recognition theorem.
Gravitational positivity bounds are constraints on a renormalizable theory in the presence of a massless graviton, under the assumption that the gravitational theory is ultraviolet-completed by a perturbative string theory. ... Λ ≲ 10^10 GeV (Eq. 29)
-
IndisputableMonolith/Cost/FunctionalEquation.leanwashburn_uniqueness_aczel unclear?
unclearRelation between the paper passage and the cited Recognition theorem.
B_non-grav = λ_hϕ² + λ_ϕ² / (16 π² Λ⁴) (Eq. 22); gravitational contribution from t-channel graviton loops (Eq. 23)
What do these tags mean?
- matches
- The paper's claim is directly supported by a theorem in the formal canon.
- supports
- The theorem supports part of the paper's argument, but the paper may add assumptions or extra steps.
- extends
- The paper goes beyond the formal theorem; the theorem is a base layer rather than the whole result.
- uses
- The paper appears to rely on the theorem as machinery.
- contradicts
- The paper's claim conflicts with a theorem or certificate in the canon.
- unclear
- Pith found a possible connection, but the passage is too broad, indirect, or ambiguous to say the theorem truly supports the claim.
Reference graph
Works this paper leans on
-
[1]
Vanda Silveira and A. Zee. SCALAR PHANTOMS. Phys. Lett. B, 161:136–140, 1985
work page 1985
-
[2]
Gauge singlet scalars as cold dark matter
John McDonald. Gauge singlet scalars as cold dark matter. Phys. Rev. D, 50:3637–3649, 1994
work page 1994
-
[3]
C. P. Burgess, Maxim Pospelov, and Tonnis ter Veldhuis. The Minimal model of non- baryonic dark matter: A Singlet scalar. Nucl. Phys. B, 619:709–728, 2001
work page 2001
-
[4]
Dark Matter through the Higgs portal
Giorgio Arcadi, Abdelhak Djouadi, and Martti Raidal. Dark Matter through the Higgs portal. Phys. Rept., 842:1–180, 2020
work page 2020
-
[5]
Oleg Lebedev. The Higgs portal to cosmology. Prog. Part. Nucl. Phys., 120:103881, 2021
work page 2021
-
[6]
Positivity bounds on Higgs- Portal dark matter
Seong-Sik Kim, Hyun Min Lee, and Kimiko Yamashita. Positivity bounds on Higgs- Portal dark matter. JHEP, 06:124, 2023. 20
work page 2023
-
[7]
Positivity bounds on Higgs- portal freeze-in dark matter
Seong-Sik Kim, Hyun Min Lee, and Kimiko Yamashita. Positivity bounds on Higgs- portal freeze-in dark matter. JHEP, 11:119, 2023
work page 2023
-
[8]
Higgs-portal spin-1 dark matter with parity-violating interaction
Kimiko Yamashita. Higgs-portal spin-1 dark matter with parity-violating interaction. JHEP, 10:205, 2024
work page 2024
-
[9]
Higgs- Portal Stueckelberg Dark Matter
Antonio De Felice, Takehiro Ogura, Shinji Tsujikawa, and Kimiko Yamashita. Higgs- Portal Stueckelberg Dark Matter. arXiv:2512.17231 [hep-ph]
-
[10]
Causality, analyticity and an IR obstruction to UV completion.JHEP, 10:014, 2006
Allan Adams, Nima Arkani-Hamed, Sergei Dubovsky, Alberto Nicolis, and Riccardo Rattazzi. Causality, analyticity and an IR obstruction to UV completion.JHEP, 10:014, 2006
work page 2006
-
[11]
T. N. Pham and Tran N. Truong. Evaluation of the Derivative Quartic Terms of the Meson Chiral Lagrangian From Forward Dispersion Relation. Phys. Rev. D, 31:3027, 1985
work page 1985
-
[12]
B. Ananthanarayan, D. Toublan, and G. Wanders. Consistency of the chiral pion pion scattering amplitudes with axiomatic constraints. Phys. Rev. D, 51:1093–1100, 1995
work page 1995
-
[13]
Xu Li, Ken Mimasu, Kimiko Yamashita, Chengjie Yang, Cen Zhang, and Shuang-Yong Zhou. Moments for positivity: using Drell-Yan data to test positivity bounds and reverse-engineer new physics. JHEP, 10:107, 2022
work page 2022
-
[14]
Gravitational positivity bounds
Junsei Tokuda, Katsuki Aoki, and Shin’ichi Hirano. Gravitational positivity bounds. JHEP, 11:054, 2020
work page 2020
-
[15]
Weak Gravity Conjecture from Uni- tarity and Causality
Yuta Hamada, Toshifumi Noumi, and Gary Shiu. Weak Gravity Conjecture from Uni- tarity and Causality. Phys. Rev. Lett., 123(5):051601, 2019
work page 2019
-
[16]
Is the Standard Model in the Swampland? Consistency Requirements from Gravitational Scattering
Katsuki Aoki, Tran Quang Loc, Toshifumi Noumi, and Junsei Tokuda. Is the Standard Model in the Swampland? Consistency Requirements from Gravitational Scattering. Phys. Rev. Lett., 127(9):091602, 2021
work page 2021
-
[17]
Gravitational positivity bounds on scalar poten- tials
Toshifumi Noumi and Junsei Tokuda. Gravitational positivity bounds on scalar poten- tials. Phys. Rev. D, 104(6):066022, 2021
work page 2021
-
[18]
Phenomenological motivation for gravitational positivity bounds: A case study of dark sector physics
Toshifumi Noumi, Sota Sato, and Junsei Tokuda. Phenomenological motivation for gravitational positivity bounds: A case study of dark sector physics. Phys. Rev. D, 108(5):056013, 2023. 21
work page 2023
-
[19]
Gravitational positivity for phenomenologists: Dark gauge boson in the swampland
Katsuki Aoki, Toshifumi Noumi, Ryo Saito, Sota Sato, Satoshi Shirai, Junsei Tokuda, and Masahito Yamazaki. Gravitational positivity for phenomenologists: Dark gauge boson in the swampland. Phys. Rev. D, 110(1):016002, 2024
work page 2024
-
[20]
Constraining Millicharged dark matter with Gravitational positivity bounds
Suro Kim and Pyungwon Ko. Constraining Millicharged dark matter with Gravitational positivity bounds. arXiv:2405.04454 [hep-ph]
-
[21]
Can WIMP Dark Matter overcome the Nightmare Scenario? Phys
Shinya Kanemura, Shigeki Matsumoto, Takehiro Nabeshima, and Nobuchika Okada. Can WIMP Dark Matter overcome the Nightmare Scenario? Phys. Rev. D, 82:055026, 2010
work page 2010
- [22]
-
[23]
Asymptotic behavior and subtractions in the Mandelstam represen- tation
Marcel Froissart. Asymptotic behavior and subtractions in the Mandelstam represen- tation. Phys. Rev., 123:1053–1057, 1961
work page 1961
-
[24]
A. Martin. Unitarity and high-energy behavior of scattering amplitudes. Phys. Rev., 129:1432–1436, 1963
work page 1963
-
[25]
Yuta Hamada, Rinto Kuramochi, Gregory J. Loges, and Sota Nakajima. On (scalar QED) gravitational positivity bounds. JHEP, 05:076, 2023
work page 2023
-
[26]
Softness and amplitudes’ positivity for spinning particles
Brando Bellazzini. Softness and amplitudes’ positivity for spinning particles. JHEP, 02:034, 2017
work page 2017
-
[27]
Claudia de Rham, Scott Melville, Andrew J. Tolley, and Shuang-Yong Zhou. Massive Galileon Positivity Bounds. JHEP, 09:072, 2017
work page 2017
-
[28]
Claudia de Rham, Scott Melville, and Andrew J. Tolley. Improved Positivity Bounds and Massive Gravity. JHEP, 04:083, 2018
work page 2018
-
[29]
Clifford Cheung and Grant N. Remmen. Naturalness and the Weak Gravity Conjecture. Phys. Rev. Lett., 113:051601, 2014
work page 2014
-
[30]
Clifford Cheung and Grant N. Remmen. Infrared Consistency and the Weak Gravity Conjecture. JHEP, 12:087, 2014
work page 2014
-
[31]
A Tower Weak Gravity Conjecture from Infrared Consistency
Stefano Andriolo, Daniel Junghans, Toshifumi Noumi, and Gary Shiu. A Tower Weak Gravity Conjecture from Infrared Consistency. Fortsch. Phys., 66(5):1800020, 2018. 22
work page 2018
-
[32]
Lasma Alberte, Claudia de Rham, Sumer Jaitly, and Andrew J. Tolley. Positivity Bounds and the Massless Spin-2 Pole. Phys. Rev. D, 102(12):125023, 2020
work page 2020
-
[33]
Lasma Alberte, Claudia de Rham, Sumer Jaitly, and Andrew J. Tolley. QED positivity bounds. Phys. Rev. D, 103(12):125020, 2021
work page 2021
-
[34]
Lasma Alberte, Claudia de Rham, Sumer Jaitly, and Andrew J. Tolley. Reverse Boot- strapping: IR Lessons for UV Physics. Phys. Rev. Lett., 128(5):051602, 2022
work page 2022
-
[35]
M. Herrero-Valea, A. S. Koshelev, and A. Tokareva. UV graviton scattering and posi- tivity bounds from IR dispersion relations. Phys. Rev. D, 106(10):105002, 2022
work page 2022
-
[36]
Claudia de Rham, Sumer Jaitly, and Andrew J. Tolley. Constraints on Regge behavior from IR physics. Phys. Rev. D, 108(4):046011, 2023
work page 2023
-
[37]
String loops and gravitational positivity bounds: imprint of light particles at high energies
Simon Caron-Huot and Junsei Tokuda. String loops and gravitational positivity bounds: imprint of light particles at high energies. JHEP, 11:055, 2024
work page 2024
-
[38]
Unitarity bounds on charged/neutral state mass ratios
Wei-Ming Chen, Yu-Tin Huang, Toshifumi Noumi, and Congkao Wen. Unitarity bounds on charged/neutral state mass ratios. Phys. Rev. D, 100(2):025016, 2019
work page 2019
-
[39]
Nima Arkani-Hamed, Yu-tin Huang, Jin-Yu Liu, and Grant N. Remmen. Causality, unitarity, and the weak gravity conjecture. JHEP, 03:083, 2022
work page 2022
-
[40]
Higher derivative corrections to black brane ther- modynamics and the weak gravity conjecture
Toshifumi Noumi and Hibiki Satake. Higher derivative corrections to black brane ther- modynamics and the weak gravity conjecture. JHEP, 12:130, 2022
work page 2022
-
[41]
Yoshihiko Abe, Toshifumi Noumi, and Kaho Yoshimura. Black hole extremality in nonlinear electrodynamics: a lesson for weak gravity and Festina Lente bounds. JHEP, 09:024, 2023
work page 2023
-
[42]
Kimiko Yamashita, Cen Zhang, and Shuang-Yong Zhou. Elastic positivity vs extremal positivity bounds in SMEFT: a case study in transversal electroweak gauge-boson scat- terings. JHEP, 01:095, 2021
work page 2021
-
[43]
Neil D. Christensen and Claude Duhr. FeynRules - Feynman rules made easy. Comput. Phys. Commun., 180:1614–1641, 2009
work page 2009
-
[44]
Christensen, C´ eline Degrande, Claude Duhr, and Benjamin Fuks
Adam Alloul, Neil D. Christensen, C´ eline Degrande, Claude Duhr, and Benjamin Fuks. FeynRules 2.0 - A complete toolbox for tree-level phenomenology. Comput. Phys. Commun., 185:2250–2300, 2014. 23
work page 2014
-
[45]
Generating feynman diagrams and amplitudes with feynarts 3
Thomas Hahn. Generating feynman diagrams and amplitudes with feynarts 3. Computer Physics Communications, 140(3):418–431, 2001
work page 2001
- [46]
-
[47]
New Developments in FeynCalc 9.0
Vladyslav Shtabovenko, Rolf Mertig, and Frederik Orellana. New Developments in FeynCalc 9.0. Comput. Phys. Commun., 207:432–444, 2016
work page 2016
-
[48]
FeynCalc 9.3: New features and improvements
Vladyslav Shtabovenko, Rolf Mertig, and Frederik Orellana. FeynCalc 9.3: New features and improvements. Comput. Phys. Commun., 256:107478, 2020
work page 2020
-
[49]
FeynCalc 10: Do multiloop integrals dream of computer codes? Comput
Vladyslav Shtabovenko, Rolf Mertig, and Frederik Orellana. FeynCalc 10: Do multiloop integrals dream of computer codes? Comput. Phys. Commun., 306:109357, 2025
work page 2025
-
[50]
Hiren H. Patel. Package-X: A Mathematica package for the analytic calculation of one-loop integrals. Comput. Phys. Commun., 197:276–290, 2015
work page 2015
-
[51]
Nicolas Bernal and Xiaoyong Chu.Z 2 SIMP Dark Matter. JCAP, 01:006, 2016
work page 2016
-
[52]
Feng, Huitzu Tu, and Hai-Bo Yu
Jonathan L. Feng, Huitzu Tu, and Hai-Bo Yu. Thermal Relics in Hidden Sectors.JCAP, 10:043, 2008
work page 2008
-
[53]
Lotty Ackerman, Matthew R. Buckley, Sean M. Carroll, and Marc Kamionkowski. Dark Matter and Dark Radiation. Phys. Rev. D, 79:023519, 2009
work page 2009
-
[54]
Stringent Constraints on Self-Interacting Dark Matter Using Milky-Way Satellite Galaxies Kinematics
Shin’ichiro Ando, Kohei Hayashi, Shunichi Horigome, Masahiro Ibe, and Satoshi Shi- rai. Stringent Constraints on Self-Interacting Dark Matter Using Milky-Way Satellite Galaxies Kinematics. arXiv:2503.13650 [astro-ph.CO]
-
[55]
Unitarity and unstable-particle scattering amplitudes
Katsuki Aoki. Unitarity and unstable-particle scattering amplitudes. Phys. Rev. D, 107(6):065017, 2023
work page 2023
-
[56]
Anomalous thresholds for the S-matrix of unstable particles
Katsuki Aoki and Yu-tin Huang. Anomalous thresholds for the S-matrix of unstable particles. JHEP, 09:045, 2024
work page 2024
-
[57]
J. A. Oller and Marcela Pel´ aez. Unitarization of electron scattering with an external potential at NLO in QED. JHEP, 11:113, 2024
work page 2024
-
[58]
TikZ-Feynman: Feynman diagrams with TikZ
Joshua Ellis. TikZ-Feynman: Feynman diagrams with TikZ. Comput. Phys. Commun., 210:103–123, 2017. 24
work page 2017
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