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String Theory and Grand Unification Suggest a Sub-Microelectronvolt QCD Axion

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Pith's one-line read This paper argues that combining string theory, grand unification, and proton-decay bounds fixes the QCD axion mass to a narrow window between $3\times10^{-11}$ eV and $10^{-8}$ eV, within reach of planned axion dark matter searches.

desk verdict A serious, well-caveated scan that maps a plausible neV window for closed-string QCD axions, but the window's edges are sample-limited rather than proven. read the letter →

arxiv 2505.15884 v1 pith:47DD7YRZ submitted 2025-05-21 hep-ph hep-th

Joshua N. Benabou , Katherine Fraser , Mario Reig , Benjamin R. Safdi This is my paper
classification hep-phhep-th
keywords QCDaxionmasswindowgrandunificationstringcompactificationaxiverseprotondecaydarkmatterKreuzer-Skarke
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 if the QCD axion arises from a closed-string gauge field and grand unification is real, the axion mass cannot wander freely: the string scale must stay above the GUT scale, which caps the compactification volume and therefore bounds the axion decay constant. Using partial-wave unitarity arguments and explicit type IIB compactifications built from the complete list of reflexive polytopes, the authors derive a favored window $3\times10^{-11}\ \mathrm{eV}\lesssim m_a\lesssim10^{-8}\ \mathrm{eV}$. The same requirement limits the axiverse in these constructions to at most about 47 axions. This matters because the predicted window is exactly where near-future axion dark matter experiments are designed to look, making the combination of string theory, grand unification, and proton decay directly testable.

What carries the argument

The load-bearing mechanism is the geometric link between compactification volume and two physical scales: the string scale falls as $M_s\propto M_{\mathrm{pl}}/\sqrt{V_6}$ as the six-dimensional volume grows, while the axion decay constant falls as $f_a\propto M_{\mathrm{pl}}/V_6^{p/6}$ for a $p$-form axion. Requiring $M_s\ge M_{\mathrm{GUT}}$ therefore bounds $V_6$ from above, which in turn bounds $f_a$ from below and the axion mass from above; a partial-wave unitarity bound on gluon-gluon scattering, $f_a\gtrsim M_{\mathrm{KK}}\alpha_s(M_{\mathrm{KK}})/\sqrt{2\pi^3}$, supplies an independent lower bound on $f_a$. The explicit computations run over the Kreuzer-Skarke database of Calabi-Yau threefolds, the full set of 473,800,776 reflexive polytopes, where axion decay constants and masses are computed from the Kähler metric at the tip of the stretched Kähler cone, with one randomly selected prime toric divisor hosting QCD and its volume rescaled to match the observed QCD coupling.

What would settle it

A single explicit type IIB orientifold compactification with $h^{1,1}\ge48$, string scale above $2\times10^{16}$ GeV, and a QCD axion mass above $10^{-8}$ eV would falsify the central bound; a complete enumeration of regular triangulations for $48\le h^{1,1}\le60$ would settle whether the claimed cutoff is an artifact of sampling.

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Extended reading notes

Core claim

The central claim, stated as equation (1), is that in weakly coupled type IIB string compactifications with closed-string axions and with the string scale kept at or above the SUSY GUT scale $M_{\mathrm{GUT}}=2\times10^{16}$ GeV, the QCD axion mass satisfies $3\times10^{-11}\ \mathrm{eV}\lesssim m_a\lesssim10^{-8}\ \mathrm{eV}$. The upper side follows because larger decay constants would require smaller compactification volumes and hence string scales below the GUT scale, while the lower side comes from a partial-wave unitarity bound applied up to the KK scale and, in the explicit sample, from the absence of decay constants above $2\times10^{17}$ GeV. The authors further find that only compactifications with up to $h^{1,1}\simeq47$ axions satisfy $M_s\ge M_{\mathrm{GUT}}$, so the axiverse in this ensemble is capped at roughly 47 axions. They also report that no sampled compactification yields an axion with decay constant large enough to explain the DESI evolving-dark-energy hints.

Load-bearing premise

The load-bearing premise is that the sampled triangulations fairly represent the full Kreuzer-Skarke ensemble, since both the roughly 47-axion cap and the lower mass bound would dissolve if unsampled compactifications with more axions or larger decay constants exist.

Editorial extensions

If this is right

  • If the window is right, the next generation of low-mass axion dark matter searches, such as lumped-element and spin-precession experiments, covers the predicted mass range, so a definitive test is within reach.
  • The axiverse in these compactifications has at most about 47 axions, which sharpens expectations for black-hole superradiance and other probes of many-light-axion spectra.
  • The DESI evolving-dark-energy interpretation through a single ultralight axion is disfavored, since no sampled compactification reaches $f_a\gtrsim2.5\times10^{17}$ GeV with $m_a\lesssim H_0$; the paper argues such high decay constants are generically hard to obtain.
  • Field-theory axions with $f_a\ll M_{\mathrm{GUT}}$ remain viable, so a future detection of a heavier axion would point toward a field-theory, warped, or non-geometric origin rather than flat closed-string compactifications.
  • The mass range is set by the minimal and maximal nonzero values in the sampled distribution, so a detection outside the window would directly contradict the prediction.

Reading between the lines

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

  • I would read the $h^{1,1}\le47$ result as a geometric selection effect: large Hodge numbers correlate with large volumes, which push the string scale below the GUT scale; a complete enumeration of regular triangulations for intermediate $h^{1,1}$ would test whether the cutoff is sharp.
  • If the window survives more exhaustive sampling, the same volume-based logic should apply to other closed-string axions, suggesting that the only light axions from flat compactifications consistent with GUTs are the neV-scale ones.
  • The warped-compactification and anomalous-$U(1)$ loopholes the authors list could serve as a discriminator: a detection of an axion above $10^{-8}$ eV would favor those non-standard constructions, while a detection inside the window would favor flat closed-string axions.
  • A natural extension would be to repeat the scan with the QCD divisor chosen not randomly but by requiring realistic Standard Model matter localization and gauge-coupling unification at the GUT scale, which could sharpen or shift the mass window.
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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

3 major / 6 minor

Summary. This paper argues that QCD axions arising as zero modes of closed-string gauge fields in flat-space type IIB compactifications, when combined with the requirement that the string scale lie above the SUSY GUT scale (Ms ≥ MGUT = 2×10^16 GeV), populate a narrow mass window, 3×10^-11 eV ≲ ma ≲ 10^-8 eV (Eq. (1)), and that the Kreuzer–Skarke axiverse is limited to h1,1 ≲ 47. The argument proceeds in three tiers: (i) a partial-wave unitarity bound on the axion–gluon amplitude, which gives ma ≲ 6×10^-8 eV if the axion EFT must be valid up to the KK scale; (ii) analytic dimensional-reduction relations for orbifold GUTs, p-form axions, and factorizable or strongly anisotropic geometries, which tie fa to αGUT Mpl in the factorizable limit and give the general bound fa ≳ αs^2 Mpl / sqrt(V6); and (iii) a scan of roughly 1.7×10^6 KS compactifications using CYTools, from which the upper bound ma ≲ 10^-8 eV, the lower bound ma ≳ 3×10^-11 eV, and the h1,1 ≤ 47 cap are read off. Loopholes such as warped compactifications, non-geometric anomalous-U(1) axions, and fermion localization are enumerated explicitly and are argued to be non-minimal or to spoil standard GUT phenomenology. As an application, the scan finds no sampled axion with fa ≳ 2.5×10^17 GeV and ma ≲ H0 compatible with the DESI evolving-dark-energy hints, with the caveat that the search is incomplete.

Significance. If the central range is robust, the result is significant: it turns the string axiverse into a concrete experimental target for ABRACADABRA, DMRadio, and CASPEr, and it would impose a sharp cap on the number of closed-string axions compatible with grand unification. The strengths of the paper are real: the unitarity bound in Eq. (5) is simple, derivable, and anchored in existing amplitude results; the dimensional-reduction relations of Sec. III are explicit and checkable; the numerical scan uses publicly available code (CYTools) and is in principle reproducible; and the DESI null result is a falsifiable application. The authors are also commendably candid about limitations: they flag the low-volume high-fa region as unreliable, warn that the analytic upper bound on fa 'should be treated with caution' (Sec. III C), admit that the KS search 'might not be complete' (Sec. V), and explicitly say the lower mass bound 'should be treated with some degree of suspicion' (Sec. IV). The main concern is that the two sharpest advertised numbers, the lower edge of Eq.

major comments (3)
  1. [Sec. IV, Fig. 2, and footnote 9] The exclusion of compactifications with h1,1 ≳ 48, and hence the h1,1 ≤ 47 cap, is inferred from the absence of any sampled triangulation satisfying Ms ≥ MGUT, but the sample is limited to up to 100 favorable polytopes and 500 triangulations per polytope for each h1,1 ≤ 60, and the triangulations are not generated fairly. Footnote 9 argues that the range calculation does not require a fair sampling, but that statement is only correct for the existence part of the range; the extremes, which set the boundaries of Eq. (1), are exclusion claims that do require some coverage of the extremal geometries. Since larger h1,1 anticorrelates with fa, a missed h1,1 ≥ 48 compactification would push the mass range above 10^-8 eV, so the cap is load-bearing for the upper end of the central claim. A targeted dense scan of the h1,1 = 48–60 boundary region, or a quantitative statement such as a confidence-level upper bound on the fraction of triangulations satisfying Ms ≥ MGUT, is needed before the cap can be presented as a result.
  2. [Sec. III C and Sec. IV, Eq. (1)] The lower edge of Eq. (1), ma ≳ 3×10^-11 eV, is the least supported part of the central range. It rests on the absence of fa > 2×10^17 GeV in the sample and on the analytic estimate fa ≲ 3×10^17 GeV, about which the text itself says 'this upper bound fa ≲ 3×10^17 GeV should be treated with caution' (Sec. III C); Sec. IV adds that the high-fa examples have low total volume V6, that the low-V6 points 'are not necessarily reliable' because α' corrections are uncontrolled, and that 'our lower QCD axion mass prediction ma ≳ 3×10^-11 eV should be treated with some degree of suspicion.' These passages sit exactly on the headline range, yet the abstract and Eq. (1) present 3×10^-11 eV as an unqualified boundary while the qualification appears only later. Either the lower edge must be softened in the abstract and introduction, or it must be supported by a quantitative estimate of the leading small-volume corrections at the extremal points; as written, the lower bound is doubly uncertain on statistical and systematic grounds.
  3. [Sec. II, Eq. (5), versus Eq. (1)] The model-independent unitarity argument yields only ma ≲ 6×10^-8 eV, a factor of six weaker than the 10^-8 eV upper bound in Eq. (1). The tighter value is a property of the scanned sample and therefore inherits the sampling limitation identified above. The body of the paper does distinguish these derivations, but the abstract and Fig. 1 present the tighter scan value as the headline constraint, so a reader could reasonably attribute the upper bound to the unitarity argument rather than to the sample extremum. The provenance of the two bounds (unitarity versus sample extremum) should be stated wherever the range is advertised, since the factor of six between them is experimentally meaningful for the proposed search program.
minor comments (6)
  1. [Abstract and Eq. (1)] The abstract quotes the range as 10^-11 eV ≲ ma ≲ 10^-8 eV while Eq. (1) gives 3×10^-11 eV ≲ ma ≲ 10^-8 eV; these boundary values should be harmonized, particularly since the paper emphasizes that the histogram extrema are physically meaningful numbers.
  2. [Sec. I] The text cites 'the construction of Batryev [54]'; the name should be spelled Batyrev.
  3. [Fig. 1 caption] The sentence 'The minimal and maximal non-zero values of this histogram are prior independent and bound the possible axion masses' overstates the status of the extrema: they are prior-independent within the sampled set, but the sampled set has not been shown to contain the extremal geometries, so the caption should carry the same sampling caveat as the text of Sec. IV.
  4. [Fig. 3 and Sec. IV] The unitarity, string-tension, and WGC bounds in Fig. 3 are plotted at gs = 1; the text notes that the string-tension and magnetic-WGC bounds scale as gs^{1/4}, so displaying the gs-dependence as a band, or at least stating the scaling explicitly in the caption, would help the reader assess the robustness of the plotted comparison.
  5. [App. C and Figs. 5–6] The DESI analysis switches from the axion–gluon-coupling definition of fa used in Eq. (2) to the periodicity definition of the canonically normalized field; the difference is flagged in footnotes, but it should be stated in the main text where the DESI conclusion is drawn, since the two definitions can differ by O(1–10) factors in multi-axion compactifications.
  6. [General] A number of typos and layout artifacts remain, including 'the 5 th dimension' and displaced glyphs around Eqs. (12)–(13) and (B1)–(B2); a final proofreading pass is needed.

Circularity Check

0 steps flagged · score 2.0 of 10

No significant circularity: the axion-mass range and the h^{1,1} \u2264 47 cap are computed outputs of a scan filtered by M_s \u2265 M_GUT and QCD-coupling matching, not fitted targets or renamed inputs.

full rationale

On the circularity axis, the derivation chain is self-contained. The central claim (Eq. 1) and the h^{1,1} \u2264 47 cap are computed outputs, not fitted targets: the KS ensemble is filtered by (i) M_s \u2265 M_GUT = 2\u00d710^{16} GeV, (ii) matching the QCD gauge coupling via homothetic rescaling (Vol(D_QCD) = 25 in string units), and (iii) a geometric-coarseness cut (all divisor volumes \u2265 1). None of these filters is a function of the axion mass; m_a is computed afterwards from the geometric decay constants with the standard QCD relation m_a \u2248 5.7\u00d710^{-6} eV (10^{12} GeV/f_a). The upper edge m_a \u2272 10^{-8} eV and the absence of M_s \u2265 M_GUT compactifications at h^{1,1} \u2265 48 are histogram boundaries of the computed sample, and the partial-wave-unitarity bound (f_a \u2273 10^{14} GeV, m_a \u2272 6\u00d710^{-8} eV) is derived independently from gluon scattering with s = M_KK^2 and M_KK \u2265 M_GUT. The analytic estimates f_a = \u03b1_GUT M_pl/\u221a(8\u03c0\u00b2) (Eqs. 14-17, 23) follow from the definitions of M_pl and \u03b1_GUT together with the normalization of the p-form kinetic term, with no fitted parameter. The string-tension conjecture (Sec. IV.A) is taken from an external reference (Reece [25]) and is explicitly approximate; the authors' own prior papers on axion strings and axion DM are cited only illustratively and are not needed for Eq. (1). The genuine weaknesses are statistical and systematic, not circular: footnote 9 concedes the fast-triangulation sample is not fair, and the extremal points (largest f_a, smallest V_6) are where \u03b1\u2032 corrections are uncontrolled, so the m_a \u2273 3\u00d710^{-11} eV lower edge and the h^{1,1} \u2264 47 boundary may shift under a denser, unbiased sample. That is an unproven-completeness robustness concern, not an input-output equivalence.

Assumptions & free parameters 2 free parameters · 4 assumptions · 0 invented entities

The central claim rests on four domain assumptions: the representativeness of the KS ensemble, the necessity of Ms >= MGUT, the control of alpha-prime corrections, and the representativeness of one Kahler cone point. The free parameters are the string coupling and the QCD divisor volume normalization, both fixed by hand or by gauge coupling matching. No new particles, forces, or dimensions are introduced.

free parameters (2)
  • String coupling gs = 1 (set by hand in explicit scans)
    Used for the KS computations and Fig. 3. The authors note the minimal fa scales mildly with gs as gs^{-1/4}, so the precise mass boundaries shift with this choice, though not dramatically.
  • QCD divisor volume Vol(D_QCD) = 25 in string units
    Imposed by homothetic rescaling of the Kahler cone to reproduce the observed QCD gauge coupling. The entire fa and ma distribution depends on this normalization, which is a data-matching condition rather than a derived quantity.
assumptions (4)
  • domain assumption Type IIB O3/O7 orientifolds of toric Calabi-Yau hypersurfaces from the Kreuzer-Skarke database are a representative proxy for the string axiverse relevant to QCD axions.
    The central range is derived from this ensemble in Sec. IV. Warped, heterotic, and non-geometric constructions are explicitly set aside as loopholes, so the result is conditional on this class of compactifications.
  • domain assumption The string scale must be above MGUT = 2e16 GeV to preserve SUSY gauge unification and avoid fast proton decay.
    This requirement selects the compactifications and produces the upper bound on ma. Sec. I argues it from unification running and proton decay, but it is a phenomenological requirement imposed from outside string theory, not a derived string constraint.
  • domain assumption Alpha-prime and other corrections to the Kahler potential are negligible at the sampled points.
    Invoked implicitly when computing fa at the tip of the stretched Kahler cone. The authors themselves flag the low-volume, high-fa points as unreliable, so this assumption is load-bearing for the lower mass bound.
  • domain assumption Axion EFT data at the tip of the stretched Kahler cone is representative of the moduli space.
    Stated in Sec. IV and tested only partially in the cited literature. If the EFT data varies strongly across moduli space, the computed mass range may not be robust.

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Cite this review

Pith. "Pith review of String Theory and Grand Unification Suggest a Sub-Microelectronvolt QCD Axion." pith.science (2026). https://pith.science/paper/47DD7YRZ

@misc{pith2026250515884,
  author       = {Pith},
  title        = {Pith review of: String Theory and Grand Unification Suggest a Sub-Microelectronvolt QCD Axion},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/47DD7YRZ}},
  note         = {Machine review of arXiv:2505.15884}
}
abstract

Axions, grand unification, and string theory are each compelling extensions of the Standard Model. We show that combining these frameworks imposes strong constraints on the QCD axion mass. Using unitarity arguments and explicit string compactifications - such as those from the Kreuzer-Skarke (KS) type IIB ensemble - we find that the axion mass is favored to lie within the range $10^{-11}$ eV $\lesssim m_a \lesssim$ $10^{-8}$ eV. This range is directly relevant for near-future axion dark matter searches, including ABRACADABRA/DMRadio and CASPEr. We argue that grand unification and the absence of proton decay suggest a compactification volume that keeps the string scale above the unification scale ($\sim$$10^{16}$ GeV), which in turn limits how heavy the axion can be. The same requirements limit the KS axiverse to have at most $\sim$47 axions. As an additional application of our methodology, we search for axions in the KS axiverse that could explain the recent Dark Energy Spectroscopic Instrument (DESI) hints of evolving dark energy but find none with high enough decay constant ($f_a \gtrsim 2.5 \times 10^{17}$ GeV); we comment on why such high decay constants and low axion masses are difficult to obtain in string compactifications more broadly.

Figures

Figures reproduced from arXiv: 2505.15884 by the authors.

Figure 1
Figure 1. The distribution of the QCD axion mass ma in the Kreuzer-Skarke (KS) axiverse, restricting to compactifi￾cations for which Ms ≳ 2 × 1016 GeV (histogram, see text for details). The minimal and maximal non-zero values of this histogram are prior independent and bound the possible axion masses consistent with proton decay and grand unifi￾cation in these constructions. Note that lower QCD axion masses are disfavored in … view at source ↗
Figure 2
Figure 2. The fraction of KS compactifications for which [PITH_FULL_IMAGE:figures/full_fig_p008_2.png] view at source ↗
Figure 3
Figure 3. The joint distribution QCD axion decay constants [PITH_FULL_IMAGE:figures/full_fig_p011_3.png] view at source ↗
Figures from the paper (2 more)
Figure 4
Figure 4. Figure 4: (Left) For individual values of h 1,1 , the distribution of the QCD axion mass at fixed h 1,1 (in the form of a kernel density estimate (KDE)), restricting to compactifications for which Ms ≥ MGUT (see [PITH_FULL_IMAGE:figures/full_fig_p021_4.png]
Figure 5
Figure 5. Figure 5: Including all sampled compactifications with the [PITH_FULL_IMAGE:figures/full_fig_p022_5.png]

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Forward citations

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Reference graph

Works this paper leans on

175 extracted references · 6 canonical work pages · cited by 9 Pith papers

  1. [1]

    One of the simplest realizations where the relevant scales can be separated include theories with anomalous U (1)’s where the axion comes from the mixing between a higher-form axion and a phase of a complex scalar, ϕ. In these theories there can be cancellations in the D-term potential for ϕ, VD ∝ |ϕ|2 + P i qi ∂K ∂τi 2 , leading to field 11 100 103 106 1...

  2. [2]

    In this case, one could imag- ine a compact space which is very large V6 ≫ 1 leading to a low string scale Ms ≪ Mpl or, alternatively, keeping Ms > MGUT but warping down fa and MKK

    Of course, another possibility—within the context of closed-string axions—is simply to accept a string scale or KK scale below MGUT. In this case, one could imag- ine a compact space which is very large V6 ≫ 1 leading to a low string scale Ms ≪ Mpl or, alternatively, keeping Ms > MGUT but warping down fa and MKK. Mini- mal realizations of this idea are ch...

  3. [3]

    A New Light Boson?

    Steven Weinberg, “A New Light Boson?” Phys. Rev. Lett. 40, 223–226 (1978)

    1978

  4. [4]

    CP Conservation in the Presence of Instantons,

    R. D. Peccei and Helen R. Quinn, “CP Conservation in the Presence of Instantons,” Phys. Rev. Lett. 38, 1440– 1443 (1977)

    1977

  5. [5]

    Constraints Im- posed by CP Conservation in the Presence of Instan- tons,

    R. D. Peccei and Helen R. Quinn, “Constraints Im- posed by CP Conservation in the Presence of Instan- tons,” Phys. Rev. D16, 1791–1797 (1977)

    1977

  6. [6]

    A Cosmological Bound on the Invisible Axion,

    L. F. Abbott and P. Sikivie, “A Cosmological Bound on the Invisible Axion,” Phys. Lett. 120B, 133–136 (1983)

    1983

  7. [7]

    Problem of Strong p and t Invariance in the Presence of Instantons,

    Frank Wilczek, “Problem of Strong p and t Invariance in the Presence of Instantons,” Phys. Rev. Lett. 40, 279–282 (1978)

    1978

  8. [8]

    Cos- mology of the Invisible Axion,

    John Preskill, Mark B. Wise, and Frank Wilczek, “Cos- mology of the Invisible Axion,” Phys. Lett. 120B, 127– 132 (1983)

    1983

Show all 175 references
  1. [9]

    The landscape of QCD axion models,

    Luca Di Luzio, Maurizio Giannotti, Enrico Nardi, and Luca Visinelli, “The landscape of QCD axion models,” Phys. Rept. 870, 1–117 (2020), arXiv:2003.01100 [hep- ph]

    2020 arXiv

  2. [10]

    The Not So Harmless Axion,

    Michael Dine and Willy Fischler, “The Not So Harmless Axion,” Phys. Lett. 120B, 137–141 (1983)

    1983

  3. [11]

    TASI Lectures on the Strong CP Problem and Axions,

    Anson Hook, “TASI Lectures on the Strong CP Problem and Axions,” PoS T ASI2018, 004 (2019), arXiv:1812.02669 [hep-ph]

    2019 arXiv

  4. [12]

    The QCD ax- ion, precisely,

    Giovanni Grilli di Cortona, Edward Hardy, Javier Pardo Vega, and Giovanni Villadoro, “The QCD ax- ion, precisely,” JHEP 01, 034 (2016), arXiv:1511.02867 [hep-ph]

    2016 arXiv

  5. [13]

    TASI Lectures on the Parti- cle Physics and Astrophysics of Dark Matter,

    Benjamin R. Safdi, “TASI Lectures on the Parti- cle Physics and Astrophysics of Dark Matter,” PoS T ASI2022, 009 (2024), arXiv:2303.02169 [hep-ph]

    2024 arXiv

  6. [14]

    Cosmology of axion dark matter,

    Ciaran A. J. O’Hare, “Cosmology of axion dark matter,” PoS COSMICWISPers, 040 (2024), arXiv:2403.17697 [hep-ph]

    2024 arXiv

  7. [15]

    Planck scale physics and the Peccei-Quinn mechanism,

    Marc Kamionkowski and John March-Russell, “Planck scale physics and the Peccei-Quinn mechanism,” Phys. Lett. B 282, 137–141 (1992), arXiv:hep-th/9202003

    1992 arXiv

  8. [16]

    Grand Unified Models With an Automatic Peccei-Quinn Symmetry,

    Howard M. Georgi, Lawrence J. Hall, and Mark B. Wise, “Grand Unified Models With an Automatic Peccei-Quinn Symmetry,” Nucl. Phys. B 192, 409–416 (1981)

    1981

  9. [17]

    Phenomenology and Cosmology With Superstrings,

    George Lazarides, C. Panagiotakopoulos, and Q. Shafi, “Phenomenology and Cosmology With Superstrings,” Phys. Rev. Lett. 56, 432 (1986)

    1986

  10. [18]

    Solutions to the strong CP prob- lem in a world with gravity,

    Richard Holman, Stephen D. H. Hsu, Thomas W. Kephart, Edward W. Kolb, Richard Watkins, and Lawrence M. Widrow, “Solutions to the strong CP prob- lem in a world with gravity,” Phys. Lett. B282, 132–136 (1992), arXiv:hep-ph/9203206

    1992 arXiv

  11. [19]

    In- stability of the invisible axion,

    S. Ghigna, Maurizio Lusignoli, and M. Roncadelli, “In- stability of the invisible axion,” Phys. Lett. B 283, 278– 281 (1992)

    1992

  12. [20]

    Planck scale cor- rections to axion models,

    Stephen M. Barr and D. Seckel, “Planck scale cor- rections to axion models,” Phys. Rev. D 46, 539–549 (1992)

    1992

  13. [21]

    Harmful Axions in Su- perstring Models,

    Kiwoon Choi and Jihn E. Kim, “Harmful Axions in Su- perstring Models,” Phys. Lett. B 154, 393 (1985), [Er- ratum: Phys.Lett.B 156, 452 (1985)]

    1985

  14. [22]

    The quality/cosmology tension for a post-inflation QCD ax- ion,

    Qianshu Lu, Matthew Reece, and Zhiquan Sun, “The quality/cosmology tension for a post-inflation QCD ax- ion,” JHEP 07, 227 (2024), arXiv:2312.07650 [hep-ph]

    2024 arXiv

  15. [23]

    Some Properties of O(32) Super- strings,

    Edward Witten, “Some Properties of O(32) Super- strings,” Phys. Lett. B 149, 351–356 (1984)

    1984

  16. [24]

    String Axiverse,

    Asimina Arvanitaki, Savas Dimopoulos, Sergei Dubovsky, Nemanja Kaloper, and John March- 13 Russell, “String Axiverse,” Phys. Rev. D 81, 123530 (2010), arXiv:0905.4720 [hep-th]

    2010 arXiv

  17. [25]

    favorable

    for a recent review) implies, for an O(1) constant c,8 that fa ≤ cMpl/Sinst ≈ 1.5c × 1016 GeV, assuming Sinst = 2π/αUV and αUV = 1/25. (Our conjectured up- per bound is essentially equivalent to that of the WGC if one takes αUV = 1 for the latter, or if the instanton correspon...

  18. [26]

    Harmless Axions in Superstring The- ories,

    Stephen M. Barr, “Harmless Axions in Superstring The- ories,” Phys. Lett. B 158, 397–400 (1985)

    1985

  19. [27]

    Axions In String Theory,

    Peter Svrcek and Edward Witten, “Axions In String Theory,” JHEP 06, 051 (2006), arXiv:hep-th/0605206

    2006 arXiv

  20. [28]

    Extra-Dimensional Axion Expecta- tions,

    Matthew Reece, “Extra-Dimensional Axion Expecta- tions,” (2024), arXiv:2406.08543 [hep-ph]

    2024 arXiv

  21. [29]

    High-quality axions from higher-form symmetries in extra di- mensions,

    Nathaniel Craig and Marius Kongsore, “High-quality axions from higher-form symmetries in extra di- mensions,” Phys. Rev. D 111, 015047 (2025), arXiv:2408.10295 [hep-ph]

    2025 arXiv

  22. [30]

    Ax- ion Couplings in Heterotic String Theory,

    Prateek Agrawal, Michael Nee, and Mario Reig, “Ax- ion Couplings in Heterotic String Theory,” (2024), arXiv:2410.03820 [hep-ph]

    2024 arXiv

  23. [31]

    Unity of All Elementary Particle Forces,

    H. Georgi and S. L. Glashow, “Unity of All Elementary Particle Forces,” Phys. Rev. Lett. 32, 438–441 (1974)

    1974

  24. [32]

    Unified Interac- tions of Leptons and Hadrons,

    Harald Fritzsch and Peter Minkowski, “Unified Interac- tions of Leptons and Hadrons,” Annals Phys. 93, 193– 266 (1975)

    1975

  25. [33]

    Gauge symmetry breaking from extra space S**1 / Z(2),

    Yoshiharu Kawamura, “Gauge symmetry breaking from extra space S**1 / Z(2),” Prog. Theor. Phys. 103, 613– 619 (2000), arXiv:hep-ph/9902423

    2000 arXiv

  26. [34]

    Triplet doublet splitting, proton stability and extra dimension,

    Yoshiharu Kawamura, “Triplet doublet splitting, proton stability and extra dimension,” Prog. Theor. Phys. 105, 999–1006 (2001), arXiv:hep-ph/0012125

    2001 arXiv

  27. [35]

    Gauge unifi- cation in higher dimensions,

    Lawrence J. Hall and Yasunori Nomura, “Gauge unifi- cation in higher dimensions,” Phys. Rev. D 64, 055003 (2001), arXiv:hep-ph/0103125

    2001 arXiv

  28. [36]

    A Complete theory of grand unification in five-dimensions,

    Lawrence J. Hall and Yasunori Nomura, “A Complete theory of grand unification in five-dimensions,” Phys. Rev. D 66, 075004 (2002), arXiv:hep-ph/0205067

    2002 arXiv

  29. [37]

    A Minimal S**1 / (Z(2) x Z-prime (2)) orbifold GUT,

    Arthur Hebecker and John March-Russell, “A Minimal S**1 / (Z(2) x Z-prime (2)) orbifold GUT,” Nucl. Phys. B 613, 3–16 (2001), arXiv:hep-ph/0106166

    2001 arXiv

  30. [38]

    SU(5) grand unification in extra dimensions and proton decay,

    Guido Altarelli and Ferruccio Feruglio, “SU(5) grand unification in extra dimensions and proton decay,” Phys. Lett. B 511, 257–264 (2001), arXiv:hep-ph/0102301

    2001 arXiv

  31. [39]

    Grand unification at intermediate mass scales through extra dimensions,

    Keith R. Dienes, Emilian Dudas, and Tony Gherghetta, “Grand unification at intermediate mass scales through extra dimensions,” Nucl. Phys. B 537, 47–108 (1999), arXiv:hep-ph/9806292

    1999 arXiv

  32. [40]

    Running and matching from five- dimensions to four-dimensions,

    R. Contino, L. Pilo, R. Rattazzi, and En- rico Trincherini, “Running and matching from five- dimensions to four-dimensions,” Nucl. Phys. B 622, 227–239 (2002), arXiv:hep-ph/0108102

    2002 arXiv

  33. [41]

    Grand unification in RS1,

    Kaustubh Agashe, Antonio Delgado, and Raman Sun- drum, “Grand unification in RS1,” Annals Phys. 304, 145–164 (2003), arXiv:hep-ph/0212028

    2003 arXiv

  34. [42]

    Power - like threshold corrections to gauge unification in ex- tra dimensions,

    Arthur Hebecker and Alexander Westphal, “Power - like threshold corrections to gauge unification in ex- tra dimensions,” Annals Phys. 305, 119–136 (2003), arXiv:hep-ph/0212175

    2003 arXiv

  35. [43]

    Gauge uni- fication in extra dimensions: Power corrections vs. higher-dimension operators,

    Arthur Hebecker and Alexander Westphal, “Gauge uni- fication in extra dimensions: Power corrections vs. higher-dimension operators,” Nucl. Phys. B 701, 273– 298 (2004), arXiv:hep-th/0407014

    2004 arXiv

  36. [44]

    Seeing Higher- Dimensional Grand Unification In Primordial Non- Gaussianities,

    Soubhik Kumar and Raman Sundrum, “Seeing Higher- Dimensional Grand Unification In Primordial Non- Gaussianities,” JHEP 04, 120 (2019), arXiv:1811.11200 [hep-ph]

    2019 arXiv

  37. [45]

    On Gauge Threshold Corrections for Local IIB/F-theory GUTs,

    Joseph P. Conlon and Eran Palti, “On Gauge Threshold Corrections for Local IIB/F-theory GUTs,” Phys. Rev. D 80, 106004 (2009), arXiv:0907.1362 [hep-th]

    2009 arXiv

  38. [46]

    Symmetry breaking patterns in super- string models,

    Edward Witten, “Symmetry breaking patterns in super- string models,” Nucl. Phys. B 258, 75–100 (1985)

    1985

  39. [47]

    Grand Unified Theories and Proton Decay,

    Paul Langacker, “Grand Unified Theories and Proton Decay,” Phys. Rept. 72, 185 (1981)

    1981

  40. [48]

    Proton decay and grand uni- fication,

    Goran Senjanovic, “Proton decay and grand uni- fication,” AIP Conf. Proc. 1200, 131–141 (2010), arXiv:0912.5375 [hep-ph]

    2010 arXiv

  41. [49]

    Proton decay in SUSY GUTs,

    Junji Hisano, “Proton decay in SUSY GUTs,” PTEP 2022, 12B104 (2022), arXiv:2202.01404 [hep-ph]

    2022 arXiv

  42. [50]

    Proton decay,

    Tommy Ohlsson, “Proton decay,” Nucl. Phys. B 993, 116268 (2023), arXiv:2306.02401 [hep-ph]

    2023 arXiv

  43. [51]

    Hyper- Kamiokande Design Report,

    K. Abe et al. (Hyper-Kamiokande), “Hyper- Kamiokande Design Report,” (2018), arXiv:1805.04163 [physics.ins-det]

    2018 arXiv

  44. [52]

    Proton decay in intersecting D-brane models,

    Igor R. Klebanov and Edward Witten, “Proton decay in intersecting D-brane models,” Nucl. Phys. B 664, 3–20 (2003), arXiv:hep-th/0304079

    2003 arXiv

  45. [53]

    Hierarchies without symmetries from extra dimensions,

    Nima Arkani-Hamed and Martin Schmaltz, “Hierarchies without symmetries from extra dimensions,” Phys. Rev. D 61, 033005 (2000), arXiv:hep-ph/9903417

    2000 arXiv

  46. [54]

    Intersecting brane worlds,

    G. Aldazabal, S. Franco, Luis E. Ibanez, R. Rabadan, and A. M. Uranga, “Intersecting brane worlds,” JHEP 02, 047 (2001), arXiv:hep-ph/0011132

    2001 arXiv

  47. [55]

    Bulk fields and supersymmetry in a slice of AdS,

    Tony Gherghetta and Alex Pomarol, “Bulk fields and supersymmetry in a slice of AdS,” Nucl. Phys. B 586, 141–162 (2000), arXiv:hep-ph/0003129

    2000 arXiv

  48. [56]

    Complete clas- sification of reflexive polyhedra in four-dimensions,

    Maximilian Kreuzer and Harald Skarke, “Complete clas- sification of reflexive polyhedra in four-dimensions,” Adv. Theor. Math. Phys. 4, 1209–1230 (2000), arXiv:hep-th/0002240

    2000 arXiv

  49. [57]

    Dual polyhedra and mirror symme- try for Calabi-Yau hypersurfaces in toric varieties,

    Victor V. Batyrev, “Dual polyhedra and mirror symme- try for Calabi-Yau hypersurfaces in toric varieties,” J. Alg. Geom. 3, 493–545 (1994), arXiv:alg-geom/9310003

    1994 arXiv

  50. [58]

    The Kreuzer-Skarke Axiverse,

    Mehmet Demirtas, Cody Long, Liam McAllister, and Mike Stillman, “The Kreuzer-Skarke Axiverse,” JHEP 04, 138 (2020), arXiv:1808.01282 [hep-th]

    2020 arXiv

  51. [59]

    CYTools: A Software Package for Analyz- ing Calabi-Yau Manifolds,

    Mehmet Demirtas, Andres Rios-Tascon, and Liam McAllister, “CYTools: A Software Package for Analyz- ing Calabi-Yau Manifolds,” (2022), arXiv:2211.03823 [hep-th]

    2022 arXiv

  52. [60]

    Glimmers from the Axiverse,

    Naomi Gendler, David J. E. Marsh, Liam McAllis- ter, and Jakob Moritz, “Glimmers from the Axiverse,” (2023), arXiv:2309.13145 [hep-th]

    2023 arXiv

  53. [61]

    Towards string theory expectations for photon couplings to axionlike particles,

    James Halverson, Cody Long, Brent Nelson, and Gus- tavo Salinas, “Towards string theory expectations for photon couplings to axionlike particles,” Phys. Rev. D 100, 106010 (2019), arXiv:1909.05257 [hep-th]

    2019 arXiv

  54. [62]

    The type IIB string axiverse and its low-energy phe- nomenology,

    Michele Cicoli, Mark Goodsell, and Andreas Ringwald, “The type IIB string axiverse and its low-energy phe- nomenology,” JHEP 10, 146 (2012), arXiv:1206.0819 [hep-th]

    2012 arXiv

  55. [63]

    Mixed Mediation of Super- symmetry Breaking with Anomalous U(1) Gauge Sym- metry,

    Kiwoon Choi, Kwang Sik Jeong, Ken-Ichi Okumura, and Masahiro Yamaguchi, “Mixed Mediation of Super- symmetry Breaking with Anomalous U(1) Gauge Sym- metry,” JHEP 06, 049 (2011), arXiv:1104.3274 [hep-ph]

    2011 arXiv

  56. [64]

    Axion-like Particles from String Compactifications,

    Michele Cicoli, “Axion-like Particles from String Compactifications,” in 9th Patras Workshop on Ax- ions, WIMPs and WISPs (2013) pp. 235–242, arXiv:1309.6988 [hep-th]

    2013 arXiv

  57. [65]

    Explicit de Sitter Flux Vacua for Global String Models with Chiral Matter,

    Michele Cicoli, Denis Klevers, Sven Krippendorf, Christoph Mayrhofer, Fernando Quevedo, and Roberto Valandro, “Explicit de Sitter Flux Vacua for Global String Models with Chiral Matter,” JHEP 05, 001 (2014), arXiv:1312.0014 [hep-th]

    2014 arXiv

  58. [66]

    Heterotic QCD axion,

    Evgeny I. Buchbinder, Andrei Constantin, and An- dre Lukas, “Heterotic QCD axion,” Phys. Rev. D 91, 046010 (2015), arXiv:1412.8696 [hep-th]. 14

    2015 arXiv

  59. [67]

    String theoretic QCD axions in the light of PLANCK and BICEP2,

    Kiwoon Choi, Kwang Sik Jeong, and Min-Seok Seo, “String theoretic QCD axions in the light of PLANCK and BICEP2,” JHEP 07, 092 (2014), arXiv:1404.3880 [hep-th]

    2014 arXiv

  60. [68]

    Correlation between Dark Mat- ter and Dark Radiation in String Compactifications,

    Rouzbeh Allahverdi, Michele Cicoli, Bhaskar Dutta, and Kuver Sinha, “Correlation between Dark Mat- ter and Dark Radiation in String Compactifications,” JCAP 10, 002 (2014), arXiv:1401.4364 [hep-ph]

    2014 arXiv

  61. [69]

    Open String Axiverse,

    Rudin Petrossian-Byrne and Giovanni Villadoro, “Open String Axiverse,” (2025), arXiv:2503.16387 [hep-ph]

    2025 arXiv

  62. [70]

    Higher Axion Strings,

    Vazha Loladze, Arthur Platschorre, and Mario Reig, “Higher Axion Strings,” (2025), arXiv:2503.18707 [hep- ph]

    2025 arXiv

  63. [71]

    Fayet- Iliopoulos Terms in String Theory,

    Michael Dine, N. Seiberg, and Edward Witten, “Fayet- Iliopoulos Terms in String Theory,” Nucl. Phys. B 289, 589–598 (1987)

    1987

  64. [74]

    A Search for Invisible Axion Dark Matter with the Axion Dark Matter Experiment,

    N. Du et al. (ADMX), “A Search for Invisible Axion Dark Matter with the Axion Dark Matter Experiment,” Phys. Rev. Lett. 120, 151301 (2018), arXiv:1804.05750 [hep-ex]

    2018 arXiv

  65. [75]

    Extended Search for the In- visible Axion with the Axion Dark Matter Experiment,

    T. Braine et al.(ADMX), “Extended Search for the In- visible Axion with the Axion Dark Matter Experiment,” Phys. Rev. Lett. 124, 101303 (2020), arXiv:1910.08638 [hep-ex]

    2020 arXiv

  66. [76]

    Axion dark matter exper- iment: Run 1B analysis details,

    C. Bartram et al. (ADMX), “Axion dark matter exper- iment: Run 1B analysis details,” Phys. Rev. D 103, 032002 (2021), arXiv:2010.06183 [astro-ph.CO]

    2021 arXiv

  67. [77]

    Results from phase 1 of the HAYSTAC microwave cavity axion experiment,

    L. Zhong et al. (HAYSTAC), “Results from phase 1 of the HAYSTAC microwave cavity axion experiment,” Phys. Rev. D 97, 092001 (2018), arXiv:1803.03690 [hep- ex]

    2018 arXiv

  68. [79]

    A quantum-enhanced search for dark matter axions,

    K. M. Backes et al.(HAYSTAC), “A quantum-enhanced search for dark matter axions,” Nature 590, 238–242 (2021), arXiv:2008.01853 [quant-ph]

    2021 arXiv

  69. [80]

    Dielectric Haloscopes: A New Way to De- tect Axion Dark Matter,

    Allen Caldwell, Gia Dvali, B´ ela Majorovits, Alexander Millar, Georg Raffelt, Javier Redondo, Olaf Reimann, Frank Simon, and Frank Steffen (MADMAX Work- ing Group), “Dielectric Haloscopes: A New Way to De- tect Axion Dark Matter,” Phys. Rev. Lett. 118, 091801 (2017), arXiv:16...

    2017 arXiv

  70. [81]

    MADMAX: A new road to axion dark matter de- tection,

    B. Majorovits et al. (MADMAX interest Group), “MADMAX: A new road to axion dark matter de- tection,” J. Phys. Conf. Ser. 1342, 012098 (2020), arXiv:1712.01062 [physics.ins-det]

    2020 arXiv

  71. [82]

    A new experimental ap- proach to probe QCD axion dark matter in the mass range above 40 µeV,

    P. Brun et al. (MADMAX), “A new experimental ap- proach to probe QCD axion dark matter in the mass range above 40 µeV,” Eur. Phys. J. C 79, 186 (2019), arXiv:1901.07401 [physics.ins-det]

    2019 arXiv

  72. [83]

    First search for ax- ion dark matter with a Madmax prototype,

    B. Ary dos Santos Garcia et al., “First search for ax- ion dark matter with a Madmax prototype,” (2024), arXiv:2409.11777 [hep-ex]

    2024 arXiv

  73. [84]

    Tun- able axion plasma haloscopes,

    Matthew Lawson, Alexander J. Millar, Matteo Pan- caldi, Edoardo Vitagliano, and Frank Wilczek, “Tun- able axion plasma haloscopes,” Phys. Rev. Lett. 123, 141802 (2019), arXiv:1904.11872 [hep-ph]

    2019 arXiv

  74. [85]

    Ex- ploration of Wire Array Metamaterials for the Plasma Axion Haloscope,

    Mackenzie Wooten, Alex Droster, Al Kenany, Dajie Sun, Samantha M. Lewis, and Karl van Bibber, “Ex- ploration of Wire Array Metamaterials for the Plasma Axion Haloscope,” Annalen Phys. 536, 2200479 (2024), arXiv:2203.13945 [hep-ex]

    2024 arXiv

  75. [86]

    Searching for dark matter with plasma haloscopes,

    Alexander J. Millar et al.(ALPHA), “Searching for dark matter with plasma haloscopes,” Phys. Rev. D 107, 055013 (2023), arXiv:2210.00017 [hep-ph]

    2023 arXiv

  76. [87]

    Broadband Solenoidal Halo- scope for Terahertz Axion Detection,

    Jesse Liu et al.(BREAD), “Broadband Solenoidal Halo- scope for Terahertz Axion Detection,” Phys. Rev. Lett. 128, 131801 (2022), arXiv:2111.12103 [physics.ins-det]

    2022 arXiv

  77. [88]

    First Results from a Broadband Search for Dark Photon Dark Matter in the 44 to 52 µeV Range with a Coaxial Dish Antenna,

    Stefan Knirck et al. (BREAD), “First Results from a Broadband Search for Dark Photon Dark Matter in the 44 to 52 µeV Range with a Coaxial Dish Antenna,” Phys. Rev. Lett. 132, 131004 (2024), arXiv:2310.13891 [hep-ex]

    2024 arXiv

  78. [89]

    Discov- ery prospects with the Dark-photons & Axion-like parti- cles Interferometer,

    Javier De Miguel, Juan F. Hern´ andez-Cabrera, Elvio Hern´ andez-Su´ arez, Enrique Joven-´Alvarez, Chiko Otani, and J. Alberto Rubi˜ no Mart ´ ın (DALI), “Discov- ery prospects with the Dark-photons & Axion-like parti- cles Interferometer,” Phys. Rev. D 109, 062002 (2024), arX...

    2024 arXiv

  79. [90]

    A dark matter telescope prob- ing the 6 to 60 GHz band,

    Javier De Miguel, “A dark matter telescope prob- ing the 6 to 60 GHz band,” JCAP 04, 075 (2021), arXiv:2003.06874 [physics.ins-det]

    2021 arXiv

  80. [91]

    Axion Dark Matter,

    C. B. Adams et al., “Axion Dark Matter,” in Snowmass 2021 (2022) arXiv:2203.14923 [hep-ex]

    2022 arXiv

  81. [92]

    The dark-matter axion mass,

    Vincent B. . Klaer and Guy D. Moore, “The dark-matter axion mass,” JCAP 11, 049 (2017), arXiv:1708.07521 [hep-ph]

    2017 arXiv

  82. [93]

    Axions from Strings: the Attractive Solution,

    Marco Gorghetto, Edward Hardy, and Giovanni Vil- ladoro, “Axions from Strings: the Attractive Solution,” JHEP 07, 151 (2018), arXiv:1806.04677 [hep-ph]

    2018 arXiv

  83. [94]

    Early seeds of axion miniclusters,

    Alejandro Vaquero, Javier Redondo, and Julia Stadler, “Early seeds of axion miniclusters,” JCAP 04, 012 (2019), arXiv:1809.09241 [astro-ph.CO]

    2019 arXiv

  84. [95]

    Radiation from Global Topological Strings using Adaptive Mesh Re- finement: Methodology and Massless Modes,

    Amelia Drew and E. P. S. Shellard, “Radiation from Global Topological Strings using Adaptive Mesh Re- finement: Methodology and Massless Modes,” (2019), arXiv:1910.01718 [astro-ph.CO]

    2019 arXiv

  85. [96]

    Radiation from global topological strings using adaptive mesh refine- ment: Massive modes,

    Amelia Drew and E. P. S. Shellard, “Radiation from global topological strings using adaptive mesh refine- ment: Massive modes,” Phys. Rev. D 107, 043507 (2023), arXiv:2211.10184 [astro-ph.CO]

    2023 arXiv

  86. [97]

    Axion string source modeling,

    Amelia Drew, Tomasz Kinowski, and E. P. S. Shel- lard, “Axion string source modeling,” Phys. Rev. D110, 043513 (2024), arXiv:2312.07701 [astro-ph.CO]

    2024 arXiv

  87. [98]

    More axions from strings,

    Marco Gorghetto, Edward Hardy, and Giovanni Vil- ladoro, “More axions from strings,” SciPost Phys. 10, 050 (2021), arXiv:2007.04990 [hep-ph]

    2021 arXiv

  88. [99]

    Comments on axions, domain walls, and cosmic strings,

    Michael Dine, Nicolas Fernandez, Akshay Ghalsasi, and Hiren H. Patel, “Comments on axions, domain walls, and cosmic strings,” JCAP 11, 041 (2021), arXiv:2012.13065 [hep-ph]

    2021 arXiv

  89. [100]

    Dark matter from axion strings with adaptive mesh refinement,

    Malte Buschmann, Joshua W. Foster, Anson Hook, Adam Peterson, Don E. Willcox, Weiqun Zhang, and Benjamin R. Safdi, “Dark matter from axion strings with adaptive mesh refinement,” Nature Commun. 13, 1049 (2022), arXiv:2108.05368 [hep-ph]

    2022 arXiv

  90. [101]

    Axion dark matter from cosmic string network,

    Heejoo Kim, Junghyeon Park, and Minho Son, “Axion dark matter from cosmic string network,” JHEP07, 150 15 (2024), arXiv:2402.00741 [hep-ph]

    2024 arXiv

  91. [102]

    Spectrum of global string networks and the axion dark matter mass,

    Ken’ichi Saikawa, Javier Redondo, Alejandro Vaquero, and Mathieu Kaltschmidt, “Spectrum of global string networks and the axion dark matter mass,” (2024), arXiv:2401.17253 [hep-ph]

    2024 arXiv

  92. [103]

    More Scalings from Cos- mic Strings,

    Heejoo Kim and Minho Son, “More Scalings from Cos- mic Strings,” (2024), arXiv:2411.08455 [hep-ph]

    2024

  93. [104]

    Axion mass prediction from adaptive mesh refinement cosmological lattice sim- ulations,

    Joshua N. Benabou, Malte Buschmann, Joshua W. Fos- ter, and Benjamin R. Safdi, “Axion mass prediction from adaptive mesh refinement cosmological lattice sim- ulations,” (2024), arXiv:2412.08699 [hep-ph]

    2024 arXiv

  94. [105]

    Exploring the String Axiverse with Precision Black Hole Physics,

    Asimina Arvanitaki and Sergei Dubovsky, “Exploring the String Axiverse with Precision Black Hole Physics,” Phys. Rev. D 83, 044026 (2011), arXiv:1004.3558 [hep- th]

    2011 arXiv

  95. [106]

    Black hole superradiance of self- interacting scalar fields,

    Masha Baryakhtar, Marios Galanis, Robert Lasenby, and Olivier Simon, “Black hole superradiance of self- interacting scalar fields,” Phys. Rev. D 103, 095019 (2021), arXiv:2011.11646 [hep-ph]

    2021 arXiv

  96. [107]

    Stepping up superradiance constraints on axions,

    Samuel J. Witte and Andrew Mummery, “Stepping up superradiance constraints on axions,” Phys. Rev. D 111, 083044 (2025), arXiv:2412.03655 [hep-ph]

    2025 arXiv

  97. [108]

    Broadband and Resonant Approaches to Axion Dark Matter Detection,

    Yonatan Kahn, Benjamin R. Safdi, and Jesse Thaler, “Broadband and Resonant Approaches to Axion Dark Matter Detection,” Phys. Rev. Lett. 117, 141801 (2016), arXiv:1602.01086 [hep-ph]

    2016 arXiv

  98. [109]

    First Results from ABRACADABRA-10 cm: A Search for Sub-µeV Axion Dark Matter,

    Jonathan L. Ouellet et al. (ABRACADABRA), “First Results from ABRACADABRA-10 cm: A Search for Sub-µeV Axion Dark Matter,” Phys. Rev. Lett. 122, 121802 (2019), arXiv:1810.12257 [hep-ex]

    2019 arXiv

  99. [110]

    Design and implemen- tation of the ABRACADABRA-10 cm axion dark matter search,

    Jonathan L. Ouellet et al., “Design and implemen- tation of the ABRACADABRA-10 cm axion dark matter search,” Phys. Rev. D 99, 052012 (2019), arXiv:1901.10652 [physics.ins-det]

    2019 arXiv

  100. [111]

    Search for Low-Mass Ax- ion Dark Matter with ABRACADABRA-10 cm,

    Chiara P. Salemi et al., “Search for Low-Mass Ax- ion Dark Matter with ABRACADABRA-10 cm,” Phys. Rev. Lett. 127, 081801 (2021), arXiv:2102.06722 [hep- ex]

    2021 arXiv

  101. [112]

    Projected sensitiv- ity of DMRadio-m3: A search for the QCD axion below 1 µeV,

    L. Brouwer et al. (DMRadio), “Projected sensitiv- ity of DMRadio-m3: A search for the QCD axion below 1 µeV,” Phys. Rev. D 106, 103008 (2022), arXiv:2204.13781 [hep-ex]

    2022 arXiv

  102. [113]

    Proposal for a definitive search for GUT-scale QCD axions,

    L. Brouwer et al.(DMRadio), “Proposal for a definitive search for GUT-scale QCD axions,” Phys. Rev. D 106, 112003 (2022), arXiv:2203.11246 [hep-ex]

    2022 arXiv

  103. [114]

    Lumped- element axion dark matter detection beyond the magne- toquasistatic limit,

    Joshua N. Benabou, Joshua W. Foster, Yonatan Kahn, Benjamin R. Safdi, and Chiara P. Salemi, “Lumped- element axion dark matter detection beyond the magne- toquasistatic limit,” Phys. Rev. D 108, 035009 (2023), arXiv:2211.00008 [hep-ph]

    2023 arXiv

  104. [115]

    Electromagnetic mod- eling and science reach of DMRadio-m 3,

    A. AlShirawi et al.(DMRadio), “Electromagnetic mod- eling and science reach of DMRadio-m 3,” (2023), arXiv:2302.14084 [hep-ex]

    2023 arXiv

  105. [116]

    Axion Dark Matter Detection by Superconduct- ing Resonant Frequency Conversion,

    Asher Berlin, Raffaele Tito D’Agnolo, Sebastian A. R. Ellis, Christopher Nantista, Jeffrey Neilson, Philip Schuster, Sami Tantawi, Natalia Toro, and Kevin Zhou, “Axion Dark Matter Detection by Superconduct- ing Resonant Frequency Conversion,” JHEP 07, 088 (2020), arXiv:1912.11...

    2020 arXiv

  106. [117]

    Design of axion and axion dark matter searches based on ultra high Q SRF cavities,

    B. Giaccone et al., “Design of axion and axion dark matter searches based on ultra high Q SRF cavities,” (2022), arXiv:2207.11346 [hep-ex]

    2022 arXiv

  107. [118]

    New Ob- servables for Direct Detection of Axion Dark Matter,

    Peter W. Graham and Surjeet Rajendran, “New Ob- servables for Direct Detection of Axion Dark Matter,” Phys. Rev. D 88, 035023 (2013), arXiv:1306.6088 [hep- ph]

    2013 arXiv

  108. [119]

    Proposal for a Cosmic Axion Spin Precession Experiment (CASPEr),

    Dmitry Budker, Peter W. Graham, Micah Ledbetter, Surjeet Rajendran, and Alex Sushkov, “Proposal for a Cosmic Axion Spin Precession Experiment (CASPEr),” Phys. Rev. X 4, 021030 (2014), arXiv:1306.6089 [hep- ph]

    2014 arXiv

  109. [120]

    Overview of the Cosmic Axion Spin Precession Experiment (CASPEr),

    Derek F. Jackson Kimball et al. , “Overview of the Cosmic Axion Spin Precession Experiment (CASPEr),” Springer Proc. Phys. 245, 105–121 (2020), arXiv:1711.08999 [physics.ins-det]

    2020 arXiv

  110. [121]

    Quantum sensitivity limits of nuclear magnetic res- onance experiments searching for new fundamental physics,

    Deniz Aybas, Hendrik Bekker, John W. Blanchard, Dmitry Budker, Gary P. Centers, Nataniel L. Figueroa, Alexander V. Gramolin, Derek F. Jackson Kim- ball, Arne Wickenbrock, and Alexander O. Sushkov, “Quantum sensitivity limits of nuclear magnetic res- onance experiments searchin...

    2021 arXiv

  111. [122]

    Sensitivity of Spin-Precession Ax- ion Experiments,

    Jeff A. Dror, Stefania Gori, Jacob M. Leedom, and Nicholas L. Rodd, “Sensitivity of Spin-Precession Ax- ion Experiments,” Phys. Rev. Lett. 130, 181801 (2023), arXiv:2210.06481 [hep-ph]

    2023 arXiv

  112. [123]

    On the General Theory of Collisions for Particles with Spin,

    M. Jacob and G. C. Wick, “On the General Theory of Collisions for Particles with Spin,” Annals Phys. 7, 404–428 (1959)

    1959

  113. [124]

    The Strength of Weak Interactions at Very High-Energies and the Higgs Boson Mass,

    Benjamin W. Lee, C. Quigg, and H. B. Thacker, “The Strength of Weak Interactions at Very High-Energies and the Higgs Boson Mass,” Phys. Rev. Lett. 38, 883– 885 (1977)

    1977

  114. [125]

    Weak Interactions at Very High-Energies: The Role of the Higgs Boson Mass,

    Benjamin W. Lee, C. Quigg, and H. B. Thacker, “Weak Interactions at Very High-Energies: The Role of the Higgs Boson Mass,” Phys. Rev. D 16, 1519 (1977)

    1977

  115. [126]

    Phenomenological Lagrangians,

    Steven Weinberg, “Phenomenological Lagrangians,” Physica A 96, 327–340 (1979)

    1979

  116. [127]

    Chiral Quarks and the Nonrelativistic Quark Model,

    Aneesh Manohar and Howard Georgi, “Chiral Quarks and the Nonrelativistic Quark Model,” Nucl. Phys. B 234, 189–212 (1984)

    1984

  117. [128]

    The UV fate of anomalous U(1)s and the Swampland,

    Nathaniel Craig, Isabel Garcia Garcia, and Graham D. Kribs, “The UV fate of anomalous U(1)s and the Swampland,” JHEP 11, 063 (2020), arXiv:1912.10054 [hep-ph]

    2020 arXiv

  118. [129]

    Unitarity constraints on ALP interactions,

    I. Brivio, O. J. P. ´Eboli, and M. C. Gonzalez-Garcia, “Unitarity constraints on ALP interactions,” Phys. Rev. D 104, 035027 (2021), arXiv:2106.05977 [hep-ph]

    2021 arXiv

  119. [130]

    Weak Interaction Singlet and Strong CP Invariance,

    Jihn E. Kim, “Weak Interaction Singlet and Strong CP Invariance,” Phys. Rev. Lett. 43, 103 (1979)

    1979

  120. [131]

    Can Confinement Ensure Natural CP In- variance of Strong Interactions?

    Mikhail A. Shifman, A. I. Vainshtein, and Valentin I. Zakharov, “Can Confinement Ensure Natural CP In- variance of Strong Interactions?” Nucl. Phys. B 166, 493–506 (1980)

    1980

  121. [132]

    Axion Predictions in SO(10)×U (1)PQ Models,

    Anne Ernst, Andreas Ringwald, and Carlos Tamarit, “Axion Predictions in SO(10)×U (1)PQ Models,” JHEP 02, 103 (2018), arXiv:1801.04906 [hep-ph]

    2018 arXiv

  122. [133]

    SU(5) and the Invisible Axion,

    Mark B. Wise, Howard Georgi, and Sheldon L. Glashow, “SU(5) and the Invisible Axion,” Phys. Rev. Lett. 47, 402 (1981)

    1981

  123. [134]

    Axion mass prediction from minimal grand unification,

    Luca Di Luzio, Andreas Ringwald, and Car- los Tamarit, “Axion mass prediction from minimal grand unification,” Phys. Rev. D 98, 095011 (2018), arXiv:1807.09769 [hep-ph]

    2018 arXiv

  124. [135]

    The QCD Axion and Unification,

    Pavel Fileviez P´ erez, Clara Murgui, and Alexis D. Plas- cencia, “The QCD Axion and Unification,” JHEP 11, 16 093 (2019), arXiv:1908.01772 [hep-ph]

    2019 arXiv

  125. [136]

    A QCD axion from higher dimen- sional gauge field,

    Ki-woon Choi, “A QCD axion from higher dimen- sional gauge field,” Phys. Rev. Lett. 92, 101602 (2004), arXiv:hep-ph/0308024

    2004 arXiv

  126. [137]

    Ax- ion couplings in grand unified theories,

    Prateek Agrawal, Michael Nee, and Mario Reig, “Ax- ion couplings in grand unified theories,” JHEP 10, 141 (2022), arXiv:2206.07053 [hep-ph]

    2022 arXiv

  127. [138]

    Polchinski, String theory

    J. Polchinski, String theory. Vol. 2: Superstring theory and beyond, Cambridge Monographs on Mathematical Physics (Cambridge University Press, 2007)

    2007

  128. [139]

    A Large mass hi- erarchy from a small extra dimension,

    Lisa Randall and Raman Sundrum, “A Large mass hi- erarchy from a small extra dimension,” Phys. Rev. Lett. 83, 3370–3373 (1999), arXiv:hep-ph/9905221

    1999 arXiv

  129. [140]

    Axion clockworks from heterotic M-theory: the QCD- axion and its ultra-light companion,

    Sang Hui Im, Hans Peter Nilles, and Marek Olechowski, “Axion clockworks from heterotic M-theory: the QCD- axion and its ultra-light companion,” JHEP 10, 159 (2019), arXiv:1906.11851 [hep-th]

    2019 arXiv

  130. [141]

    Extra space-time dimensions and unification,

    Keith R. Dienes, Emilian Dudas, and Tony Gherghetta, “Extra space-time dimensions and unification,” Phys. Lett. B 436, 55–65 (1998), arXiv:hep-ph/9803466

    1998 arXiv

  131. [142]

    The QCD axion and moduli stabil- isation,

    Joseph P. Conlon, “The QCD axion and moduli stabil- isation,” JHEP 05, 078 (2006), arXiv:hep-th/0602233

    2006 arXiv

  132. [143]

    On the possibility of large axion decay con- stants,

    Tom Banks, Michael Dine, Patrick J. Fox, and Elie Gorbatov, “On the possibility of large axion decay con- stants,” JCAP 06, 001 (2003), arXiv:hep-th/0303252

    2003 arXiv

  133. [144]

    The String landscape, black holes and gravity as the weakest force,

    Nima Arkani-Hamed, Lubos Motl, Alberto Nicolis, and Cumrun Vafa, “The String landscape, black holes and gravity as the weakest force,” JHEP 06, 060 (2007), arXiv:hep-th/0601001

    2007 arXiv

  134. [145]

    Fuzzy Axions and Associated Relics,

    Elijah Sheridan, Federico Carta, Naomi Gendler, Mudit Jain, David J. E. Marsh, Liam McAllister, Nicole Righi, Keir K. Rogers, and Andreas Schachner, “Fuzzy Axions and Associated Relics,” (2024), arXiv:2412.12012 [hep- th]

    2024 arXiv

  135. [146]

    PQ axiverse,

    Mehmet Demirtas, Naomi Gendler, Cody Long, Liam McAllister, and Jakob Moritz, “PQ axiverse,” JHEP 06, 092 (2023), arXiv:2112.04503 [hep-th]

    2023 arXiv

  136. [147]

    Axion minima in string theory,

    Naomi Gendler, Oliver Janssen, Matthew Kleban, Joan La Madrid, and Viraf M. Mehta, “Axion minima in string theory,” (2023), arXiv:2309.01831 [hep-th]

    2023 arXiv

  137. [148]

    Superradiance in string theory,

    Viraf M. Mehta, Mehmet Demirtas, Cody Long, David J. E. Marsh, Liam McAllister, and Matthew J. Stott, “Superradiance in string theory,” JCAP 07, 033 (2021), arXiv:2103.06812 [hep-th]

    2021 arXiv

  138. [149]

    Measurement of the Permanent Electric Dipole Moment of the Neutron,

    C. Abel et al., “Measurement of the Permanent Electric Dipole Moment of the Neutron,” Phys. Rev. Lett. 124, 081803 (2020), arXiv:2001.11966 [hep-ex]

    2020 arXiv

  139. [150]

    The Strong CP problem and ax- ions,

    R. D. Peccei, “The Strong CP problem and ax- ions,” Lect. Notes Phys. 741, 3–17 (2008), arXiv:hep- ph/0607268

    2008

  140. [151]

    The Cosmological Dynamics of String Theory Axion Strings,

    Joshua N. Benabou, Quentin Bonnefoy, Malte Buschmann, Soubhik Kumar, and Benjamin R. Safdi, “The Cosmological Dynamics of String Theory Axion Strings,” (2023), arXiv:2312.08425 [hep-ph]

    2023 arXiv

  141. [152]

    Green, J

    Michael B. Green, J. H. Schwarz, and Edward Wit- ten, SUPERSTRING THEORY. VOL. 1: INTRO- DUCTION, Cambridge Monographs on Mathematical Physics (1988)

    1988

  142. [153]

    The Weak Gravity Conjecture and axion strings,

    Ben Heidenreich, Matthew Reece, and Tom Rudelius, “The Weak Gravity Conjecture and axion strings,” JHEP 11, 004 (2021), arXiv:2108.11383 [hep-th]

    2021 arXiv

  143. [154]

    Axion Periodic- ity and Coupling Quantization in the Presence of Mix- ing,

    Katherine Fraser and Matthew Reece, “Axion Periodic- ity and Coupling Quantization in the Presence of Mix- ing,” JHEP 05, 066 (2020), arXiv:1910.11349 [hep-ph]

    2020 arXiv

  144. [155]

    Search for proton decay via p → e+π0 and p → µ+π0 with an enlarged fiducial volume in Super-Kamiokande I-IV,

    A. Takenaka et al. (Super-Kamiokande), “Search for proton decay via p → e+π0 and p → µ+π0 with an enlarged fiducial volume in Super-Kamiokande I-IV,” Phys. Rev. D 102, 112011 (2020), arXiv:2010.16098 [hep-ex]

    2020

  145. [156]

    Dark dimension and the grand uni- fication of forces,

    Jonathan J. Heckman, Cumrun Vafa, Timo Weigand, and Fengjun Xu, “Dark dimension and the grand uni- fication of forces,” Phys. Rev. D 111, 046014 (2025), arXiv:2409.01405 [hep-th]

    2025 arXiv

  146. [157]

    Mass Hierarchies versus proton Decay in MSSM Ori- entifold Compactifications,

    Mirjam Cvetic, James Halverson, and Robert Richter, “Mass Hierarchies versus proton Decay in MSSM Ori- entifold Compactifications,” (2009), arXiv:0910.2239 [hep-th]

    2009 arXiv

  147. [158]

    The Weinberg Operator and a Lower String Scale in Orientifold Compactifications,

    Mirjam Cvetic, James Halverson, Paul Langacker, and Robert Richter, “The Weinberg Operator and a Lower String Scale in Orientifold Compactifications,” JHEP 10, 094 (2010), arXiv:1001.3148 [hep-th]

    2010 arXiv

  148. [159]

    DESI DR2 Results II: Measurements of Baryon Acoustic Oscillations and Cosmological Constraints,

    M. Abdul Karim et al. (DESI), “DESI DR2 Results II: Measurements of Baryon Acoustic Oscillations and Cosmological Constraints,” (2025), arXiv:2503.14738 [astro-ph.CO]

    2025 arXiv

  149. [160]

    Extended Dark Energy analy- sis using DESI DR2 BAO measurements,

    K. Lodha et al. , “Extended Dark Energy analy- sis using DESI DR2 BAO measurements,” (2025), arXiv:2503.14743 [astro-ph.CO]

    2025 arXiv

  150. [161]

    DESI 2024: reconstructing dark energy using crossing statistics with DESI DR1 BAO data,

    R. Calderon et al. (DESI), “DESI 2024: reconstructing dark energy using crossing statistics with DESI DR1 BAO data,” JCAP 10, 048 (2024), arXiv:2405.04216 [astro-ph.CO]

    2024 arXiv

  151. [162]

    DESI 2024: Constraints on physics-focused aspects of dark energy using DESI DR1 BAO data,

    K. Lodha et al. (DESI), “DESI 2024: Constraints on physics-focused aspects of dark energy using DESI DR1 BAO data,” Phys. Rev. D 111, 023532 (2025), arXiv:2405.13588 [astro-ph.CO]

    2025 arXiv

  152. [163]

    Towards natural inflation from weakly coupled heterotic string theory,

    Hiroyuki Abe, Tatsuo Kobayashi, and Hajime Ot- suka, “Towards natural inflation from weakly coupled heterotic string theory,” PTEP 2015, 063E02 (2015), arXiv:1409.8436 [hep-th]

    2015 arXiv

  153. [164]

    Large Field Inflation from Axion Mixing,

    Gary Shiu, Wieland Staessens, and Fang Ye, “Large Field Inflation from Axion Mixing,” JHEP 06, 026 (2015), arXiv:1503.02965 [hep-th]

    2015 arXiv

  154. [165]

    Planckian Axions in String Theory,

    Thomas C. Bachlechner, Cody Long, and Liam McAl- lister, “Planckian Axions in String Theory,” JHEP 12, 042 (2015), arXiv:1412.1093 [hep-th]

    2015 arXiv

  155. [166]

    Of pngb quintessence,

    Nemanja Kaloper and Lorenzo Sorbo, “Of pngb quintessence,” JCAP 04, 007 (2006), arXiv:astro- ph/0511543

    2006

  156. [167]

    Cosmological Constant and Axions in String Theory,

    Peter Svrcek, “Cosmological Constant and Axions in String Theory,” (2006), arXiv:hep-th/0607086

    2006 arXiv

  157. [168]

    The stochastic axiverse,

    Mario Reig, “The stochastic axiverse,” JHEP 09, 207 (2021), arXiv:2104.09923 [hep-ph]

    2021 arXiv

  158. [169]

    Warped axions,

    Thomas Flacke, Ben Gripaios, John March-Russell, and David Maybury, “Warped axions,” JHEP 01, 061 (2007), arXiv:hep-ph/0611278

    2007 arXiv

  159. [170]

    Upper Limit on the QCD Axion Mass from Isolated Neutron Star Cooling,

    Malte Buschmann, Christopher Dessert, Joshua W. Fos- ter, Andrew J. Long, and Benjamin R. Safdi, “Upper Limit on the QCD Axion Mass from Isolated Neutron Star Cooling,” Phys. Rev. Lett. 128, 091102 (2022), arXiv:2111.09892 [hep-ph]

    2022 arXiv

  160. [171]

    Gauge bosons in a five-dimensional the- ory with localized gravity,

    Alex Pomarol, “Gauge bosons in a five-dimensional the- ory with localized gravity,” Phys. Lett. B 486, 153–157 (2000), arXiv:hep-ph/9911294

    2000 arXiv

  161. [172]

    Grand unified theories without the desert,

    Alex Pomarol, “Grand unified theories without the desert,” Phys. Rev. Lett. 85, 4004–4007 (2000), arXiv:hep-ph/0005293. 17

    2000 arXiv

  162. [173]

    Axions in string theory — slaying the Hydra of dark radiation,

    Michele Cicoli, Arthur Hebecker, Joerg Jaeckel, and Manuel Wittner, “Axions in string theory — slaying the Hydra of dark radiation,” JHEP 09, 198 (2022), arXiv:2203.08833 [hep-th]

    2022 arXiv

  163. [174]

    Ibanez and Angel M

    Luis E. Ibanez and Angel M. Uranga, String theory and particle physics: An introduction to string phenomenol- ogy (Cambridge University Press, 2012)

    2012

  164. [175]

    Factoring the Strong CP Problem,

    Prateek Agrawal and Kiel Howe, “Factoring the Strong CP Problem,” JHEP 12, 029 (2018), arXiv:1710.04213 [hep-ph]

    2018 arXiv

  165. [176]

    Color unified dynamical axion,

    M. K. Gaillard, M. B. Gavela, R. Houtz, P. Quilez, and R. Del Rey, “Color unified dynamical axion,” Eur. Phys. J. C 78, 972 (2018), arXiv:1805.06465 [hep-ph]

    2018 arXiv

  166. [177]

    Strong CP problem with low-energy emergent QCD: The 4321 case,

    Javier Fuentes-Mart ´ ın, Mario Reig, and Avelino Vi- cente, “Strong CP problem with low-energy emergent QCD: The 4321 case,” Phys. Rev. D100, 115028 (2019), arXiv:1907.02550 [hep-ph]

    2019 arXiv

  167. [178]

    UV Sensitivity of the Axion Mass from Instantons in Partially Broken Gauge Groups,

    Csaba Cs´ aki, Maximilian Ruhdorfer, and Yuri Shirman, “UV Sensitivity of the Axion Mass from Instantons in Partially Broken Gauge Groups,” JHEP 04, 031 (2020), arXiv:1912.02197 [hep-ph]. 18 Appendix A: W arped extra dimension One of the original motivations for warped extra d...

    2020 arXiv

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