REVIEW
Planck Scale Symmetry Breaking and Majoron Physics
High Energy Physics - Phenomenology · Submitted 6 Jan 1993 · 40 references
Pith's verdict: A solid, honest model-building paper: the charge bookkeeping in Sections 3 and 5 is the real contribution, and the cosmology is order-of-magnitude throughout and labeled as such.
T0 · AI review
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Referee report
The paper
The paper claims
Gravity can give the majoron a small mass without destroying the neutrino-mass models that need it.
The reading
What carries the argument
The load-bearing device is the accidental global symmetry: a $U(1)$ that is not imposed by hand but emerges because the gauged $B-L$ charges of the two singlets forbid every renormalizable operator that would break it. Choosing $q_2 = 1/2, 4/3, 3,$ or $8$ gives $d = 5$; other choices give larger $d$ and exponentially smaller majoron masses. This single construction does two jobs at once: it suppresses the majoron mass by powers of $M_{pl}$, and it decouples the majoron-neutrino coupling from the neutrino mass, since only $2_1$ couples to right-handed neutrinos while the majoron is mostly the other phase.
Extended reading notes
Core claim
The authors construct models in which $U(1)_{B-L}$ is a local gauge symmetry and two singlet scalars carry $B-L$ charge, with charges $q_1 = 2$ for the field that couples to right-handed neutrinos and a fractional $q_2$ for the second field. If $q_2$ is chosen so that no gauge-invariant operator of dimension four or less breaks the would-be global symmetry, the lowest allowed symmetry-breaking term is $g_{grav} 2^{-n_2} M_{pl}^{-(d-4)}$ (their Eq. 11), and the majoron mass is $m_chi^2 = 2 g_{grav} v_1^{n_1} v_2^{n_2} M_{pl}^{-(d-4)} n_2 n_1 q_2 q_1 / v_{eff}^2$ (Eq. 17). The majoron is the orthogonal combination of the two scalar phases, so its diagonal coupling to neutrinos is reduced by the mixing factor $q_2 v_{eff}/v_1$ (Eq. 15), where $v_{eff}^2 = v_1^2 v_2^2/(q_1^2 v_1^2 + q_2^2 v_2^2)$. The paper then works through the consequences: thermal relic abundance, coherent oscillations, a string-wall network that must be able to dissipate, big-bang nucleosynthesis, and SN 1987A.
Load-bearing premise
The majoron mass is set by a single Planck-suppressed operator whose dimensionless coefficient is taken to be of order one; every mass, lifetime, and dark-matter conclusion in the paper scales with that number, and the paper does not argue why it should be near unity.
Editorial extensions
If this is right
- Majorons can be stable enough to be warm dark matter for operator dimension $d = 7$ and above, where the lifetime exceeds the age of the universe.
- For $d = 5$ the majoron mass sits near a keV and the lifetime near $10^4$ s, so the majorons decay before dominating but leave decay neutrinos only mildly more energetic than the thermal background.
- The usual link between neutrino mass and majoron coupling is broken: the coupling can be suppressed by $v_{eff}/v_1$, softening supernova and nucleosynthesis bounds even for light majorons.
- Only certain $B-L$ charge assignments are allowed, because a network of strings with more than one wall attached cannot dissipate and would overclose the universe.
- Coherent misalignment oscillations matter only for $d \geq 10$; below that the thermal population dominates.
Reading between the lines
- Because the majoron mass and lifetime both scale with $g_{grav}$, the dark-matter window is really a statement about the unknown coefficient of the Planck-suppressed operator, not about the gauge structure; a modestly small $g_{grav}$ would move the viable dimension down by one or two.
- The same accidental-symmetry trick could be applied to other Goldstone-boson problems where a global symmetry is expected to be violated at the Planck scale, provided the gauged charges can be chosen to forbid all operators up to some dimension.
- If majorons are the warm dark matter, their free-streaming length at keV masses should leave an imprint on small-scale structure; that is a place where this model could be told apart from a sterile-neutrino or axion account of the same density.
- The requirement that the string-wall network dissipate gives a rare handle in which a cosmological relic density argument constrains a particle-physics charge assignment rather than a mass or coupling.
Original abstract
Majoron models provide neutrino masses via the spontaneous breaking of a global $U(1)$ symmetry. However, it may be argued that all global symmetries will be explicitly violated by gravitational effects. We show that it is possible to preserve most of the usual features of majoron models by invoking $U(1)_{B-L}$ to be a gauge symmetry and adding a second singlet scalar field. The majoron gets a small model dependent mass. The couplings of majorons to neutrinos may be of ordinary strength or may be made arbitrarily weak. We discuss the cosmological and astrophysical consequences of majoron models in the context of a model dependent majoron mass and neutrino coupling. For an appropriate choice of parameters majorons can play the role of dark matter.
The compiled record
The paper's own sentences, arranged, kept beside the review and separate from it. Each label is drawn from a closed vocabulary; the number beside it is the probability the classifier gave that label. Numbers in the tables are the authors', checked by code. No sentence in this record was written by a model.
The abstract, sentence by sentence
Majoron models provide neutrino masses via the spontaneous breaking of a global $U(1)$ symmetry. However, it may be argued that all global symmetries will be explicitly violated by gravitational effects. We show that it is possible to preserve most of the usual features of majoron models by invoking $U(1)_{B-L}$ to be a gauge symmetry and adding a second singlet scalar field. The majoron gets a small model dependent mass. The couplings of majorons to neutrinos may be of ordinary strength or may be made arbitrarily weak. We discuss the cosmological and astrophysical consequences of majoron models in the context of a model dependent majoron mass and neutrino coupling. For an appropriate choice of parameters majorons can play the role of dark matter.
background contribution method result interpretation main claim
| # | sentence | role | the authors' own work | states the main conclusion | strength |
|---|---|---|---|---|---|
| s0 | Majoron models provide neutrino masses via the spontaneous breaking of a global $U(1)$ symmetry. | background 1.00 | 0.05 | 0.04 | asserted 1.00 |
| s1 | However, it may be argued that all global symmetries will be explicitly violated by gravitational effects. | background 0.92 | 0.05 | 0.03 | hedged possibility 0.99 |
| s2 | We show that it is possible to preserve most of the usual features of majoron models by invoking $U(1)_{B-L}$ to be a gauge symmetry and adding a second singlet scalar field. | contribution 0.81 | 0.88 | 0.66 | asserted 0.74 |
| s3 | The majoron gets a small model dependent mass. | result 0.99 | 0.71 | 0.12 | asserted 1.00 |
| s4 | The couplings of majorons to neutrinos may be of ordinary strength or may be made arbitrarily weak. | result 0.98 | 0.64 | 0.11 | hedged possibility 0.99 |
| s5 | We discuss the cosmological and astrophysical consequences of majoron models in the context of a model dependent majoron mass and neutrino coupling. | contribution 0.97 | 0.74 | 0.09 | asserted 0.78 |
| s6 | For an appropriate choice of parameters majorons can play the role of dark matter. | result 0.50 | 0.65 | 0.19 | hedged possibility 0.97 |
What was examined, and what was not
- arXiv listing abstract v1
- full text
- figures and tables
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- relations to other papers
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Figures
Figures reproduced from arXiv:hep-ph/9301213 by the authors.
References
How the literature uses it
57 arXiv papers cite this in 82 sentences
Papers citing it · 60 sentences without a confident label
Compares with it 1 paper
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Our approach differs from that of Ref. [ref] in that we do not allow gravitational symmetry violations, unless they are mediated by “instanton” effects, making such violations exponentially suppressed.
Gravitational Interactions and Neutrino Masses · Introduction · 0.94
Cites it as background 20 papers
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Majoron cosmology was discussed long ago in the context of Planck-suppressed breaking of global lepton number, with overclosure constraints already emphasized in Refs. [ref] and the majoron as a DM candidate considered in Refs. [ref] .
Majoron Dark Matter, High-Scale Seesaw, and Leptogenesis · Introduction · 0.99
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The production mechanisms of majoron DM with mass of $keV–10 TeV$ has been proposed in Ref. [ref] .
Updated Constraints and Future Prospects on Majoron Dark Matter · Singlet majoron model · 0.87
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Assuming these effects are suppressed by powers of $M_P$, they can be used to generate a Majoron mass at the keV scale [ref] , which has been extensively studied as DM candidate [ref] .
Sub-GeV dark matter as pseudo-Goldstone from the seesaw scale · Approximate symmetries of the seesaw sector · 0.86
Discussion
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