REVIEW
Proposal for a Supersymmetric Standard Model
High Energy Physics - Phenomenology · Submitted 29 Aug 2005 · 16 references
Pith's verdict: A clean, genuinely new identification of the NMSSM singlet with the right-handed neutrino superfield, but the μ problem is relocated rather than solved and the numerical claims are unbacked.
T0 · AI review
Why Pith says this
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Referee report
The paper
The paper claims
The MSSM's missing Higgs-mixing term can come from the neutrino superfields that neutrino masses already require, with no extra singlet added.
The reading
What carries the argument
The machinery is the superpotential $W = epsilon_{ab}(Y^u_{ij} hat H^b_2 hat Q^a_i hat u^c_j + Y^d_{ij} hat H^a_1 hat Q^b_i hat d^c_j + Y^e_{ij} hat H^a_1 hat L^b_i hat e^c_j + Y^nu_{ij} hat H^b_2 hat L^a_i hat nu^c_j) - epsilon_{ab} lambda_i hat nu^c_i hat H^a_1 hat H^b_2 + frac{1}{3} kappa_{ijk} hat nu^c_i hat nu^c_j hat nu^c_k$, together with its soft-breaking counterpart. The $lambda$ term supplies the effective $mu$ once $langle tilde nu^c rangle neq 0$; the $kappa$ term supplies the explicit lepton-number breaking that keeps the pseudoscalar spectrum free of an unacceptable axion and feeds the see-saw. The see-saw itself is carried by the block matrix $M_n = begin{pmatrix} M & m m^T & 0 end{pmatrix}$, where $M$ is the NMSSM-like neutralino matrix with $tilde nu^c$ playing the role of $S$, and $m^T = (-g_1 nu/sqrt{2}, g_2 nu/sqrt{2}, 0, Y_nu nu^c, Y_nu v_2)$ holds the small entries that make one eigenvalue tiny. The same structure repeats in the charged sector, where charginos mix with charged leptons and a light eigenvalue equal to $Y_e v_1$ survives automatically.
Extended reading notes
Core claim
The claim is that the $mu$ problem of the MSSM can be solved without the extra singlet superfield of the NMSSM, by reusing the gauge-singlet neutrino superfields that neutrino masses already motivate. The superpotential contains no bare $mu$ term, only trilinear couplings: the MSSM Yukawas plus $Y^{ij}_nu hat H_2 hat L_i hat nu^c_j$, the $mu$-generating $lambda_i hat nu^c_i hat H_1 hat H_2$, and $frac{1}{3} kappa_{ijk} hat nu^c_i hat nu^c_j hat nu^c_k$. When the scalar partner of the right-handed neutrino takes a vacuum expectation value, an effective $mu = lambda_i langle tilde nu^c_i rangle$ appears at the electroweak scale. Because the left-handed sneutrino vacuum expectation value is suppressed by the tiny Dirac Yukawa, the minimization conditions collapse to exactly the NMSSM ones with $tilde nu^c$ replacing the singlet $S$, so the parameter-space solutions already known for the NMSSM carry over. The neutralino mass matrix becomes $6 times 6$ (or $10 times 10$ with three generations), mixing gauginos and Higgsinos with the $tilde nu^c$ and $tilde nu$ fermions; for a Dirac neutrino mass of order $10^{-4}$ GeV the lightest eigenvalue lands near $10^{-2}$ eV, the observed neutrino scale.
Load-bearing premise
The whole mechanism rests on the right-handed sneutrino vacuum expectation value sitting naturally at the electroweak scale, an assumption the paper supports only by noting that its minimization conditions are the NMSSM's with the singlet renamed, so that known NMSSM solutions exist.
Editorial extensions
If this is right
- An effective $mu$ term of electroweak size arises with no fundamental $mu$ parameter and no additional singlet superfield beyond the three right-handed neutrino singlets already needed for neutrino mass.
- Majorana neutrino masses are generated at the electroweak scale through a dynamical see-saw that is always present in the neutralino mass matrix, so Yukawa couplings of order the electron's are enough and no grand-unified scale is required.
- R-parity and lepton number are explicitly broken, so the lightest R-odd particle decays, the neutralino cannot be the dark matter, and alternative candidates such as the gravitino must be considered.
- The neutralino, chargino and Higgs mass matrices all mix with neutrino and sneutrino states, giving light CP-odd Higgs bosons, Higgs–sneutrino mixing and charged-Higgs–slepton mixing that distinguish the model from the MSSM and the NMSSM.
- The superpotential retains a $Z_3$ symmetry and therefore inherits the NMSSM's cosmological domain-wall problem, which the authors argue can be cured by small non-renormalizable operators that lift the vacuum degeneracy without introducing hierarchies.
Reading between the lines
- Because the $mu$ term is now a dynamical variable fixed by the sneutrino vacuum expectation value, the model ties the Higgsino mass to the same sector that fixes neutrino masses; a measurement of both would over-determine the $lambda$ and $Y_nu$ couplings and give a sharp consistency check.
- The explicit R-parity breaking makes the lightest neutralino decay, typically with displaced vertices or missing-energy signatures that differ from the MSSM; existing collider limits on R-parity-violating couplings therefore already constrain the parameter space, even though the paper does not attempt that comparison.
- The mapping onto the NMSSM with $tilde nu^c leftrightarrow S$ means the model inherits the NMSSM's fine-tuning questions about the singlet soft mass; whether an electroweak-scale sneutrino vacuum expectation value survives renormalization-group running to the weak scale without tuning is the calculation that would decide how natural the solution really is.
- If the cubic $kappa$ coupling is small, the see-saw scale is effectively the electroweak scale and the light neutrino mass scales quadratically in the Dirac mass; this predicts a correlated pattern between the neutrino mass hierarchy and the neutralino mixing angles that future precision measurements could probe.
Original abstract
The fact that neutrinos are massive suggests that the minimal supersymmetric standard model (MSSM) might be extended in order to include three gauge-singlet neutrino superfields with Yukawa couplings of the type $H_2 L \nu^c$. We propose to use these superfields to solve the $\mu$ problem of the MSSM without having to introduce an extra singlet superfield as in the case of the next-to-MSSM (NMSSM). In particular, terms of the type $\nu^c H_1 H_2$ in the superpotential may carry out this task spontaneously through sneutrino vacuum expectation values. In addition, terms of the type $(\nu^c)^3$ avoid the presence of axions and generate effective Majorana masses for neutrinos at the electroweak scale. On the other hand, these terms break lepton number and R-parity explicitly implying that the phenomenology of this model is very different from the one of the MSSM or NMSSM. For example, the usual neutralinos are now mixed with the neutrinos. For Dirac masses of the latter of order $10^{-4}$ GeV, eigenvalues reproducing the correct scale of neutrino masses are obtained.
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
The fact that neutrinos are massive suggests that the minimal supersymmetric standard model (MSSM) might be extended in order to include three gauge-singlet neutrino superfields with Yukawa couplings of the type $H_2 L \nu^c$. We propose to use these superfields to solve the $\mu$ problem of the MSSM without having to introduce an extra singlet superfield as in the case of the next-to-MSSM (NMSSM). In particular, terms of the type $\nu^c H_1 H_2$ in the superpotential may carry out this task spontaneously through sneutrino vacuum expectation values. In addition, terms of the type $(\nu^c)^3$ avoid the presence of axions and generate effective Majorana masses for neutrinos at the electroweak scale. On the other hand, these terms break lepton number and R-parity explicitly implying that the phenomenology of this model is very different from the one of the MSSM or NMSSM. For example, the usual neutralinos are now mixed with the neutrinos. For Dirac masses of the latter of order $10^{-4}$ GeV, eigenvalues reproducing the correct scale of neutrino masses are obtained.
background contribution method result interpretation main claim
| # | sentence | role | the authors' own work | states the main conclusion | strength |
|---|---|---|---|---|---|
| s0 | The fact that neutrinos are massive suggests that the minimal supersymmetric standard model (MSSM) might be extended in order to include three gauge-singlet neutrino superfields with Yukawa couplings of the type $H_2 L \nu^c$. | background 0.98 | 0.08 | 0.11 | hedged possibility 0.85 |
| s1 | We propose to use these superfields to solve the $\mu$ problem of the MSSM without having to introduce an extra singlet superfield as in the case of the next-to-MSSM (NMSSM). | contribution 0.97 | 0.71 | 0.48 | asserted 0.54 |
| s2 | In particular, terms of the type $\nu^c H_1 H_2$ in the superpotential may carry out this task spontaneously through sneutrino vacuum expectation values. | method 0.70 | 0.37 | 0.13 | hedged possibility 1.00 |
| s3 | In addition, terms of the type $(\nu^c)^3$ avoid the presence of axions and generate effective Majorana masses for neutrinos at the electroweak scale. | contribution 0.62 | 0.46 | 0.12 | asserted 0.90 |
| s4 | On the other hand, these terms break lepton number and R-parity explicitly implying that the phenomenology of this model is very different from the one of the MSSM or NMSSM. | interpretation 0.64 | 0.49 | 0.15 | asserted 1.00 |
| s5 | For example, the usual neutralinos are now mixed with the neutrinos. | result 0.55 | 0.54 | 0.06 | asserted 1.00 |
| s6 | For Dirac masses of the latter of order $10^{-4}$ GeV, eigenvalues reproducing the correct scale of neutrino masses are obtained. | result 1.00 | 0.79 | 0.13 | asserted 0.97 |
What was examined, and what was not
- arXiv listing abstract v3
- full text
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- references and citing sentences
- relations to other papers
- P abstract
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References
How later papers used it
63 later papers cite it
1 paper by the same authors is listed below: 1 used its method or tool.
Uses its method or tool 1 paper · 1 by the same authors
By the same authors
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Determined the neutrino Yukawa couplings through the 10x10 neutral fermion mass matrix written as in this paper, with a 7x7 matrix of the MSSM neutralino mass matrix and its mixing with the neutrino superfields and a 7x3 mixing matrix.
Analysis of the parameter space and spectrum of the $\mu \nu$SSM (2008) (same authors) · 0.82 · paraphrased: the licence does not allow quoting
How the literature uses it
63 arXiv papers cite this in 210 sentences
Papers citing it · 131 sentences without a confident label
Builds on it 2 papers
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[ref] , where the characteristics of the $μν$SSM were introduced, and only some points concerning its phenomenology were sketched.
Analysis of the parameter space and spectrum of the $\mu \nu$SSM · Introduction · 1.00
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In the present paper, we study the phenomenology of the $μν$SSM, extending previous work [ref] .
LHC phenomenology of the $\mu\nu$SSM · Introduction · 1.00
Uses its method or tool 1 paper
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At this point we determine the neutrino Yukawa couplings through the $10×10$ neutral fermion mass matrix which can be written as [ref] [equation] where $M$ is a $7×7$ matrix composed by the MSSM neutralino mass matrix and its mixing with the $ν^c_i$, while $m$ is a $7×3$ matrix containing the mixing of the $ν_i$ with MSSM neutralinos and the $ν^c_i$.
Analysis of the parameter space and spectrum of the $\mu \nu$SSM · Strategy for the analysis · 0.82
Compares with it 1 paper
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The nature of neutrino mass generation mechanism in this framework appears similar to the one in $μν$SSM model [ref] .
Weak scale right-handed neutrino as pseudo-Goldstone fermion of spontaneously broken $U(1)_{L_\mu-L_\tau}$ · Summary and Discussions · 0.98
Cites it as support 3 papers
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In fact, the couplings $λ_ijk$ and $λ'_ijk$ can be naturally added to $W_$μν$SSM$ [ref] .
Right-handed neutrinos, domain walls and tadpoles in the superstring inspired $\mu\nu$SSM · The $$ and renormalizable terms · 0.97
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Moreover, as shown in [ref] , taking the limit $h_ν→0$ and, consequently, $v_i →0$, one recovers the tadpole equations of the NMSSM, ensuring the existence of solutions to this set of equations.
LHC phenomenology of the $\mu\nu$SSM · Scalar potential and its minimization · 0.99
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The smallness of the left sneutrino VEVs for a correct description of the neutrino sector, compatible with current data, has been shown in Refs. [ref] .
$U(1)'$ extensions of the $\mu \nu$SSM · The scalar potential · 0.99
Cites it as background 44 papers
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As explained in the Introduction, this model was proposed [ref] as a SUSY standard model for solving the crucial $μ$ problem of SUSY constructions, generating at the same time the small neutrino masses through a dynamical see-saw at the electroweak scale.
Analysis of the parameter space and spectrum of the $\mu \nu$SSM · Conclusions and outlook · 0.84
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Since it was proposed [ref] , the $μν$SSM has been studied in Ref. MuNuSSM2
The seesaw mechanism in the $\mu \nu$SSM · Introduction · 0.98
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The superpotential of the $μν$SSM is given by [ref] [Although we assume three families of right-handed neutrinos motivated by the Standard Model generation replication pattern, a different number of right-handed neutrinos can be used.]: [equation]
The Higgs sector of the munuSSM and collider physics · The $μν$SSM · 0.80
Discussion
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