REVIEW
Finite Higgs mass without Supersymmetry
High Energy Physics - Theory · Submitted 1 Aug 2001 · 14 references
Pith's verdict: A solid, honest paper: the toroidal finiteness result is real and cross-checked, but the orbifold case that carries the 'chiral' claim rests on a condition the paper states rather than verifies for its own model.
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Referee report
The paper
The paper claims
The Higgs can be a gauge field component in extra dimensions, and its one-loop mass then comes out finite without supersymmetry, in a six-dimensional U(3)×U(3) model that reduces to the Standard Model with two Higgs doublets on a T²/Z₂ orb.
The reading
What carries the argument
The load-bearing object is the Wilson line, or constant background of the internal gauge field, $a_I = frac{1}{2pi} q oint g A_I, dy$, which shifts the Kaluza–Klein masses as $M^2_{vec m} = sum_i (m_i + a_i)^2/R_i^2$ with no accompanying six-dimensional mass. Because the shift enters only through the combination $m_i + a_i$, Poisson resummation over the full tower converts the one-loop integral into a sum over dual lattice vectors $vec n eq vec 0$ of $cos(2pi n_i a_i)/[sum n_i^2 R_i^2]^{(4+d)/2}$, which converges and is cutoff-independent. The orbifold step is what makes the spectrum chiral, and it is also where the argument becomes conditional: the ${{Z}}_2$ projection introduces fixed points, and any localized (twisted) states coupling to the Higgs would reintroduce UV divergences unless they are absent or come in degenerate boson–fermion pairs.
Extended reading notes
Core claim
The central claim is that a class of chiral models exists in which the one-loop effective potential for the Higgs is finite without supersymmetry, precisely when the Higgs fields are identified with the components $A_5, A_6$ of a gauge field along compactified extra dimensions. The mechanism is a cancellation of two things that usually ruin such a computation. First, the six-dimensional gauge symmetry forbids a six-dimensional mass term $M_I^2(phi)$, which is the term whose loop contributions are quadratically divergent and UV-sensitive; only the shift $a_I = q g oint A_I dy / 2pi$ in the Kaluza–Klein masses is allowed. Second, summing the entire infinite Kaluza–Klein tower and Poisson-resumming turns the one-loop potential into a rapidly convergent sum over the dual lattice, Eq. (2.7), whose $phi$-dependent part is finite and depends only on low-energy data. The authors then construct a six-dimensional $U(3)times U(3)$ model with three families in fundamental and bi-fundamental representations, orbifold it on $T^2/{{Z}}_2$ with an internal rotation $Theta = mathrm{diag}(1,1,-1)$, and obtain exactly the Standard Model fermions plus two Higgs doublets $H_1, H_2$ from the adjoint of the weak $U(3)$. The tree-level quartic potential $V_0 = (g^2/8)(|H_1^0|^2 - |H_2^0|^2)^2$ comes from the commutator term $mathrm{Tr}[A_M,A_N]^2$, giving an MSSM-like potential with $g'^2 = 3g^2$ fixed by the embedding of hypercharge in $SU(3)_w$. The one-loop Higgs mass parameters are computed twice — once from the effective potential and once diagrammatically from the Yukawa couplings of the Kaluza–Klein tower — and the two agree, with the orbifold result equal to half the toroidal one, $N_F^{mathrm{orb}} = N_F^{mathrm{torus}}/2$. Finally, the two anomalous $U(1)$ factors are cancelled by a Green–Schwarz mechanism whose Fayet–Iliopoulos-like term $xi phi/sqrt{G}$ shifts $tan beta$ away from one and, through the minimization condition, relates the compactification radius to the weak scale.
Load-bearing premise
For the orbifold case, the finiteness claim depends on the assumption that states localized at the $T^2/{{Z}}_2$ fixed points either do not couple to the Higgs or come in degenerate boson–fermion pairs, and the paper states this condition rather than demonstrating that its own $U(3)times U(3)$ model satisfies it.
Editorial extensions
If this is right
- The one-loop Higgs mass is a calculable function of $1/R$ and the gauge couplings, so the electroweak scale is tied to the compactification scale rather than to a cutoff; in the one-extra-dimension limit the minimum sits at $a = 1/2$, giving $1/R = 2 m_t$.
- In two extra dimensions with equal radii, the minimum of the potential fixes $|a_1| = |a_2| = a$ as a function of the torus angle: $a = 1/2$ (hence $1/R = 2m_t$) for $cos theta < 0.4$, switching to $a = 1/4$ ($1/R = 4m_t approx 0.7$ TeV) above that.
- The tree-level quartic coupling is fixed by gauge invariance to the MSSM form with $g'^2 = 3g^2$, so the model predicts a light Higgs in the absence of further radiative quartics — a tension the authors flag as making the simplest version unrealistic.
- Hypercharge is the unique anomaly-free combination $Q_Y = Q_1/6 - 2Q_2/3 - Q_3/3$, giving $sin^2theta_w = 1/4 + (2/3) g^2/g_3^2$ at the string scale.
- Anomaly cancellation via a Green–Schwarz axion induces a Fayet–Iliopoulos term that shifts $tan beta = sqrt{(v^2+kappa^2)/(v^2-kappa^2)}$ and, for finite radii, allows $1/R gg v$ over a range of torus angles.
Reading between the lines
- The finiteness argument is really a statement about which operators the higher-dimensional gauge symmetry forbids, so it should generalize to any scalar realized as an internal gauge component, not just the specific $U(3)times U(3)$ model — a natural check would be whether the same Poisson-resummation argument goes through for $SU(N)$ with $N>3$.
- Because all Yukawa couplings are fixed to the gauge coupling when the Higgs is a gauge component, the model has no fermion-mass hierarchy; the authors say so and defer it, but this suggests the framework is more naturally a statement about the Higgs sector alone than a complete account of flavor.
- The paper's own two-loop remark — that divergences there are absorbed into wave-function renormalization and require $M_s$ not far above $1/R$ — implies an upper bound of roughly two orders of magnitude on the ratio of string to compactification scale, which is a sharper and more testable statement than the one-loop finiteness itself.
- The dependence of the minimum on the torus angle $cos theta$ suggests that if the compactification geometry were fixed by some independent modulus-stabilization mechanism, the Higgs mass would become a discrete prediction rather than a continuous function.
Original abstract
We identify a class of chiral models where the one-loop effective potential for Higgs scalar fields is finite without any requirement of supersymmetry. It corresponds to the case where the Higgs fields are identified with the components of a gauge field along compactified extra dimensions. We present a six dimensional model with gauge group U(3)xU(3) and quarks and leptons accomodated in fundamental and bi-fundamental representations. The model can be embedded in a D-brane configuration of type I string theory and, upon compactification on a T^2/Z_2 orbifold, it gives rise to the standard model with two Higgs doublets.
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
We identify a class of chiral models where the one-loop effective potential for Higgs scalar fields is finite without any requirement of supersymmetry. It corresponds to the case where the Higgs fields are identified with the components of a gauge field along compactified extra dimensions. We present a six dimensional model with gauge group U(3)xU(3) and quarks and leptons accomodated in fundamental and bi-fundamental representations. The model can be embedded in a D-brane configuration of type I string theory and, upon compactification on a T^2/Z_2 orbifold, it gives rise to the standard model with two Higgs doublets.
background contribution method result interpretation main claim
| # | sentence | role | the authors' own work | states the main conclusion | strength |
|---|---|---|---|---|---|
| s0 | We identify a class of chiral models where the one-loop effective potential for Higgs scalar fields is finite without any requirement of supersymmetry. | result 0.53 | 0.93 | 0.89 | asserted 1.00 |
| s1 | It corresponds to the case where the Higgs fields are identified with the components of a gauge field along compactified extra dimensions. | interpretation 0.81 | 0.53 | 0.07 | asserted 1.00 |
| s2 | We present a six dimensional model with gauge group U(3)xU(3) and quarks and leptons accomodated in fundamental and bi-fundamental representations. | contribution 0.69 | 0.84 | 0.06 | asserted 1.00 |
| s3 | The model can be embedded in a D-brane configuration of type I string theory and, upon compactification on a T^2/Z_2 orbifold, it gives rise to the standard model with two Higgs doublets. | result 0.50 | 0.76 | 0.17 | asserted 0.70 |
What was examined, and what was not
- arXiv listing abstract v2
- full text
- figures and tables
- references and citing sentences
- relations to other papers
- P abstract
- S sections
- T body sentences
- C citations
- R cross-paper relations
Figures
Figures reproduced from arXiv:hep-th/0108005 by the authors.
References
How later papers used it
63 later papers cite it
1 later paper by other authors is listed below: 1 used its method or tool.
Uses its method or tool 1 of 5 papers with this label
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Once the latter develops a VEV, the effective potential determining its value is computed by properly applying the one-loop Coleman-Weinberg formalism [ref] , which depends on the spectrum as a function of the VEVs.
General vacuum stability of orbifold gauge breaking and application to asymptotic grand unification (2024) · Methodology and classification · 0.99
How the literature uses it
60 arXiv papers cite this in 72 sentences
Papers citing it · 38 sentences without a confident label
Contests it 1 paper
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In fact, contrary to what is typically done in the literature [ref] , we have stressed that in the one-loop calculation of $ρ__EFT$ the five components of the $5$D loop momentum $p̂=(p_1,p_2,p_3,p_4,n/R)$ have to be cut in a coherent manner (for simplicity we stick to the compactification on a circle of radius $R$, for which $p_5=n/R$).
Does the Cosmological Constant really indicate the existence of a Dark Dimension? · Summary and Conclusions · contest 0.77
Builds on it 1 paper
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In the way similar to [ref] but extended for the warped space-time, we obtain the effective potential: [equation] where we have neglected contributions from other quarks and leptons, because they have small contributions to the effective potential with their large bulk masses.
Radiatively Induced Spontaneous Symmetry Breaking by Wilson Line in a Warped Extra Dimension · $SU(3)_w$ model · 0.98
Uses its method or tool 4 papers
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The formula of effective potential is given by [ref] [equation]
Electroweak Symmetry Breaking in Two Higgs Doublet Model from 6D Gauge-Higgs Unification on $T^2/Z_2$ · One-loop effective potential · 0.92
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[$h$ appears via UV boundary conditions and it leads to analogous expressions to ([ref]) and ([ref]) with the replacement $v→h$, since $H=(ϕ^+,1/√(2)[h+iϕ^0])^T$.] The previous infinite sum can be exchanged by an integral on the Minkowski space [ref] , [equation] where $k= √(p^2)$, and $ρ_h,π^(ω^2), ω∈ℂ$, is some spectral function, holomorphic in the $Re(ω)>0$ part of the complex plane and with roots in the real axis encoding the spectrum of $𝔸_μ(x,z)$ in the presence of the background fields $π^$ and $h$, i.e., [equation] Such a function will be proportional to the determinant of the linear system of equations resulting from imposing the IR boundary conditions after we remove the NGBs $π^$ from the bulk via the following 5D gauge transformation [equation] where $𝒜_M∈{L_M^i S_L^i, R_M^i S_R^i,W_M^a T^a}$ (see Appendices [ref] and [ref] for the definition of the different generators) and
Composite Dark Sectors · Gauge interactions, scalar potential and masses · 0.85
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Following the way in [ref] , we introduce $SU(3)_w$-triplet fermions, namely “quarks” $Ψ_=u,c,t$, and “leptons” $Ψ_=e,μ,τ$:
Radiatively Induced Spontaneous Symmetry Breaking by Wilson Line in a Warped Extra Dimension · $SU(3)_w$ model · 0.85
Compares with it 1 paper
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This situation is exactly the same as the one encountered in gauge-Higgs models when considering the gauge part in isolation [ref] .
A new mechanism for symmetry breaking from nilmanifolds · From $SU(3)$ to $SU(2)×U(1)$ · 0.87
Cites it as background 26 papers
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One proposal for that is Gauge Higgs Unification (GHU), where one begins with an extra dimensional theory and the Higgs boson is the higher dimensional component of a gauge field [ref] .
Left Right Model from Gauge Higgs Unification with Dark Matter · Introduction · 1.00
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One of the promising frameworks is the Gauge-Higgs Unification (GHU) theory [ref] .
Gauge symmetry breaking with $S^2$ extra dimensions · Introduction · 0.81
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$ν_±$ become [equation] Since the term with $s=0$ has no dependence on $v$, it may be removed and we obtain the regularized one-loop effective potentials of without-flux type $ν_reg,±$ [equation] Note that this periodic potential often appears in gauge-Higgs unification [ref] .
Gauge Symmetry Breaking in Flux Compactification with Wilson-line Scalar Condensate · The potential calculation · 0.82
Discussion
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