REVIEW
Real Higgs singlet and the electroweak phase transition in the standard model, (UM-P-93/80, OZ-93/20)
High Energy Physics - Phenomenology · Submitted 6 Aug 1993 · 16 references
Pith's verdict: The existence claim holds up, but Table 1's Vc/Tc is not the quantity the sphaleron bound constrains, so the reported margins overstate the transition strength.
T0 · AI review
Why Pith says this
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Referee report
The paper
The paper claims
Adding one real Higgs singlet to the Standard Model may open a window where the electroweak phase transition is strong enough to preserve a baryon asymmetry, while the lightest Higgs boson stays above about 60 GeV.
The reading
What carries the argument
The finite-temperature effective potential $V(u,v)$ in the two background fields, built from the tree-level potential plus the one-loop Coleman-Weinberg piece and the thermal piece, with the dominant higher-order corrections resummed through self-energies $Pi_j(0)$ so that the cubic terms use $M_j^2 = m_j^2 + Pi_j$. The load-bearing ingredient is the tree-level cubic structure: the $-alpha v^3/3$ term and the $-sigma u^2 v/4$ term break the $v$ to $-v$ symmetry of the potential, which is what allows two approximately parallel valleys to exist and to become degenerate at $T_c$ with a barrier between them. This is the same qualitative role that tree-level cubic terms play in the singlet extension of the minimal supersymmetric model, and the paper's stated motivation is to see whether that trend recurs in the smallest possible extension of the Standard Model Higgs sector.
Extended reading notes
Core claim
The claim is that a region of parameter space exists in the Standard Model plus a real Higgs singlet for which the electroweak phase transition is first order and strong enough to avoid sphaleron erasure of baryon asymmetry, while the lightest Higgs boson remains above the experimental bound of roughly 60 GeV. The authors construct the one-loop finite-temperature effective potential, including the ring-resummed self-energy corrections to the cubic terms, and reduce the seven free parameters to five by fixing the zero-temperature global minimum at $u = 246$ GeV and expressing the mass parameters in terms of the extrema of the tree-level potential. They then test randomly chosen parameter sets against four conditions: correct zero-temperature global minimum, lightest Higgs mass at or above 60 GeV, an existing first-order transition, and $m_i/T_c < 1$ where that transition occurs. Table 1 lists seven surviving sets with $m_{phi,S}$ between 61 and 103 GeV and $V_c/T_c$ values such as $170/107$ and $390/93$, where $V_c$ is the distance between the two degenerate minima at $T_c$. The qualitative picture is that the tree-level cubic terms tilt the potential in the $v$ direction so that two valleys roughly parallel to the $u$-axis can become degenerate, letting the global minimum tunnel from a point with $u > 0$ to a point with $u = 0$ and thereby restoring electroweak symmetry.
Load-bearing premise
The parameter scan is run with the temperature-induced cubic terms switched off, and the claim that the accepted sets survive their inclusion rests on a single polynomial fit to those terms around the degenerate minima of the seven tabulated sets, not on a recomputation across the scanned region.
Editorial extensions
If this is right
- The minimal singlet extension of the Standard Model Higgs sector joins the list of models that can satisfy the sphaleron bound and the Higgs mass bound at the same time, unlike the minimal Standard Model itself.
- The presence of any non-zero tree-level cubic coefficient $alpha$ removes the upper bound on the Higgs mass above which the transition becomes second order, so the self-energy corrections do not kill the first-order transition the way they do in the minimal model.
- A rough measure of a model's viability for electroweak baryogenesis can be read off from whether its Higgs potential contains tree-level cubic terms, rather than from the temperature-induced cubic terms alone.
- The model predicts, for some parameter sets, an additional first-order phase transition purely in the singlet direction at temperatures above the electroweak transition; the authors note this is not required for baryogenesis.
- Because no Majoron is present, the singlet cannot relax the Higgs mass bound through invisible decay channels, so the 60 GeV constraint must be met directly by the parameters.
Reading between the lines
- The scan is performed with the temperature-induced cubic terms omitted, and the robustness argument is a polynomial fit to those terms around the degenerate minima of the seven tabulated sets; a reader could reasonably want the fit repeated across the whole accepted region, since a shift in barrier height near threshold is exactly what decides whether $v(T_c)/T_c$ stays above one.
- If the mechanism is really the $v$ to $-v$ asymmetry, then the size of the surviving window should scale with how large $alpha$ and $sigma$ can be made without violating the zero-temperature minimum condition; that scaling is not plotted here and would be a cheap diagnostic for neighbouring singlet models.
- The same tree-level-cubic logic should transfer to any extension where a gauge-singlet scalar gets a cubic self-coupling, which makes the presence or absence of such a term a quick filter when surveying models for electroweak baryogenesis.
- The paper's transition temperatures are of order 100 GeV and its $V_c/T_c$ values are computed from a potential that neglects the temperature-independent one-loop terms; a lattice or fully resummed treatment near $T_c$ would be the natural next check on whether the two-valley picture survives.
Original abstract
The effective potential at finite temperature is constructed within the minimal standard model when a real Higgs singlet is added on. We find that a region of parameter space exists for which one can find a first order transition strong enough to prevent the erasure due to sphalerons of baryon asymmetry, while keeping the mass of the smallest Higgs boson above the experimental lower bound of about 60 GeV.
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 effective potential at finite temperature is constructed within the minimal standard model when a real Higgs singlet is added on. We find that a region of parameter space exists for which one can find a first order transition strong enough to prevent the erasure due to sphalerons of baryon asymmetry, while keeping the mass of the smallest Higgs boson above the experimental lower bound of about 60 GeV.
background contribution method result interpretation main claim
| # | sentence | role | the authors' own work | states the main conclusion | strength |
|---|---|---|---|---|---|
| s0 | The effective potential at finite temperature is constructed within the minimal standard model when a real Higgs singlet is added on. | method 0.67 | 0.88 | 0.04 | asserted 0.99 |
| s1 | We find that a region of parameter space exists for which one can find a first order transition strong enough to prevent the erasure due to sphalerons of baryon asymmetry, while keeping the mass of the smallest Higgs boson above the experimental lower bound of about 60 GeV. | result 1.00 | 0.95 | 0.91 | asserted 0.99 |
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
Showing 2 of the paper's 4 figures. See all figures in the PDF ↗ Figures reproduced from arXiv:hep-ph/9308234 by the authors.
References
How the literature uses it
44 arXiv papers cite this in 62 sentences
Papers whose main result relates to this one's
States the same result 1 paper
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It is found that there are parameter values for which this model at the one-loop level with finite temperature effect may allow the desired phase transition.
Electroweak phase transition in an extension of the standard model with a real Higgs singlet · 0.82
Papers citing it · 45 sentences without a confident label
Cites it as background 15 papers
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[ref] and its recent revival in form of hidden sector theories [ref] .
Strong electroweak phase transitions without collider traces · The Model · 0.90
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This fact has been used in the literature to constrain various EWBG models [ref] and also in context of the zero temperature EW vacuum stability [ref] .
Gravitational wave, collider and dark matter signals from a scalar singlet electroweak baryogenesis · Introduction · 0.84
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The first model is a $ℤ_2$-symmetric real singlet scalar extension of the SM, which is regarded as the most minimal extension capable of rendering a strong first-order EWPT, and has been studied extensively in the literature [ref] .
The Discriminant Power of Bubble Wall Velocities: Gravitational Waves and Electroweak Baryogenesis · Wall Velocity Calculation in Benchmark Models · 0.96
Discussion
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