REVIEW
Could two NMSSM Higgs bosons be present near 125 GeV?
High Energy Physics - Phenomenology · Submitted 6 Jul 2012 · 12 references
Pith's verdict: An honest, competent NMSSM scan showing two light CP-even states can share the 123–128 GeV window; the physics is fine, the soft spot is that the whole result lives at the edge of one code's large-λ capability.
T0 · AI review
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Referee report
The paper
The paper claims
In GUT-scale NMSSM models with a large superpotential coupling lambda, the two lightest CP-even Higgs bosons can both sit in the 123–128 GeV window, so the single observed 125 GeV resonance could be two overlapping states whose diphoton and
The reading
What carries the argument
The machinery is a signal-combination prescription applied to a constrained parameter scan. For each scalar the authors define $R^{gg}_{h_i}(X) = Gamma(gg -> h_i) BR(h_i -> X) / Gamma(gg -> h_{SM}) BR(h_{SM} -> X)$ and the analogous $R^{VBF}_{h_i}(X)$ for weak-boson fusion, computed self-consistently with the same radiative corrections for the Standard Model reference. They then define a rate-weighted effective mass $m_h^Y(X) = (R_{h_1}^Y(X) m_{h_1} + R_{h_2}^Y(X) m_{h_2}) / (R_{h_1}^Y(X) + R_{h_2}^Y(X))$ and a net signal $R_h^Y(X) = R_{h_1}^Y(X) + R_{h_2}^Y(X)$, which is what lets a pair of individually sub-Standard-Model scalars masquerade as one enhanced resonance at the LHC's resolution of about 1.5 GeV.
Extended reading notes
Core claim
The central claim is that a degenerate pair of NMSSM Higgs bosons near 125 GeV is a natural outcome of GUT-scale semi-unified parameters once $lambda$ is large, and that such a pair can reproduce or overshoot the observed diphoton and $ZZ^* -> 4 ell$ rates. The authors scan $0 <= m_0 <= 3000$, $100 <= m_{1/2} <= 3000$, $1 <= tan beta <= 40$, $0.1 <= lambda <= 0.7$, $0.05 <= kappa <= 0.5$ and the soft $A$ terms, keep only points passing RGE convergence, Landau-pole, LSP, Higgs and SUSY mass, B-physics, relic-density ($Omega h^2 < 0.136$) and XENON100 constraints, and then require $123 < m_{h_1}, m_{h_2} < 128$ GeV. A large fraction of surviving points give $R^{gg}_{h_1}(gamma gamma) + R^{gg}_{h_2}(gamma gamma) > 1$, with the largest values at $lambda ~ 0.6$, moderate $kappa$, $tan beta < 5$ and $mu_eff < 150$ GeV. The paper also reports that no point of this kind can reach the muon anomalous magnetic moment window, that the relic-density window points have a dominantly higgsino LSP of 60–80 GeV with about a 20% singlino admixture, and that the largest diphoton enhancements come with $a_2$, $h_3$ and $H^pm$ below roughly 500 GeV and $a_1$ below roughly 150 GeV.
Load-bearing premise
The load-bearing premise is that the two Higgs signals can simply be added as rates with a rate-weighted average mass; the paper does not treat the quantum interference between two CP-even states of the same quantum numbers, which would change both the summed rate and the apparent peak position.
Editorial extensions
If this is right
- If the diphoton rate near 125 GeV is around 1.5 times the Standard Model value, this framework forces the gluon-fusion $VV$ rate to be at least about 1.2, since the two are correlated roughly as $R^{gg}(gamma gamma) ~ 1.25 R^{gg}(VV)$.
- The $gamma gamma$ and $4 ell$ mass peaks should be broader than the experimental resolution, and the apparent mass extracted in the two channels can differ by a fraction of a GeV.
- Points in the relic-density window have a light higgsino-dominated LSP around 60–80 GeV with spin-independent proton cross sections spanning roughly $10^{-11}$ to $10^{-9}$ pb.
- The same scenarios cannot supply the muon anomalous magnetic moment: the largest $delta a_mu$ found is about $1.8 times 10^{-10}$, and the relic-density points with large diphoton rates fall below $6 times 10^{-11}$.
- Large diphoton enhancements come with a compressed heavy-Higgs spectrum, with $a_2$, $h_3$ and $H^pm$ near or below 500 GeV and $a_1$ near or below 150 GeV, all with small diphoton rates of their own.
Reading between the lines
- The combination rule adds rates rather than amplitudes. Two CP-even states with the same quantum numbers a few GeV apart contribute coherently to $gg -> h -> gamma gamma$ before squaring, so the true peak height and effective mass could shift in either direction from the quoted incoherent sum; a full amplitude-level treatment would be the natural next calculation.
- Because the two states need not be exactly degenerate, a measured offset between the diphoton and four-lepton peak positions would be a channel-independent discriminator between this scenario and any single-state explanation of the 125 GeV signal.
- The quoted spin-independent cross sections down to a few times $10^{-11}$ pb sit near the reach of the direct-detection bounds the paper already applies, so a modest improvement in exposure would either find this higgsino-singlino LSP or close the relic-density window for these points.
- The failure to reach the muon $g-2$ window cuts both ways: if improved measurements confirm the discrepancy, this degenerate large-$lambda$ corner becomes disfavoured regardless of what the LHC sees at 125 GeV.
Original abstract
We examine GUT-scale NMSSM scenarios in which {\it both} $h_1$ and $h_2$ lie in the 123 -- 128 GeV mass range. Very substantially enhanced $\gamma\gamma$ and other rates are possible. Broadened mass peaks are natural.
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 examine GUT-scale NMSSM scenarios in which {\it both} $h_1$ and $h_2$ lie in the 123 -- 128 GeV mass range. Very substantially enhanced $\gamma\gamma$ and other rates are possible. Broadened mass peaks are natural.
background contribution method result interpretation main claim
| # | sentence | role | the authors' own work | states the main conclusion | strength |
|---|---|---|---|---|---|
| s0 | We examine GUT-scale NMSSM scenarios in which {\it both} $h_1$ and $h_2$ lie in the 123 -- 128 GeV mass range. | contribution 0.99 | 0.73 | 0.14 | asserted 0.71 |
| s1 | Very substantially enhanced $\gamma\gamma$ and other rates are possible. | result 0.94 | 0.53 | 0.29 | hedged possibility 1.00 |
| s2 | Broadened mass peaks are natural. | result 0.69 | 0.44 | 0.12 | asserted 0.74 |
What was examined, and what was not
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- figures and tables
- references and citing sentences
- relations to other papers
- P abstract
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Figures
Showing 6 of the paper's 8 figures. See all figures in the PDF ↗ Figures reproduced from arXiv:1207.1545 by the authors.
References
How later papers used it
65 later papers cite it
1 later paper by other authors is listed below: 1 used its method or tool. 1 more paper by the same authors is listed: 1 used its data or values.
Uses its method or tool 1 of 3 papers with this label
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Combined the two Higgs boson productions and decays as this paper did to form one Higgs particle observed at the LHC for highly mass-degenerate light CP-even neutral Higgs bosons.
Electroweak Supersymmetry (EWSUSY) in the NMSSM (2013) · 0.86 · paraphrased: the licence does not allow quoting
Uses its data or values 1 paper · 1 by the same authors
By the same authors
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Illustrated its technique using the NMSSM scenarios generated for this paper, in which the two lightest CP-even Higgs bosons both lie in the 123-128 mass window.
Diagnosing Degenerate Higgs Bosons at 125 GeV (2012) (same authors) · 0.87 · paraphrased: the licence does not allow quoting
How the literature uses it
65 arXiv papers cite this in 97 sentences
Papers citing it · 63 sentences without a confident label
Uses its method or tool 3 papers
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We perform scans of the relevant parameter space [ref] of the model using the public program NMSSMCALC [ref] to search for all possible $∼125$ GeV Higgs boson scenarios, with the CPV phase of the coupling $κ$ set to five different values, including $0^∘$ - the rNMSSM limit - in each case.
Two Higgs bosons near 125 GeV in the complex NMSSM and the LHC Run-I data · Introduction · 0.93
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Specifically, we use points from scans performed using NMSSMTools 3.2.0 [ref] , which includes the scans of [ref] supplemented by additional runs following the same procedure as well as specialized MCMC chain runs designed to focus on parameter regions of particular interest.
Higgs Bosons at 98 and 125 GeV at LEP and the LHC · Higgs Boson Production and Decay · 1.00
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For the last case in which the two light CP-even neutral Higgs bosons are highly mass degenerate (say, $Δm <2$ GeV), we combine these two Higgs boson productions and decays as Ref. [ref] did to form one Higgs particle observed at the LHC.
Electroweak Supersymmetry (EWSUSY) in the NMSSM · Setup · 0.86
Uses its data or values 1 paper
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In Fig. [ref], we plot the numerator versus the denominator of the double ratios I) and II), III) being very like I) due to the correlation between the $$ and $$ values discussed in [ref] .
Diagnosing Degenerate Higgs Bosons at 125 GeV · Introduction · 0.87
Compares with it 2 papers
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This is in contrast to a two resonance case where one particle is dominant in both channels [ref] .
A tale of two Higgs · Introduction · 0.83
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Our collider phenomena with the nearly degenerate $(h^0, H^0)$ differs from [ref] substantially, due to the new gauge bosons and vector-like heavy fermions, as well as the absence of charged Higgs boson and superpartners in our model.
LHC Higgs Signatures from Extended Electroweak Gauge Symmetry · Signatures of h$^0$ via Gluon Fusion · 0.99
Cites it as background 25 papers
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In [ref] scenarios were investigated where the two lightest NMSSM Higgs bosons are closely spaced near 126 GeV, leading to very enhanced decay rates, and in [ref] scenarios with Higgs bosons both consistent with the LEP 98 GeV excess and the 126 GeV Higgs boson of the LHC search were studied, while [ref] discussed the case where the NMSSM Higgs sector could both explain the 126 GeV discovery and the small excess observed by CMS at 136 GeV.
Natural NMSSM Higgs Bosons · Introduction · 0.93
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This topic was discussed in [ref] in the context of the NMSSM, in [ref] in the context of a 2HDM, and most recently in [ref] where general conditions for detection of such resonances were derived (see also [ref] ).
A tale of two Higgs · Introduction · 1.00
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For a full discussion of the kind of NMSSM model employed see [ref] .
Higgs Bosons at 98 and 125 GeV at LEP and the LHC · Higgs Boson Production and Decay · 0.88
What it cites · 6 sentences without a confident label
Builds on 1 paper
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We perform scans covering the following parameter ranges, which correspond to an expanded version of those considered in [ref] : $0 ≤m_0 ≤3000$; $100 ≤m_1/2 ≤3000$; $1 ≤tanβ≤40$; $-6000 ≤A_0 ≤6000$; $0.1 ≤λ≤0.7$; $0.05 ≤κ≤0.5$; $-1000 ≤A_λ≤1000$; $-1000 ≤A_κ≤1000$; $100 ≤μ_eff ≤500$.
Higgs bosons near 125 GeV in the NMSSM with constraints at the GUT scale · Introduction · 0.98
Uses the method or tool of 3 papers
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For the numerical analysis, we use NMSSMTools [ref] [ref] [ref] version 3.2.0, which has improved convergence of RGEs in the case of large Yukawa couplings and thus allows us to explore parameter regions that where left uncharted in [ref] .
The constrained NMSSM and Higgs near 125 GeV · Introduction · 1.00
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For the numerical analysis, we use NMSSMTools [ref] [ref] [ref] version 3.2.0, which has improved convergence of RGEs in the case of large Yukawa couplings and thus allows us to explore parameter regions that where left uncharted in [ref] .
NMHDECAY: A Fortran Code for the Higgs Masses, Couplings and Decay Widths in the NMSSM · Introduction · 1.00
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For the numerical analysis, we use NMSSMTools [ref] [ref] [ref] version 3.2.0, which has improved convergence of RGEs in the case of large Yukawa couplings and thus allows us to explore parameter regions that where left uncharted in [ref] .
NMHDECAY 2.0: An updated program for Sparticle masses, Higgs masses, couplings and decay widths in the NMSSM · Introduction · 1.00
Uses data or values from 2 papers
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For the latter, we assume $∼1.5$ [ref] .[The values for $$ quoted in this paper range from $1.39$–$1.84$ to $2.76$–$3.19$, the better resolutions being for the case where both photons are in the barrel and the worse resolutions for when one or both photons are in the endcap.
Search for the standard model Higgs boson decaying into two photons in pp collisions at sqrt(s)=7 TeV · Introduction · 0.98
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In addition, we impose bounds on the spin-independent LSP–proton scattering cross section implied by the neutralino-mass-dependent Xenon100 bound [ref] .
Dark Matter Results from 100 Live Days of XENON100 Data · Introduction · 0.86
Discussion
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