REVIEW
Indirect Probes of the MSSM after the Higgs Discovery
High Energy Physics - Phenomenology · Submitted 8 Nov 2012 · 211 references
Pith's verdict: A careful, honest constraint synthesis for the MFV MSSM; the new ζ parameter and the gaugino-loop flavor terms are the real contributions, and the only soft spot is the reconstructed CMS ττ benchmark, which the authors flag themselves.
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Referee report
The paper
The paper claims
Even with the most conservative flavor assumptions, rare B decays reach supersymmetric particles and heavy Higgs bosons that the LHC cannot yet produce, because the relevant loop effects grow with tan β and shrink only with the heavy Higgs–
The reading
What carries the argument
The machinery is a consistent all-orders resummation of $tan beta$-enhanced loop corrections to Higgs-fermion couplings, packaged in the parameters $epsilon_b$, $epsilon_t$, $epsilon_ell$, $epsilon_0$ and the flavor-changing $epsilon_{FC}$. These arise from Higgsino-squark, gluino-squark and wino-sfermion loops and are written in Eqs. (19)-(26) in terms of a single loop function $g(x,y,z)$ collected in the appendix. The resummation matters because at large $tan beta$ the one-loop correction is not a small perturbation: it can flip the sign of the bottom Yukawa or make it non-perturbative, and it changes every prediction that depends on Higgs couplings, including the light Higgs mass, the heavy Higgs production cross sections, and the flavor-changing couplings that drive $B_s to mu^+ mu^-$. Around this core sit three supporting structures: the $zeta$ parameter of Eq. (2) that fixes the flavor alignment of left-handed squark splitting, a three-channel vacuum-stability calculation using a straight-line path and bounce-action estimates cross-checked against a dedicated tunneling code, and a two-loop renormalization group run from the GUT scale that translates a small set of minimal supergravity parameters into the TeV-scale spectrum the flavor analysis uses.
Extended reading notes
Core claim
The central claim is that flavor observables constrain the MFV MSSM beyond the reach of direct SUSY and heavy-Higgs searches, and that this survives even under minimal flavor violation, where the only source of flavor structure is the Standard Model Yukawa couplings. The load-bearing piece is the Higgs-penguin contribution to $B_s to mu^+ mu^-$, written in Eq. (45) as an amplitude proportional to $epsilon_{FC}, tan^3 beta$ divided by $M_A^2$ and by the resummation factors $(1+epsilon_b tan beta)(1+epsilon_0 tan beta)(1+epsilon_ell tan beta)$. Because that amplitude scales with the heavy Higgs mass rather than with the squark or gaugino masses, raising the supersymmetric scale does not switch it off. The authors show that for $mathrm{sign}(mu A_t) = -1$, where the supersymmetric amplitude interferes constructively with the Standard Model one, the current LHCb bound on $B_s to mu^+ mu^-$ excludes heavy Higgs masses up to roughly 1 TeV at $tan beta approx 30$. Separately, $B to X_s gamma$ excludes charged Higgs masses below about 300 GeV for small $tan beta$ even with all squarks decoupled. The paper also establishes a structural point about the MFV squark spectrum: a splitting between the first two and the third generation of left-handed squarks requires one extra parameter, $zeta$, describing whether that splitting is aligned with the up-type or down-type Yukawas, and $zeta$ controls the size of gaugino-loop contributions to flavor-changing processes. Running from minimal supergravity boundary conditions gives $zeta approx 0.8$ at $tan beta = 45$ and splittings of 20 to 35 percent, so the effect is neither zero nor negligible.
Load-bearing premise
That the boundary where direct heavy-Higgs searches stop can be faithfully reconstructed by translating the CMS $tau^+ tau^-$ limits from one benchmark scenario into a cross-section times branching-ratio bound and reinterpreting it for other scenarios under an assumption of constant efficiencies.
Editorial extensions
If this is right
- If the analysis holds, the MSSM with minimal flavor violation is already pressed by $B_s to mu^+ mu^-$ into heavy-Higgs masses near 1 TeV at moderate $tan beta$, in a region where the LHC heavy-Higgs searches in the $tau^+ tau^-$ channel stop at 800 GeV.
- The destructive-interference region, where the supersymmetric amplitude roughly cancels the Standard Model one, is the blind spot: a future LHCb measurement of $B_s to mu^+ mu^-$ at the Standard Model value with an uncertainty near $pm 0.5 times 10^{-9}$ would close it, leaving only narrow strips of allowed parameter space.
- There is a hard lower bound of one half the Standard Model branching ratio in this framework, so any confirmed measurement below that value would rule out the MFV MSSM rather than merely constrain it.
- Vacuum stability and bottom-Yukawa perturbativity together remove the parameter corner where the bottom Yukawa flips sign, which means the one region that could have made the charged Higgs interfere constructively in $B to tau nu$ is not available.
- In the region where both $mu$ and $A_t$ are positive, the $B_s to mu^+ mu^-$ and $B to X_s gamma$ bounds are simultaneously weakest, which singles that corner out as the place where the MSSM is hardest to exclude with flavor data.
Reading between the lines
- The paper's comparison benchmark, the boundary where direct heavy-Higgs searches stop, is not taken from a published exclusion but reconstructed: footnote 3 of Sec. III B says the CMS $tau^+ tau^-$ limits exist only in the $m_h^{max}$ scenario, so the authors convert them into a cross-section times branching-ratio bound and reinterpret that for their own scenarios assuming constant efficiencies. E
- Because the Higgs-penguin amplitude does not decouple with the supersymmetric scale, this class of constraint is one of the few places where a 10 TeV squark spectrum could still be probed indirectly; that suggests treating $B_s to mu^+ mu^-$ as a discovery channel for heavy-Higgs physics rather than only as an exclusion tool.
- The $zeta$ parameter is effectively a new flat direction of the MFV parameter space, and the paper's own RGE estimate pins it near 0.8 rather than leaving it free; a dedicated study of how strongly $zeta$ is fixed by the messenger scale and $tan beta$ would sharpen or loosen every gaugino-loop bound quoted here.
- The dark matter direct detection bounds are the least robust of the set, since they assume the lightest neutralino is all of the dark matter and depend on nuclear matrix elements and the local velocity distribution; a reader should weight the flavor exclusions far more heavily than the $M_1 approx mu$ exclusion when judging how closed the parameter space really is.
Original abstract
We study the minimal supersymmetric standard model (MSSM) with minimal flavor violation (MFV), imposing constraints from flavor physics observables and MSSM Higgs searches, in light of the recent discovery of a 125 GeV Higgs boson by ATLAS and CMS. We analyze the electroweak vacuum stability conditions to further restrict the MSSM parameter space. In addition, a connection to ultraviolet physics is shown via an implementation of renormalization group running, which determines the TeV-scale spectrum from a small set of minimal supergravity parameters. Finally, we investigate the impact from dark matter direct detection searches. Our work highlights the complementarity of collider, flavor and dark matter probes in exploring the MSSM, and shows that even in a MFV framework, flavor observables constrain the MSSM parameter space well beyond the current reach of direct SUSY particle searches.
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 study the minimal supersymmetric standard model (MSSM) with minimal flavor violation (MFV), imposing constraints from flavor physics observables and MSSM Higgs searches, in light of the recent discovery of a 125 GeV Higgs boson by ATLAS and CMS. We analyze the electroweak vacuum stability conditions to further restrict the MSSM parameter space. In addition, a connection to ultraviolet physics is shown via an implementation of renormalization group running, which determines the TeV-scale spectrum from a small set of minimal supergravity parameters. Finally, we investigate the impact from dark matter direct detection searches. Our work highlights the complementarity of collider, flavor and dark matter probes in exploring the MSSM, and shows that even in a MFV framework, flavor observables constrain the MSSM parameter space well beyond the current reach of direct SUSY particle searches.
background contribution method result interpretation main claim
| # | sentence | role | the authors' own work | states the main conclusion | strength |
|---|---|---|---|---|---|
| s0 | We study the minimal supersymmetric standard model (MSSM) with minimal flavor violation (MFV), imposing constraints from flavor physics observables and MSSM Higgs searches, in light of the recent discovery of a 125 GeV Higgs boson by ATLAS and CMS. | contribution 0.94 | 0.85 | 0.05 | asserted 0.90 |
| s1 | We analyze the electroweak vacuum stability conditions to further restrict the MSSM parameter space. | method 0.53 | 0.92 | 0.03 | asserted 0.93 |
| s2 | In addition, a connection to ultraviolet physics is shown via an implementation of renormalization group running, which determines the TeV-scale spectrum from a small set of minimal supergravity parameters. | method 0.95 | 0.88 | 0.03 | asserted 1.00 |
| s3 | Finally, we investigate the impact from dark matter direct detection searches. | contribution 0.93 | 0.85 | 0.03 | asserted 0.67 |
| s4 | Our work highlights the complementarity of collider, flavor and dark matter probes in exploring the MSSM, and shows that even in a MFV framework, flavor observables constrain the MSSM parameter space well beyond the current reach of direct SUSY particle searches. | interpretation 0.80 | 0.88 | 0.93 | asserted 1.00 |
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Figures
Showing 13 of the paper's 15 figures. See all figures in the PDF ↗ Figures reproduced from arXiv:1211.1976 by the authors.
References
How later papers used it
67 later papers cite it
5 later papers by other authors are listed below: 2 used its method or tool, 1 used its data or values, 1 compared its own results with it and 1 cited it as support.
Uses its method or tool 2 papers
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Used this paper's formulas for the corrections to the b to s gamma amplitude, proportional to tan beta over 1 plus epsilon_b tan beta, in all of its computations.
Naturalness, b to s gamma, and SUSY Heavy Higgses (2014) · 0.90 · paraphrased: the licence does not allow quoting
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Calculated the new physics contribution to BR(B_s to mu+ mu-) using the estimation given in this paper.
Indirect Searches of the Degenerate MSSM (2016) · 0.95 · paraphrased: the licence does not allow quoting
Uses its data or values 1 of 4 papers with this label
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Used this paper for the averaged result of all recent Belle and BABAR data, Br(B to tau nu) = (1.16 ± 0.22) x 10^-4.
Implication of Higgs at 125 GeV within Stochastic Superspace Framework (2012) · 1.00 · paraphrased: the licence does not allow quoting
Compares with it 1 of 2 papers with this label
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Noted that the lower reachable value it obtained is smaller than the one obtained in this paper.
Supersymmetry confronts Bs -> mu+mu-: Present and future status (2012) · 0.93 · paraphrased: the licence does not allow quoting
Cites it as support 1 of 5 papers with this label
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Said that in the MSSM the Higgs, chargino and gluino contributions to B to X_s gamma are generically competitive and that cancellation patterns among them are not difficult to obtain, citing this paper.
Search strategies for pair production of heavy Higgs bosons decaying invisibly at the LHC (2017) · 0.95 · paraphrased: the licence does not allow quoting
How the literature uses it
67 arXiv papers cite this in 91 sentences
Papers citing it · 65 sentences without a confident label
Uses its method or tool 2 papers
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In all of our computations, we will use the formulas of Ref. [ref] , in which the corrections to the $b →sγ$ amplitude are proportional to $tanβ/(1 + ϵ_b tanβ)$, where $ϵ_b$ in the denominator is a loop factor correcting for the wrong-Higgs contribution to the $b$-quark mass.
Naturalness, b to s gamma, and SUSY Heavy Higgses · The uplifted Higgs region · 0.90
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We also calculate the new physics contribution to BR$(B_s→μ^+μ^-)$ using the estimation given in [ref] .
Indirect Searches of the Degenerate MSSM · $B →X_s γ$ and $B_s →μ^+ μ^-$ · 0.95
Uses its data or values 4 papers
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For the experimental bound on $b →sγ$, we will follow Ref. [ref] in taking the SM prediction to be [ref] $Br(B →X_s γ)_SM = (3.15 ±0.23) ×10^-4$ and the experimental value to be [ref] $Br(B →X_s γ)_exp = (3.43 ±0.22) ×10^-4$.
Naturalness, b to s gamma, and SUSY Heavy Higgses · Interpreting the experimental results on $b →s γ$ · 1.00
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We use Ref. [ref] for the result of averaging of all the recent Belle and BABAR data which is $Br(B→τν)_exp= (1.16 ±0.22) ×10^-4$.
Implication of Higgs at 125 GeV within Stochastic Superspace Framework · Results · 1.00
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The leading dependence is roughly [ref] [equation] The recently updated Standard Model prediction [ref] is $Br(B →X_s γ)_SM ≈(3.36 ±0.23) ×10^-4$ while the experimental result is $Br(B →X_s γ)_exp ≈(3.43 ±0.21 ±0.07) ×10^-4$ [ref] .
Electric Dipole Moments in Natural Supersymmetry · Comparison to the $b →sγ$ constraint on stops and higgsinos · 0.92
Compares with it 2 papers
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The numerical exclusion limit shown in Fig. [ref] agrees well with independent previous analyses on a similar situation [ref] and are a bit stricter than the final results of [ref] , whereas a similar necessary condition was found for a slightly different direction in field space [ref] .
Charge and color breaking constraints in the Minimal Supersymmetric Standard Model associated with the bottom Yukawa coupling · Finding CCB minima · 1.00
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This observation is important for the prospect of improving the lower experimental bound on the decay rate.[Note that the lower reachable value we obtain is smaller than the one obtained in the recent study of Ref. [ref] .
Supersymmetry confronts Bs -> mu+mu-: Present and future status · pMSSM model · 0.93
Cites it as support 3 papers
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However SUSY scenarios with such a large $tanβ$ are always fine-tuned at worse than 1% level in flavor observables such as $B_s →X_s γ$ [ref] .
A New Look at Higgs Constraints on Stops · Possible Caveats · 0.97
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The working of HSMU hypothesis requires large values of $tanβ$ which is also consistent with constraints imposed by SUSY searches [ref] .
Predictions from High Scale Mixing Unification Hypothesis · Magnification of Mixing Angles via RG Evolution · 0.96
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However, we do not consider this constraint as the parameter space of interest in our analysis, in particular the large masses of the charged Higgs bosons and values of $tanβ$, do not result in MSSM contributions beyond the combined experimental and theoretical uncertainty [ref] .
Relic density of wino-like dark matter in the MSSM · Collider and flavour constraints · 0.97
Cites it as background 14 papers
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Similar bounds on $μ$ have been investigated in the past [ref] .
Large BR(h->tau mu) in the MSSM? · Charge breaking minima · 0.87
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All these new results have profound implications for a light neutralino scenario within the MSSM, and some of these aspects have already been investigated in a number of recent studies [ref] .
Naturalness of Light Neutralino Dark Matter in pMSSM after LHC, XENON100 and Planck Data · Introduction · 0.91
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There are flavour violating processes which are enhanced at large $tanβ$, in particular B-meson decays (See e.g. [ref] ).
Enlarging Regions of the MSSM Parameter Space for Large $\tan\beta$ via SUSY Decays of the Heavy Higgs Bosons · Analytical Motivation · 0.80
What it cites · 95 sentences without a confident label
Uses data or values from 20 papers
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The much smaller sensitivity of $K →μν$ to charged Higgs effects compared to the $B$ decays is compensated by its extremely high experimental precision and the excellent control on theoretical uncertainties giving [ref]
An evaluation of |Vus| and precise tests of the Standard Model from world data on leptonic and semileptonic kaon decays · B –> tau nu, B –> D(*) tau nu and K –> mu nu · 0.90
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Interestingly, recent results from BaBar [ref] on these ratios are around $2σ$ above the SM predictions in both decay modes.
Evidence for an excess of B -> D(*) Tau Nu decays · B –> tau nu, B –> D(*) tau nu and K –> mu nu · 0.87
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Using the PDG value $|V_ub| = (3.89 ±0.44) ×10^-3$ [ref] , a conservative average over direct determinations from inclusive and exclusive semi-leptonic $B$ decays, and an average of recent precise lattice determinations of the decay constant $f_B = (190 ±4)$ MeV [ref] , we find
High-Precision $f_{B_s}$ and HQET from Relativistic Lattice QCD · B –> tau nu, B –> D(*) tau nu and K –> mu nu · 1.00
Compares with 1 paper
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Note that the upper bound in ([ref]) is considerably weaker than the official combination of the previous LHCb result [ref] with the ATLAS and CMS bounds [ref] .
Strong constraints on the rare decays Bs -> mu+ mu- and B0 -> mu+ mu- · Bs –> mu+ mu- · 0.92
Cites as support 3 papers
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In this framework, the experimental data on $B →K^* ℓ^+ℓ^-$ does not put additional restrictions, once the bounds from BR$(B →X_s γ)$ are taken into account [ref] .
Model-independent constraints on new physics in b --> s transitions · B –> Xs gamma · 0.98
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In this framework, the experimental data on $B →K^* ℓ^+ℓ^-$ does not put additional restrictions, once the bounds from BR$(B →X_s γ)$ are taken into account [ref] .
Cornering New Physics in b --> s Transitions · B –> Xs gamma · 0.98
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Indeed, as shown in [ref] , a tiny phase for $b_3$ is always generated during RGE running.] We see that formally $ζ= 1 + 𝒪(y_b^2)$.
Supersymmetric models with minimal flavour violation and their running · Sfermion Spectrum · 0.98
Cites as background 56 papers
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Searches for the heavy neutral Higgs bosons of the MSSM have been performed in the $H/A →bb$ and $H/A →τ^+ τ^-$ channels both at the Tevatron [ref] and the LHC [ref] .
Search for Neutral Higgs Bosons in Events with Multiple Bottom Quarks at the Tevatron · Searches for Heavy Scalars and Pseudoscalars · 0.88
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Searches for the heavy neutral Higgs bosons of the MSSM have been performed in the $H/A →bb$ and $H/A →τ^+ τ^-$ channels both at the Tevatron [ref] and the LHC [ref] .
Search for neutral Higgs bosons decaying to tau pairs in pp collisions at sqrt(s) = 7 TeV · Searches for Heavy Scalars and Pseudoscalars · 0.88
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Searches for the heavy neutral Higgs bosons of the MSSM have been performed in the $H/A →bb$ and $H/A →τ^+ τ^-$ channels both at the Tevatron [ref] and the LHC [ref] .
Search for Higgs bosons predicted in two-Higgs-doublet models via decays to tau lepton pairs in 1.96 TeV proton-antiproton collisions · Searches for Heavy Scalars and Pseudoscalars · 0.88
Discussion
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