REVIEW
Dark matter and collider signatures of the MSSM
High Energy Physics - Phenomenology · Submitted 6 Jun 2013 · 158 references
Pith's verdict: A competent p9MSSM global fit whose headline window is narrower than the abstract implies, but the Sigma_piN treatment of XENON100 is genuinely worth having.
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Referee report
The paper
The paper claims
A nine-parameter version of supersymmetry still leaves a narrow window where a neutralino can be the dark matter, satisfy the muon magnetic-moment anomaly, and escape the LHC's electroweak searches.
The reading
What carries the argument
The argument runs on a profile-likelihood analysis of about $1.8×10^6$ MultiNest-sampled points, in which each point is passed through spectrum calculation, flavour and dark-matter codes, and then through purpose-built likelihoods for the experiments. Two of those likelihoods carry the weight. The first is an on-the-fly reimplementation of the CMS $α_T$ inclusive search and the CMS $3l+E_T^{miss}$ electroweak search: signal events are generated with PYTHIA 6.4, passed through a tuned PGS4 detector simulation, and compared to the published observed and background yields with a Poisson likelihood. The second is a XENON100 likelihood that separates an experimental Poisson part (two observed events, background marginalised at $b=1$, $δb=0.2$) from a theoretical part, and then profiles over $Σ_{πN}$ with a Gaussian, so that each point floats to whichever $Σ_{πN}$ maximises its likelihood. The authors are explicit about the cost of the electroweak search: because so many points are affected, that likelihood is computed only on a randomly chosen sample of roughly $40{,}000$ points, and the validation against the official simplified-model limit leaves a chargino-mass discrepancy of up to about $50$ GeV.
Extended reading notes
Core claim
The central claim is that the p9MSSM — the MSSM with nine free parameters $M_2$, $M_3$, $m_{Q_3}$, $m_{L_3}$, $A_t$, $A_τ$, $m_A$, $μ$, $��β$ — retains a viable neutralino dark matter candidate that satisfies the Planck relic density, the measured Higgs mass, $b$-physics constraints, and the muon $g-2$ anomaly at $2σ$, while not being excluded by the strongest LHC search for electroweakino pair production. The upper edge of the allowed range comes from $δ(g-2)_μ$, which in this parametrization depends only on the neutralino mass once the other constraints are applied; the lower edge comes from the CMS $3l+E_T^{miss}$ search at $8$ TeV with $9.2$ fb$^{-1}$. The resulting window is $200$ GeV $≲ m_χ ≲ 500$ GeV. Separately, the authors show that a recent determination of the pion–nucleon $Σ$ term, $Σ_{πN}=43±12$ MeV, shrinks the excluded region from XENON100 to a small set of mixed bino/higgsino points near $m_χ ≃ 60$–$90$ GeV; with the older $Σ_{πN}=66±6$ MeV the mixed region is almost entirely excluded. They note a residual tension: the best-fit $χ^2$ with all constraints combined is slightly worse than with either $g-2$ or XENON100 alone.
Load-bearing premise
The lower edge of the allowed window rests entirely on the authors' own simulation of the CMS three-lepton plus missing-energy search, which is validated only to within about 50 GeV in chargino mass, uses leading-order cross sections that differ from the experimental ones by a factor of about 1.8, and is applied to a randomly chosen 2 percent of the scan.
Editorial extensions
If this is right
- If the window is real, the $14$ TeV LHC run should close it: the authors state that the higher-energy run will definitely probe the $200$–$500$ GeV neutralino region.
- A future XENON1T or LUX null result would strike at the mixed bino/higgsino composition that the surviving region relies on, even under the more forgiving $Σ_{πN}$ value.
- If $Σ_{πN}$ settles near the older $66$ MeV value rather than the CHAOS $43$ MeV value, most of the mixed gaugino/higgsino parameter space is excluded at $95\%$ confidence by XENON100 alone.
- The surviving points predict spin-dependent cross sections within reach of the five-year IceCube-86 sensitivity, so solar neutrino searches offer an independent handle on the same region.
- The three benchmark points — gaugino-like at $70$ GeV, mixed at $211$ GeV, higgsino-like at $1.36$ TeV — give concrete targets for gamma-ray and positron searches, though matching AMS02 positron data would need boost factors of order $60$–$120$.
Reading between the lines
- The lower edge of the window is not an experimental number in any direct sense: it is the output of the authors' own detector simulation and Poisson comparison, so a reader should treat $200$ GeV as a soft boundary whose position moves with the reimplementation, not as a published limit.
- Because the electroweak likelihood was applied to only about $2\%$ of the scan, the quoted window is a statement about a thinned sample; a full application could in principle shift the lower edge or reveal excluded pockets inside the window that the sampling missed.
- The paper's treatment of $Σ_{πN}$ as a profiled nuisance parameter is a template that generalises: any direct-detection bound quoted against supersymmetric models inherits a comparable factor-of-five spread in the spin-independent cross section from hadronic inputs alone.
- The reported tension between $g-2$ and XENON100 is a two-sided squeeze: improving the $g-2$ measurement's precision would tighten the upper edge, while a deeper direct-detection limit would remove the mixed-composition points that sit near the lower edge.
Original abstract
We explore the MSSM with 9 free parameters (p9MSSM) that have been selected as a minimum set that allows an investigation of neutralino dark matter and collider signatures while maintaining consistency with several constraints. These include measurement of the dark matter relic density from PLANCK, main properties of the discovered Higgs boson, LHC direct SUSY searches, recent evidence for a Standard Model-like BR(Bs -> \mu+ \mu-), and the measurement of \delta(g-2), plus a number of other electroweak and flavor physics constraints. We perform a simulation of two LHC direct SUSY searches at sqrt(s)=8 TeV: the CMS inclusive \alpha_T search for squarks and gluinos and the CMS electroweak production search with 3l+E_T^miss in the final state. We use the latter to identify the regions of the parameter space, consistent at 2\sigma\ with \delta(g-2), that are not excluded by the direct limits from the electroweak production. We find that they correspond to a neutralino mass in the window 200 GeV<m_\chi<500 GeV. We also implement the likelihood for the XENON100 exclusion bound, in which we consider for the first time the impact of a recent determination of the \Sigma_{\pi N} term from CHAOS data, \Sigma_{\pi N}=43\pm12 MeV. We show that in light of this measurement, the present statistical impact of the XENON100 bound is greatly reduced, although future sensitivities of the LUX and XENON1T experiments will have decisive impact on the mixed bino/higgsino composition of the neutralino. We point out some tension between the constraints from \delta(g-2) and XENON100. Finally, we present prospects for various indirect searches of dark matter, namely \gamma-ray fluxes from dSphs and the Galactic Center at Fermi-LAT, and the positron flux at AMS02. We also show the 5-year sensitivity on the spin-dependent neutralino-proton cross section due to neutrino fluxes from the Sun at IceCube.
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 explore the MSSM with 9 free parameters (p9MSSM) that have been selected as a minimum set that allows an investigation of neutralino dark matter and collider signatures while maintaining consistency with several constraints. These include measurement of the dark matter relic density from PLANCK, main properties of the discovered Higgs boson, LHC direct SUSY searches, recent evidence for a Standard Model-like BR(Bs -> \mu+ \mu-), and the measurement of \delta(g-2), plus a number of other electroweak and flavor physics constraints. We perform a simulation of two LHC direct SUSY searches at sqrt(s)=8 TeV: the CMS inclusive \alpha_T search for squarks and gluinos and the CMS electroweak production search with 3l+E_T^miss in the final state. We use the latter to identify the regions of the parameter space, consistent at 2\sigma\ with \delta(g-2), that are not excluded by the direct limits from the electroweak production. We find that they correspond to a neutralino mass in the window 200 GeV<m_\chi<500 GeV. We also implement the likelihood for the XENON100 exclusion bound, in which we consider for the first time the impact of a recent determination of the \Sigma_{\pi N} term from CHAOS data, \Sigma_{\pi N}=43\pm12 MeV. We show that in light of this measurement, the present statistical impact of the XENON100 bound is greatly reduced, although future sensitivities of the LUX and XENON1T experiments will have decisive impact on the mixed bino/higgsino composition of the neutralino. We point out some tension between the constraints from \delta(g-2) and XENON100. Finally, we present prospects for various indirect searches of dark matter, namely \gamma-ray fluxes from dSphs and the Galactic Center at Fermi-LAT, and the positron flux at AMS02. We also show the 5-year sensitivity on the spin-dependent neutralino-proton cross section due to neutrino fluxes from the Sun at IceCube.
background contribution method result interpretation main claim
| # | sentence | role | the authors' own work | states the main conclusion | strength |
|---|---|---|---|---|---|
| s0 | We explore the MSSM with 9 free parameters (p9MSSM) that have been selected as a minimum set that allows an investigation of neutralino dark matter and collider signatures while maintaining consistency with several constraints. | contribution 0.80 | 0.77 | 0.04 | asserted 0.98 |
| s1 | These include measurement of the dark matter relic density from PLANCK, main properties of the discovered Higgs boson, LHC direct SUSY searches, recent evidence for a Standard Model-like BR(Bs -> \mu+ \mu-), and the measurement of \delta(g-2), plus a number of other electroweak and flavor physics constraints. | method 0.68 | 0.08 | 0.02 | asserted 0.96 |
| s2 | We perform a simulation of two LHC direct SUSY searches at sqrt(s)=8 TeV: the CMS inclusive \alpha_T search for squarks and gluinos and the CMS electroweak production search with 3l+E_T^miss in the final state. | method 0.91 | 0.94 | 0.03 | asserted 0.99 |
| s3 | We use the latter to identify the regions of the parameter space, consistent at 2\sigma\ with \delta(g-2), that are not excluded by the direct limits from the electroweak production. | method 0.79 | 0.90 | 0.09 | asserted 0.79 |
| s4 | We find that they correspond to a neutralino mass in the window 200 GeV<m_\chi<500 GeV. | result 1.00 | 0.96 | 0.26 | asserted 1.00 |
| s5 | We also implement the likelihood for the XENON100 exclusion bound, in which we consider for the first time the impact of a recent determination of the \Sigma_{\pi N} term from CHAOS data, \Sigma_{\pi N}=43\pm12 MeV. | method 0.56 | 0.83 | 0.05 | asserted 0.99 |
| s6 | We show that in light of this measurement, the present statistical impact of the XENON100 bound is greatly reduced, although future sensitivities of the LUX and XENON1T experiments will have decisive impact on the mixed bino/higgsino composition of the neutralino. | interpretation 0.62 | 0.82 | 0.15 | asserted 0.98 |
| s7 | We point out some tension between the constraints from \delta(g-2) and XENON100. | result 0.56 | 0.77 | 0.09 | asserted 0.95 |
| s8 | Finally, we present prospects for various indirect searches of dark matter, namely \gamma-ray fluxes from dSphs and the Galactic Center at Fermi-LAT, and the positron flux at AMS02. | contribution 0.91 | 0.83 | 0.05 | asserted 0.94 |
| s9 | We also show the 5-year sensitivity on the spin-dependent neutralino-proton cross section due to neutrino fluxes from the Sun at IceCube. | result 0.58 | 0.85 | 0.04 | asserted 1.00 |
What was examined, and what was not
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- P abstract
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Figures
Figures reproduced from arXiv:1306.1567 by the authors.
References
How the literature uses it
52 arXiv papers cite this in 97 sentences
Papers citing it · 55 sentences without a confident label
Builds on it 2 papers
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We extend the procedure developed in [ref] .
Natural MSSM after the LHC 8 TeV run · LHC SUSY limits · 1.00
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The purpose of this work is to improve and update on previous papers [ref] that have explored the observational status and prospects of detecting neutralino DM within the Minimal Supersymmetric Standard Model (MSSM).
Testing dark matter with Cherenkov light -- prospects of H.E.S.S. and CTA for exploring minimal supersymmetry · Introduction · 0.82
Uses its method or tool 10 papers
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New results from the LHC 13 TeV are taken into account by employing the recast procedure developed and described in detail in Refs. [ref] .
Phenomenological MSSM in light of new 13 TeV LHC data · 13 TeV LHC SUSY searches · 1.00
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The scans in this study are performed with the BayesFITS package [ref] , which interfaces several publicly available tools to direct the scanning procedure and calculate physical observables.
What next for the CMSSM and the NUHM: Improved prospects for superpartner and dark matter detection · Scanning methodology and experimental constraints · 1.00
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The CMS 3-lepton search [ref] is recast using the code designed by some of us and described in detail in Refs. [ref] .
GUT-inspired SUSY and the muon g-2 anomaly: prospects for LHC 14 TeV · Numerical implementation of LHC searches · 0.91
Uses its data or values 3 papers
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For each scenario we create a sample of more than 5000 points subject to the following constraints, whose central values are taken from Table 2 of Ref. [ref] and the uncertainties are obtained from the same table by adding the experimental and theoretical errors in quadrature. and are always satisfied at $2σ$.[With respect to Table 2 of Ref. [ref] , the measured value of was very recently updated by the LHCb and CMS Collaborations [ref] .
Natural MSSM after the LHC 8 TeV run · Naturalness in the MSSM · 0.98
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The limits are given in Eq. (2) of Ref. [ref] , with the exception of the limit on the neutralino mass that has been replaced here by the LEP limit on the invisible $Z$ width, $Γ(Z→χχ)$ [ref] .
GUT-inspired SUSY and the muon g-2 anomaly: prospects for LHC 14 TeV · GUT-defined models and experimental constraints · 0.88
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The limits are given in Eq. (2) of Ref. [ref] , with the exception of the limit on the neutralino mass that has been replaced here by the LEP limit on the invisible $Z$ width, $Γ(Z→χχ)$ [ref] .
Prospects for dark matter searches in the pMSSM · Scanning methodology and experimental constraints · 0.82
Compares with it 1 paper
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The results for the higgsino DM relic density agree well with other recent analyses (see, e.g., [ref] ).
Neutralino and gravitino dark matter with low reheating temperature · The MSSM · 1.00
Cites it as support 2 papers
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However, several studies have shown [ref] that if the experimental limits provided by the CMS and ATLAS collaborations are reinterpreted and applied to more general MSSM scenarios the 8 LHC results can only constrain a small part of the available parameter space, so that ample room still remains to attribute a supersymmetric (SUSY) origin to .
GUT-inspired SUSY and the muon g-2 anomaly: prospects for LHC 14 TeV · Introduction · 0.96
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It has been shown, see e.g., [ref] , that there are good prospects for future detection of an $≃1$ neutralino.
Low fine tuning in the MSSM with higgsino dark matter and unification constraints · Spectra and phenomenology · 0.96
Cites it as background 15 papers
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The collider, flavour and DM constraints on the general pMSSM were explored in several publications [ref] and the impact of stop searches was also considered [ref] .
Light stop in the MSSM after LHC Run 1 · Introduction · 0.95
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Recently, a number of studies have considered the status of the pMSSM post 7 and/or 8 TeV runs of the LHC [ref] and more specifically of the light neutralino.
The invisible decay of Higgs boson in the context of a thermal and non-thermal relic in MSSM · Introduction · 0.89
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Recent parameter scans of different supersymmetric scenarios, including the present work, include uncertainties in the estimation of the local dark matter density and velocity dispersion, as well as in nuclear physics quantities, like in the hadronic nucleon matrix elements [ref] .
Impact of nucleon matrix element uncertainties on the interpretation of direct and indirect dark matter search results · Introduction · 0.85
What it cites · 118 sentences without a confident label
Builds on 2 papers
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In order to implement the impact of direct SUSY search limits on the p9MSSM parameter space, we extend the procedure developed previously in [ref] for the derivation of approximate but accurate likelihood maps.
Two ultimate tests of constrained supersymmetry · Likelihood for LHC direct SUSY searches · 0.91
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In order to implement the impact of direct SUSY search limits on the p9MSSM parameter space, we extend the procedure developed previously in [ref] for the derivation of approximate but accurate likelihood maps.
Constrained MSSM favoring new territories: The impact of new LHC limits and a 125 GeV Higgs boson · Likelihood for LHC direct SUSY searches · 0.91
Uses the method or tool of 17 papers
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DM observables, such as the relic density and DD and ID observables, are calculated with [ref] and [ref] .
DarkSUSY: Computing Supersymmetric Dark Matter Properties Numerically · Model description and numerical methodology · 1.00
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DM observables, such as the relic density and DD and ID observables, are calculated with [ref] and [ref] .
micrOMEGAs2.0: a program to calculate the relic density of dark matter in a generic model · Model description and numerical methodology · 1.00
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The color code indicates the boost factor required at each point to maximize the dSphs likelihood [ref] .
A generic method to constrain the dark matter model parameters from Fermi observations of dwarf spheroids · $γ$ rays from dSphs · 0.97
Uses data or values from 8 papers
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In this paper we apply the results from two different searches: CMS inclusive search for SUSY final states with large missing transverse energy and $b$-quark jets in $pp$ collisions with the variable [ref] ; and direct EW production of charginos and neutralinos in $pp$ collisions at [ref] .
Search for supersymmetry in hadronic final states with missing transverse energy using the variables AlphaT and b-quark multiplicity in pp collisions at 8 TeV · Likelihood for LHC direct SUSY searches · 0.89
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For the relic density we use the recent determination by PLANCK [ref] .
Planck 2013 results. XVI. Cosmological parameters · Statistical treatment of experimental constraints · 1.00
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Likewise we construct an approximate but accurate likelihood function to incorporate limits on the spin-independent (SI) neutralino-nucleon cross section, , from XENON100 [ref] .
Dark Matter Results from 225 Live Days of XENON100 Data · Introduction · 0.95
Compares with 3 papers
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In fig:at_8tev_smsfig:a we present the bounds obtained from our likelihood in the gluino-LSP plane for model T1 of pair-produced gluinos decaying into a neutralino and quarks of the first two generations [ref] .
Search for supersymmetry in hadronic final states with missing transverse energy using the variables AlphaT and b-quark multiplicity in pp collisions at 8 TeV · Likelihood for LHC direct SUSY searches · 0.96
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This value is substantially lower than the values previously calculated using phase-shift analyses from the GWU/SAID database [ref] , or using chiral perturbation theory [ref] , and it can have substantial implications, as we shall see, when deriving limits on SUSY from DD experiments.
The chiral representation of the $\pi N$ scattering amplitude and the pion-nucleon sigma term · XENON100 likelihood · 0.93
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gives $^SM_time ave=3.87×10^-9$, which is higher than the most recent time-averaged calculation, $^SM_time ave=(3.56±0.18)×10^-9$ [ref] .
Probing New Physics with the B_s to {\mu}+ {\mu}- Time-Dependent Rate · Statistical treatment of experimental constraints · 0.95
Cites as support 7 papers
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However, such a possibility is confined to a very fine-tuned region of the parameter space, which is essentially ruled out by the direct search limits on the lightest Higgs $h$ and the pseudo-scalar Higgs $A$ and other experimental constraints from flavor physics [ref] .
MSSM Higgs Bosons at The LHC · Statistical treatment of experimental constraints · 0.98
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However, such a possibility is confined to a very fine-tuned region of the parameter space, which is essentially ruled out by the direct search limits on the lightest Higgs $h$ and the pseudo-scalar Higgs $A$ and other experimental constraints from flavor physics [ref] .
Implications of 98 GeV and 125 GeV Higgs scenario in non-decoupling SUSY with updated ATLAS, CMS and PLANCK data · Statistical treatment of experimental constraints · 0.98
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However, such a possibility is confined to a very fine-tuned region of the parameter space, which is essentially ruled out by the direct search limits on the lightest Higgs $h$ and the pseudo-scalar Higgs $A$ and other experimental constraints from flavor physics [ref] .
MSSM Higgs Boson Searches at the LHC: Benchmark Scenarios after the Discovery of a Higgs-like Particle · Statistical treatment of experimental constraints · 0.98
Cites as background 22 papers
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Most of the papers on these “p$n$MSSM” models analyzed the impact of constraints from direct LHC SUSY searches [ref] , from the Higgs discovery [ref] , from $b$-physics [ref] , and from direct and indirect detection of DM [ref] .
Supersymmetry Without Prejudice at the LHC · Introduction · 0.95
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Most of the papers on these “p$n$MSSM” models analyzed the impact of constraints from direct LHC SUSY searches [ref] , from the Higgs discovery [ref] , from $b$-physics [ref] , and from direct and indirect detection of DM [ref] .
Constraints on the MSSM from the Higgs Sector - A pMSSM Study of Higgs Searches, Bs -> mu+ mu- and Dark Matter Direct Detection · Introduction · 0.95
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Most of the papers on these “p$n$MSSM” models analyzed the impact of constraints from direct LHC SUSY searches [ref] , from the Higgs discovery [ref] , from $b$-physics [ref] , and from direct and indirect detection of DM [ref] .
Supersymmetric constraints from Bs -> mu+mu- and B -> K* mu+mu- observables · Introduction · 0.95
Discussion
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