Summary of the ATLAS experiment’s sensitivity to supersymmetry after LHC Run 1 — interpreted in the phenomenological MSSM

Aad, G.; Bergeås, Elin Kuutmann; Brenner, R.; Ekelöf, T.; Ellert, M.; Ferrari, A.; Gradin, Joakim; Isaksson, C.; Alexa, C.; Öhman, H.; Pelikan, D.; Rangel-Smith, C.; Zwalinski, L.

doi:10.1007/jhep10(2015)134

Cited by 100 publications

(172 citation statements)

References 115 publications

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“…[3,5]. Of course, in realistic SUSY models, the limits on the different masses can be significantly weaker compared to the results of simplified models [106,107]. In addition we require all charged electroweak states such as charginos to have masses larger than 100 GeV.…”

Section: Constraintsmentioning

confidence: 99%

Revisiting fine-tuning in the MSSM

Ross

Schmidt-Hoberg

Staub

2017

J. High Energ. Phys.

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Abstract:We evaluate the amount of fine-tuning in constrained versions of the minimal supersymmetric standard model (MSSM), with different boundary conditions at the GUT scale. Specifically we study the fully constrained version as well as the cases of non-universal Higgs and gaugino masses. We allow for the presence of additional nonholomorphic soft-terms which we show further relax the fine-tuning. Of particular importance is the possibility of a Higgsino mass term and we discuss possible origins for such a term in UV complete models. We point out that loop corrections typically lead to a reduction in the fine-tuning by a factor of about two compared to the estimate at treelevel, which has been overlooked in many recent works. Taking these loop corrections into account, we discuss the impact of current limits from SUSY searches and dark matter on the fine-tuning. Contrary to common lore, we find that the MSSM fine-tuning can be as small as 10 while remaining consistent with all experimental constraints. If, in addition, the dark matter abundance is fully explained by the neutralino LSP, the fine-tuning can still be as low as ∼ 20 in the presence of additional non-holomorphic soft-terms. We also discuss future prospects of these models and find that the MSSM will remain natural even in the case of a non-discovery in the foreseeable future.

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Section: Constraintsmentioning

confidence: 99%

Revisiting fine-tuning in the MSSM

Ross

Schmidt-Hoberg

Staub

2017

J. High Energ. Phys.

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“…See the SModelS v1.1.1 manual [10] for a detailed explanation of the procedure. For a fair comparison with [7], we employ only the 8 TeV results in the v1.1.1 database. In order to maximize the coverage by SMS, we consider, however, also CMS 8 TeV results, as they may give complementary constraints.…”

Section: Setup Of the Analysismentioning

confidence: 99%

“…In [7] ATLAS has analyzed in total more than 310k pMSSM parameter points with SUSY masses below 4 TeV and a neutralino as the lightest SUSY particle (LSP). These points from an extensive scan, based on previous phenomenological studies [18][19][20][21], satisfy constraints from previous collider searches, flavor and electroweak (EW) precision measurements, cold dark matter relic density and direct dark matter searches.…”

Section: Setup Of the Analysismentioning

confidence: 99%

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On the coverage of the pMSSM by simplified model results

et al. 2018

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We investigate to which extent the SUSY search results published by ATLAS and CMS in the context of simplified models actually cover the more realistic scenarios of a full model. Concretely, we work within the phenomenological MSSM (pMSSM) with 19 free parameters and compare the constraints obtained from SModelS v1.1.1 with those from the ATLAS pMSSM study in arXiv:1508.06608. We find that about 40-45% of the points excluded by ATLAS escape the currently available simplified model constraints. For these points we identify the most relevant topologies which are not tested by the current simplified model results. In particular, we find that topologies with asymmetric branches, including 3-jet signatures from gluino-squark associated production, could be important for improving the current constraining power of simplified models results. Furthermore, for a better coverage of light stops and sbottoms, constraints for decays via heavier neutralinos and charginos, which subsequently decay visibly to the lightest neutralino are also needed.

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“…Furthermore, the diversity of phenomena covered by the pMSSM is also helpful in suggesting new approaches to searches for SUSY at the LHC. A similar study has been performed by the ATLAS experiment [39]. The paper is organized as follows.…”

mentioning

confidence: 99%

Phenomenological MSSM interpretation of CMS searches in pp collisions at s = 7 $$ \sqrt{s}=7 $$ and 8 TeV

Khachatryan¹,

Sirunyan²,

Tumasyan³

et al. 2016

J. High Energ. Phys.

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Searches for new physics by the CMS collaboration are interpreted in the framework of the phenomenological minimal supersymmetric standard model (pMSSM). The data samples used in this study were collected at √ s = 7 and 8 TeV and have integrated luminosities of 5.0 fb −1 and 19.5 fb −1 , respectively. A global Bayesian analysis is performed, incorporating results from a broad range of CMS supersymmetry searches, as well as constraints from other experiments. Because the pMSSM incorporates several well-motivated assumptions that reduce the 120 parameters of the MSSM to just 19 parameters defined at the electroweak scale, it is possible to assess the results of the study in a relatively straightforward way. Approximately half of the model points in a potentially accessible subspace of the pMSSM are excluded, including all pMSSM model points with a gluino mass below 500 GeV, as well as models with a squark mass less than 300 GeV. Models with chargino and neutralino masses below 200 GeV are disfavored, but no mass range of model points can be ruled out based on the analyses considered. The nonexcluded regions in the pMSSM parameter space are characterized in terms of physical processes and key observables, and implications for future searches are discussed. Keywords: Hadron-Hadron scattering (experiments), SupersymmetryArXiv ePrint: 1606.03577Open Access, Copyright CERN, for the benefit of the CMS Collaboration. Article funded by SCOAP 3 .doi : The CMS collaboration 35 IntroductionSupersymmetry (SUSY) [1-6] is a strongly motivated candidate for physics beyond the standard model (SM). Searches for the superpartner particles (sparticles) predicted by SUSY performed in a variety of channels at the CERN LHC at √ s = 7 and 8 TeV have been reported [7][8][9][10][11][12][13][14][15][16][17][18]. The results, found to be consistent with the SM, are interpreted as limits on SUSY parameters, based mostly on models with restricted degrees of freedom, such as the constrained minimal supersymmetric standard model (cMSSM) [19][20][21][22][23][24][25], or, more recently, within the simplified model spectra (SMS) approach [26][27][28]. The cMSSM models feature specific relations among the soft-breaking terms at some mediation scale that translate into specific mass patterns typical for the model. While this problem is avoided in the SMS approach, the signatures of realistic models cannot always be fully covered by SMS topologies. This holds true, for instance, in the case of long decay chains that do not correspond to any SMS, t-channel exchanges of virtual sparticles in production, or the presence of multiple production modes that overlap in kinematic distributions. In the work reported here, data taken with the CMS experiment at the LHC are revisited with an alternative approach that is designed to assess more generally the coverage of SUSY parameter space provided by these searches. The method is based on the minimal supersymmetric standard model (MSSM) and combines several search channels and external constraints. Giv...

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Summary of the ATLAS experiment’s sensitivity to supersymmetry after LHC Run 1 — interpreted in the phenomenological MSSM

Cited by 100 publications

References 115 publications

Revisiting fine-tuning in the MSSM

Revisiting fine-tuning in the MSSM

On the coverage of the pMSSM by simplified model results

Phenomenological MSSM interpretation of CMS searches in pp collisions at s = 7 $$ \sqrt{s}=7 $$ and 8 TeV

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