Seeking a coherent explanation of LHC excesses for compressed spectra

Abstract

The most recent searches by the ATLAS and CMS Collaborations in final states with soft leptons and missing transverse energy show mild excesses predominantly associated with dilepton invariant masses of about 10-20 GeV, which can result from decays of electroweakinos that are heavier than the lightest neutralino by O(10) GeV. On the other hand, these analyses are insensitive to electroweakino mass splittings smaller than about 5 GeV. In previous work, we demonstrated that while recent searches in the monojet channel can exclude some of the smallest O(1) GeV mass splitting configurations for electroweakinos, they also exhibit excesses that can overlap with the soft-lepton excesses in certain models, including a simplified scenario with pure higgsinos. In this work we dive deeper into these excesses, studying the analyses in detail and exploring an array of models that go beyond the simplified scenarios considered by the experimental collaborations. We show that, in the Minimal Supersymmetric Standard Model, the overlapping excesses are not unique to the pure-higgsino limit, instead persisting in realistic parameter space featuring a bino-like lightest supersymmetric particle with some wino admixture. On the other hand, for the Next-to-Minimal Supersymmetric Standard Model with a singlino-like lightest supersymmetric particle and higgsino-like next-to-lightest supersymmetric particle(s), the excess in the two-lepton channel fits rather well with the parameter space predicting the correct relic abundance through freeze out, but the monojet fit is much poorer. Interestingly, the excesses either do not overlap or do not exist at all for two non-supersymmetric models seemingly capable of producing the correct final states.

31 pages, 17 figures

References in corpus (30)

• The automated computation of tree-level and next-to-leading order differential cross sections, and their matching to parton shower simulations
• LHAPDF6: parton density access in the LHC precision era
• Automatic spin-entangled decays of heavy resonances in Monte Carlo simulations
• MadAnalysis 5, a user-friendly framework for collider phenomenology
• A standard format for Les Houches Event Files
• QCD radiation in the production of heavy colored particles at the LHC
• Designing and recasting LHC analyses with MadAnalysis 5
• Minimal Kinematic Constraints and MT2
• HiggsTools: BSM scalar phenomenology with new versions of HiggsBounds and HiggsSignals
• Search for new phenomena in events with an energetic jet and missing transverse momentum in $pp$ collisions at $\sqrt{s}=13$ TeV with the ATLAS detector
• micrOMEGAs 6.0: N-component dark matter
• Two-Loop Higgs mass calculations in supersymmetric models beyond the MSSM with SARAH and SPheno
• Search for chargino--neutralino pair production in final states with three leptons and missing transverse momentum in $\sqrt{s}=13$ TeV $pp$ collisions with the ATLAS detector
• Search for new particles in events with energetic jets and large missing transverse momentum in proton-proton collisions at $\sqrt{s}=$ 13 TeV
• Constraining new physics with SModelS version 2
• On the two-loop corrections to the Higgs masses in the NMSSM
• Recursive Jigsaw Reconstruction: HEP event analysis in the presence of kinematic and combinatoric ambiguities
• Supersymmetric and non-supersymmetric models without catastrophic Goldstone bosons
• Search for supersymmetry in final states with two or three soft leptons and missing transverse momentum in proton-proton collisions at $\sqrt{s}=$ 13 TeV
• Perspectives for the detection and measurement of Supersymmetry in the focus point region of mSUGRA models with the ATLAS detector at LHC
• SModelS v2.3: enabling global likelihood analyses
• $M_W$, Dark Matter and $a_{\mu }$ in the NMSSM
• Electroweak superpartner production at 13.6 TeV with Resummino
• Indirect dark-matter detection with MadDM v3.2 -- Lines and Loops
• Type-II see-saw: searching the LHC elusive low-mass triplet-like Higgses at $e^{-}{e}^{+}$ colliders
• Light lepton portal dark matter meets the LHC
• Spey: smooth inference for reinterpretation studies
• Probing compressed mass spectra in the type-II seesaw model at the LHC
• LHC constraints on electroweakino dark matter revisited
• Taking aim at the wino-higgsino plane with the LHC

Cited by in corpus (8)

• The LHC has ruled out Supersymmetry -- really?
• t-channel dark matter at the LHC -- a whitepaper
• Monojets from compressed weak frustrated dark matter
• A joint explanation for the soft lepton and monojet LHC excesses in the wino-bino model
• Machine-Learning Analysis of Radiative Decays to Dark Matter at the LHC
• Implementation of full and simplified likelihoods in CheckMATE
• Deciphering compressed electroweakino excesses with MadAnalysis 5
• Feasibility to probe the dynamical scotogenic model at the LHC