Signals of a superlight gravitino at the LHC

Abstract

Very light gravitinos could be produced at a sizeable rate at colliders and have been searched for in the mono-photon or mono-jet plus missing momentum signature. Strategies for enhancing the signal over background and interpretations of the experimental results are typically obtained within an effective field theory approach where all SUSY particles except the gravitino are heavy and are not produced resonantly. We extend this approach to a simplified model that includes squarks and gluinos in the TeV range. In such a case, the jet(s)-plus-missing-momentum signature can be generated through three different concurring mechanisms: gravitino-pair production with an extra jet, associated gravitino production with a squark or a gluino, or squark/gluino pair production with their subsequent decay to a gravitino and a jet. By using a matrix-element parton-shower merging procedure, we take into account all the relevant production processes consistently, explore the SUSY parameter space with the LHC Run-I data set, and give prospects for the Run II. We also consider the reach of other signatures involving electroweak particles, e.g., the mono-photon, -Z, or -W plus missing momentum. The current mono-jet and mono-photon LHC analyses are interpreted to set a lower bound on the gravitino mass. We show how the limit of $m_{3/2}>1.7\times 10^{-13}$ GeV obtained in the effective field theory hypothesis is modified when the squarks and/or the gluino are in the TeV range.

24 pages, 12 figures, 1 table; v2: a reference added

References in corpus (13)

• PYTHIA 6.4 Physics and Manual
• The automated computation of tree-level and next-to-leading order differential cross sections, and their matching to parton shower simulations
• Big-Bang Nucleosynthesis
• MadAnalysis 5, a user-friendly framework for collider phenomenology
• QCD radiation in the production of heavy colored particles at the LHC
• Search for dark matter in events with a Z boson and missing transverse momentum in pp collisions at $\sqrt{s}$=8 TeV with the ATLAS detector
• Study of ${\chi }_{cJ}$ decaying into $\varphi$ $K^{\ast }(892)$ $\bar{K}$
• Search for new particles in events with one lepton and missing transverse momentum in $pp$ collisions at $\sqrt{s}$ = 8 TeV with the ATLAS detector
• Search for Large Extra Dimensions via Single Photon plus Missing Energy Final States at sqrt(s) = 1.96 TeV
• Search for monotop signatures in proton-proton collisions at sqrt(s) = 8 TeV
• Signals of a superlight gravitino at the LHC
• New Results for Light Gravitinos at Hadron Colliders - Tevatron Limits and LHC Perspectives
• HELAS and MadGraph with goldstinos

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• $Z\gamma$ production at NNLO including anomalous couplings
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• Ripples in Spacetime from Broken Supersymmetry
• Gravitational waves from first-order electroweak phase transition in a model with light sgoldstinos
• A Novel Solution to the Gravitino Problem