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Living Long At the LHC G. WATTS (UW/SEATTLE/MARSEILLE) WG3: EXOTIC HIGGS DECAYS @ FERMILAB MAY 21, 2015
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What is long lived? G. Watts (UW/Seattle/CPPM) 2 Jets Flavor Further Displaced Vertices Lepton Jets # of leptons Lepton Flavor(s) For me, started with the worry we’d miss the Standard Model Higgs SM couplings still allow a lot of room for something new… But what!? Can’t be too driven by a model… but can’t ignore them completely! Be as final state and model independent as possible
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How are we going to look for it? G. Watts (UW/Seattle/CPPM) 3 Two jet decays Single jet decays Topologies Final States Jets Where did it decay? Lepton Jets Additional cuts as needed to reduce background…
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G. Watts (UW/Seattle/CPPM) 4
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5 Hadronic Signatures Lepton Jets Miscellaneous Comments & Conclusions
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Hadronic Jets G. Watts (UW/Seattle/CPPM) 6
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ATLAS Displaced Jets G. Watts (UW/Seattle/CPPM) 7 http://arxiv.org/abs/1501.04020http://arxiv.org/abs/1504.03634 Require evidence of two displaced jets Detector signature evolves with decay length Keep backgrounds under control Decay in each sub-detector is a new analysis
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ATLAS Displaced Jets G. Watts (UW/Seattle/CPPM) 8 Displaced Vertex Trackless, low EMF Jet Jet of particles in the Muon Spectrometer
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ATLAS Displaced Jets G. Watts (UW/CPPM) 9 Inner detector Vertexing, looser track impact parameter cuts than normal vertexing Sensitivity: 4 cm – 27 cm Calorimeter Muon Spectrometer Tracking & Jet veto, vertexing in the MS Sensitivity: 4.5 m – 14 m ATL-COM-PHYS-2013-683 Z’ ATL-COM-PHYS-2013-683 ATL-COM-PHYS-2013-113 Sensitivity: 1.75 m - 3.75 m
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ATLAS Displaced Jets G. Watts (UW/Seattle/CPPM) 10 Look for associated production Can use standard triggers Take a hit in cross section! Custom trigger to look for the signal http://arxiv.org/abs/1305.2284
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ATLAS Displaced Jets G. Watts (UW/Seattle/CPPM) 11 Inner Detector Vertex Reconstruction
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ATLAS Displaced Jets G. Watts (UW/Seattle/CPPM) 12 CalRatio Jet Finding Muon Spectrometer Vertexing Custom vertex finding algorithm Tracklets formed from MS hits Tracklets are fit to a vertex using a custom vertex finding algorithm Track and jet isolation similar to trigger level cuts
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ATLAS Displaced Jets G. Watts (UW/Seattle/CPPM) 13 Displaced Trigger Topology (Vertex Locations) Yes-2 ID YesMSID + MS YesMS2 MS -CalRatio2 CalRatio Combined Limits are derived for each of the various senarios
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ATLAS Displaced Jets G. Watts (UW/Seattle/CPPM) 14
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ATLAS DV and 2 Lepton Search G. Watts (UW/Seattle/CPPM) 15 http://arxiv.org/abs/1504.05162 DV Jet DV DV+ Searches optimized for for RPV SUSY, split SUSY, GMSB Long lived: both decays to leptons and to jets!
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ATLAS DV and 2 Lepton Search G. Watts (UW/Seattle/CPPM) 16 Displaced Vertex
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ATLAS DV and 2 Lepton Search G. Watts (UW/Seattle/CPPM) 17 The vertex reconstruction efficiency Pixel Layers
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ATLAS DV and 2 Lepton Search G. Watts (UW/Seattle/CPPM) 18 Complex background model (Control Regions simultaniously fit)
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ATLAS DV and 2 Lepton Search G. Watts (UW/Seattle/CPPM) 19 Example limits
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2 Jets from one Vertex Pro: Can do a mass cut G. Watts (UW/Seattle/CPPM) 20 Two jets coming from a single vertex Only requires a single LLP Mass cut possible in a way it isn’t in other search topologies
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CMS 2-Jet Vertex Search G. Watts (UW/Seattle/CPPM) 21 http://arxiv.org/abs/1411.6530 All the models in the paper expect two of these displaced vertices “Nothing but b-tag”
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CMS 2-Jet Vertex Search G. Watts (UW/Seattle/CPPM) 22
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LHCb 2-Jet Vertex Search 7 TeV Result Mass Cut http://arxiv.org/abs/1412.3021 G. Watts (UW/Seattle/CPPM) 23
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LHCb 2-Jet Vertex Search G. Watts (UW/Seattle/CPPM) 24
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Lepton Jets G. Watts (UW/Seattle/CPPM) 25
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CMS Displaced 2-Lepton Jets G. Watts (UW/Seattle/CPPM) 26 Both predict two displaced vertices Look for two leptons originating from a displaced vertex But only one required
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CMS Displaced 2-Lepton Jets G. Watts (UW/Seattle/CPPM) 27
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ATLAS Displaced Lepton Jets G. Watts (UW/CPPM) 28 http://arxiv.org/abs/1409.0746 (FRVZ, 1007.3496) Dark photon decays to standard model leptons if it’s mass is MeV-GeV 4-8 leptons in these models An attempt to be as inclusive as possible:
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ATLAS Displaced Lepton Jets G. Watts (UW/Seattle/CPPM) 29 Separate background issues for each LJ type!
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ATLAS Displaced Lepton Jets G. Watts (UW/Seattle/CPPM) 30
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Miscellaneous G. Watts (UW/Seattle/CPPM) 31
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CMS LL Slow Particles Decaying to Photons G. Watts (UW/Seattle/CPPM) 32 http://lanl.arxiv.org/abs/1212.1838 Slow!
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ATLAS Long Lived Charged Particle Search G. Watts (UW/Seattle/CPPM) 33 http://arxiv.org/abs/1411.6795 This is not an exotics Higgs search They are heavy and they are slow Cal Only
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Ignored G. Watts (UW/Seattle/CPPM) 34
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Conclusions WHY HAVE ONLY ONE SLIDE? G. Watts (UW/Seattle/CPPM) 35
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Detectors Are Different G. Watts (UW/Seattle/CPPM) 36 CMS has amazing tracking ATLAS’ Muon Spectrometer can be used stand-alone
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G. Watts (UW/Seattle/CPPM) 37 Side comment: Timing cuts exist: Explicit in the measurement, or The timing window for the experiment trigger Combinitorics: More than one LL particle in each event Start With: A limit at a single proper lifetime Range of actual lifetimes may be limited for distribution expected for long proper lifetimes! Toy-MC often used to extrapolate
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Summary Plots G. Watts (UW/Seattle/CPPM) 38
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The ATLAS combined plot G. Watts (UW/Seattle/CPPM) 39
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The Reach of the experiments G. Watts (UW/Seattle/CPPM) 40 (old)
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Run 2 G. Watts (UW/Seattle/CPPM) 41 Run 2 has enough luminosity we can really look at WH finally? Most LL analyses are not threshold analyses Detector Upgrades New sub-detectors have been added to both experiments New triggering capabilities
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LHC Schedule G. Watts (UW/Seattle/CPPM) 42
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13 TeV From Last Night!!! G. Watts (UW/Seattle/CPPM) 43 With new inner detector!!
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Experiment’s Physics Schedule G. Watts (UW/Seattle/CPPM) 44 Conference LHC Results But, data will pour in until Winter Conference Cut off 50 ns to 25 ns transition
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Conclusions Thanks to everyone that has started to use these measurements We are aware of the comments, and please keep them coming We are designing the Run 2 versions of these analyses as we speak (well, already moving past that stage). Detector design differences can make a real difference The program is strong Lots of current measurements. A huge amount of work by both theorists and experimentalists to get to this point! We are still missing quite a bit… input on what is important to first fill out is always helpful (for Run 2 and beyond) G. Watts (UW/Seattle/CPPM) 45
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