Search for Supersymmetry Karri Folan DiPetrillo, on behalf Karri - PowerPoint PPT Presentation

Search for Supersymmetry Karri Folan DiPetrillo, on behalf Karri Folan DiPetrillo, on behalf of the ATLAS Collabora7on of the ATLAS Collabora7on in events with a displaced Moriond Electroweak Moriond Electroweak vertex and a muon 20 March 2019 20 March 2019

Mo<va<on �2 R-parity viola<ng Supersymmetry (SUSY) small 𝜇 ’ couplings result in a long-lived lightest SUSY particle, undergoes semi-leptonic decay q p ˜ µ t λ 0 23 k µ ˜ t λ 0 p 23 k q Most interested in life<mes 𝜐 ≈ 𝒫 (ps) - 𝒫 (10 ns) - long-lived particle decays result in Inner Detector displaced vertices - also complementary to prompt searches Karri Folan DiPetrillo — Moriond EW 2019

Analysis Overview �3 Conf Note: ATL-COM-PHYS-2019-006 dataset = 136 X -1 √s=13 TeV pp-collisions collected in 2016-2018 Triggers Muon Spectrometer only or Missing transverse momentum (E Tmiss ) trigger Special reconstruc<on for displaced tracks and secondary vertices Event Selec<on at least one displaced muon and at least one displaced vertex (DV) *muon need not be associated to DV Karri Folan DiPetrillo — Moriond EW 2019

Muon Selec<on �4 Transverse impact parameter requirement, |d0|>2 mm E Tmiss trigger selection: pT > 25 GeV, |eta|<2.5 Muon trigger selection: pT > 62 GeV, |eta|<1.05 Dedicated vetoes to reject muons from backgrounds cosmics, heavy flavor decays and algorithm fakes also used to form control regions for background estimation Cosmics Heavy Flavor Decays Algorithm Fakes µ hadronic jet combinations of random hits µ Karri Folan DiPetrillo — Moriond EW 2019

Displaced Vertex Selec<on �5 Fiducial volume Rxy < 300 mm and |Z|<300 mm ensures displaced tracks can be reconstructed by strip detector Displacement Rxy > 4 mm Material veto to reject hadronic interactions Final Selec<on mass > 20 GeV and at least 3 tracks rejects random track crossings PhysRevD.97.052012 Karri Folan DiPetrillo — Moriond EW 2019

Results �6 Signal Region Expected Observed E Tmiss trigger 0.43 ± 0.16 (stat.) ± 0.16 (syst.) 0 Muon trigger 1.88 ± 0.20 (stat.) ± 0.28 (syst.) 1 Events Events 8 ATLAS Preliminary ATLAS Preliminary Data Heavy Flavor Data Heavy Flavor -1 -1 s =13 TeV, 136 fb Fakes Cosmics 20 s =13 TeV, 136 fb Fakes Cosmics (m , τ )=(1.7 TeV, 0.01 ns) (m , τ )=(1.0 TeV, 0.01 ns) ~ ~ miss ~ ~ E Trigger Selection t Muon Trigger Selection t t t T (m , )=(1.7 TeV, 0.1 ns) (m , )=(1.0 TeV, 0.1 ns) τ τ ~ ~ ~ ~ 6 Full Muon Selection Full Muon Selection t t t t (m , )=(1.7 TeV, 1 ns) (m , )=(1.0 TeV, 1 ns) τ τ ~ ~ ~ ~ 15 Preselected DVs t Preselected DVs t t t Highest mass DV w/ 3 Tracks Highest mass DV w/ 3 Tracks ≥ ≥ 4 10 2 5 0 0 2 3 4 2 3 4 1 10 10 10 10 1 10 10 10 10 m [GeV] m [GeV] DV DV Karri Folan DiPetrillo — Moriond EW 2019

Conclusions �7 arXiv:1810.12602 q p ˜ µ t λ 0 23 k µ ˜ ATLAS DV+muon t λ 0 p 23 k Hand drawn ˜ t → q μ q Exclusion limit for ~ t ➝ µ+jet No Supersymmetry discovery yet, But much more phase space to explore, especially in long-lived scenarios! Karri Folan DiPetrillo — Moriond EW 2019

Backup

R-parity viola<on and constraints on 𝜇 ’ ijk �9 If we write down SUSY in most generic form we get the following lepton & baryon number violating couplings W ∆B,L = 𝜇 ijk L i L j E k + 𝜇 ’ ijk L i Q j D k + 𝜇 ’ ijk U i D j D k + 𝜆 i L i H u q l q ¯ q ˜ ˜ q ˜ l λ λ ′ � ′ � λ ′ � ¯ q ¯ ¯ l l LQD couplings 𝜇 ’ ijk - most constraints on light flavors from CKM measurements, B-physics results, and neutrino less double beta decay 𝜇 ’ 23k > 0.45 excluded from Z partial width - LEP Karri Folan DiPetrillo — Moriond EW 2019

New trigger strategy �10 Run 1 Analysis: PhysRevD.97.052012 In Run 1: Muon Spectrometer only trigger agnostic to inner detector activity limited to | 𝜃 (µ)|<1.05 due to high rates in endcap compare to | 𝜃 (µ)|<2.4 for standard triggers Run 2: added a missing transverse momentum (E Tmiss ) trigger high pT muons deposit small fraction of their energy in calorimeter ➝ signal events fire the E Tmiss trigger! improves overall signal acceptance·efficiency by over 40% for benchmark model, with negligible increase in backgrounds Karri Folan DiPetrillo — Moriond EW 2019

Non-standard reconstruc<on �11 Inner Detector Tracking standard ATLAS tracking requires |d0| < 10 mm large radius tracking is an additional pass of tracking with loosened impact parameter and hit requirements ATL-PHYS-PUB-2017-014 Standard Track IBL B-Layer Layer 1 Layer 2 Large Radius IBL Tracks B-Layer Pixel Layer 1 Layer 2 r prod SCT Layer 1 SCT Layer 2 Secondary Vertexing forms vertices using tracks with pT > 1 GeV and |d0| > 2 mm Karri Folan DiPetrillo

Cuflows �12 8 Events Events 10 ATLAS Preliminary ATLAS Preliminary 6 7 10 10 miss 6 E Trigger Selection Muon Trigger Selection 5 10 10 T 5 10 4 10 4 10 3 3 10 10 2 2 10 10 10 10 1 1 1 − 10 Signal Efficiency Signal Efficiency 0 1 2 3 4 5 6 7 8 9 10 0 1 2 3 4 5 6 7 8 9 10 -1 1 Data, s = 13 TeV, 136 fb 1 ~ ~ m( t )=1.4 TeV, ( t )=0.01 ns τ ~ ~ m( t )=1.4 TeV, ( t )=0.1 ns τ ~ ~ 1 − 10 m( t )=1.4 TeV, ( t )=1 ns τ 1 − 10 -1 Data, s = 13 TeV, 136 fb ~ ~ − 2 m( t )=1.4 TeV, ( t )=0.01 ns 10 τ ~ ~ m( t )=1.4 TeV, τ ( t )=0.1 ns 2 − 10 ~ ~ m( t )=1.4 TeV, ( t )=1 ns τ 3 − 10 1 Preselected muon Fake-muon veto 1 Preselected muon Fake-muon veto Initial Filter Trigger > 180 GeV Cosmic-muon veto 3 Initial Filter Muon Trigger < 180 GeV Cosmic-muon veto 3 Heavy-flavor veto 1 Preselected DV > 20 GeV Heavy-flavor veto 1 Preselected DV > 20 GeV ≥ ≥ Tracks Tracks DV DV miss n n T DV DV E miss miss m m T T E E ≥ ≥ ≥ ≥ Karri Folan DiPetrillo — Moriond EW 2019

Data-driven background es<ma<on �13 Transfer factors for muon backgrounds f i = N ( events passing veto i ) N ( events failing veto i ) Karri Folan DiPetrillo — Moriond EW 2019

Valida<ng background es<ma<on �14 Events Events ATLAS Preliminary ATLAS Preliminary Data Heavy Flavor Data Heavy Flavor 3 4 -1 -1 10 10 s =13 TeV, 136 fb s =13 TeV, 136 fb Fakes Cosmics Fakes Cosmics miss E Trigger Selection Muon Trigger Selection (m , )=(1.7 TeV, 0.01 ns) (m , )=(1.0 TeV, 0.01 ns) τ τ ~ ~ T ~ ~ t t 3 t t 10 Full Muon Selection Full Muon Selection (m , )=(1.7 TeV, 0.1 ns) (m , )=(1.0 TeV, 0.1 ns) τ τ 2 ~ ~ ~ ~ 10 t t t t 2 10 10 10 1 1 Data/BG Data/BG 2 2 1.5 1.5 1 1 0.5 0.5 0 0 0 DVs Mat. two-track Mat. three-track VR two-track VR low-mass SR 0 DVs Mat. two-track Mat. three-track VR two-track VR low-mass SR Karri Folan DiPetrillo — Moriond EW 2019

Uncertain<es �15 Background measure transfer factors in events with DVs in material and as a function of muon impact parameter Signal Source of uncertainty Relative impact on ✏ sel for signal events [%] Total 18 − 20 Tracking and vertex reconstruction 15 Displaced muon e ffi ciency 10 − 12 ( 0 . 01 − 0 . 7 ) ⊕ ( 0 . 9 − 4 . 0 ) Prompt muon e ffi ciency Radiation modeling in MC simulation 3 Pileup modeling 0 . 37 − 2 . 2 Hadronic energy scale and resolution (a ff ecting E miss ) 2 . 1 T Integrated luminosity of dataset 1 . 7 E miss trigger e ffi ciency < 0 . 2 T Karri Folan DiPetrillo — Moriond EW 2019

Track Mul<plicity Distribu<ons �16 DVs DVs 5 5 10 ATLAS Preliminary 10 ATLAS Preliminary Data Heavy Flavor Data Heavy Flavor -1 -1 s =13 TeV, 136 fb Fakes Cosmics s =13 TeV, 136 fb Fakes Cosmics (m , )=(1.7 TeV, 0.01 ns) (m , )=(1.0 TeV, 0.01 ns) 4 τ 4 τ 10 ~ 10 ~ miss ~ ~ E Trigger Selection t Muon Trigger Selection t t t T (m , )=(1.7 TeV, 0.1 ns) (m , )=(1.0 TeV, 0.1 ns) τ τ ~ ~ ~ ~ Full Muon Selection Full Muon Selection t t t t (m , )=(1.7 TeV, 1 ns) (m , )=(1.0 TeV, 1 ns) τ τ ~ ~ 3 ~ 3 ~ Preselected DVs Preselected DVs t t 10 10 t t 2 2 10 10 10 10 1 1 1 1 − − 10 10 2 4 6 8 10 12 2 4 6 8 10 12 DV DV n n Tracks Tracks Karri Folan DiPetrillo — Moriond EW 2019

Cross sec<on limits �17 q p ˜ µ t λ 0 23 k Upper limit on cross section [pb] µ ˜ t λ 0 1 − ATLAS Preliminary 10 p 23 k Obs. limit -1 q s = 13 TeV, L = 136 fb Exp. limit ( 1 ) ± σ exp ~ All limits at 95% CL ( t ) = 1.00 ns τ ~ ~ t j → µ 2 − ( t ) = 0.10 ns τ 10 ~ ( t ) = 0.01 ns τ σ (pp ~ → ~ t t ) [NNLO+NNLL] 3 − 10 4 − 10 1 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2 ~ m( t ) [TeV] Karri Folan DiPetrillo — Moriond EW 2019

Karri Folan DiPetrillo — Moriond EW 2019

Karri Folan DiPetrillo — Moriond EW 2019