Search for Electroweakinos with the ATLAS Detector at the LHC

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Collaboration The Third Annual Large Hadron Collider

1 Search for Electroweakinos with the ATLAS Detector at the LHC Alexander Mann On behalf of the ATLAS Collaboration The Third Annual Large Hadron Collider Physics Conference St. Petersburg, Russia, 3st August 5th September 5

Introduction Search for Electroweakinos Electroweakinos = charginos, + neutralinos,,3,4 (mixtures of bino, winos, higgsinos) Superpartners of U() Y and SU() L gauge bosons and Higgs doublets σ tot

2 Introduction Search for Electroweakinos Electroweakinos = charginos, + neutralinos,,3,4 (mixtures of bino, winos, higgsinos) Superpartners of U() Y and SU() L gauge bosons and Higgs doublets σ tot [pb]: pp SUSY S = 8 TeV ν eν e* o + l el e* o g t t * q q q q * m average [GeV] q g g g Superpartners: squarks, sleptons, gauginos and higgsinos Motivation Complementarity: EWK production may dominate at LHC if squarks and gluinos heavy Naturalness: masses of lightest charginos and neutralinos accessible at LHC Alexander Mann (LMU München) Search for EWKinos with ATLAS LHCp.9.5

3 Introduction Status Quo Run- of LHC has begun, past months: push to finalize remaining Run- SUSY analyses Not enough Run- data yet to produce competitive new results for EWK production Here: recent EWK results from ATLAS, fb at s = 8 TeV ( dataset from Run-) Searches produced null results (no significant excess beyond SM expectation observed) limits on masses of supersymmetric particles ATLAS SUSY Searches* - 95% CL Lower Limits Status: July 5 Model e, µ, τ, γ Jets E miss T ATLAS Preliminary s = 7, 8 TeV L dt[fb ] Mass limit s = 8 TeV Reference EW direct ll,r ll,r, l l e, µ Yes.3 l 9-35 GeV m( )= GeV , + lν(l ν) e, µ Yes GeV m( )= GeV, m( l, ν)=.5(m( )+m( )) , + τν(τ ν) τ - Yes.3-35 GeV m( )= GeV, m( τ, ν)=.5(m( )+m( )) llν lll( νν), l ν lll( νν) 3 e, µ Yes.3 7 GeV m( )=m( ), m( )=, m( l, ν)=.5(m( )+m( )) 4.79, W Z -3 e, µ - jets Yes.3 4 GeV m( )=m( ), m( )=, sleptons decoupled , 4.79, W h, h b b/ww/ττ/γγ e, µ, γ - b Yes.3 5 GeV m( )=m( ), m( )=, sleptons decoupled 5.7, 3,,3 lrl 4 e, µ Yes.3 6 GeV m( )=m( 3), m( )=, m( l, ν)=.5(m( )+m(,3 )) GGM (wino NLSP) weak prod. e, µ + γ - Yes.3 W 4-36 GeV cτ< mm Mass scale [TeV] *Only a selection of the available mass limits on new states or phenomena is shown. All limits quoted are observed minus σ theoretical signal cross section uncertainty. Excerpt from ATLAS mass reach plot Alexander Mann (LMU München) Search for EWKinos with ATLAS LHCp.9.5 3

4 Introduction Recent Results from the ATLAS Electroweak Searches h γ(γ)+ E T via / : Search for exotic Higgs-boson decays in events with at least one photon, missing transverse momentum, and two forward jets produced in s = 8 TeV pp collisions with the ATLAS detector (ATLAS-CONF-5-, Feb. 5) via Wh: Search for direct pair production of a chargino and a neutralino decaying to the 5 GeV Higgs boson in s = 8 TeV pp collisions with the ATLAS detector (Eur. Phys. J. C, 75:8, May 5) EWK Summary Paper: Search for the electroweak production of supersymmetric particles in s = 8 TeV pp collisions with the ATLAS detector (ATLAS-SUSY-4-5, to appear) Alexander Mann (LMU München) Search for EWKinos with ATLAS LHCp.9.5 4

5 EWK Summary Paper ATLAS-SUSY-4-5 Scope Goal: summarize and extend search for electroweak supersymmetry Focus: improvements for compressed scenarios and models with low cross sections New Analyses OS τ (MVA) SS l (VBF) OS l (ISR) SS l (MVA) 3l incl. SFOS l pair (ISR) Extend reach through lower lepton-p T thresholds, exploit ISR & VBF, use MVA techniques New Aspects Statistical combinations of new and existing searches Impact of mass of intermediate slepton in simplified models on exclusion reach is tested Alexander Mann (LMU München) Search for EWKinos with ATLAS LHCp.9.5 5

6 EWK Summary Paper ATLAS-SUSY-4-5 Interpretations Simplified models: (specific production mode, fixed decay chain, BR = %) τ τ q q W W q q l l ν l ν l in VBF 3 Phenomenological models: Electroweak pmssm (phenomenological Minimal Supersymmetric Standard Model) only direct production of and, relevant parameters: tan β, M, M, µ NUHM (two-parameter Non-Universal Higgs Masses model): CMSSM with additional parameters GMSB (Gauge-Mediated Supersymmetry Breaking) LSP is G, electroweak production dominates for large Λ R-parity assumed to be conserved Alexander Mann (LMU München) Search for EWKinos with ATLAS LHCp.9.5 6

7 OS τ (MVA) Overview ATLAS-SUSY-4-5 Analysis Update of simple cut-based analysis published in JHEP 4 (4) 96, arxiv:47.35 Event Preselection Exactly two opposite-sign taus (light lepton veto) Veto on b-tagged jets and Z boson decays MVA Train boosted decision trees on input variables with good discriminatory power: E T, m eff, m T, m ττ, φ(τ, τ), η(τ, τ), p τ T, p τ T, mtτ, mtτ, φ( E T, τ ) and φ( E T, τ ). One SR based on BDT output Events /.5 6 ATLAS Preliminary Data/MC s = 8 TeV,. fb τ MVA Data multi jet Z+jets W+jets (m,m τr ) = (9, ) GeV Total SM Top quark diboson BDT Score.8.6 SR BDT Score BDT output prior to SR cut Alexander Mann (LMU München) Search for EWKinos with ATLAS LHCp.9.5 7

8 OS τ (MVA) Results ATLAS-SUSY-4-5 σ [pb] Simplified Model: + τ τ τ Observed 95% CL Expected 95% CL NLO Theory ( σ) ATLAS Preliminary s=8 TeV,. fb m( )= GeV m( )= GeV m( )=4 GeV σ [pb] m( )=6 GeV m( )=8 GeV m( )= GeV m τ [GeV] m τ [GeV] m τ [GeV] 95 % CL upper limits on cross-section for combined production of τ L τ L and τ R τ R, m( ) ranging from GeV to GeV No excess beyond SM expectation set limits in simplified model MVA improves upon previous expected limits Best observed upper limit for m( τ) = 9 GeV and massless Alexander Mann (LMU München) Search for EWKinos with ATLAS LHCp.9.5 8

9 SS l (VBF) Overview ATLAS-SUSY-4-5 Analysis Benefits VBF (lower cross-section): additional jets means to separate signal from background chargino often boosted energetic decay products even in compressed spectra Event Selection Exactly SS light leptons + jets + E T > GeV ( E T trigger) One cut-based SR exploit VBF topology (large m jj, η jj, η j η j ) + cuts to suppress SM backgrounds (mainly diboson + top quark) q q q W W q l l ν l ν l Events / 3 GeV ATLAS Preliminary s = 8 TeV,.3 fb VR Fakes Data Total SM WW Charge Flip Wγ Reducible ZV Others (m,m )=(,75) GeV (m,m )=(,95) GeV VR-Fakes: test prediction of dominant backgrounds from W + jets and t t production with fake and non-prompt leptons (fake factor method) Events / 3 GeV ATLAS Preliminary s = 8 TeV,.3 fb miss VBF l l jj + E T Data Total SM WW Charge Flip Wγ Reducible ZV Others (m,m )=(,75) GeV (m,m )=(,95) GeV miss E T [GeV] SR miss E T [GeV] Alexander Mann (LMU München) Search for EWKinos with ATLAS LHCp.9.5 9

10 SS l (VBF) Results ATLAS-SUSY-4-5 q q ν l q W W q l l ν l ~ 3 Simplified Model: jj l ATLAS Preliminary σ [fb] s = 8 TeV,.3 fb ν (ν l) jj l ν Observed limit Expected limit ( σ exp ) LO Theory σ jj ~ 3 Simplified Model: jj l ATLAS Preliminary σ [fb] s = 8 TeV,.3 fb ν (ν l) jj l ν Observed limit Expected limit ( σ exp ) LO Theory σ jj SS VBF m( ) = GeV m ~ = (m + m )/ ν, l SS m( VBF ) = GeV m ~ = (m + m )/ ν, l m m [GeV] m m [GeV] 95 % CL upper limits on cross-section for VBF production as function of mass splitting (m( ) = and GeV) Best observed upper limit for m( ) = GeV and m( ) m( ) = 5 GeV: excluded cross-section.9 fb, theoretical LO cross-section 4.33 fb Alexander Mann (LMU München) Search for EWKinos with ATLAS LHCp.9.5

11 OS l (ISR) Overview ATLAS-SUSY-4-5 Analysis Extends previous analysis to small mass splittings m(, ) by exploiting ISR jets Event Selection Exactly OS light leptons, require high-p T ISR jet Veto on b-tagged / forward jets and Z boson decays SR based on super-razor variables and R Events /.5 8 ATLAS Preliminary s = 8 TeV,.3 fb 7 SRl a SF channel Data Total SM WW Others Top quark Reducible ZV (m, m ) = (, 8) GeV (m, m ) = (, 35) GeV distribution of Data/SM R = E T E T +p T l+pl T in SR a R Alexander Mann (LMU München) Search for EWKinos with ATLAS LHCp.9.5

12 3l incl. SFOS l pair (ISR) Overview ATLAS-SUSY-4-5 Analysis Extends previous analysis to small mass splittings m(, ) New: includes 3l triggers with low-p T thresholds and also defines SR with ISR jets Event Selection Exactly 3 light leptons, incl. SFOS l pair Veto on b-tagged jets and Υ meson decays SR: veto or require jet > 5 GeV, m min SFOS between 5 5 GeV or 5 5 GeV Events / GeV Data/SM 3 ATLAS Preliminary s = 8 TeV,.3 fb Data Reducible miss E T [GeV] WZ (m ~,m ~ Total SM ZZ Others )=(,85) GeV SR3L a E T and m lll in 3l SR before cut Events / GeV Data/SM ATLAS Preliminary s = 8 TeV,.3 fb SR3L b Data Reducible m lll [GeV] WZ (m ~,m ~ Total SM ZZ Others )=(5,5) GeV Alexander Mann (LMU München) Search for EWKinos with ATLAS LHCp.9.5

13 SS l (MVA) Overview ATLAS-SUSY-4-5 Analysis Complements 3l search in case one lepton not reconstructed Extends reach for small mass splittings Event Selection Exactly SS light leptons Veto on b-tagged jets and m SFOS < GeV Train 8 BDT 8 SR: optimized for four mass-splitting scenarios m(, ), each with and w/o ISR jet scalar sum of leptons and jet H T in the non-isr VR (VR defined based on BDT output) Events / 5 GeV 6 ATLAS Preliminary Data Reducible 5 s = 8 TeV,.3 fb Charge Flip no ISR VR VV(V) 4 3 Total SM Wγ Higgs, ttv (m, m ) = (,9) GeV, m ) = (6,4) GeV (m Data/SM.5 Observable [GeV] H T Alexander Mann (LMU München) Search for EWKinos with ATLAS LHCp.9.5 3

14 l L l L Results Production ATLAS-SUSY-4-5 [GeV] m ~ ~ Simplified Model: l ν l L l(ν L 6 ATLAS Preliminary s=8 TeV,.3 fb Combined SS MVA, 3l m = m ν), l ν ~ l L l (ν m~ m = m = m ν) l ν +.95*(m l l (ν m ) ν) SUSY Observed limit ( σ ) theory Expected limit ( σ exp ) Observed limit 3l Observed limit SS MVA [GeV] m Simplified Model: m~ m = (m = m m = m + m )/ ~ l L ν ~ l L l(ν ATLAS Preliminary SUSY Observed limit ( σtheory ) Expected limit ( σ exp ) Observed limit 3l Observed limit 3l ν), l ν ~ l L l (ν arxiv:4.79 soft/isr ν) l ν s=8 TeV,.3 fb l l (ν ν) Combined SS MVA, 3l, 3l soft/isr [GeV] m Simplified Model: ATLAS Preliminary s=8 TeV,.3 fb m =(m τ +m )/ L m =m m < m τ τ ν), τν τ L τ(ν L τ(ν L ν ν) τν ττ(νν) Combined τ, 3l SUSY Observed limit ( σ theory ) Expected limit ( σ exp ) Observed limit τ arxiv:47.35 Observed limit 3l arxiv:4.79 LEP (3.5 GeV) [GeV] m l-mediated decays, m( l) =.95m( ) +.5m( ) m [GeV] l-mediated decays, m( l) = (m( ) + m( )) [GeV] m,m τ -mediated decays, m( τ) = (m( ) + m( )) Left: complementarity of the new SS l (MVA) and the 3l analysis (for sleptons close to in mass) Middle: improved sensitivity in compressed scenarios from new 3l analysis (for sleptons halfway between and in mass) Right: new combination of τ and 3l analyses, improves limits in stau-mediated decays Alexander Mann (LMU München) Search for EWKinos with ATLAS LHCp.9.5 4

15 Results / 3 Production ATLAS-SUSY-4-5 [GeV] m ~ Simplified Model: lν (ν l) lν 45 SUSY ATLAS Preliminary Observed limit ( σ theory ) 4 s = 8 TeV,.3 fb Expected limit ( σ exp ) m ~ = (m + m )/ Observed limit l, ν, l 35 arxiv: SRl m = m [GeV] m Simplified Model: m 3 = m 3 /3 m ATLAS Preliminary s=8 TeV,.3 fb Combined 3l, 4l = m ~ l l R l l SUSY Observed limit ( σ ) theory Expected limit ( σ exp ) Observed limit 3l Observed limit 4l arxiv: m [GeV] production with slepton-mediated decays [GeV] m 3 production with slepton-mediated decays /3 Left: nice complementarity of new OS l (ISR) analysis at small mass splittings Right: new combination of 3l and 4l analyses shows 3 GeV improvement in limits Alexander Mann (LMU München) Search for EWKinos with ATLAS LHCp.9.5 5

16 Impact of Variable Slepton Mass ATLAS-SUSY-4-5 σ [pb] ATLAS Preliminary s = 8 TeV,.3 fb Simplified Model: ~ l L ν ~ l L l(ν ν), l ν ~ l L l (ν 3l ν) l ν m~ = x * l m l l (ν m( ) = GeV ν) NLO Theory ( σ) Observed Limit Expected Limit x =.5 x =.5 x =.5 x =.75 x = m [GeV] Comparison of exclusion limits for several different m( l) = x m(isp) Impact of intermediate slepton mass on limit small Same picture for the other models (, 3) (m( ) = GeV) Alexander Mann (LMU München) Search for EWKinos with ATLAS LHCp.9.5 6

17 New Summary Plots with Interpretations in Simplified Models ATLAS-SUSY-4-5 m( ) [GeV] 5 5 ATLAS Preliminary + m via WW via WZ via Wh = m.3 fb, l, arxiv: l+3l, arxiv: lbb+lγγ+l l +3l, arxiv:5.7 m = m + m Z m = m + m h s=8 TeV m Expected limits Observed limits = m ) [GeV] m( ATLAS Preliminary + 3 via via via via via via m ~ l L / ~ l L / τ L / ~ l L / τ L / ~ l R ν ν ν τ ν = m ν τ l, arxiv: SRl τ, arxiv:47.35 SS MVA + 3l soft/isr + 3l τ 3l+4l + 3l.3 fb, m s=8 TeV Expected limits Observed limits m ~ l L / = m τ / L ν =.5(m + m ) m(, ) [GeV] W /Z /h-boson mediated decays via WW, via WZ /Wh Small sensitivity from new analyses ( no combination) m(,, ) [GeV] 3 l-mediated decays,, 3 production with slepton-mediated decays light blue: new analysis red: combination with new analyses green, orange: new combinations Alexander Mann (LMU München) Search for EWKinos with ATLAS LHCp.9.5 7

18 Interpretation in Phenomenological Models ATLAS-SUSY-4-5 M [GeV] M = 5 GeV, tan β = ( GeV) (4 GeV) [GeV] m / NUHM: m =5TeV,tanβ=5,A =.6m,m =TeV,µ> A ATLAS Preliminary s=8 TeV,.3 fb Combined l, 3l, 4l tan β 6 5 GMSB: M mess =5 TeV, N =3, µ >, C = 5 grav Theory excl ATLAS Preliminary s = 8 TeV,.3 fb Combined l, 3l, Wh (3 GeV) SUSY Observed limit ( σ ) theory Expected limit ( σ exp ) Observed limit l, 3l LEP (3.5 GeV) arxiv: SUSY Observed limit ( σ ) theory Expected limit ( σ exp) LEP (3.5 GeV) Observed limit l Observed limit 3l Observed limit 4l 4 3 ATLAS Preliminary s=8 TeV,.3 fb 4l Observed limit SUSY ( σ ) theory Expected limit ( σ exp ) Observed limit SS/3 l + jets arxiv: µ [GeV] pmssm µ [GeV] NUHM Λ [TeV] GMSB pmssm (µ-m plane): new combination of l, 3l, and Wh (added) NUHM (µ-m / plane): new interpretation of l, 3l (drives exclusion limit), and 4l GMSB (Λ-tan β plane): new reinterpretation of 4l analysis, yields improvement by 5 TeV w. r. t. earlier combination of SS / 3l analyses Alexander Mann (LMU München) Search for EWKinos with ATLAS LHCp.9.5 8

19 Summary & Outlook End of Run- No strong signs for physics beyond the Standard Model found in Run- data Large number of SUSY analyses have been made public Presented the new EWK summary paper with final s = 8 TeV ATLAS limits for EWK production not only a summary, but also new analyses and new combinations Onto Run- Run- is on-going, new data already flowing in First months certainly belong to strong searches stronger benefit from higher center-of-mass energy, quick re-not-discovery of SUSY Electroweak searches need more data to become competitive with Run- results will be able to build upon lots of experience from Run- profit on long term from higher integrated luminosity in Run- Web Page Overview of public results on searches for supersymmetry using ATLAS: SupersymmetryPublicResults Alexander Mann (LMU München) Search for EWKinos with ATLAS LHCp.9.5 9

21 Backup Alexander Mann (LMU München) Search for EWKinos with ATLAS LHCp.9.5

22 ATLAS-CONF-5- Alexander Mann (LMU München) Search for EWKinos with ATLAS LHCp.9.5

23 VBF H γ(γ)+ E T in GMSB / NMSSM ATLAS-CONF-5- (Feb. 5) Search for exotic Higgs decays, photon + E T final state Motivation: BR(h BSM) O(5 %) possible VBF Higgs production, m h = 5 GeV Interpretation: GMSB: h G (or ), Gγ NMSSM: h (or ), γ Diphoton final states also considered (for m > m, h/) Event selection: isolated photon, E T > 5 GeV separated jets with high inv. mass lepton veto, non-vbf jet veto Signal region yields: expected: (dominant background: γ+jets, multijet) observed in data: 5 Exclusion limits in mono-photon channel Alexander Mann (LMU München) Search for EWKinos with ATLAS LHCp.9.5 3

24 Eur. Phys. J. C, 75:8 (May 5) Alexander Mann (LMU München) Search for EWKinos with ATLAS LHCp.9.5 4

25 via Wh Eur. Phys. J. C, 75:8 (May 5) Search for pp decaying via Wh Focus on scenarios where h dominant: and wino-like, m( ) m( ) Always: W l+ E T Combination of 3 signatures: SM-like h bb / γγ / lνqq bb: γγ: SR based on transverse mass m W T, cotransv. mass m CT dominant bg.: W and top-quark production SR based on m W γ, T, W and h roughly back-to-back dominant bg.: multijets + Zγ (misid. γ from leptons or jets) WW : SR for each ee, eµ, µµ based on η ll, m eff, mt max dominant bg.: dibosons (irr.), non-prompt leptons (red.) common: Higgs-mass window / sidebands Alexander Mann (LMU München) Search for EWKinos with ATLAS LHCp.9.5 5

26 via Wh Eur. Phys. J. C, 75:8 (May 5) Event yields: consistent with SM expectations in all signal regions Interpretation: upper limits on visible cross section and in simplified models Limits: in individual channels and as combination (incl. 3l analysis) bb channel: strongest limits for massless LSP overall, but actual exclusion from γγ stronger at low gaugino masses SUSY 95% CL Limit on σ/σ ATLAS s = 8 TeV,.3 fb SUSY Observed limit ( σtheory ) Expected limit ( σ exp ) Combination W h, m = GeV lbb observed limit l l observed limit lγγ observed limit 3l observed limit m [GeV] Limits on signal strength for massless [GeV] m ATLAS s = 8 TeV,.3 fb Combination W h m = m m m < m h SUSY Observed limit ( σ ) theory Expected limit ( σ exp) 3l observed limit l l observed limit lγγ observed limit lbb observed limit m [GeV], Exclusion limits in mass plane Alexander Mann (LMU München) Search for EWKinos with ATLAS LHCp.9.5 6

27 Additional Material Alexander Mann (LMU München) Search for EWKinos with ATLAS LHCp.9.5 7

28 EWK Summary Plot (Feb. 5) [GeV] m ATLAS Preliminary.3 fb, s=8 TeV Status: Feb 5 6 ~ via L ν, L / 3L, arxiv:4.79 Expected limits ~ + via L ν, L / l, arxiv: Observed limits via τ ν L / τ, 3L, arxiv: via τ ν L / τ, τ, arxiv: via τ ν L / τ, τ, arxiv:47.35 via WZ, l+3l, arxiv: via Wh, lbb+lγγ+l l +3L, arxiv:5.7 + via WW, l, arxiv: m ~ l L / τ / L L = e/µ/τ l = e/µ m =.5(m + m ) ν = m m = m + m Z m = m - + m h m = m m (=m ) [GeV] Alexander Mann (LMU München) Search for EWKinos with ATLAS LHCp.9.5 8

29 Summary of Exclusion Ranges from ATLAS SUSY Searches in Run- Alexander Mann (LMU München) Search for EWKinos with ATLAS LHCp.9.5 9

30 l l /3 Impact of Variable Slepton Mass ATLAS-SUSY-4-5 σ [pb] Simplified Model: + ATLAS Preliminary s = 8 TeV,.3 fb ~ lν( νl) lν m ~ = x*m ν, m( ) = GeV l NLO Theory ( σ) Observed Limit Expected Limit x =.5 x =.5 x =.5 x =.75 x =.95 σ [pb] ATLAS Preliminary s = 8 TeV,.3 fb Simplified Model: ~ l L ν ~ l L l(ν ν), l ν ~ l L l (ν 3l ν) l ν m~ = x * m l l (ν m( ) = GeV ν) NLO Theory ( σ) Observed Limit Expected Limit x =.5 x =.5 x =.5 x =.75 x =.95 σ [pb] Simplified Model: 3 ATLAS Preliminary s = 8 TeV,.3 fb ~ l l R ll m~ = x*m l m( ) = GeV Combined 3l, 4l NLO Theory ( σ) Observed Limit Expected Limit x =.5 x =.5 x =.5 x =.75 x = m [GeV] m [GeV] m [GeV] /3 Comparison of 95 % exclusion limits for m( ) = GeV and m( l) = x m(isp) Impact of intermediate slepton mass very small for all three models (exception: x =.95) Alexander Mann (LMU München) Search for EWKinos with ATLAS LHCp.9.5 3

31 EWK Summary Paper ATLAS-SUSY-4-5 Interpretations Simplified models: (specific production mode, fixed decay chain, BR = %) τ τ q q W W q q l l ν l ν l in VBF 3 Phenomenological models: Electroweak pmssm (phenomenological Minimal Supersymmetric Standard Model) only direct production of and (sfermions and others decoupled) reduced set of parameters: tan β, M, M, µ (instead of 9) NUHM (two-parameter Non-Universal Higgs Masses model): CMSSM + additional parameters, µ and m A little fine-tuning, Higgs mass 5 GeV, squark masses of few TeV electroweak production dominates for heavy gluino masses GMSB (Gauge-Mediated Supersymmetry Breaking) LSP is G, electroweakino decays yield final states with many leptons electroweak production dominates for large Λ R-parity assumed to be conserved Alexander Mann (LMU München) Search for EWKinos with ATLAS LHCp.9.5 3

32 EWK Summary Paper EWK Production Cross Sections ATLAS-SUSY-4-5 Cross section [pb] ATLAS Preliminary s = 8 TeV (pure wino) + (pure wino) (higgsino like) 3 + τ L τ L + τ R τ R [GeV] m sparticle Production cross sections for the simplified models of the direct production of,, 3, and τ + τ Alexander Mann (LMU München) Search for EWKinos with ATLAS LHCp.9.5 3

33 EWK Summary Paper List of Triggers / Compressed Spectra ATLAS-SUSY-4-5 Table : The triggers used in the analyses and the offline pt threshold used, ensuring that the lepton(s) or E miss T triggering the event are in the plateau region of the trigger efficiency. Where multiple triggers are listed for an analysis, events are used if any of the triggers is passed. Muons are triggered within a restricted range of η <.4. Trigger pt threshold [ GeV] Analysis Single τ 5 Double τ 4,5 Single Isolated e 5 Single Isolated µ 5 Double e Double µ 4,4 5, 4,4 8, Direct stau production Compressed spectra l + l, 3l Compressed spectra l + l, l l, 3l Compressed spectra l + l, l l, 3l Triple e,9,9 Compressed spectra 3l Triple µ Combined eµ 7,7,7 9,5,5 4(e),(µ) 8(µ),(e) 9(e),9(e),7(µ) 9(e),7(µ),7(µ) Compressed spectra 3l Compressed spectra 3l ET miss Chargino production via VBF Compressed Spectra For small mass splittings between sparticles and LSP low-momentum decay products experimentally challenging Motivation: naturalness light higgsino,, usually higgsino-dominated small m( ) m( ), m( ) Alexander Mann (LMU München) Search for EWKinos with ATLAS LHCp

34 EWK Summary Paper Interpretation of Search Results: Mapping of Analyses to Models ATLAS-SUSY-4-5 Exclusion limits are calculated by statistically combining results from disjoint SRs Where SRs overlap, the best expected SR is used for each grid point Table 3: Searches used to probe each of the models described in Section. Model W h [3] l [9] τ [] 3l [] 4l [] τ MVA SRl- SS MVA SR3l-/ SRl- τ τ + via ll with x =.5 + via ll with variable x + via WW via VBF via τl via ll with x =.5 via ll with variable x via W Z via W h 3 via ll with x =.5 3 via ll with variable x pmssm NUHM GMSB The opposite-sign, two-lepton signal regions in Ref. [9] and Section 8. overlap. The two-tau signal regions in Ref. [] and Section 7 overlap. The three-lepton signal regions in Ref.. [] and Section 8.3 overlap. The same-sign, two-lepton signal regions in Section 8. and Section 9 overlap. Alexander Mann (LMU München) Search for EWKinos with ATLAS LHCp

35 EWK Summary Paper Definition of Super-Razor Variables (R, M R, φβ R ) ATLAS-SUSY-4-5 mt The stransverse mass is calculated as [ ( mt = min max l/τ mt( pt, qt),mt( pt l/τ, ET miss qt) )], qt meff where l/τ and l/τ denote the highest- and second-highest-pt leptons or taus in the event, respectively, and qt is a test transverse vector that minimizes the larger of the two transverse masses mt. The mt distribution has a kinematic endpoint for events where two massive pair-produced particles each decay to two objects, one of which is detected and the other escapes undetected [8, 9]. The scalar sum of the transverse momenta of the signal leptons, taus, jets and ET miss in the event: meff = E miss T + Σp leptons T + ΣpT taus + Σp jets T. In the case of the two-tau analysis, only the sum of the ET miss and two taus is used. R The quantity R is defined as R = E miss T ET miss + pt l + pl T The R distribution is shifted towards unity for signal events compared to the background, due to the existence of the LSPs that results in a larger ET miss fraction. M R, φβ The super-razor quantities R MR and φβ R are defined in Ref. []. These variables are motivated by the generic process of the pair production of two massive particles, each decaying into a set of visible and invisible particles (i.e. lνl ). Similar to mt, M R is sensitive to the squared mass difference of the pair-produced massive particle and the invisible particle, via a kinematic endpoint. These two variables are expected to have a similar performance. For systems where the invisible particle has mass that is comparable to the pair-produced massive particle (i.e. compressed spectra), the variable φ β R has a pronounced peak near π. The effect is magnified as the spectrum becomes more and more compressed, making this variable a good discriminator for compressed spectra searches.. Alexander Mann (LMU München) Search for EWKinos with ATLAS LHCp

36 EWK Summary Paper Signal MC ATLAS-SUSY-4-5 Signal MC τ τ,, : Herwig++ (.5.) 3, VBF : MadGraph5 (-.5. / _amc@nlo-..) + Pythia (6.46) Signal Grids: EWKino Composition, : both and pure wino and mass-degenerate, pure bino, slepton-mediated decays: BR= /6 for all 3 l L / ν, stau-mediated: BR= / for τ L / ν τ 3: and 3 pure higgsino and mass-degenerate, pure bino, BR=/ for ẽ R, µ R SS -pair production in VBF: pure wino, pure bino, BR= /6 for all 3 l L / ν Interpretation: GMSB Bump For most of the parameter space: co-nlsp (stau and slepton) Low tan β: just slepton as NLSP BR to light leptons larger Since light-lepton analyses usually better reach better sensitivity there Alexander Mann (LMU München) Search for EWKinos with ATLAS LHCp

37 EWK Summary Paper Signal MC ATLAS-SUSY-4-5 Dominating Backgrounds OS τ (MVA): reducible ( fake taus): W + jets (multi-jet) irreducible ( prompt taus): diboson (t t, Z + jets) OS l (ISR) irreducible ( prompt leptons): WW, top, (ZV, Higgs, Z + jets) reducible ( fake leptons, e. g. e conversions): small SS l (MVA) irreducible ( prompt SS leptons): diboson (triboson, t tv, tz, higgs) reducible ( fake leptons): Wγ charge flip ( lepton with mismeasured charge) 3l incl. SFOS l pair (ISR) reducible ( fake leptons): t t, Z + jets (W + jets, WW, top) irreducible (3 prompt leptons): WZ /ZZ (triboson, t tv, tz, higgs) SS l (VBF) reducible ( fake leptons): W + jets (t t, Wγ) irreducible ( prompt leptons): WZ, WW charge flip ( lepton with mismeasured charge) Alexander Mann (LMU München) Search for EWKinos with ATLAS LHCp

38 EWK Summary Paper Signal MC ATLAS-SUSY-4-5 Dominating Systematic Uncertainties OS τ (MVA): stat. unc. on MC samples ( %), E T soft-term resolution ( %); total: 35 % OS l (ISR): theory & modeling (generator modeling, parton shower,..., 4 %); total: 3 8 % SS l (MVA): stat. unc. on MC samples (7 74 %), real lepton subtraction 8 33 %), jet-energy resolution ( 35 %); total: 8 8 % 3l incl. SFOS l pair (ISR): stat. unc. on reducible bg. estimate ( 34 %), muon misidentification probability (red. bg. est., < 7 %), total: 5 59 % SS l (VBF): fake-factor closure test (3 %), stat. unc. on the red. bg. ( %), total: % Alexander Mann (LMU München) Search for EWKinos with ATLAS LHCp

VBF H γ(γ)+ E T in GMSB / NMSSM ATLAS-CONF-5- (Feb. 5) Monophoton signals Diphoton signals [GeV] m LSP 6 5 4 3 ATLAS Preliminary - s = 8 TeV,.

39 VBF H γ(γ)+ E T in GMSB / NMSSM ATLAS-CONF-5- (Feb. 5) Monophoton signals Diphoton signals [GeV] m LSP ATLAS Preliminary - s = 8 TeV,.3fb m LSP >m NLSP γγ m LSP +m NLSP >5 GeV Observed limits [GeV] m NLSP - Obs 95% CL upper limit on (σ/σ SM ) BF(h NLSP+LSP) Diphoton production Alexander Mann (LMU München) Search for EWKinos with ATLAS LHCp

40 via Wh Eur. Phys. J. C, 75:8 (May 5) Individual limits in 3 channels (lbb, lγγ, ll + l ): SUSY 95% CL Limit on σ/σ ATLAS s = 8 TeV,.3 fb SUSY Observed limit ( σtheory ) Expected limit ( σ exp ) lbbchannel SUSY 95% CL Limit on σ/σ ATLAS s = 8 TeV,.3 fb SUSY Observed limit ( σtheory ) Expected limit ( σ exp ) lγγchannel SUSY 95% CL Limit on σ/σ - ATLAS s = 8 TeV,.3 fb SUSY Observed limit ( σtheory ) Expected limit ( σ exp ) l l channel W h, m = GeV m [GeV] W h, m = GeV m [GeV] - W h, m = GeV m [GeV] [GeV] m 8 ATLAS s = 8 TeV,.3 fb lbb channel W h SUSY Observed limit ( σ ) theory Expected limit ( σ exp) [GeV] m ATLAS s = 8 TeV,.3 fb lγγ channel W h SUSY Observed limit ( σ ) theory Expected limit ( σ exp) [GeV] m ATLAS s - = 8 TeV,.3 fb l l channel W h SUSY Observed limit ( σ ) theory Expected limit ( σ exp) 6 m = m 4 m = m 4 m = m 4 m m < m h 3 m m < m h 3 m - m < m h m [GeV] m [GeV], m [GeV], Alexander Mann (LMU München) Search for EWKinos with ATLAS LHCp.9.5 4

41 via Wh Eur. Phys. J. C, 75:8 (May 5) Discriminating Variables Cotransverse mass m CT = (E b + T E b T ) p b T pb T t t: upper endpoint at approximately top mass Transverse mass m W T = E l T E miss T W + jets: at low values p l T pmiss T m W γ, T = (mt W ) + ET W E γ i T pw T pγ i T including photon in transverse mass allows to identify lept. W decays with photon FSR φ(w, h): W lν and hγγ back-to-back m max T = max{m T(l ), m T(l )} (against W ) m eff = sum of p T of leptons, jets and E T (against diboson) E miss,rel T = E T reduced by component along direction of nearest lepton or jet (against Z, non-prompt leptons, reduced impact from mismeasurements) small η ll against WZ, ZZ Alexander Mann (LMU München) Search for EWKinos with ATLAS LHCp.9.5 4

42 The ATLAS Detector Alexander Mann (LMU München) Search for EWKinos with ATLAS LHCp.9.5 4

43 SUSY Models msugra / CMSSM Parameters gravity-mediated SUSY breaking m : mass of scalar particles m / : gaugino masses A : trilinear Higgs-sfermion-sfermion coupling parameter tan β = ν u/ν d : ratio of the vacuum expectation values of the two Higgs doublets sign of the Higgsino mass parameter µ NUHM: adds m Hu, m Hd, trade for µ, m A GMSB Parameters gauge-mediated SUSY breaking Λ: SUSY breaking mass scale felt by the low-energy sector M mes: mass scale of the messenger fields N 5: number of SU(5) messenger fields C grav: scale factor of the gravitino coupling tan β = ν u/ν d : ratio of the vacuum expectation values of the two Higgs doublets sign of the Higgsino mass parameter µ NGM starts from General Gauge Mediation GGM: no specific SUSY mass hierarchy is predicted for colored and uncolored states gluinos and squarks can be below the TeV scale = within reach of LHC NGM: decouple all sparticles not related to fine-tuning of Higgs sector light stop and light gluino as only light (relevant) coloured sparticle some additional mechanism needed (as in GMSB) to produce correct Higgs mass Alexander Mann (LMU München) Search for EWKinos with ATLAS LHCp

Searches for electroweak production of supersymmetric gauginos and sleptons with the ATLAS detector

Searches for electroweak production of supersymmetric gauginos and sleptons with the ATLAS detector Christopher Bock on behalf of the ATLAS Collaboration SUSY5 - August 7, 5 Introduction Outline Introduction