ATLAS SUSY search in 0-lepton channel with boosted W bosons

Transcription

1 ATLAS SUSY search in -lepton channel with boosted W bosons Tomas Javurek supervised by: Gregor Herten, Zuzana Rurikova, Valerio Consorti University of Freiburg 3 th April 4 Tomas Javurek (UNI Freiburg) Boosted techniues in SUSY 3 th April 4 / 8

2 Introduction Ongoing events: paper in Atlas circulation: (ATL-COM-PHYS-4-94) int note: (ATL-COM-PHYS-3-4) presented at Atlas Weekly: ( today s open presentation: ( In preparation: pmssm legacy paper (RunI) prospects for RunII: ( Tomas Javurek (UNI Freiburg) Boosted techniues in SUSY 3 th April 4 / 8

3 Supersymmetry supersymmetry: symmetry of Lagrangian resulting to new particles and interactions has to be broken (similar to electroweak symmetry) Theoretical motivations for SUSY searches: dark matter gauge coupling unification hierarchy problem Motivation for SUSY searches with ATLAS: reachable sparticles production cross-section sensitivity to other theories (searching for discrepancy between SM and data in general) Tomas Javurek (UNI Freiburg) Boosted techniues in SUSY 3 th April 4 3 / 8

4 Definition of susy -lepton analysis p p jet proton MissingE g χ ± χ g jet proton jet3 MET W p χ χ p W NOlepton!!! χ χ -lepton Signal Regions (SRs): jets:, g decay to and g making jets MET: because of R-parity conservation, LSP does not decay further and contributes to MET lepton veto: to be orthogonal to other SUSY analysis Aiming signals: msugra, simplified models (gg-onestep on the left), MUED, NUHMG Tomas Javurek (UNI Freiburg) Boosted techniues in SUSY 3 th April 4 4 / 8

5 Selection criteria ATLAS Work in progress Reuirement Targetted signal Channel j 3j 4j 6j jl jm jt jw 3j 4jw 4jvl 4jl 4jm 6jm 6jt 6jvt g g g & g g g g direct one-step direct one-step direct one-step one-step ET miss [GeV] > 6 p T (j) [GeV] > 3 p T (j) [GeV] > 6 p ( j3) [GeV] > p T (j4) [GeV] > p T (j5) [GeV] > 6 6 p T (j6) [GeV] > 6 φ(j,,(3), ET miss >.4 φ(j i>3, ET miss > ). W candidates W j W j W jj ET miss H T > ET miss /m eff(nj) > m eff (incl.) [GeV] > NUHM Definition of W candidates will come later in this talk. Powerful executing variables: E T miss, m meff = p T + E T miss, E T miss/m meff Two W signal regions SRjW and SR4jW have been newly developed. Tomas Javurek (UNI Freiburg) Boosted techniues in SUSY 3 th April 4 5 / 8

6 Hadronic boosted W Introduction p g χ ± W χ There are two Ws present in one-step simplified models. They mostly decay hadronically: W ( 68%). They can be highly boosted for large values of m( χ ± χ ) ( x for LSP=6GeV) We defined resolved W = jets and unresolved W = jet (AntiKt.4) (right fig.) We try to reconstruct Ws in the final state using the windows in the invariant mass of one or two jets (next slide). Resolved χ Unresolved χ W-finder W χ W χ p g χ Jet Find unresolved Ws among the jets. Find resolved Ws as a combination of two closest jets in R among rest of the jets. Jet χ W Jet Tomas Javurek (UNI Freiburg) Boosted techniues in SUSY 3 th April 4 6 / 8

7 Hadronic boosted W Introduction R R(,) vs. P (W) T ATLAS Work in progress truth level study m g = GeV m =36 GeV χ m LSP =6 GeV R R(,) vs. P (W) T ATLAS Work in progress truth level study m g = GeV m =6 GeV χ m LSP =6 GeV P T (W) P T (W) suark chargino LSP,m(LSP) = 6[GeV] gluino chargino LSP,m(LSP) = 6[GeV] We have been using AntiKt.4 jets so far to be consistent with previous -lepton analysis. The plan is to switch to AntiKt. Tomas Javurek (UNI Freiburg) Boosted techniues in SUSY 3 th April 4 7 / 8

8 Hadronic boosted W Introduction Distribution of invariant mass for candidates on resolved W when N(unres.W ) events/ 6GeV ATLAS Workinprogress - SR -4jets L dt=.3fb Data( s=8tev) Multijet W+jets SMTotal Z+jets Diboson ggm( g)=,m(χ ± )=5,m(χ )=6 tt(+x)&singletop m( )=7,m(χ ± )=675,m(χ )=6 6- GeV window was used to reconstruct W SRjw: N(unres.W ) DATA /MC m(j,j )[GeV] i k m(j,j )[GeV] i k SR4jw: N(unres.W ), N(res.W ) 4 χ (ax +bx+c+sigmc)=.98 Alternative statistical treatment Background can be fitted by uadratic function and χ -test can be used to test hypothesis of signal χ (ax +bx+c+n.sigmc)=.9 χ (ax +bx+c+n.sigmc) in VR=.3 N=. ±.3 ATLAS Work in progress - L dt =.3 fb all BG uadr.+n*sigmc fit MC BG uadr.+sigmc fit MC BG SM_SS_onestep_6_575_6 Validation Region not used for fit Mass of jets [GeV] Tomas Javurek (UNI Freiburg) Boosted techniues in SUSY 3 th April 4 8 / 8

9 - - miss eff Interesting distributions for jw region events / 6 GeV 4 - ATLAS Work in progress L dt =.3 fb SR - jets Data ( s = 8 TeV) 3 SM Total gg m( g)=,m(χ ± )=5,m(χ )=6 m( )=7,m(χ ± )=675,m(χ )=6 Multijet Z+jets W+jets tt(+x) & single top Diboson events /.4 ATLAS Work in progress L dt =.3 fb SR - jets (W) Data ( s = 8 TeV) SM Total gg m( g)=,m(χ ± )=5,m(χ )=6 Multijet Z+jets W+jets tt(+x) & single top Diboson jw DATA / MC m(j) [GeV] m(j) [GeV] mass of whichever jet in jet SRs E miss T DATA / MC E ) /m (N miss E T ) /m (N /m eff distribution for jw region events / 6 GeV ATLAS Work in progress L dt =.3 fb SR - jets Data ( s = 8 TeV) SM Total gg m( g)=,m(χ ± )=5,m(χ )=6 m( )=7,m(χ ± )=675,m(χ )=6 Multijet Z+jets W+jets - events/ 4GeV ATLAS Workinprogress SR -jets(w) L dt=.3fb Data( s=8tev) SMTotal ggm( g)=,m(χ ± )=5,m(χ )=6 Multijet Z+jets W+jets tt(+x) & single top jw tt(+x)&singletop Diboson Diboson DATA / MC m(j) [GeV] m(j) [GeV] mass of whichever jet, unresolved W reuired, jet SRs DATA/MC m eff (incl.)[gev] m eff (incl.)[gev] m eff distribution for jw region Tomas Javurek (UNI Freiburg) Boosted techniues in SUSY 3 th April 4 9 / 8

10 - - i - - miss eff Interesting distributions for 4jW region events / 6 GeV 3 ATLAS Work in progress L dt =.3 fb SR - 4 jets Data ( s = 8 TeV) SM Total gg m( g)=,m(χ ± )=5,m(χ )=6 m( )=7,m(χ ± )=675,m(χ )=6 Multijet Z+jets W+jets tt(+x) & single top Diboson events /.4 3 ATLAS Work in progress L dt =.3 fb SR - 4 jets (W) Data ( s = 8 TeV) SM Total m( )=7,m(χ ± )=675,m(χ )=6 Multijet Z+jets W+jets tt(+x) & single top Diboson 4jW DATA / MC m(j) [GeV] m(j) [GeV] mass of whichever jet in 4jet SRs E miss T DATA / MC E ) /m (N miss E T ) /m (N /m eff distribution for 4jW region events/ 6GeV ATLAS Workinprogress SR -4jets L dt=.3fb Data( s=8tev) Multijet W+jets SMTotal Z+jets Diboson ggm( g)=,m(χ ± )=5,m(χ )=6 tt(+x)&singletop m( )=7,m(χ ± )=675,m(χ )=6 events/ GeV ATLAS Workinprogress SR - 4jets(W) L dt=.3fb Data( s=8tev) SMTotal m( )=7,m(χ ± )=675,m(χ )=6 Multijet Z+jets W+jets 4jW tt(+x)&singletop Diboson DATA /MC m(j,j )[GeV] k m(j,j )[GeV] mass of remaining di-jet combination, unresolved W reuired, 4jet SRs DATA/MC m eff (incl.)[gev] m eff (incl.)[gev] m eff distribution for 4jW region Tomas Javurek (UNI Freiburg) Boosted techniues in SUSY 3 th April 4 / 8

11 Statistical treatment Main background: Z,W+jets, Top, QCD, Diboson Control regions (CR): CRY, CRQ, CRW, CRT Signal regions (SR): N SR raw Nexp SR = Nobs CR Nraw CR transfer factor normalized through all CRs via likelihood fit Likelihood: L(n µ,s,b,θ) = P SR P CRY P CRQ P CRT P CRW C syst CR SR Background CR process CR selection CRY Z( νν)+jets γ+jets Isolated photon Reversed φ(j CRQ Multijets Multijets i, ET miss miss ) and ET / H T or ET miss /mmeff(nj) cuts CRW W ( lν)+jets W ( lν)+jets 3 GeV < m T (l, ET miss ) < GeV, b-veto CRT t t and single-t t t bb lν 3 GeV < m T (l, ET miss ) < GeV, b-tag ATLAS Work in progress Tomas Javurek (UNI Freiburg) Boosted techniues in SUSY 3 th April 4 / 8

12 Expected exclusion limits for one-step simplified models, m(lsp) = 6[GeV],LSP),LSP)/ m( ± x= m(χ.4. + Simplified model, * χ + χ W W χ χ Observed limit (4.7 fb, 7 TeV) Expected limit (± σ exp ) m(lsp)=6[gev] ATLAS Work in progress L dt =.3 fb, s=8 TeV 3jW 3jW jw jw jw 4jl 4jl 4jl jw jw 3jW 3jW 3jW jw jw jw 4jl 4jl 4jl 3jW 4jl 4jl jw jw 4jl 3jW jw 4jl 4jl 3jW jw jl 6jt.8 4jl 6jt.6.4 4jl 4jl. 4jl 4jl jm 4jl 4jl 4jl 4jl jt jt jt 3j 3j suark mass [GeV] lepton combined g,lsp),lsp)/ m( ± x= m(χ.4. ± Simplified model, g g χ ± χ ± W W ± Observed limit (4.7 fb, 7 TeV) Expected limit (± σ exp ) m(lsp)=6[gev] χ χ ATLAS Work in progress L dt =.3 fb, s=8 TeV 3jW 3jW jw jw 4jl 4jl 3jW jw jw 3jW 3jW jw jw jw jw jw 4jl jw jw jw jw 4jl 4jl 3jW jw jw jw jw 4jl jw jw 4jl 3jW 3jW jw jw jw 4jl 4jl 3jW 3jW 3jW jw 3jW.8 4jl 3jW 6jt 6jt 6jt 4jm 6jt 6jm 6jt 6jt.6 6jt 6jm 6jm 6jm.4 3jW. 4jm 4jl gluino mass [GeV] lepton combined suark chargino LSP,m(LSP) = 6[GeV] gluino chargino LSP,m(LSP) = 6[GeV] Older results with 3jW. Boosted SRs improve exlusion limit for x (m g,lsp) (m χ,lsp )! Tomas Javurek (UNI Freiburg) Boosted techniues in SUSY 3 th April 4 / 8

13 Ongoing studies Tomas Javurek (UNI Freiburg) Boosted techniues in SUSY 3 th April 4 3 / 8

14 Motivation for implementation of M T variable M T def. min p +p=met [max[m T (W, p ), M T (W, p )]] p p g g χ ± χ W χ χ W M T is designed to reconstruct mass of particle which is produced in pair and decays into invisible (ν, χ ) in our case: target is to reconstruct mass of intermediate gauginos: χ W χ χ H χ and use M T to suppress the background Tomas Javurek (UNI Freiburg) Boosted techniues in SUSY 3 th April 4 4 / 8

15 M T distribution in unres-res + unres-unres W channels events / GeV DATA / MC ATLAS SR Internal - L dt =.3 fb Data ( s = 8 TeV) SM Total 7,69,6 7,46,6 8,79,6 gg,9,6 Multijet Z+jets W ) [GeV] m T (W m (W W ) [GeV] T γ+jets W+jets ttbar & single top Diboson Selection: all preselection -letpton cuts used p T (j ) >3GeV, p T (j ) >6GeV, ET miss >6GeV cd redc.: (φ)(j,,3 ) >.4 ET miss /m eff >.3 (only bottom fig.) events / GeV DATA / MC ATLAS SR Internal - L dt =.3 fb Data ( s = 8 TeV) SM Total 7,69,6 7,46,6 8,79,6 gg,9,6 Multijet Z+jets W ) [GeV] m T (W m (W W ) [GeV] T γ+jets W+jets ttbar & single top Diboson Interesting: see gg-step point (nice separation from background) M T > 5. suppress QCD see effect of ET miss /m eff >.3 (bottom figure on the left) Tomas Javurek (UNI Freiburg) Boosted techniues in SUSY 3 th April 4 5 / 8

16 Correlation between m eff and M T sig_meff_mt_corr allbg M T M T m eff m eff gg-onestep m g =,m χ+ = 9,m lsp = 6[GeV] Sum of all SM backgrounds, M T > 3? Tomas Javurek (UNI Freiburg) Boosted techniues in SUSY 3 th April 4 6 / 8

17 Significance, combination of cuts m eff : m eff >5[GeV] E miss T /m eff : E miss T /m eff >.3 M T : M T >5[GeV] m eff m eff,m T ET miss /m eff ET miss /m eff,m T ET miss /m eff,m eff ET miss /m eff,m eff,m T allbg g g s/ b + s( ) s/ b + s( g g) Impact of combination of cuts on significance. g g-step: m(gl) =,m(char) = 9,m(lsp) = 6. -step: m(s) = 8,m(char) = 79,m(lsp) = 6. At least unresolved and resolved W or unresolved W reuired. Selection same as on previous slides. Best significancies achieved when combining all three cuts. Tomas Javurek (UNI Freiburg) Boosted techniues in SUSY 3 th April 4 7 / 8

18 Conclusions&Plans Conclusions: boosted W regions have been developed data/mc ratio is fairly close to one for all distributions in SRs and CRs such new SRs improve expected exclusion limits Plans: finishing -lepton paper and work on pmssm paper preparing boosted -lepton analysis for 4 TeV studying possibility of using shape fits on W mass peak studying jet substructure and MT Tomas Javurek (UNI Freiburg) Boosted techniues in SUSY 3th April 4 8 / 8

19 back-up Tomas Javurek (UNI Freiburg) Boosted techniues in SUSY 3 th April 4 / 4

20 SUSY analysis using some boosted techniue -lepton: ATL-COM-PHYS-3-4 -lepton stop: ATL-COM-PHYS-3-9 -lepton stop: ATL-COM-PHYS-3-49 (boosted top tagging, AntiKt Jets) boosted 3jet RPV: ATL-COM-PHYS--793 (7TeV, 8TeV in progress) Tomas Javurek (UNI Freiburg) Boosted techniues in SUSY 3 th April 4 / 4

21 m eff distribution in unres-res + unres-unres W channels events / ATLAS SR Internal L dt =.3 fb Data ( s = 8 TeV) SM Total 7,69,6 7,46,6 8,79,6 gg,9,6 Multijet Z+jets γ+jets W+jets ttbar & single top Diboson events / ATLAS SR Internal L dt =.3 fb Data ( s = 8 TeV) SM Total 7,69,6 7,46,6 8,79,6 gg,9,6 Multijet Z+jets γ+jets W+jets ttbar & single top Diboson DATA / MC GeV GeV DATA / MC GeV GeV m eff distribution before ET miss /m eff cut with same selection as on previous slides E miss T /m eff >.3, m eff is unfortunately as powerful as M T, but their combination could give improvement! Tomas Javurek (UNI Freiburg) Boosted techniues in SUSY 3 th April 4 3 / 4

22 Correlation between MET /m eff and M T sig_metmeff_mt_corr allbg M T - M T MET/ m eff MET/m eff gg-onestep m g =,m χ+ = 9,m lsp = 6[GeV] Sum of all background, M T > 3? Tomas Javurek (UNI Freiburg) Boosted techniues in SUSY 3 th April 4 4 / 4