Yu Bai (IHEP, Beijing) On behalf of the SUSY Weak Production team ACCM 23, Mar 3, 2013 Search of SUSY Weak Production with hadronic taus Search of SUSY Weak Production with hadronic taus

SUSY Approval Meeting2 Support note: Editors: Anyes Taffard Christophe Clement Federica Legger Xuai Zhuang Editorial Board: Dan Tovey (chair) Shirkma Bressler Masahiro Kuze Sadrine Laplace Present study on fb -1, √s=8 TeV Data Conference note:

Outline Introduction Signal grids Object and event selection Signal region definition Background estimation Results Interpretation Summary SUSY Approval Meeting3

Introduction  Either for natural SUSY, or heavy scalars, it is fairly generic for the gauginos to be light.  Higgs into di-photon rate can be enhanced via staus without changing the Higgs to WW/ZZ rates, so light stau with large mixing may help  First study of direct gaugino through the final states with at least two taus, which is complementary of emu final states. SUSY Approval Meeting4

Signal Grids Direct Gaugino Decay pMSSM Signal Grid: Heavy Squarks and Gluinos tan β = 50 M 1 = 50 GeV M 2 and μ ranging from 100 to 500 GeV Mass of stau fixed at 95 GeV, other sleptons are heavy Mode A (chargino-neutralino decay): Mode C (chargino-chargino decay): SUSY Approval Meeting5

Objects Pre-Selection Electrons and muons Base line Selection Overlap removal Taus Baseline Overlap removal Loose tauid Tight tauid(at least 1 in each event) MET : Egamma10NoTau Trigger : Di-tau trigger || soft-met trigger Di-tau Trigger: EF_tau29Ti_medium1_tau20Ti_Medium_1 Soft-met Trigger: EF_xe80_tclcw Jet : Baseline Overlap removal L25: light jet B20: bjet F30: forward jet SUSY Approval Meeting6

SR definition SR definition Two SRs have been defined require at least 1 OS tau pair one SR is after jet veto another SR is only applying bjet veto Suppress Z+jets BG through Z-veto MET>40 GeV to suppress fake tau background Apply large m T2 cut to enhance SUSY sensitivity m T2 cut has been optimized SUSY Approval Meeting7

SR Optimization - mode A m T2 > 80 GeV m T2 > 90 GeVm T2 > 100 GeV m T2 jet veto m T2 b-veto m T2 jet-veto: pick m T2 >90 GeV (similar performance) m T2 b-veto: m T2 >100 GeV (best performance) Other models are checked, consistent with mode A 8 5fb-1 data used mT2 jet veto Mt2>80GeV: 3 Mt2>90GeV: 2 Mt2>100GeV: 1 mT2 b-veto Mt2>80GeV: 20 Mt2>90GeV: 4 Mt2>100GeV: 2 SUSY Approval Meeting

Background components in SRs Two classes of backgrounds: fake tau (qcd+W, ~75-80%) and real tau background (top, Z+jets, diboson) Fake tau background: estimated with data-driven approach (ABCD method ） Real tau background: use MC simulation SUSY Approval Meeting9

Background Estimation : fake tau background SUSY Approval Meeting10 Fake Background QCD di-jet (2 fake tau) W+jets (1 fake tau) Can be estimated together due to same fake tau character Not modeled well in MC due to fake rate Huge cross section, limited MC statistics

The ABCD method Use transfer factor (TF) from QCD events (low m T2 region from data) and take the TF difference between QCD and W+jets as systematics SUSY Approval Meeting11 Variables: m T2, tauid Base line control region A high m T2, loose tauid B low m T2,, loose tauid C low m T2, tight+medium tauid extrapolation from A to D through a TF (C/B) Alternative ABCD method checked (W CR-AB)

Correlation between tauid and m T2 m T2 jet vetom T2 b-veto No strong correlation between tau id and mT2 The correlation has been taken into account to syst. SUSY Approval Meeting12

Fake tau background purity m T2 jet vetom T2 b-veto 2 loose tauid tight tau veto 1 tight tau +1medium tau In QCD+W CR-C,B (low m T2 region), QCD + W purity is high (>96%) In QCD+W CR-A (high m T2 region), QCD+W purity is ~90% non fake tau bkg in CR-A has been subtracted from MC and taken into account to syst. SUSY Approval Meeting13

Signal contamination in region A m T2 jet-veto m T2 b-veto Mode A Mode C The SUSY contamination in the QCD+W control region A is around 10% for SR OS-mT2 and OS-mT2-nobjet SUSY Approval Meeting14

Fake tau background estimation: Result m T2 jet veto m T2 b-veto  Good Data/MC Agreement in non-signal region (mT2 < 90 GeV) QCD+W Results: In m T2 - jet veto region : 8.38+/-2.98 In m T2 b-veto region : /-4.48 SUSY Approval Meeting15

Kinematic distributions  Good data/MC agreement for leading and next leading tau pt and eta distributions  The ABCD method works well SUSY Approval Meeting16

Validation of QCD+W estimation I  We validated QCD+W estimation in different SM bkg enriched region.  The QCD+W control region definition is close to SM BG validation regions but use loose tau id SUSY Approval Meeting17

Validation of QCD+W estimation I  Good data/MC agreement in all BG enriched VRs SUSY Approval Meeting18

Validation of QCD+W estimation II: Alternative ABCD Method  We also checked the QCD+W estimation using CRs with different bkg components (1L+1M w/o tight).  Good data/MC agreement in alternative ABCD method  The ABCD method proves to be reliable even change the components in the control regions SUSY Approval Meeting19

Real Tau Background Estimation and Validation  top and Z+jets:  No event left at one of the SRs due to low statistics  use “ABCD”-like MC driven estimation as default  CR definition is similar as QCD+W CR definition but from MC events (loose tau id, remove MET cut)  Diboson has reasonable statistics, use the MC simulation directly and validated with above “ABCD”-like method  we use two different sets of SFs for real and fake taus. This is why we don't check that all taus are real when we use MC SUSY Approval Meeting20

Real Tau Background  The numbers in SRs are consistent between MC prediction and MC- driven estimation within statistical uncertainty SUSY Approval Meeting21

Results  Results from SM Bkg estimation are compared with the total number of data events in table 19  mT2 distribution for data and SM bkg in eash SR is at fig 20.  The observed and expected number of events in the table (together with uncertainty) are used to calculate the exclusion limit SUSY Approval Meeting 22

Model independent upper limits on the visible cross-section  Table 22 shows the model-independent upper limits based on the observed and expected number of events in each SR SUSY Approval Meeting23

Best Exclusion Limits – simplified model SUSY Approval Meeting24  Masses of degenerate and are excluded up to GeV in the chargino-neutralino simplified model for light (below GeV); In the chargino-chargino simplified model, we exclude masses of 200< <330GeV for very light ( below GeV)

Best Exclusion Limits - pMSSM Holes formed due to relatively lower signal yield with higher statistical err. SUSY Approval Meeting25

Summary  Two signal regions with high mT2 cut have been defined and optimized  No significant excess observed in the signal regions.  Given exclusion limits with pMSSM and simplified model (mode A,C)  Masses of degenerate and are excluded up to GeV in the chargino-neutralino simplified model for light (below GeV)  In the chargino-chargino simplified model, we exclude masses of 200< <330GeV for very light (below GeV)  Aiming at Moriond CONF note SUSY Approval Meeting26

Backup SUSY Approval Meeting27

Acceptance*Efficiency of at least two taus for signal grid SUSY Approval Meeting28

Triggers Using following Oring trigger: EF tau29Ti medium1 tau20Ti medium1 => 2taus, p T leading > 40, p T next-leading > 25 GeV EF xe80 tclcw, =>MET> 150 GeV Good Turn-on Curve Efficiency of EF_xe80_tclcw Trigger Matching Leading tau matches to EF tau29Ti medium1 Next Leading tau matches to tau20Ti medium1 Tau Trigger Reweighting Use TauSF from tau performance group recommendation SUSY Approval Meeting29

Datasets  Data : fb -1, √s=8 TeV (JetTauEtmiss Stream)  Standard Model MC ： SUSY Approval Meeting30

Objects and Events Selection SUSY Approval Meeting31

Overlap removal SUSY Approval Meeting32

m T2 without MET cut SUSY Approval Meeting33 b-veto m T2 b-veto jet-veto m T2 jet-veto

Systematic Uncertainty of QCD+W estimation Correlation between tauid and m T2 : difference between high mT2 region and low mT2 region high m T2 : 40 GeV< m T2 < 90 GeV low m T2 : m T2 < 40 GeV transfer factor difference: T_W : from MC f_W: from fitting on W MC m T2 distribution W fraction in region A: 17% Non QCD/W backgrounds in region A Systematic uncertainty taken from background study Statistic uncertainty in region A SUSY Approval Meeting34

W fraction estimation SUSY Approval Meeting35 OS-mT2 OS-mT2 -nobjet

The result of fake tau background estimation SUSY Approval Meeting36

mt2 distribution of alternative ABCD method SUSY Approval Meeting37

Correlation between tauid and mt2 in alternative ABCD method SUSY Approval Meeting38

Results from alternative ABCD method SUSY Approval Meeting39

Result with alternative JVF Cut(>0.25) SUSY Approval Meeting40

 D: SR (medium + tight tau, mT2>90GeV)  A: Top/Z/Diboson Control Region: close to SR except using loose tauID and remove met cut  CB: Normalization Region, close to D,A except 40<mT2<80GeV for OS mT2 region  We can extrapolate from Top/Z/Diboson Control region A to signal region D trough a transfer factor from C/B: D = A* C/B AD BC LooseMedium Tau ID MT2 Signal Region Top/Z/Diboson Control Region 2012/11/20 41 ABCD-like method Normalization Region SUSY BG Meeting

mt2 distribution of Z+jets SUSY Approval Meeting42

Z+jets mt2 fit SUSY Approval Meeting43

Z+jets systematic uncertainty: mt2 jet-veto SUSY Approval Meeting44

Z+jets systematic uncertainty: mt2 b- veto SUSY Approval Meeting45

mt2 distribution of top SUSY Approval Meeting46

mt2 fit of top SUSY Approval Meeting47

Top estimation systematic uncertainty : mt2 jet-veto SUSY Approval Meeting48

Top estimation systematic uncertainty : mt2 b-veto SUSY Approval Meeting49

Diboson samples and events number(raw number) in SR SUSY Approval Meeting50

Diboson systematic uncertainty : mt2 jet-veto SUSY Approval Meeting51

Diboson systematic uncertainty : mt2 b-veto SUSY Approval Meeting52

ABCD-like diboson estimation SUSY Approval Meeting53

Acceptance of at least two taus for pMSSM 54SUSY Approval Meeting

Acceptance of at least two taus for modeA/C 55SUSY Approval Meeting

Signal Optimisation Signal Region –  mt2>90GeV –  mt2>100GeV Signal Mode – Pmssm – Simplified modeA – Simplified modeC 56SUSY Approval Meeting

Signal Optimization Background estimation in Signal region: – The number of events with 5 fb-1 are scaled to fb-1. – Systematical uncertainty is quoted as 15%. 57SUSY Approval Meeting

SR opt with 5fb-1 modeA modeC pMSSM  Data (5fb-1)  Mt2>80GeV: 3  Mt2>90GeV: 2  Mt2>100GeV: 1 Mt2>80GeV Mt2>90GeVMt2>100GeV 58SUSY Approval Meeting

SR opt with 5fb-1 modeA modeC pMSSM  Data (5fb-1)  Mt2>80GeV: 20  Mt2>90GeV: 4  Mt2>100GeV: 2 Mt2>80GeV Mt2>90GeVMt2>100GeV 59SUSY Approval Meeting

Zn check for two modeA grids OSmt2 modeA C1 = 150 N1 = 50 s = b = significance = C1 = 150 N1 = 50 s = b = significance = C1 = 150 N1 = 50 s = b = significance = C1 = 250 N1 = 100 s = b = significance = C1 = 250 N1 = 100 s = b = significance = C1 = 250 N1 = 100 s = b = significance = OSmt2-nobjet modeA C1 = 150 N1 = 50 s = b = significance = C1 = 150 N1 = 50 s = b = significance = C1 = 150 N1 = 50 s = b = significance = C1 = 250 N1 = 100 s = b = significance = C1 = 250 N1 = 100 s = b = significance = C1 = 250 N1 = 100 s = b = significance = SUSY Approval Meeting

Expected signal yields(21fb-1) pMSSM 61SUSY Approval Meeting

Expected signal yields(21fb-1) pMSSM 62SUSY Approval Meeting

Signal yields at x/y axis (OSmt2) RunNb= mu=100;M2=100 signal yield=0+0 RunNb= mu=110;M2=100 signal yield= RunNb= mu=120;M2=100 signal yield= RunNb= mu=140;M2=100 signal yield= RunNb= mu=160;M2=100 signal yield=0 RunNb= mu=180;M2=100 signal yield=0 RunNb= mu=210;M2=100 signal yield=0 RunNb= mu=250;M2=100 signal yield=0 RunNb= mu=300;M2=100 signal yield=0 RunNb= mu=350;M2=100 signal yield=0 RunNb= mu=400;M2=100 signal yield=0 RunNb= mu=450;M2=100 signal yield=0 RunNb= mu=500;M2=100 signal yield=0 RunNb= mu=100;M2=110 signal yield=0 RunNb= mu=100;M2=120 signal yield= RunNb= mu=100;M2=160 signal yield= RunNb= mu=100;M2=180 signal yield= RunNb= mu=100;M2=210 signal yield= RunNb= mu=100;M2=250 signal yield= RunNb= mu=100;M2=300 signal yield= RunNb= mu=100;M2=350 signal yield= RunNb= mu=100;M2=400 signal yield=0 RunNb= mu=100;M2=450 signal yield=0 RunNb= mu=100;M2=500 signal yield=0 63SUSY Approval Meeting

Expected signal yields(21fb-1) OSmt2-jetveto(left) / OSmt2-bjetveto(right) modeA modeC modeA modeC 64SUSY Approval Meeting

Cross-section upper limits for Dstau samples A rough idea of the value. More will be done soon. Better exclusion cross-section upper limits is provided by OSmt2 jet veto SR. 65SUSY Approval Meeting

164604:mu=500,M2=350 Cut 0 : no cut Cut 1 : GRL cut Cut 2 : LAr hole veto + TTC incomplete event veto Cut 3 : jet cleaning + LarError cut Cut 4 : >= 1 primary vertex with >4 tracks Cut 5 : cosmic muon veto+ Bad muon veto Cut 6 : at least 2leptons Cut 7 : tau-tau (pt>40,25GeV or MET>150GeV) *** Cut 8 : tau-tau with trigger match Cut 22 : //SR4: OS && jet veto &&Z veto && MET>40 Cut 24 : && mT2_new > 90 *** Cut 25 : SR5:OS && bjet veto && zveto Cut 26 : && MET>40GeV Cut 27 : && mT2 > 100 GeV SUSY Approval Meeting66

164602:mu=400,M2=350 Cut 0 : no cut Cut 1 : GRL cut Cut 2 : LAr hole veto + TTC incomplete event veto Cut 3 : jet cleaning + LarError cut Cut 4 : >= 1 primary vertex with >4 tracks Cut 5 : cosmic muon veto+ Bad muon veto Cut 6 : at least 2leptons Cut 7 : tau-tau (pt>40,25GeV or MET>150GeV) *** Cut 8 : tau-tau with trigger match Cut 22 : //SR4: OS && jet veto &&Z veto && MET>40 Cut 24 : && mT2_new > 90 *** Cut 25 : SR5:OS && bjet veto && zveto Cut 26 : && MET>40GeV Cut 27 : && mT2 > 100 GeV SUSY Approval Meeting67

Exclusion Limits – mode A SUSY Approval Meeting68  Masses of degenerate and are excluded up to GeV in the chargino-neutralino simplified model for light (below GeV)

Exclusion Limits – mode C SUSY Approval Meeting69  In the chargino-chargino simplified model, we exclude masses of 200< <330GeV for very light ( below 30-50GeV)

Exclusion Limits - pMSSM Holes formed due to relatively lower signal yield with higher statistical err. SUSY Approval Meeting70