Boosted Boson Type Tagging March 26, 2014 1 / 21

BoostedATLAS Boson SUSY Type Results Tagging Jet ETmiss Boosted BosonBenjamin Type Nachman Tagging Jet ETmiss

Benjamin Nachman and Ariel Schartzman BenjaminSLAC, Nachman Stanford and University Ariel Schartzman

SLAC,March Stanford 26, University 2014 March 26, 2014

B. Nachman (SLAC) Boosted Boson Type Tagging March 26, 2014 1 / 21

B. Nachman (SLAC) Boosted Boson Type Tagging March 26, 2014 1 / 21 Boosted Boson Type Tagging The ATLAS SUSY GroupJet ETmiss Boosted Boson Type Tagging 2

OrganizedBenjamin Nachman byJet production ETmiss and Ariel + Schartzman decay:

SLAC, Stanford University inclusive squarks and gluinos 0L, 1L, Z+MET, etc. Benjamin NachmanMarch 26, and 2014 Ariel Schartzman 3rd generationSLAC, Stanfordstop, Universitysbottom, stau + 0L, 1L, 2L

March 26, 2014

cross-section electroweak neutralinos, charginos

B. Nachman (SLAC) Boosted Boson Type Tagging March 26, 2014 1 / 21 RPV/LL little or no MET and/or long lived

B. Nachman (SLAC) Boosted Boson Type Tagging March 26, 2014 1 / 21 https://twiki.cern.ch/twiki/bin/view/ (see summary papers AtlasPublic/SupersymmetryPublicResults for overview!) Boosted Boson Type Tagging Run 1 Legacy Jet ETmiss Boosted Boson Type Tagging 3 generic Benjamin NachmanJet ETmiss and Ariel Schartzmansquarks ~1 TeV

SLAC, Stanford University generic gluinos Benjamin NachmanMarch 26, and 2014 Ariel Schartzman~1.5 TeV SLAC, Stanford University stops up to March 26, 2014 ~700 GeV

B. Nachman (SLAC) Boosted Boson Type Tagging a stealthMarch 26, 2014 stop 1 / 21 nearly ruled out t p B. Nachman (SLAC) Boosted Boson Type Tagging Marcht˜1 26, 20140 1 / 21 ˜1

˜0 t˜1 1 p N.B. t1L = SLAC-led effort t Boosted Boson Type Tagging Jet ETmiss Run 1 Legacy (cont.) 4

Boosted Boson Type Tagging1508.06608 Benjamin NachmanJet ETmiss and Ariel Schartzman

SLAC, Stanford University

Benjamin NachmanMarch 26, and 2014 Ariel Schartzman SLAC, Stanford University

March 26, 2014

B. Nachman (SLAC) Boosted Boson Type Tagging March 26, 2014 1 / 21

B. Nachman (SLAC) Boosted Boson Type Tagging March 26, 2014 1 / 21 Dedicated re-interpretation of all simpliﬁed model searches with the pMSSM (with Tom); good coverage by channel searches! Boosted Boson Type Tagging Jet ETmiss Excesses 5 Boosted Boson Type Tagging The data are (too…Jet ?) ETmiss consistent with the background;Benjamin a few excesses, Nachman and but Ariel nothing Schartzman convincing. SLAC, Stanford University

Distribution of p-values for excesses B.N. and T. RudeliusBenjamin 1410.2270 Nachman and Ariel Schartzman 0.3 March 26, 2014 Pr(p-value) SLAC, Stanford University 0.25 Gaussian (Expected) Gaussian (Observed) March 26, 2014 0.2 Log-normal (Expected) 1503.03290 Log-normal (Observed)

0.15 B. Nachman (SLAC) Boosted Boson Type Tagging March 26, 2014 1 / 21

0.1

0.05 B. Nachman (SLAC) Boosted Boson Type Tagging March 26, 2014 1 / 21

0 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 p-value Boosted Boson Type Tagging Jet ETmiss Early 13 TeV 6 3.2/fb of Boosted13 TeV is already Boson pushing Type out the limits Tagging beyond Run 1! ~~ ~ 0 gg production; g→ q q χ∼ Jet ETmiss1400 1 Benjamin Nachman and ArielATLAS Schartzman SUSY Observed limit (±1 σtheory)

[GeV] miss 0 1 ∼ χ 1200 0-lepton + 2-6 jets + E T Expected limit (±1 σexp) m -1 SLAC, Stanford Universitys = 13 TeV, 3.2 fb ATLAS 8 TeV, 20.3 fb-1 1000 1605.03814 gluinos All limits at 95% CL Benjaminsquarks NachmanMarch 26, and800 2014 Ariel Schartzman 600

0 ∼ SLAC, Stanford Universityχ 1 < m ~ m g 400

March 26,200 2014

0 200 400 600 800 1000 1200 1400 1600 1800 2000

m~g [GeV] B. Nachman (SLAC) Boosted Boson Type Tagging March 26, 2014 1 / 21 Not Line: Observed Limit Excluded Band: Signal xs Theory Uncertainties

B. Nachman (SLAC) Boosted Boson Type Tagging March 26, 2014 1 / 21

m(N)LSP Line: Expected Limit Excluded Band: All other Uncertainties

m[primary SUSY particle] Limit: CLs < 0.05 (not exactly 95% conﬁdence) Boosted Boson Type Tagging Jet ETmiss A Brief Aside: Simulation 7 Boosted Boson Type Tagging (Amazingly, ) both ATLAS and CMS use Benjamin NachmanJet ETmiss and Ariel Schartzman the ~same simulation setup in Run II. SLAC, Stanford University MG5_aMC + Pythia 8 (+EvtGen for ATLAS) Benjamin NachmanMarch 26, and 2014 Ariel Schartzman with up to 2SLAC, extra Stanford partons University from the ME

MadGraph onlyMarch produces 26, 2014 the ﬁrst SUSY particle - decays are all handled by Pythia B. Nachman (SLAC) Boosted Boson Type Tagging March 26, 2014 1 / 21 We may need to improve this for high acceptance and ISR selections (thinking about this w/ M. Kraemer since the last Jamboree) B. Nachman (SLAC) Boosted Boson Type Tagging March 26, 2014 1 / 21 more details: B.N., SUSY MC @ ATLAS-CMS MC Generators Workshop Boosted Boson Type Tagging Jet ETmiss No time for all searches; will instead focus on one 8 DirectBoosted stop pair production Boson TypeSignature: Tagging ttbar + MET 500 Jet ETmiss ATLAS InternalBenjamin Nachman and Ariel Schartzman t p

400 4.7 fb-1, s = 7 TeV [Phys. Rev. Lett. 109, 211803 (2012)] t˜1 0 SLAC, Stanford University ˜1 13 fb-1, s = 8 TeV [ATLAS-CONF-2012-166]

-1 20.7 fb , s = 8 TeV [ATLAS-CONF-2013-037] 0

Neutralino Mass [GeV] Benjamin Nachman and Ariel Schartzman ˜ -1 t˜1 1 300 20.3 fb , s = 8 TeV [JHEP 1411,118 (2014)]March 26, 2014 p 3.2 fb-1 s = 13 TeV [ATLAS-CONF-2016-007] SLAC, Stanford University t

200 top + m March 26, 2014

neutralino this talk 100 = m (and on the arXiv B. Nachman (SLAC) Boosted Boson Type Tagging March 26, 2014 1 / 21 m stop tomorrow)

0 0 100 200 300 400 500 600 700 800 900 1000 Stop Mass [GeV] B. Nachman (SLAC) Boosted Boson Type Tagging March 26, 2014 1 / 21 In addition to being an important ﬁnal state to search for, it is also experimentally challenging (i.e. fun): diverse backgrounds with many components = amenable to innovative strategies! Boosted Boson Type Tagging There are many models withJet ETmissttbar+MET Boosted Boson Type Tagging 9 For the early 2015 data, not enough data for a bigBenjamin jump in Nachman (direct)Jet ETmiss and stop Ariel sensitivity Schartzman SLAC,t Stanford University t p Benjamin NachmanMarch 26, andp 2014 Ariel Schartzman soft ˜ t1 SLAC,˜0 Stanford Universityg˜ 1 ˜0 t˜1 1 March 26, 2014 t˜1 ˜0 ˜0 1 t˜1 1 g˜ p B. Nachman (SLAC) Boosted Boson Typep Tagging March 26, 2014soft 1 / 21 t t

B. Nachman (SLAC) Boosted Boson Type Tagging March 26, 2014 1 / 21 Consider in addition gluino mediated models that are not covered by the usual Gtt search. 9 Boosted Boson Type Tagging Jet ETmiss There are many models with ttbar+MET 10 Boostedt Boson Typet Tagging p soft p Naturalness? g˜ t˜1 ˜0 ˜0 Jet ETmiss1 t˜1Benjamin1 Nachman and Ariel Schartzman t˜ 0 1 ˜1 0 g˜ ˜ ˜1 t1 B->D*tn? t p soft SLAC,p Stanford University p Relic Density? t t LQ Benjamin Nachman and Ariel Schartzman ⌫ 100 March 26, 2014 ⌫ SLAC, Stanford University LQ 10 p t 1 March 26, 2014

0.1 Vector LQ (k=1) B. Nachman (SLAC) Boosted Boson Type Tagging March 26, 2014 1 / 21 0.01 Vector LQ (k=0) Stop / Scalar LQ 0.001 GMS 13 TeV Cross-sec-on [pb] 0.0001 B. Nachman (SLAC) Boosted Boson Type Tagging March 26, 2014 1 / 21

0.00001 500 700 900 1100 1300 1500 1700 1900 New Par-cle Mass [GeV] 10 Boosted Boson Type Tagging More sensitive than inclusiveJet searches ETmiss Boosted Boson Type Tagging 11 ~~ ~ ~ pp→ gg, g→ tt , m ~ m∼0 1 ~ χ t1 1 1000 Jet ETmiss ATLAS SS leptonsBenjamin [1404.2500] Nachman and Ariel Schartzman ATLAS stop 1L (tN_shape + tN_med + tN_high) t 900 ATLAS monojet [1407.0608]SLAC, Stanford Universityp soft ATLAS gluino 1L [1501.03555] g˜ 800 B.N. 1505.00994Benjamin Nachman and Ariel Schartzman ˜0 March 26, 2014 t˜1 1 Stop Mass [GeV] 700 t˜ 0 SLAC, Stanford University 1 ˜1 g˜ 600 p soft March 26, 2014 500 t No equivalent stop model B. Nachman (SLAC) Boosted Boson Type Tagging March 26, 2014 1 / 21 400 Re-casting Kinematically Forbidden 300 Run 1 200B. Nachman (SLAC) Boosted Boson Type Tagging March 26, 2014 1 / 21

100 400 500 600 700 800 900 1000 1100 1200 1300 Gluino Mass [GeV] 11 Boosted Boson Type Tagging Analysis Technique(s) Jet ETmiss Boosted Boson Type Tagging 12

Benjamin NachmanJet ETmiss and Ariel SchartzmanMain strategy: 4 jets (1 b-jet) + 1L SLAC, Stanford University + high mT Benjamin NachmanMarch 26, and 2014 Ariel Schartzman SLAC, Stanford University + MET + generalization of March 26, 2014 mT (called mT2) + more B. Nachman (SLAC) Boosted Boson Type Tagging March 26, 2014 1 / 21

~1/2 e/mu and B. Nachman (SLAC) Boosted Boson Type Tagging 1/2 1L1tauMarch 26, 2014 1 / 21

(stolen from CMS, 1308.1586. Our version is not public) CHAPTER 1. OBJECT AND VARIABLE DEFINITIONS 35

1.2.1.2.3 Tailoring mT2 for the stop search

With a high multiplicity ﬁnal state, there are many choices for Vi and mCi in

constructing an mT2 variable for the stop search. This section describes two particular

mT2 variables that are designed to suppress dilepton t¯t events. After requiring mT >

mW,Fig.1.8 showed that the majority of surviving t¯t events have a second lepton that is either lost, mis-identiﬁed, or is a hadronically decaying ⌧ lepton. First, consider the case in which the second lepton is undetected so that ~pmiss ~p⌫1 + ~p⌫2 + ~plost `. T ⇡ T T T One could construct an mT2 variable using the b-jets as the Vi and then grouping C1 C2 everything downstream of the b-quarks in the top decay chain into ~pT +~pT .However,

additional information is available by using asymmetric objects [40, 43]fortheVi.

Following an idea in Ref. [44], the asymmetric mT2 (amT2)isformedbylettingV1

be the b-jet from one top quark decay and setting V2 to be the four-vector sum of the b-jet and lepton from the other top quark decay. As illustrated in Fig. 1.20,this Boostedmeans Boson that the missing Type particle Tagging for the top branch is an entire W boson and on the

bottom branch,Jet ETmiss only a neutrino. Therefore, mC1 = mW and mC2 = m⌫ 0.With CHAPTER 1. OBJECTMain AND strategy: VARIABLE 4 DEFINITIONS jets (1 b-jet) + 1L + high23 mT 13 ⇡ these choices, am m for the background depicted in Fig. 1.20. Boosted BosonT2 Type top Tagging

V2 Jet ETmiss Benjamin Nachman and Ariel Schartzmanb l

SLAC, Stanford University P C 1 1 t ⌫ Benjamin~Emiss Nachman and Ariel Schartzman T March 26, 2014 P2 C2 SLAC, Stanford Universityt ⌫ A (Very) Brief Introduction to Stransverse Mass MT 2 March 26, 2014 2) Constructing VM1T 2 [14] b l Figure 1.11: A schematic diagram showing the generic m setup. 1) Generic Setup Figure 1.20: AT2 schematic diagram of dileptonic t¯t decay where one of the charged MTB.2 Nachman (SLAC)min max(MBoostedTa , M BosonTb) Type Tagging March 26, 2014 1 / 21 ⌘ C C ~ { leptons is lost. Lost} particles are circled with a dashed line. For the amT2 variable, ~pa +~pb = E/T va the visible particle on the top (bottom) branch is the b-jet (sum of the b-jet and Vi Ci amT2: one lepton is lost, mP. This is because m maxi m ~p , ~p ,mlepton).V ,mC The missingmP, as particle shown in in the top (bottom) branch is a W boson (neutrino). T2  T T T i i  P Sec. 1.2.1.1C .Figure1.12MdemonstratesTB.2 Nachmanis the⌦ (SLAC) the minimum⇣ power of m parentT2 inBoosted events⌘ mass↵ Boson with Type two TaggingW bosonsC1 = W1 andMarch C2 26, = 2014 n2. 1 / 21 where one W decays intoconsistent a hadronically with decaying observed⌧ and kinematics the other W boson decays

P into anC electron or muon (`). Multiple neutrinos contribute to the missing momentum miss so the mT of the ` and theDepends~p can on a exceed trial mass the mM˜W boundfor the as mass long of as the the bosons are • T C notvb produced at rest. Inchild contrast, particle theCmT2 using V1 = `, V2 = ⌧, mC1 = mC2 = 0 is kinematically bound by mW (neglecting m⌧). Unlike the mT case, the mT2 endpoint Depends on the upstream pT -themomentum is not as saturated due• to the minimization in the definition. Symmetric decay against which the signal recoils • The visible objects V1 and V2 from Fig. 1.11 are often composite systems of parti- C particles momenta unknown - sum For a given p and M˜ ,thereexistsaknown • cles.Forexample,Vi•might be the combinationT C of a b-jet and a lepton. In such cases, of the momenta is measured max it is often true that mVrelationship= mV .Whenthecompositesystemsarenotevenmadeof between Mp, ma, mb, MC and M [8] 1 6 2 T 2 the same types of constituent particles, the presumed lost children may not be the same and in general mC = mC .Justlikethegeneralizedm from Sec. 1.2.1.1,the 1 6 2 T general mT2 variable is bounded from below by max{mC + mV ,mC + mV }. This B. Nachman (SLAC) Stop search with MT 2 March1 19, 20161 2 3 / 1 2 is readily calculated by taking the derivative of each mT branch with respect to the assigned missing particle momentum pCi for ↵ {x, y}, shown in Eq. 1.9. The ↵,test 2 second implication (2) in Eq. 1.9 is from summing and squaring the first implication (1) and the third implication (3) is the result of simplifying after inserting the second implication (2) back into the first one (1). Boosted Boson Type Tagging (a few of the) Innovations sinceJet ETmiss Run 1 Boosted Boson Type Tagging 14

200 ATLAS Total SM Jet ETmissATLAS Data Benjamin Nachman and80 Ariel Schartzman s = 13 TeV, 3.2 fb-1 Total Data s = 13 TeV, 3.2 fb-1 tt 1L1τ 1L Preselection Total tt VR 1L1τ tt 2L 150 Total Other Events / 7 GeV tt 1L

SLAC, StanfordEvents / 20 GeV University Data ≤ 2 jets 60 Single Top tt ≤ 2 jets Other Other ≤ 2 jets Total SM 100 BenjaminData 1 jet Nachman and Ariel Schartzman (m ,m ) = (800,1) GeV 100 March 26, 2014 ~ 0 × 40 t χ tt 1 jet 1 1 Other SLAC,1 jet Stanford University 50 20 March 26, 2014 100 200 300 0 50 100 150 200 1.5 ~miss 1.5 ~miss E = Emiss with photon added [GeV] E = Emiss with photon added [GeV] 1 T T 1 T T 0.5 0.5 Data / SM B. Nachman (SLAC) Boosted Boson TypeData / SM Tagging March 26, 2014 1 / 21 100 200 300 0 50 100 150 200 τ Jet Mass [GeV] mT2 [GeV]

re-clustered jet mass for the combine mT2 with tau ID to abilityB. Nachman to optimize (SLAC) the radiusBoosted Boson Typemake Tagging a powerfulMarch tau 26, 2014veto 1 / 21 ATLAS Internal Data 30 s = 13 TeV, 3.2 fb-1 tt 2L STCR1 tt 1L

Events / 0.3 Single Top ATLAS Internal W+jetsData 2030 s = 13 TeV, 3.2 fb-1 ttt+Vt 2L ATLASSTCR1 InternalVVtt 1L Data 30 s = 13 TeV, 3.2 fb-1 tt 2L

Events / 0.3 Single Top STCR1 Total SM tt 1L

Events / 0.3 W+jets Single Top W+jets 20 tt+V tt+V 20 ATLAS Internal Data 30 s = 13 TeV, 3.2 fb-1 tt 2L STCR1 tt 1L VV VV ATLAS Internal Data 10 Events / 0.3 Single Top 10 -1 30 ATLASs = 13 TeV, Internal 3.2 fb ttData 2LW+jets -1 tt 1L 30 20STCR1s = 13 TeV, 3.2 fb tt 2Ltt+V Total SM

Events / 0.3 STCR1 Singlett 1LVV Top Total SM W+jets

Events / 0.3 SingleTotal Top SM 20 DatattW+jets+V ATLAS Internal Boosted Boson Type Tagging VV 10 20 tt+V Jet ETmiss10 Total SM Normalize backgrounds with control-regions 15 VV 10 BoostedATLAS BosonInternal Type TaggingtData t 2LTotal SM -1 NEW Jet ETmiss tt 2L Benjamin Nachman-1 and10 Ariel Schartzman [GeV] s = 13 TeV, 3.2 fb SingleNb-tags Top = 0 s = 13 TeV, 3.2 fb T2 8 SLAC, Stanford University STCR 10 Single Top 8 am SR W+jetsNb-tags ≥ 1 BenjaminSR1 Nachman and Ariel0 Schartzman1 2 3 4 5 Events / 100 GeV March 26, 20141.5 ~miss miss 200 OtherNb-tags ≥ 2 E = E with photon added [GeV] 10 175 SLAC, Stanford University1 T T TCR TVR ttN+Vg ≥ 1 0.5 W+jets 6 March 26, 20140Data / SM 1 2 3 4 5 SR1 100 1.5 Total SM miss 30 90 120 ~ miss

Events / 100 GeV 0 1 E 2 = E with3 photon added4 [GeV] 5 0 1 (m ,m~) = (1.1,0.7)2T TeVT 3 4 5 B. Nachman (SLAC) Boosted Boson Type Tagging1t March 26, 2014 1 / 21 1.51.5 ~g t ~miss miss R(b ,b ) 1 ∆ 1 2 WCR WVR WVR-tail OtherET = ET with photon added [GeV] 0.51 1 (m~,m~) = (1.1,0.8) TeV Data / SM g t 100 1 0.5NEWWt / t 0.5

B. Nachman (SLAC) Boosted Boson TypeData / SM Tagging0 1 March 26, 20142 1 / 21 3 4 5 4 TZCRt 1.5 R(b ,b ) 0 ∆ 2 0 0 1 tt2+V3 4 1 5 100 t 1.51 0 1 2 3 4 R(b ,b ) 5 mT [GeV] ∆ 2 0 Wt / t 1 ∆R(b1 ,b ) 2 3 4 5 0 1 0.51 2 1 2 3 4 5 6 1.5 Wt / t 0.50 ~miss 1.5 2 0 1 Total2 3 4 5 SM miss 0 ~miss ∆R(b ,b ) E = E with photon added [GeV] 0 1 2 3 4 1 2 5 miss T T 1 ∆R(b ,b ) (m ,m1 2~) = (1.1,0.7) TeV ~g Et = E with photon added [GeV] T1 T 0.5 1 100 200 300 400 500 600 700 800 900 Data / SM (mm [GeV],m~) = (1.1,0.8) TeV ~gT t 0 0 1 1 21 3 24 5 3 4 5 t 1.5 0.51.5 ~miss ∆R(b ,b ) 4 Data / SM miss 1 2 1 1 ET = ET with photon added [GeV] Wt / t 0.5 0 1 2 3 4 5

0 t 1.50.5 Data / SM R(b ,b ) 0 1 2 ∆ 1 2 3 4 5 2 ∆R(b ,b ) 10 1 2 3 4 5 1 2

t 1.5

Wt / t R(b ,b ) ∆ 1 2 0.51

Wt / t 0.50 100 200 300 400 0 500 1 600 2 700 3 8004 9005 0 mT [GeV] R(b ,b ) 0 1 2 3 4 ∆ 1 2 5 R(b ,b ) ∆ 1 2 page 3/6

2 2 3 6 g b~ w+ g a b~ w- b~ 3 w+ b~ 4 z Boostedb~ Boson6 Type Tagging w- b~ 4 b Jet ETmiss Single top, Wt(+b)g g b 5 16 5 1 Boosted1 Boson Type Tagging born diagram 13 QCD=2, QED=2 born diagram 14 QCD=2, QED=2 Not CHAPTERwell-constrained 1. BACKGROUND in data ESTIMATION (just observed!), can pass23 top pageJet 2/6 ETmiss Benjamin Nachman and Ariel Schartzman page 2/6 2 3 tagging,2 non-trivial3 interference with ttbar. w+ w+ g g h z b~ w- b~ SLAC,w- Stanford3 University 2 2 3 4 2 2 b~ 4 b~ w+ 4 w- 4 w+ w- g g b~ 6 Benjaminb~ Nachman6 b andg Ariel Schartzman g 3 b b t t March5 26, 2014 3 w+ 5 b t w+ t g g b b SLAC, Stanford Universityg g b~ b g g t~ b~ b 5 5 4 t~ w- 4 g 6 5 g w- 1 1 g 6 5 g b~ born diagram 15 QCD=2, QED=2 born diagram 16 QCD=2, QED=2March 26, 2014 b~ page 34/41 1 1 6 1 1 6 born diagram 7 QCD=2, QED=2 born diagram 8 QCD=2, QED=2 2 2 4 born diagram 7 QCD=2, QED=2 born diagram 8 QCD=2, QED=2 3 B. Nachman (SLAC)g Boostedw- Boson Type Tagging March 26, 2014 1 / 21 g w+ t~ 2 2 4 2 6 w- 4 b~ w- b~ b~ 6 2 2 b~ 6 4 g 2 2 t b~ 3 g g g g t~ t~ 6 3 b w+ w- b~ 3 g g w+ t~ b~ 6 t b g w+ 6 b~ b~ g b~ b~ 4 w+ w- g t g b~ g b~ t~ 4 4 w- w- B. Nachman (SLAC) Boosted3 Boson Type Tagging b~ t~ b March 26, 2014 1 / 21 4 b~ w- t 6 b t 3 g t w+ 3 g t~ g g 5 g g w+ b b~ t~ b b~ b t g 5 b w+ b g 3 w- w+ b 6 5 3 g 5 5 4 6 1 1 b~ 1 g 5 1 1 b~ 5 born diagram 17 QCD=2, QED=2 borng diagram 18 QCD=2,b QED=2 diagram 451 QCD=4, QED=2 diagram 452 QCD=4, QED=2 diagram 453 QCD=4, QED=2 4 2 g b 1 1 5 3 3 Figure 1.18: Next-to-leading-order (up21 to ↵s↵w)Feynmandiagramsfrom2 1 5 2 w+ w+ 4 MG5_aMC t¯t t w- born diagram 9 QCD=2, QED=2 thatborn diagram have 10 the QCD=2, same QED=2 outgoing particlesborn as diagramat 9 tree QCD=2, level. QED=2 The top left born diagram 10 QCD=2, QED=2 b b g b g g t Diagrams made by MadGraph5 t¯t g 3 diagram overlaps with when the two intermediate top quarkst go on-shell. The top b~ w- 4 5 g t w+ g right diagram has no top quarks at all and the bottomg diagrams contain top quarks g g 2 2 2 2 b b 6 6 w- b g b~ g b~ g 6 g 6 b but do not interfere with top quark pair production even whenb~ the intermediate4 top g b~ b~ g b 6 g g 5 g 5 quark(s) go on-shell. b~ 3 3 b~ 3 6 3 b~ b~ b~ b~ w+ w+ w+ 6 w+ 1 1 1 a h a h w- w- diagram 454 QCD=4, QED=2w- diagram 455 QCD=4, QED=2 w- diagram 456 QCD=4, QED=2 b~ 4 b~ 4 2 b~ 3 2 b~ 2 two b-jet selection when the R between b-jets is required to bew+ relatively4 large. 3 4 5 w+ ¯ b b This is because one wayb for one-lepton tt events to exceed theb amT2 endpoint is b b g g gg t g g g b 4 b 4 5 5 w- 5 4 b~ t 5 g 1 for a charm1 jet from the hadronically decaying1 W boson to be b-tagged with higher1 g w- w- g g t~ g t~ b born diagram 11 QCD=2, QED=2 born diagram 12 QCD=2, QED=2 born diagram 11 QCD=2, QED=2 born diagramb 12 QCD=2, QED=2b~ b~ b-tagging weight than a second b-jet from the top quark decay. Thisb~ is illustrated b 6 b~ t~ 5 6 6 g g g g in Fig. 1.19 at parton level. For a given choice of b-jet, amT2 ⇠ max(80, m(bl)). w+ b Diagrams made by MadGraph5 Diagrams made by MadGraph5 3 To account for combinatorics, the selected am1 T2 is minimized over both pairings5 1 of 1

diagram 457 QCD=4, QED=2 diagram 458 QCD=4, QED=2 diagram 459 QCD=4, QED=2 b-jets; therefore am ⇠ min(m(b1l),m(b2l)).Whentheb-jet entering the am T2 T2 4 2 2 3 2 3 w+ w+ w- calculation is on the same side as the lepton, then m(bl) is bounded from kinematics t~ t~ g g b~ g b~ 2 2 t~ g m - m ⇠ 155 p b 5 g by top W GeV independent of the top quark T sob~ this will5 generally be t t~ 6 b g g g smallerq than the invariant mass of the lepton and the charm-jet which increases with w+ t~ t~ 4 g 3 g w- 4 b~ g w- g g t~ b~ b~ b 6 5 1 1 1 6

diagram 460 QCD=4, QED=2 diagram 461 QCD=4, QED=2 diagram 462 QCD=4, QED=2 5 2 2 2 3 4 w+ b w- g g g b~ g t~ t t~ 5 b~ 4 t~ 6 b~ w- b g g g g w+ b~ 5 3 t~ t~ t~ b~ t b g b g g 6 g b~ w- w+ 4 3 1 1 1 6

diagram 463 QCD=4, QED=2 diagram 464 QCD=4, QED=2 diagram 465 QCD=4, QED=2

Diagrams made by MadGraph5 Boosted Boson Type Tagging Jet ETmiss Single top, Wt(+b) 17

50 Boosted Boson Type Tagging ATLAS Data ATLAS Data s = 13 TeV, 3.2 fb-1 tt 2L 30 s = 13 TeV, 3.2 fb-1 tt 2L 40 tt 1L1τ tt 1L1τ STCR1 tt 1L STCR1 tt 1L Single Top Jet ETmiss Events / 0.3 Single Top W+jets W+jets

Events / 20 GeV Benjamin Nachman and Ariel Schartzman 30 tt+V 20 tt+V VV VV Total SM Total SM 20 Wt control SLAC, Stanford University 10 10 region 0 100 200 300 Benjamin400 500 Nachman and Ariel Schartzman0 1 2 3 4 5 1.5 ~miss 1.5 ~miss E = Emiss with photon added [GeV] E = Emiss with photon added [GeV] 1 T T March(NEW 26,) 2014 1 T T 0.5 0.5 Data / SM Data / SM 0 100 200 300 400 500 0 1 2 3 4 5 t 1.5 am [GeV] SLAC, Stanford University t 1.5 ∆R(b ,b ) T2 1 2 1 1

Wt / t 0.5 Wt / t 0.5 0 0 0 100 200 300 400 500 0 1 2 3 4 5 am [GeV] R(b ,b ) T2 ∆ 1 2 500 March 26, 2014 ATLAS Data -1 tt 2L

Events s = 13 TeV, 3.2 fb 400 tt 1L1τ STCR1 tt 1L Single Top W+jets B. Nachman (SLAC) 300 Boosted Boson Typett+V Tagging March 26, 2014 1 / 21 VV Total SM 200

100

0 1 2 3 4 5 B. Nachman (SLAC) 1.5 Boosted Boson~miss Typemiss Tagging March 26, 2014 1 / 21 1 ET = ET with photon added [GeV] 0.5 Data / SM 0 1 2 3 4 5 3 b-tagged jet multiplicity 2 1 Wt / W+jets 0 0 1 2 3 4 5 b-tagged jet multiplicity Single top,Wt(+b) Arbitrary Normalization DS/DR tt+DS/tt+DR 10 10 10 10 10 .Ncmn(SLAC) Nachman B. .Ncmn(SLAC) Nachman B. 200 0 2 0 2 2 3 4 5 6 1 1 ATLAS s =13TeV,2-leptonselection ose oo yeTagging Type Boson Boosted ose oo yeTagging Type Boson Boosted Simulation Preliminary 300 ejmnNcmnadAilSchartzman Ariel and Nachman Benjamin ejmnNcmnadAilSchartzman Ariel and Nachman Benjamin 400 LC tnodUniversity Stanford SLAC, Powheg Wt(DR) Powheg t Powheg t Powheg Wt(DS) LC tnodUniversity Stanford SLAC, ose oo yeTagging Type Boson Boosted ose oo yeTagging Type Boson Boosted ac 6 2014 26, March ac 6 2014 26, March t t e ETmiss Jet +Wt(DS) +Wt(DR) e ETmiss Jet E E T miss T miss [GeV] [GeV] 500 + PS(what isthestatus Working toward WWbb 100%; can we turn 100%; canweturn DR versusDS~ the WtCRintoa measurement? (A: seemslike with Sherpa?) yes…) Aside ! ac 6 041/21 / 1 2014 26, March ac 6 041/21 / 1 2014 26, March 18 ˜0 t˜ ˜0

soft g˜ t˜ t¯ t

t¯ t g˜ soft t˜

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5 5 March 26, 2014

100 200 300 400 0 100 200 300 400 500 1.5 ~miss 1.5 ~miss E = Emiss with photon added [GeV] E = Emiss with photon added [GeV] 1 T T 1 T T B. Nachman (SLAC) Boosted Boson Type Tagging March 26, 2014 1 / 21 0.5 0.5 Data / SM Data / SM 100 200 300 400 0 100 200 300 400 500 ~miss miss m~ = m with photon added to the pmiss [GeV] ET = ET with photon added [GeV] T T T

B. Nachman(normalization (SLAC) factorBoosted Bosonof ~1.5 Type Tagging already applied)March 26, 2014 1 / 21 Boosted Boson Type Tagging Validation Jet ETmiss Boosted Boson Type Tagging 23 ttbar background is mostlyJet ETmiss 2L -> since we require 4 jets,Benjamin need to Nachman check andthe Arielextra Schartzman radiation. SLAC, Stanford University 80 ATLAS Data 150 ATLAS Data

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4 5 6 7 8 2 3 4 5 6 7 1.5 ~miss 1.5 ~miss E = Emiss with photon added [GeV] E = Emiss with photon added [GeV] 1 T T 1 T T 0.5 0.5 Data / SM B. Nachman (SLAC) Boosted Boson TypeData / SM Tagging March 26, 2014 1 / 21 4 5 6 7 8 2 3 4 5 6 7 Jet multiplicity (p > 25 GeV) Jet multiplicity (p > 25 GeV) T T Boosted Boson Type Tagging Results Jet ETmiss Boosted Boson Type Tagging 24 ATLAS Jet ETmissData Total SM Events Benjamins = 13 TeV, 3.2 Nachman fb-1 tt and 2L Ariel SchartzmanW+jets tt 1L1τ tt+V 102 SLAC, Stanfordtt 1L University VV Single Top Benjamin NachmanMarch 26, and 2014 Ariel Schartzman

10 SLAC, Stanford University

March 26, 2014

1 B. Nachman (SLAC) Boosted Boson Type Tagging March 26, 2014 1 / 21

tot 0 0.11 0.22 0.33 0.44 0.56 0.67 0.78 0.89 1 σ 2 ~miss B. Nachman (SLAC) Boosted BosonE Type = E Taggingmiss with photon added [GeV]March 26, 2014 1 / 21 ) / 0 T T exp -2 - n

obs TVR1 WVR1 TVR2 WVR2 TVR3 WVR3 SR1 SR2 SR3 (n Boosted Boson Type Tagging Results Jet ETmiss 25

Boosted~~ ~ Boson∼0 Type Tagging t1t1 production, t1→t+χ ~~ ~~~ ~ ~~ ~0 ~ 0 ~ ~ 00 1 gg production,gg gproduction,→t+t , t g→→t+∼χt450,+soft, t →∼χ +soft, ∆m( ∆tm(, t∼χ, ∼χ)) == 55 GeV GeV 1 1 11 1 1ATLAS1 1 11 Jet ETmiss Benjamin Nachman andObserved Ariel Schartzman limit (±1σth) 1200 1200 ~~ ~~ ~ ~ ~ ~~ ~ 0 0 ~ ~0 0 -1 ATLAS InternalATLAS ggInternal production,gg production, g→ gt+→t t+, tt→, t∼χ→+soft,∼χ +soft,s ∆=m( ∆Observedtm( , 13∼χt ,) ∼ χ=Observed ) 5 = TeV,GeV 5 GeV 3.2 limit limit fb ( 1( )1 Expected) limit ( 1 ) 4001 11 1 1 1 1 1 1 ± σ±th σth ± σexp 12001200 -1 -1 -1 1100 s =1100 13 TeV,s = 133.2 TeV, [GeV] fb 3.2 fb LimitExpected atExpected 95% SLAC,CL limitlimit (± Stanford 1(σ±1)σ ATLAS University) stop1L 8 TeV, 20.3 fb ATLASATLAS0 1 InternalInternal ObservedObserved limit limit (±1 (σ±1)σ ) exp exp ∼ χ -1 -1 th th -1 -1 [GeV] [GeV] Limit at 95%Limit CLat 95% CL350 ATLAS incl. 1L 8 TeV, 20.3 fb

1 ATLAS incl. 1L 8 TeV, 20.3 fb 1 obs. t t ~ ~ 11001100 s =s 13= 13 TeV, TeV, 3.2 3.2 fb fb

m ExpectedExpected limit limit ( 1 ( 1 ) )

1000 1000 Benjamin± σ±expσexp Nachman and Ariel-1 Schartzman-1 obs. obs. exp.ATLASATLAS mono-jet-1March-1 13 TeV,13 26, TeV,3.2 2014 fb 3.2 fb [GeV] [GeV] LimitLimit at at95% 95% CL CL m m ATLASATLAS incl. incl. 1L 1L8 TeV, 8 TeV, 20.3 20.3 fb fb 1 1

t t 300 ~ ~

1000 1000 900 exp.900 exp. < 0 -1 -1 t < 0 obs.obs.t ATLASATLAS mono-jet mono-jet 13 13TeV, SLAC,TeV, 3.2 3.2 fb fb Stanford University ~ - m m m ~ - m t t 250 800 800 1 900900 1 exp.exp. - m - m t < 0t < 0 m~g m~g ~ - m~ - m t 1 t 1 March 26, 2014 700 700 800800 - m - 200m m~gm~g 600 600 700700 150 B. Nachman (SLAC) Boosted Boson Type Tagging March 26, 2014 1 / 21 500 500 600600 100 400 400 500500 50 300 300 400400 B. Nachman (SLAC) Boosted Boson Type Tagging March 26, 2014 1 / 21 0 200 200 300300 500 550 600 650 700 750 800 850 800 9008001000900 11001000 11001200120013001300 14001400150015001600 1600m ~ [GeV] 200200 t1 80080090090010001000110011001200120013001300140014001500150016001600 m~g m[GeV]~g [GeV] m~gm [GeV]~g [GeV] Boosted Boson Type Tagging Jet ETmiss Results 26 Boosted~~ ~ Boson~ ~ ∼0 Type~ ∼0 Tagging gg production, g→t+t1, t1→χ +soft, ∆m(t , χ ) = 5 GeV ~~ ~~~ ~ ~~ ~0 ~ 0 ~ ~ 00 1 1 1 gg production,gg gproduction,→t+t , t g→→1200t+∼χt ,+soft, t →∼χ +soft, ∆m( ∆tm(, t∼χ, ∼χ)) == 55 GeV GeV 1 1 11 1 1ATLAS1 1 11 Jet ETmissObserved limit (±1σth) 1200 1200 ~~ ~~ ~ ~ ~ ~~ ~ 0 0 Benjamin~ ~0 0 Nachman-1 and Ariel Schartzman ATLAS InternalATLAS ggInternal production,gg production,1100 g→ gt+→t t+, tt→, t∼χ→+soft,∼χ +soft,s ∆=m( ∆Observedtm( , 13∼χt ,) ∼ χ=Observed ) 5 = TeV,GeV 5 GeV 3.2 limit limit fb ( 1( )1 Expected) limit ( 1 ) 1 11 1 1 1 1 1 1 ± σ±th σth ± σexp 12001200 -1 -1 -1 1100 s =1100 13 TeV,s = 133.2 TeV, [GeV] fb 3.2 fb Limit atExpected 95% CL limit ( 1 ) ATLAS incl. 1L 8 TeV, 20.3 fb 1 ExpectedSLAC, limit Stanford± (σ±exp1σexp University) ATLASATLASt InternalInternal ~ ObservedObserved limit limit (±1 (σ±1)σ ) 1000 -1 -1 th th -1 -1 -1 [GeV] [GeV] Limit at 95%Limit CLat 95% CL ATLAS incl. 1L 8 TeV, 20.3 fb

1 ATLAS incl. 1L 8 TeV, 20.3 fb 1 obs. ATLAS mono-jet 13 TeV, 3.2 fb t t ~ ~ 11001100 s =s 13= 13 TeV, TeV, 3.2 3.2 fb fb m ExpectedExpected limit limit ( 1 ( 1 ) )

1000 1000 ± σ±expσexp -1 -1 obs. obs. 900 exp.BenjaminATLASATLAS mono-jet Nachman-1 -1 13 TeV,13 and TeV,3.2 Ariel fb 3.2 Schartzman fb

[GeV] [GeV] LimitLimit at at95% 95% CL CL < 0 m m ATLASATLAS incl. incl. 1L 1L8 TeV, 8 TeV, 20.3 20.3 fb fb 1 1 t March 26, 2014 t t ~ ~

1000 1000 - m 900 exp.900 exp. < 0 < 0 ~ -1 -1 t obs.obs.t 800 ATLASATLAS mono-jet mono-jet t 1 13 13TeV, TeV, 3.2 3.2 fb fb m m - m ~ - m SLAC, Stanford University ~ - m ~ m g 800 800 t 1 900900 t 1 exp.exp. - m - m t < 0t < 0 m~g m~g 700 ~ - m~ - m t t 700 700 800800 - m - m1 1 March 26, 2014 m~gm~g 600 600 600 700700 B. Nachman500 (SLAC) Boosted Boson Type Tagging March 26, 2014 1 / 21 500 500 600600 400 500500 400 400 300 300 300 400400 B. Nachman (SLAC) Boosted Boson Type Tagging March 26, 2014 1 / 21 200 200 200 300300 800 900 1000 1100 1200 1300 1400 1500 1600 800 9008001000900 11001000 11001200120013001300 14001400150015001600 1600 200200 m~g [GeV] 80080090090010001000110011001200120013001300140014001500150016001600 m~g m[GeV]~g [GeV] m~gm [GeV]~g [GeV] Boosted Boson Type Tagging Jet ETmiss Boosted Boson Type Tagging 27

Benjamin NachmanJet ETmiss and Ariel Schartzman The ﬁrst 2015 analyses have pioneered new techniques and pushed out the limitsSLAC, in Stanfordthe statistically University limited regime.

Benjamin NachmanMarch 26, and 2014 Ariel Schartzman SLAC, Stanford University We will continue to push in this direction with more data (~10/fb Marchfor ICHEP) 26, 2014 in the near future.

B. Nachman (SLAC) Boosted Boson Type Tagging March 26, 2014 1 / 21 The next move is to ﬁll in gaps, taking advantage of shape ﬁts, ISR-selections, and VBF topologies. B. Nachman (SLAC) Boosted Boson Type Tagging March 26, 2014 1 / 21 (systematics-limited regime) (600 GeV large R jet with mjet ~180 GeV and MET ~ 500 GeV) Backup ~~ ~ 0 t t production, t →t+∼χ 450 1 1 1 1 ATLAS Internal 400 s = 13 TeV, 3.2 fb-1 Observed limit [GeV] 0 1

∼ χ 350 Expected limit m

300 < 0 t

0 - m ∼ 250 χ 1 - m ~ 200 m t 1 150 SR1 100 SR2 50 SR3 0 300 400 500 600 700 800 m ~ [GeV] t1 ~~ ~ ~ ~ 0 ~ 0 gg production, g→t+t , t →∼χ +soft, ∆m(t , ∼χ ) = 5 GeV 1 1 1 1 1 1200 ATLAS Internal s = 13 TeV, 3.2 fb-1 Observed limit [GeV] 1 t ~ 1000 Expected limit m

t < 0 ~ - m t 800 - m 1 m~g

600

SR1 400 SR2 SR3 200 800 900 1000 1100 1200 1300 1400 1500 1600

m~g [GeV]