Searches for high-mass resonances in ATLASpnp.ustc.edu.cn/html/upload/2018/08/29/... ·...
Transcript of Searches for high-mass resonances in ATLASpnp.ustc.edu.cn/html/upload/2018/08/29/... ·...
Searches for high-mass resonances in ATLAS
Zuzana Barnovska-Blenessy
USTC Seminar
May 4th, 2018
Zuzana Barnovska-Blenessy (USTC, ATLAS) High-mass searches in ATLAS May the 4th be with you 1 / 35
Outline
1 Standard Model
2 LHC and ATLAS detector
3 Summary of searches
4 X →WW
5 X → γγ
6 General searches
7 Summary and prospects
Zuzana Barnovska-Blenessy (USTC, ATLAS) High-mass searches in ATLAS May the 4th be with you 2 / 35
Standard model of Particle Physics
unified picture of Electroweak and Strong interactionsmatter is build of fermions (leptons, quarks) andforces are carried by bosons (gluons, γ, W±,Z)Higgs field is added to the SM to generate masses of W,Z and fermions
Zuzana Barnovska-Blenessy (USTC, ATLAS) High-mass searches in ATLAS May the 4th be with you 3 / 35
Large Hadron Collider at CERN
Zuzana Barnovska-Blenessy (USTC, ATLAS) High-mass searches in ATLAS May the 4th be with you 4 / 35
ATLAS experiment
Zuzana Barnovska-Blenessy (USTC, ATLAS) High-mass searches in ATLAS May the 4th be with you 5 / 35
ATLAS detector performance
ATLAS steadily collects data
instantaneous luminosity reaching double the desingvalue up to 2.06x1034 cm−2s−1
80 fb−1 of data usable for physics (out of 87 fb−1
recorded)
pile-up reaching up to 70 simultaneous collisions
improved performance wrt Run1: more efficienctb-tagging, new HLT algorigthms, new jet vertex tagger Mean Number of Interactions per Crossing
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= 8 TeVs2012 pp
= 13 TeVs2015 pp
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= 13 TeVs2017 pp
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Zuzana Barnovska-Blenessy (USTC, ATLAS) High-mass searches in ATLAS May the 4th be with you 6 / 35
Searches in ATLAS - SUSY and EXOTICS
Model e, µ, τ, γ Jets EmissT
∫L dt[fb−1] Mass limit Reference
Incl
usiv
eS
earc
hes
3rdge
n.g
med
.3rd
gen.
squa
rks
dire
ctpr
oduc
tion
EW
dire
ctLo
ng-li
ved
part
icle
sR
PV
Other
qq, q→qχ01 0 2-6 jets Yes 36.1 m(χ0
1)<200 GeV, m(1st gen. q)=m(2nd gen. q) 1712.023321.57 TeVq
qq, q→qχ01 (compressed) mono-jet 1-3 jets Yes 36.1 m(q)-m(χ0
1)<5 GeV 1711.03301710 GeVq
gg, g→qqχ01 0 2-6 jets Yes 36.1 m(χ0
1)<200 GeV 1712.023322.02 TeVg
gg, g→qqχ±1→qqW±χ01 0 2-6 jets Yes 36.1 m(χ0
1)<200 GeV, m(χ±)=0.5(m(χ01)+m(g)) 1712.023322.01 TeVg
gg, g→qq(ℓℓ)χ01
ee, µµ 2 jets Yes 14.7 m(χ01)<300 GeV, 1611.057911.7 TeVg
gg, g→qq(ℓℓ/νν)χ01 3 e, µ 4 jets - 36.1 m(χ0
1)=0 GeV 1706.037311.87 TeVg
gg, g→qqWZχ01 0 7-11 jets Yes 36.1 m(χ0
1) <400 GeV 1708.027941.8 TeVg
GMSB (ℓ NLSP) 1-2 τ + 0-1 ℓ 0-2 jets Yes 3.2 1607.059792.0 TeVgGGM (bino NLSP) 2 γ - Yes 36.1 cτ(NLSP)<0.1 mm ATLAS-CONF-2017-0802.15 TeVgGGM (higgsino-bino NLSP) γ 2 jets Yes 36.1 m(χ0
1)=1700 GeV, cτ(NLSP)<0.1 mm, µ>0 ATLAS-CONF-2017-0802.05 TeVg
Gravitino LSP 0 mono-jet Yes 20.3 m(G)>1.8 × 10−4 eV, m(g)=m(q)=1.5 TeV 1502.01518F1/2 scale 865 GeV
gg, g→bbχ01 0 3 b Yes 36.1 m(χ0
1)<600 GeV 1711.019011.92 TeVg
gg, g→ttχ01 0-1 e, µ 3 b Yes 36.1 m(χ0
1)<200 GeV 1711.019011.97 TeVg
b1b1, b1→bχ01 0 2 b Yes 36.1 m(χ0
1)<420 GeV 1708.09266950 GeVb1
b1b1, b1→tχ±1 2 e, µ (SS) 1 b Yes 36.1 m(χ01)<200 GeV, m(χ±1 )= m(χ0
1)+100 GeV 1706.03731275-700 GeVb1
t1 t1, t1→bχ±1 0-2 e, µ 1-2 b Yes 4.7/13.3 m(χ±1 ) = 2m(χ01), m(χ0
1)=55 GeV 1209.2102, ATLAS-CONF-2016-077t1 117-170 GeV 200-720 GeVt1
t1 t1, t1→Wbχ01 or tχ0
1 0-2 e, µ 0-2 jets/1-2 b Yes 20.3/36.1 m(χ01)=1 GeV 1506.08616, 1709.04183, 1711.11520t1 90-198 GeV 0.195-1.0 TeVt1
t1 t1, t1→cχ01 0 mono-jet Yes 36.1 m(t1)-m(χ0
1)=5 GeV 1711.0330190-430 GeVt1
t1 t1(natural GMSB) 2 e, µ (Z) 1 b Yes 20.3 m(χ01)>150 GeV 1403.5222t1 150-600 GeV
t2 t2, t2→t1 + Z 3 e, µ (Z) 1 b Yes 36.1 m(χ01)=0 GeV 1706.03986290-790 GeVt2
t2 t2, t2→t1 + h 1-2 e, µ 4 b Yes 36.1 m(χ01)=0 GeV 1706.03986320-880 GeVt2
ℓL,R ℓL,R, ℓ→ℓχ01 2 e, µ 0 Yes 36.1 m(χ0
1)=0 ATLAS-CONF-2017-03990-500 GeVℓ
χ+1 χ−1 , χ+1→ℓν(ℓν) 2 e, µ 0 Yes 36.1 m(χ0
1)=0, m(ℓ, ν)=0.5(m(χ±1 )+m(χ01 )) ATLAS-CONF-2017-039750 GeVχ±
1
χ±1 χ∓1 /χ
02, χ+1→τν(τν), χ0
2→ττ(νν) 2 τ - Yes 36.1 m(χ01)=0, m(τ, ν)=0.5(m(χ±1 )+m(χ0
1)) 1708.07875760 GeVχ±1
χ±1 χ02→ℓLνℓLℓ(νν), ℓνℓLℓ(νν) 3 e, µ 0 Yes 36.1 m(χ±1 )=m(χ0
2), m(χ01)=0, m(ℓ, ν)=0.5(m(χ±1 )+m(χ0
1)) ATLAS-CONF-2017-0391.13 TeVχ±1 , χ
02
χ±1 χ02→Wχ0
1Zχ01 2-3 e, µ 0-2 jets Yes 36.1 m(χ±1 )=m(χ0
2), m(χ01)=0, ℓ decoupled ATLAS-CONF-2017-039580 GeVχ±
1 , χ02
χ±1 χ02→Wχ0
1h χ01, h→bb/WW/ττ/γγ e, µ, γ 0-2 b Yes 20.3 m(χ±1 )=m(χ0
2), m(χ01)=0, ℓ decoupled 1501.07110χ±
1 , χ02 270 GeV
χ02χ
03, χ0
2,3 →ℓRℓ 4 e, µ 0 Yes 20.3 m(χ02)=m(χ0
3), m(χ01)=0, m(ℓ, ν)=0.5(m(χ0
2)+m(χ01)) 1405.5086χ0
2,3 635 GeVGGM (wino NLSP) weak prod., χ0
1→γG 1 e, µ + γ - Yes 20.3 cτ<1 mm 1507.05493W 115-370 GeVGGM (bino NLSP) weak prod., χ0
1→γG 2 γ - Yes 36.1 cτ<1 mm ATLAS-CONF-2017-0801.06 TeVW
Direct χ+1 χ−1 prod., long-lived χ±1 Disapp. trk 1 jet Yes 36.1 m(χ±1 )-m(χ0
1)∼160 MeV, τ(χ±1 )=0.2 ns 1712.02118460 GeVχ±1
Direct χ+1 χ−1 prod., long-lived χ±1 dE/dx trk - Yes 18.4 m(χ±1 )-m(χ0
1)∼160 MeV, τ(χ±1 )<15 ns 1506.05332χ±1 495 GeV
Stable, stopped g R-hadron 0 1-5 jets Yes 27.9 m(χ01)=100 GeV, 10 µs<τ(g)<1000 s 1310.6584g 850 GeV
Stable g R-hadron trk - - 3.2 1606.051291.58 TeVgMetastable g R-hadron dE/dx trk - - 3.2 m(χ0
1)=100 GeV, τ>10 ns 1604.045201.57 TeVg
Metastable g R-hadron, g→qqχ01 displ. vtx - Yes 32.8 τ(g)=0.17 ns, m(χ0
1) = 100 GeV 1710.049012.37 TeVg
GMSB, stable τ, χ01→τ(e, µ)+τ(e, µ) 1-2 µ - - 19.1 10<tanβ<50 1411.6795χ0
1 537 GeVGMSB, χ0
1→γG, long-lived χ01 2 γ - Yes 20.3 1<τ(χ0
1)<3 ns, SPS8 model 1409.5542χ01 440 GeV
gg, χ01→eeν/eµν/µµν displ. ee/eµ/µµ - - 20.3 7 <cτ(χ0
1)< 740 mm, m(g)=1.3 TeV 1504.05162χ01 1.0 TeV
LFV pp→ντ + X, ντ→eµ/eτ/µτ eµ,eτ,µτ - - 3.2 λ′311=0.11, λ132/133/233=0.07 1607.080791.9 TeVντ
Bilinear RPV CMSSM 2 e, µ (SS) 0-3 b Yes 20.3 m(q)=m(g), cτLS P<1 mm 1404.2500q, g 1.45 TeVχ+1 χ
−1 , χ+1→Wχ0
1, χ01→eeν, eµν, µµν 4 e, µ - Yes 13.3 m(χ0
1)>400GeV, λ12k,0 (k = 1, 2) ATLAS-CONF-2016-0751.14 TeVχ±1
χ+1 χ−1 , χ+1→Wχ0
1, χ01→ττνe, eτντ 3 e, µ + τ - Yes 20.3 m(χ0
1)>0.2×m(χ±1 ), λ133,0 1405.5086χ±1 450 GeV
gg, g→qqχ01, χ0
1 → qqq 0 4-5 large-R jets - 36.1 m(χ01)=1075 GeV SUSY-2016-221.875 TeVg
gg, g→ttχ01, χ0
1 → qqq 1 e, µ 8-10 jets/0-4 b - 36.1 m(χ01)= 1 TeV, λ112,0 1704.084932.1 TeVg
gg, g→t1t, t1→bs 1 e, µ 8-10 jets/0-4 b - 36.1 m(t1)= 1 TeV, λ323,0 1704.084931.65 TeVg
t1 t1, t1→bs 0 2 jets + 2 b - 36.7 1710.07171100-470 GeVt1 480-610 GeVt1
t1 t1, t1→bℓ 2 e, µ 2 b - 36.1 BR(t1→be/µ)>20% 1710.055440.4-1.45 TeVt1
Scalar charm, c→cχ01 0 2 c Yes 20.3 m(χ0
1)<200 GeV 1501.01325c 510 GeV
Mass scale [TeV]10−1 1
√s = 7, 8 TeV
√s = 13 TeV
ATLAS SUSY Searches* - 95% CL Lower LimitsDecember 2017
ATLAS Preliminary√s = 7, 8, 13 TeV
*Only a selection of the available mass limits on new states orphenomena is shown. Many of the limits are based onsimplified models, c.f. refs. for the assumptions made.
Model ℓ, γ Jets† EmissT
∫L dt[fb−1] Limit Reference
Ext
radi
men
sion
sG
auge
boso
nsC
ID
MLQ
Hea
vyqu
arks
Exc
ited
ferm
ions
Oth
er
ADD GKK + g/q 0 e, µ 1 − 4 j Yes 36.1 n = 2 ATLAS-CONF-2017-0607.75 TeVMD
ADD non-resonant γγ 2 γ − − 36.7 n = 3 HLZ NLO CERN-EP-2017-1328.6 TeVMS
ADD QBH − 2 j − 37.0 n = 6 1703.092178.9 TeVMth
ADD BH high∑pT ≥ 1 e, µ ≥ 2 j − 3.2 n = 6, MD = 3 TeV, rot BH 1606.022658.2 TeVMth
ADD BH multijet − ≥ 3 j − 3.6 n = 6, MD = 3 TeV, rot BH 1512.025869.55 TeVMth
RS1 GKK → γγ 2 γ − − 36.7 k/MPl = 0.1 CERN-EP-2017-1324.1 TeVGKK mass
Bulk RS GKK →WW → qqℓν 1 e, µ 1 J Yes 36.1 k/MPl = 1.0 ATLAS-CONF-2017-0511.75 TeVGKK mass
2UED / RPP 1 e, µ ≥ 2 b, ≥ 3 j Yes 13.2 Tier (1,1), B(A(1,1) → tt) = 1 ATLAS-CONF-2016-1041.6 TeVKK mass
SSM Z ′ → ℓℓ 2 e, µ − − 36.1 ATLAS-CONF-2017-0274.5 TeVZ′ mass
SSM Z ′ → ττ 2 τ − − 36.1 ATLAS-CONF-2017-0502.4 TeVZ′ massLeptophobic Z ′ → bb − 2 b − 3.2 1603.087911.5 TeVZ′ massLeptophobic Z ′ → tt 1 e, µ ≥ 1 b, ≥ 1J/2j Yes 3.2 Γ/m = 3% ATLAS-CONF-2016-0142.0 TeVZ′ mass
SSM W ′ → ℓν 1 e, µ − Yes 36.1 1706.047865.1 TeVW′ massHVT V ′ →WV → qqqq model B 0 e, µ 2 J − 36.7 gV = 3 CERN-EP-2017-1473.5 TeVV′ massHVT V ′ →WH/ZH model B multi-channel 36.1 gV = 3 ATLAS-CONF-2017-0552.93 TeVV′ massLRSM W ′
R → tb 1 e, µ 2 b, 0-1 j Yes 20.3 1410.41031.92 TeVW′ massLRSM W ′
R → tb 0 e, µ ≥ 1 b, 1 J − 20.3 1408.08861.76 TeVW′ mass
CI qqqq − 2 j − 37.0 η−LL 1703.0921721.8 TeVΛ
CI ℓℓqq 2 e, µ − − 36.1 η−LL ATLAS-CONF-2017-02740.1 TeVΛ
CI uutt 2(SS)/≥3 e,µ ≥1 b, ≥1 j Yes 20.3 |CRR | = 1 1504.046054.9 TeVΛ
Axial-vector mediator (Dirac DM) 0 e, µ 1 − 4 j Yes 36.1 gq=0.25, gχ=1.0, m(χ) < 400 GeV ATLAS-CONF-2017-0601.5 TeVmmed
Vector mediator (Dirac DM) 0 e, µ, 1 γ ≤ 1 j Yes 36.1 gq=0.25, gχ=1.0, m(χ) < 480 GeV 1704.038481.2 TeVmmed
VVχχ EFT (Dirac DM) 0 e, µ 1 J, ≤ 1 j Yes 3.2 m(χ) < 150 GeV 1608.02372700 GeVM∗
Scalar LQ 1st gen 2 e ≥ 2 j − 3.2 β = 1 1605.060351.1 TeVLQ mass
Scalar LQ 2nd gen 2 µ ≥ 2 j − 3.2 β = 1 1605.060351.05 TeVLQ mass
Scalar LQ 3rd gen 1 e, µ ≥1 b, ≥3 j Yes 20.3 β = 0 1508.04735640 GeVLQ mass
VLQ TT → Ht + X 0 or 1 e, µ ≥ 2 b, ≥ 3 j Yes 13.2 B(T → Ht) = 1 ATLAS-CONF-2016-1041.2 TeVT mass
VLQ TT → Zt + X 1 e, µ ≥ 1 b, ≥ 3 j Yes 36.1 B(T → Zt) = 1 1705.107511.16 TeVT mass
VLQ TT →Wb + X 1 e, µ ≥ 1 b, ≥ 1J/2j Yes 36.1 B(T →Wb) = 1 CERN-EP-2017-0941.35 TeVT mass
VLQ BB → Hb + X 1 e, µ ≥ 2 b, ≥ 3 j Yes 20.3 B(B → Hb) = 1 1505.04306700 GeVB mass
VLQ BB → Zb + X 2/≥3 e, µ ≥2/≥1 b − 20.3 B(B → Zb) = 1 1409.5500790 GeVB mass
VLQ BB →Wt + X 1 e, µ ≥ 1 b, ≥ 1J/2j Yes 36.1 B(B →Wt) = 1 CERN-EP-2017-0941.25 TeVB massVLQ QQ →WqWq 1 e, µ ≥ 4 j Yes 20.3 1509.04261690 GeVQ mass
Excited quark q∗ → qg − 2 j − 37.0 only u∗ and d∗, Λ = m(q∗) 1703.091276.0 TeVq∗ mass
Excited quark q∗ → qγ 1 γ 1 j − 36.7 only u∗ and d∗, Λ = m(q∗) CERN-EP-2017-1485.3 TeVq∗ mass
Excited quark b∗ → bg − 1 b, 1 j − 13.3 ATLAS-CONF-2016-0602.3 TeVb∗ massExcited quark b∗ →Wt 1 or 2 e, µ 1 b, 2-0 j Yes 20.3 fg = fL = fR = 1 1510.026641.5 TeVb∗ massExcited lepton ℓ∗ 3 e, µ − − 20.3 Λ = 3.0 TeV 1411.29213.0 TeVℓ∗ massExcited lepton ν∗ 3 e,µ, τ − − 20.3 Λ = 1.6 TeV 1411.29211.6 TeVν∗ mass
LRSM Majorana ν 2 e, µ 2 j − 20.3 m(WR ) = 2.4 TeV, no mixing 1506.060202.0 TeVN0 massHiggs triplet H±± → ℓℓ 2,3,4 e,µ (SS) − − 36.1 DY production ATLAS-CONF-2017-053870 GeVH±± massHiggs triplet H±± → ℓτ 3 e,µ, τ − − 20.3 DY production, B(H±±
L→ ℓτ) = 1 1411.2921400 GeVH±± mass
Monotop (non-res prod) 1 e, µ 1 b Yes 20.3 anon−res = 0.2 1410.5404657 GeVspin-1 invisible particle mass
Multi-charged particles − − − 20.3 DY production, |q| = 5e 1504.04188785 GeVmulti-charged particle mass
Magnetic monopoles − − − 7.0 DY production, |g | = 1gD , spin 1/2 1509.080591.34 TeVmonopole mass
Mass scale [TeV]10−1 1 10√s = 8 TeV
√s = 13 TeV
ATLAS Exotics Searches* - 95% CL Upper Exclusion LimitsStatus: July 2017
ATLAS Preliminary∫L dt = (3.2 – 37.0) fb−1
√s = 8, 13 TeV
*Only a selection of the available mass limits on new states or phenomena is shown.†Small-radius (large-radius) jets are denoted by the letter j (J).
→ usually we have exclusions up to 1 TeV, but room still left for discoveries!
Zuzana Barnovska-Blenessy (USTC, ATLAS) High-mass searches in ATLAS May the 4th be with you 7 / 35
X → WW → eνµν
Search for heavy resonances decaying into WW in the eνµν channel in pp collisions at√s = 13 TeV with the ATLAS detector
Zuzana Barnovska-Blenessy (USTC, ATLAS) High-mass searches in ATLAS May the 4th be with you 8 / 35
X→ WW - Introduction
many BSM models predict new resonances
sensitive mass range: 200-4000 GeV
Heavy Higgs models:Higgs with a Narrow Width approximation (NWA) Γ ≈ 4 MeVHiggs with a Large Width assumption (LWA) Γ = 5%, 10% and 15% of mH
new heavy resonance models:Georgi-Machacek (GM) model (VBF GM)Heavy Vector Triplet (HVT): includes qqF and VBFbulk Randall-Sundrum graviton model with spin-2 Graviton (RS-G*)spin-2 signal in the VBF production (spin-2 VBF)
Model Resonance spin Production modeggF qqA VBF
NWA Spin-0 x x2HDM x xLWA x xGM xHVT Spin-1 x x
Bulk RS Spin-2 xELM x
g
X
g
WW,Z
W,Z W
q
W +
W q
qW+
Wq
+
__
X
_
X
Zuzana Barnovska-Blenessy (USTC, ATLAS) High-mass searches in ATLAS May the 4th be with you 9 / 35
X→ WW - Data and Main backgrounds
→ using data collected by ATLAS at√s = 13 TeV, total of 36.1 fb−1
→ Monte Carlo events used for signal modelling and background estimations
Main backgrounds:
top quark: single t and tt
diboson production: WW , WZ and ZZ
Z+jets
W+jets
Zuzana Barnovska-Blenessy (USTC, ATLAS) High-mass searches in ATLAS May the 4th be with you 10 / 35
X→ WW - Event selection
Signal regions
VBF 1-jet: Njet = 1, ηjet > 2.4,min(|∆ηl ,jet |) > 1.75
VBF 2-jet: Njet ≥ 2, mjj > 500 GeV,|∆yjj | > 4
these are excluded from thequasi-inclusive ggF signal region
Control regions - cut definition
|η``|(m``) defines the WW CR, alsoimproves sensitivity in SR
max(mWT ) and psubleadT reduce Wjets and
Zjets contributions
cuts in VBF 1jet phase space are used togain sensitivity
psubleadT also improves WW puritySRggF SRVBF1J SRVBF2J
Common selectionsNb-tag = 0|∆η``| < 1.8m`` > 55GeV
p`,leadT > 45GeV
p`,subleadT > 30GeV
veto if p`,otherT > 15GeVmax(mW
T ) > 50GeVggF phase space VBF1J phase space VBF2J phase space
Inclusive in Njet but excluding Njet = 1 and Njet ≥ 2 andVBF1J and VBF2J phase space |ηj | > 2.4, min(|∆ηj`|) > 1.75 mjj > 500GeV, |∆yjj | > 4
SRggF SRVBF1J SRVBF2J
Common selectionsNb-tag = 0|∆η``| < 1.8m`` > 55GeV
p`,leadT > 45GeV
p`,subleadT > 30GeV
veto if p`,otherT > 15GeVmax(mW
T ) > 50GeVggF phase space VBF1J phase space VBF2J phase space
Inclusive in Njet but excluding Njet = 1 and Njet ≥ 2 andVBF1J and VBF2J phase space |ηj | > 2.4, min(|∆ηj`|) > 1.75 mjj > 500GeV, |∆yjj | > 4
Zuzana Barnovska-Blenessy (USTC, ATLAS) High-mass searches in ATLAS May the 4th be with you 11 / 35
X→ WW - Analysis strategy
discriminating variable: transverse mass
mT =√
(E ``T + EmissT )2 − |p``T + Emiss
T |2, where
E ``T =√|p``T |2 + m2
``
both normalization and shape of mT have to beestimated
shape: modelled using MC events
top and WW normalizations are determined froma simultaneous fit to the data in mT binneddistributions in the SR and total event yields in CR
Zuzana Barnovska-Blenessy (USTC, ATLAS) High-mass searches in ATLAS May the 4th be with you 12 / 35
X→ WW - Leading lepton pT correction
normalization of the top-quark background is determined in the Top CR (ggF)
one b-tagged jet, 97% purity of background in this CR
leading lepton pT disagreement between data and MC
correction proposed: linear reweighting of 4-10% for 50-200 GeV
Eve
nts
/ GeV
3−10
2−10
1−10
1
10
210
310
410
510 Data stat)⊕SM(sys
Top x 0.99 Other VV
WW x 1.15 ggF NWA 700
W+jets ggF NWA 2000
Z+jets
ATLAS-1 = 13 TeV, 36.1 fbs
ggF Top CRνµν e→WW→X
[GeV]Tm200 400 600 800 1000 1200
Dat
a / S
M
0.5
1
1.5E
vent
s / G
eV
3−10
2−10
1−10
1
10
210
310
410
510 Data stat)⊕SM(sys
Top x 0.99 Other VV
WW x 1.15 ggF NWA 700
W+jets ggF NWA 2000
Z+jets
ATLAS-1 = 13 TeV, 36.1 fbs
ggF Top CRνµν e→WW→X
[GeV]Tm200 400 600 800 1000 1200
Dat
a / S
M
0.5
1
1.5
Zuzana Barnovska-Blenessy (USTC, ATLAS) High-mass searches in ATLAS May the 4th be with you 13 / 35
X→ WW - Post-fit distributionsE
vent
s / G
eV
3−10
2−10
1−10
1
10
210
310
410
510 Data stat)⊕SM(sys
WW x 1.14 Other VV
Top x 0.96 ggF NWA 700
Z+jets ggF NWA 2000
W+jets
ATLAS-1 = 13 TeV, 36.1 fbs
ggF SRνµν e→WW→X
[GeV]Tm210 310
Dat
a / S
M
0.5
1
1.5
Eve
nts
/ GeV
3−10
2−10
1−10
1
10
210
310
410
Data stat)⊕SM(sys
WW x 1.00 Other VV
Top x 1.12 VBF NWA 700
Z+jets VBF NWA 2000
W+jets
ATLAS-1 = 13 TeV, 36.1 fbs
+ 1 jet VBF SRνµν e→WW→X
[GeV]Tm210 310
Dat
a / S
M
0.5
1
1.5
Eve
nts
/ GeV
3−10
2−10
1−10
1
10
210
310Data stat)⊕SM(sys
Top x 1.12 W+jets
WW x 1.00 VBF NWA 700
Z+jets VBF NWA 2000
Other VV
ATLAS-1 = 13 TeV, 36.1 fbs
2 jets VBF SR≥ + νµν e→WW→X
[GeV]Tm210 310
Dat
a / S
M
0.5
1
1.5
Signal yields in data and MC →
SRggF Top CRggF WW CRggF
WW 11 500 ± 800 820 ± 120 3 360 ± 220Top quark 11 800 ± 600 52 550 ± 330 2 610 ± 180Z/γ* 1 420 ± 110 111 ± 20 20.9 ± 2.0W+jets 1 180 ± 320 710 ± 190 280 ± 70V V 866 ± 34 101 ± 12 250 ± 11Background 26 740 ± 170 54 290 ± 250 6 510 ± 80Data 26 739 54 295 6 515
Zuzana Barnovska-Blenessy (USTC, ATLAS) High-mass searches in ATLAS May the 4th be with you 14 / 35
X→ WW - Systematic uncertainties
→ dominant uncertainties: jet energy scale, resolution and b-tagging→ for VBF 2-jet, uncertainty on MC modelling is comparable to exp. uncertainties
Zuzana Barnovska-Blenessy (USTC, ATLAS) High-mass searches in ATLAS May the 4th be with you 15 / 35
X→ WW - Results (NWA)
95% CL upper limits computed using modified frequentist method CLS
test statstic qµ, signal strength µ defined asratio of the measured σX × B(X →WW ) to the prediction
qµ = −2 ln(L(µ;θµ)L(µ;θ)
)
Limits:
[GeV]H m
500 1000 1500 2000 2500 3000 3500 4000
WW
) [p
b]→
B(H
× Hσ
2−10
1−10
1
10Observed 95% CL
Expected 95% CL
σ 1±
σ 2± (ggF, NWA)νµν e→ WW→H
ATLAS-1 = 13 TeV, 36.1 fbs
[GeV]H m
500 1000 1500 2000 2500 3000 W
W)
[pb]
→ B
(H×
Hσ
2−10
1−10
1
10Observed 95% CL
Expected 95% CL
σ 1±
σ 2± (VBF, NWA)νµν e→ WW→H
ATLAS-1 = 13 TeV, 36.1 fbs
Zuzana Barnovska-Blenessy (USTC, ATLAS) High-mass searches in ATLAS May the 4th be with you 16 / 35
X→ WW - Results (NWA)
95% CL upper limits computed using modified frequentist method CLS
test statstic qµ, signal strength µ defined asratio of the measured σX × B(X →WW ) to the prediction
qµ = −2 ln(L(µ;θµ)L(µ;θ)
)
Exclusion regions (for a 200 GeV 2HDM signal):
)α-βcos(
0.8− 0.6− 0.4− 0.2− 0 0.2 0.4 0.6 0.8
βta
n
1−10
1
10
)α-βcos(
0.8− 0.6− 0.4− 0.2− 0 0.2 0.4 0.6 0.8
βta
n
1−10
1
10
)α-βcos(
0.8− 0.6− 0.4− 0.2− 0 0.2 0.4 0.6 0.8
βta
n
1−10
1
10
)α-βcos(
0.8− 0.6− 0.4− 0.2− 0 0.2 0.4 0.6 0.8
βta
n
1−10
1
10
)α-βcos(
0.8− 0.6− 0.4− 0.2− 0 0.2 0.4 0.6 0.8
βta
n
1−10
1
10
)α-βcos(
0.8− 0.6− 0.4− 0.2− 0 0.2 0.4 0.6 0.8
βta
n
1−10
1
10
)α-βcos(
0.8− 0.6− 0.4− 0.2− 0 0.2 0.4 0.6 0.8
βta
n
1−10
1
10
)α-βcos(
0.8− 0.6− 0.4− 0.2− 0 0.2 0.4 0.6 0.8
βta
n
1−10
1
10
)α-βcos(
0.8− 0.6− 0.4− 0.2− 0 0.2 0.4 0.6 0.8
βta
n
1−10
1
10
ATLAS = 13 TeVs
-136.1 fb
=200 GeV±H=mA=mHWW m→H2HDM Type I
Observed 95% CL σ1±Expected 95% CL σ2±Excluded
)α-βcos(
0.8− 0.6− 0.4− 0.2− 0 0.2 0.4 0.6 0.8
βta
n
1−10
1
10
)α-βcos(
0.8− 0.6− 0.4− 0.2− 0 0.2 0.4 0.6 0.8
βta
n
1−10
1
10
)α-βcos(
0.8− 0.6− 0.4− 0.2− 0 0.2 0.4 0.6 0.8
βta
n
1−10
1
10
)α-βcos(
0.8− 0.6− 0.4− 0.2− 0 0.2 0.4 0.6 0.8
βta
n
1−10
1
10
)α-βcos(
0.8− 0.6− 0.4− 0.2− 0 0.2 0.4 0.6 0.8
βta
n
1−10
1
10
)α-βcos(
0.8− 0.6− 0.4− 0.2− 0 0.2 0.4 0.6 0.8
βta
n
1−10
1
10
)α-βcos(
0.8− 0.6− 0.4− 0.2− 0 0.2 0.4 0.6 0.8
βta
n
1−10
1
10
)α-βcos(
0.8− 0.6− 0.4− 0.2− 0 0.2 0.4 0.6 0.8
βta
n
1−10
1
10
)α-βcos(
0.8− 0.6− 0.4− 0.2− 0 0.2 0.4 0.6 0.8
βta
n
1−10
1
10
)α-βcos(
0.8− 0.6− 0.4− 0.2− 0 0.2 0.4 0.6 0.8
βta
n
1−10
1
10
ATLAS = 13 TeVs
-136.1 fb
=200 GeV±H=mA=mHWW m→H2HDM Type II
Observed 95% CL σ1±Expected 95% CL σ2±Excluded
)α-βcos(
0.8− 0.6− 0.4− 0.2− 0 0.2 0.4 0.6 0.8
βta
n
1−10
1
10
Zuzana Barnovska-Blenessy (USTC, ATLAS) High-mass searches in ATLAS May the 4th be with you 17 / 35
X→ WW - Results (NWA)
95% CL upper limits computed using modified frequentist method CLS
test statstic qµ, signal strength µ defined asratio of the measured σX × B(X →WW ) to the prediction
qµ = −2 ln(L(µ;θµ)L(µ;θ)
)
Exclusion regions as a function of mX :
[GeV]Hm
200 220 240 260 280 300 320 340 360 380 400
βta
n
1−10
1
10
[GeV]Hm
200 220 240 260 280 300 320 340 360 380 400
βta
n
1−10
1
10
[GeV]Hm
200 220 240 260 280 300 320 340 360 380 400
βta
n
1−10
1
10
[GeV]Hm
200 220 240 260 280 300 320 340 360 380 400
βta
n
1−10
1
10
[GeV]Hm
200 220 240 260 280 300 320 340 360 380 400
βta
n
1−10
1
10
[GeV]Hm
200 220 240 260 280 300 320 340 360 380 400
βta
n
1−10
1
10
[GeV]Hm
200 220 240 260 280 300 320 340 360 380 400
βta
n
1−10
1
10
[GeV]Hm
200 220 240 260 280 300 320 340 360 380 400
βta
n
1−10
1
10
[GeV]Hm
200 220 240 260 280 300 320 340 360 380 400
βta
n
1−10
1
10ATLAS
= 13 TeVs-136.1 fb
) = -0.1α-βWW cos (→H2HDM Type I
Observed 95% CL σ1±Expected 95% CL σ2±Excluded
[GeV]Hm
200 220 240 260 280 300 320 340 360 380 400
βta
n
1−10
1
10
[GeV]Hm
200 220 240 260 280 300 320 340 360 380 400
βta
n
1−10
1
10
[GeV]Hm
200 220 240 260 280 300 320 340 360 380 400
βta
n
1−10
1
10
[GeV]Hm
200 220 240 260 280 300 320 340 360 380 400
βta
n
1−10
1
10
[GeV]Hm
200 220 240 260 280 300 320 340 360 380 400
βta
n
1−10
1
10
[GeV]Hm
200 220 240 260 280 300 320 340 360 380 400
βta
n
1−10
1
10
[GeV]Hm
200 220 240 260 280 300 320 340 360 380 400
βta
n
1−10
1
10
[GeV]Hm
200 220 240 260 280 300 320 340 360 380 400
βta
n
1−10
1
10
[GeV]Hm
200 220 240 260 280 300 320 340 360 380 400
βta
n
1−10
1
10
[GeV]Hm
200 220 240 260 280 300 320 340 360 380 400
βta
n
1−10
1
10ATLAS
= 13 TeVs-136.1 fb
) = -0.1α-βWW cos (→H2HDM Type II
Observed 95% CL σ1±Expected 95% CL σ2±Excluded
[GeV]Hm
200 220 240 260 280 300 320 340 360 380 400
βta
n
1−10
1
10
Zuzana Barnovska-Blenessy (USTC, ATLAS) High-mass searches in ATLAS May the 4th be with you 18 / 35
X→ WW - Results (LWA ggF - left, VBF -right)
[GeV]H m
500 1000 1500 2000 2500 3000 3500 4000
WW
) [p
b]→
B(H
× Hσ
2−10
1−10
1
10Observed 95% CL
Expected 95% CL
σ 1±
σ 2± (ggF, 15% LWA)νµν e→ WW→H
ATLAS-1 = 13 TeV, 36.1 fbs
[GeV]H m
500 1000 1500 2000 2500 3000
WW
) [p
b]→
B(H
× Hσ
2−10
1−10
1
10Observed 95% CL
Expected 95% CL
σ 1±
σ 2± (VBF, 15% LWA)νµν e→ WW→H
ATLAS-1 = 13 TeV, 36.1 fbs
[GeV]H m
500 1000 1500 2000 2500 3000 3500 4000
WW
) [p
b]→
B(H
× Hσ
2−10
1−10
1
10 Obs. 5% LWA
Exp. 5% LWA
Obs. 10% LWA
Exp. 10% LWA
Obs. 15% LWA
Exp. 15% LWA
95% CL limits
(ggF , LWA)νµν e→ WW→H
ATLAS-1 = 13 TeV, 36.1 fbs
[GeV]H m
500 1000 1500 2000 2500 3000
WW
) [p
b]→
B(H
× Hσ
2−10
1−10
1
10 Obs. 5% LWA
Exp. 5% LWA
Obs. 10% LWA
Exp. 10% LWA
Obs. 15% LWA
Exp. 15% LWA
95% CL limits
(VBF , LWA)νµν e→ WW→H
ATLAS-1 = 13 TeV, 36.1 fbs
Zuzana Barnovska-Blenessy (USTC, ATLAS) High-mass searches in ATLAS May the 4th be with you 19 / 35
X→ WW - Results - other models
[GeV]X m
200 300 400 500 600 700 800 900 1000
WW
) [p
b]→
B(X
× Xσ
2−10
1−10
1
10=0.4HθGM, sin
Observed 95% CL
Expected 95% CL
σ 1±
σ 2±
(VBF, GM)νµν e→ WW→X
ATLAS-1 = 13 TeV, 36.1 fbs
[GeV]X m
200 300 400 500 600 700 800 900 1000
Hθ s
in
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
=0.4HθGM, sinObserved 95% CLExpected 95% CL
σ 1±σ 2±
(VBF, GM)νµν e→ WW→X
ATLAS-1 = 13 TeV, 36.1 fbs
[GeV]X m
1000 2000 3000 4000 5000
WW
) [p
b]→
B(X
× Xσ
2−10
1−10
1
10 =1v
HVT, g
Observed 95% CL
Expected 95% CL
σ 1±
σ 2±
(qqA, HVT)νµν e→ WW→X
ATLAS-1 = 13 TeV, 36.1 fbs
[GeV]X m
300 400 500 600 700 800 900 1000
WW
) [p
b]→
B(X
× Xσ
1−10
1
10=0
F=1, c
vHVT, g
Observed 95% CL
Expected 95% CL
σ 1±
σ 2±
(VBF, HVT)νµν e→ WW→X
ATLAS-1 = 13 TeV, 36.1 fbs
[GeV]X m
0 1000 2000 3000 4000 5000
WW
) [p
b]→
B(X
× Xσ
2−10
1−10
1
10
210 = 1.0PlMBulk RS, k/
Observed 95% CL
Expected 95% CL
σ 1±
σ 2±
(ggF, Bulk RS)νµν e→ WW→X
ATLAS-1 = 13 TeV, 36.1 fbs
[GeV]X m
0 1000 2000 3000 4000 5000
WW
) [p
b]→
B(X
× Xσ
2−10
1−10
1
10
210 = 0.5PlMBulk RS, k/
Observed 95% CL
Expected 95% CL
σ 1±
σ 2±
(ggF, Bulk RS)νµν e→ WW→X
ATLAS-1 = 13 TeV, 36.1 fbs
[GeV]X m
200 300 400 500 600 700 800 900 1000
WW
) [p
b]→
B(X
× Xσ
1−10
1
10=1i
ELM, f
Observed 95% CL
Expected 95% CL
σ 1±
σ 2±
(VBF, ELM)νµν e→ WW→X
ATLAS-1 = 13 TeV, 36.1 fbs
→ unfortunately, no excess is observed, but significant portions of the phase space areexcluded in some models
Zuzana Barnovska-Blenessy (USTC, ATLAS) High-mass searches in ATLAS May the 4th be with you 20 / 35
X→ WW - Conclusions and prospects
no significant excess has been found
exclusions:
narrow width above 6.5 pb at mH = 200 GeV, above 0.008 pb at 4 TeV for ggF
VBF: above 1.3 pb at mH = 200 GeV and above 0.006 pb at 4 TeV
heavy vector triplet model excluded below 1.3 TeV
Randall-Sundrum graviton with k/MPl = 1 excluded below 1.1 TeV
Randall-Sundrum graviton with k/MPl = 0.5 excluded below 750 GeV
analysis will be soon repeated with new 2018 data
STAY TUNED!
Zuzana Barnovska-Blenessy (USTC, ATLAS) High-mass searches in ATLAS May the 4th be with you 21 / 35
X → γγ
Search for new phenomena at high-mass in the diphoton final state at√s = 8 and 13 TeV
Zuzana Barnovska-Blenessy (USTC, ATLAS) High-mass searches in ATLAS May the 4th be with you 22 / 35
X→ γγ - Introduction (8 TeV Run1)
Zuzana Barnovska-Blenessy (USTC, ATLAS) High-mass searches in ATLAS May the 4th be with you 23 / 35
X→ γγ - Signal modelling (8 TeV Run1)
Zuzana Barnovska-Blenessy (USTC, ATLAS) High-mass searches in ATLAS May the 4th be with you 24 / 35
X→ γγ - Results (8 TeV Run1)
Zuzana Barnovska-Blenessy (USTC, ATLAS) High-mass searches in ATLAS May the 4th be with you 25 / 35
X→ γγ - Run 2, 13 TeV analysis
Changes wrt Run1 analysis:
36.7 fb−1 13 TeV ATLAS data
selection split to two categories - optimized spin 0 and spin 2 selection
spin 0: relative photon pT cuts of EγT > 0.4mγγ leading (0.3 subleading) photon,background functional form
spin 2: EγT > 55 GeV, backround: NLO prediction of spectrum shape
Zuzana Barnovska-Blenessy (USTC, ATLAS) High-mass searches in ATLAS May the 4th be with you 26 / 35
X→ γγ - mγγ distributions for spin-0 and spin-2 selection
500 1000 1500 2000 2500
Eve
nts
/ 20
GeV
1−10
1
10
210
310
410
510ATLAS
Spin-0 Selection-1 = 13 TeV, 36.7 fbs
Data
Background-only fit
[GeV]γγm500 1000 1500 2000 2500
Dat
a -
fitte
d ba
ckgr
ound
10−
5−0
5
10
15500 1000 1500 2000 2500
Eve
nts
/ 20
GeV
1−10
1
10
210
310
410
510ATLAS
Spin-2 Selection-1 = 13 TeV, 36.7 fbs
Data
Background-only fit
[GeV]γγm500 1000 1500 2000 2500
Dat
a -
fitte
d ba
ckgr
ound
10−
5−0
5
10
15
Zuzana Barnovska-Blenessy (USTC, ATLAS) High-mass searches in ATLAS May the 4th be with you 27 / 35
X→ γγ - 2D p-value scan
→ scanning the mass of a new resonance and as well as the width or k/MPl parameter
[GeV]Xm500 1000 1500 2000 2500
[%]
Xm/
XΓ
0
2
4
6
8
10
]σ [ 0Lo
cal p
0
0.5
1
1.5
2
2.5
3
Spin-0 Selection-1 = 13 TeV, 36.7 fbs ATLAS
[GeV]G*m500 1000 1500 2000 2500
Pl
M/k
0.05
0.1
0.15
0.2
0.25
0.3 ]σ [ 0Lo
cal p
0
0.5
1
1.5
2
2.5
3
Spin-2 Selection-1 = 13 TeV, 36.7 fbs ATLAS
Zuzana Barnovska-Blenessy (USTC, ATLAS) High-mass searches in ATLAS May the 4th be with you 28 / 35
X→ γγ - p-value
→ famous bump at 700-750 GeV in the resonance search- almost a discovery, until new data came - just a fluctuation :(
[GeV]Xm
0 500 1000 1500 2000 2500
Lo
ca
l p-v
alu
e
5−10
4−10
3−10
2−10
1−10
1
ATLAS-1= 13 TeV, 36.7 fbs
Spin-0 Selection
= 10%Xm/X
Γ, γγ→X
)-12015 (3.2 fb
)-12016 (33.5 fb
Combination
σ0
σ1
σ2
σ3
σ4
Zuzana Barnovska-Blenessy (USTC, ATLAS) High-mass searches in ATLAS May the 4th be with you 29 / 35
X→ γγ - exclusion limits
[GeV]Xm
500 1000 1500 2000 2500
B [f
b]×
fidσ95
% C
L U
pper
Lim
it on
1−10
1
10
210Spin-0 Selection
= 4 MeV)XΓNWA (
ATLAS-1 = 13 TeV, 36.7 fbs
limitsObserved CL limit
sExpected CL
σ 1±Expected σ 2±Expected
[GeV]G*m500 1000 1500 2000 2500 3000 3500 4000 4500 5000
B [f
b]× σ
95%
CL
Upp
er L
imit
on
2−10
1−10
1
10
210
310 limitsObserved CL limit
sExpected CL
σ 1±Expected σ 2±Expected
γγ→G*→pp limitsObserved CL
from pseudo-exp. limit
sExpected CLfrom pseudo-exp.
Spin-2 Selection = 0.10PlM/k, γγ→G*
ATLAS-1 = 13 TeV, 36.7 fbs
→ STAY TUNED for new analysis coming out very soon - low mass result! (USTC ATLASgroup is taking part - work lead by Yanwen Liu and Asma Hadef)
Zuzana Barnovska-Blenessy (USTC, ATLAS) High-mass searches in ATLAS May the 4th be with you 30 / 35
Next level - automation:General Searches
Zuzana Barnovska-Blenessy (USTC, ATLAS) High-mass searches in ATLAS May the 4th be with you 31 / 35
General search
preliminary result with 3.2 fb−1, full 13 TeV dataset paper coming out soon!ATLAS developed an algorithm to look for excesses - a framework that classifies dataevents, compares to MC and provides results as p-values or standard deviationslooking at invariant or effective mass (depends on channel)639 final states investigated (up to 700 for the upcoming paper)
2j 3j 4j 5j 6j 7j 8j 9j10
j11
j12
j13
j14
j1b
1j1b
2j1b
3j1b
4j1b
5j1b
6j1b
7j1b
8j1b
9j1b
10j
1b11
j2b
2b1j
2b2j
2b3j
2b4j
2b5j
2b6j
2b7j
2b8j
2b9j 3b
3b1j
3b2j
3b3j
3b4j
3b5j
3b6j
3b7j
3b8j
3b9j 4b
4b1j
4b2j
4b3j
4b4j
4b5j
4b6j 5b
5b1j
5b2j
5b3j
5b4j 6b
6b1j
6b2j
6b3j 7b
8b1j
Eve
nts
1−10
1
10
210
310
410
510
610
710
810Data 2015 3-/4-top Higgs +Z/W/WWtt γ+tt single top
di-/triboson )γ(γZ/W+ +jetstt )+jetsγ(γ Z/W+jets multijets
ATLAS Preliminary-1 = 13 TeV, 3.21 fbs
dijet and multijet
Zuzana Barnovska-Blenessy (USTC, ATLAS) High-mass searches in ATLAS May the 4th be with you 32 / 35
General search
How many excesses should we see?
probability that a deviation of a given sizeoccurs is modeled by pseudo-experiments
fraction of pseudo-experiments that predict atleast one, two or three event classes withdeviations below a given p-value in the scan ofminv and meff
lowest p-value found for 1m1e4b2j channel(5.10−4)
consistent at 70% level with SM expectationfrom pseudo experiment study
)min
(p10
-log0 1 2 3 4 5 6 7 8
Fra
ctio
n of
pse
udo
expe
rimen
ts
0.0
0.2
0.4
0.6
0.8
1.0
σ1 σ2 σ3 σ4 σ5
ATLAS Preliminary-1 = 13 TeV, 3.21 fbs
invvariable: m
pseudo experiments 1 class≥ 2 classes≥ 3 classes≥
Data
pseudo experiments SM-onlyincluding syst. correlations
Zuzana Barnovska-Blenessy (USTC, ATLAS) High-mass searches in ATLAS May the 4th be with you 33 / 35
Summary and plans
ATLAS continues to collect data, 2018 data-taking just started
the collaboration works tirelessly on ensuring detector safety andpublishing physics analyses
more searches coming out very soon!personal plan:
repeat the H → WW search with new dataworking on a generic Z+X search, where Z serves as a tag, and X can beanything - many channels investigated
Zuzana Barnovska-Blenessy (USTC, ATLAS) High-mass searches in ATLAS May the 4th be with you 34 / 35
Thank you for your attention :)
Zuzana Barnovska-Blenessy (USTC, ATLAS) High-mass searches in ATLAS May the 4th be with you 35 / 35
BONUS
→ a 3.6σ excess in ZZ
Zuzana Barnovska-Blenessy (USTC, ATLAS) High-mass searches in ATLAS May the 4th be with you 36 / 35