Searches for Exotic Physics at the LHC

SEARCHES FOR EXOTIC PHYSICS
Steve Worm
Rutherford Appleton Laboratory
Oxford, 3 June 2014
OUTLINE
• What is “Exo,c”?
– Standard Model, standard problems
– New energy regime
– “ExoGc” deﬁned
• Resonances and “standard stuﬀ”
– Z’ and ATLAS/CMS comparison
– W’, Dijet resonance
– High ST: black holes • Long-‐lived par,cles
– displaced jets
– HSCP
• Dark MaEer – monojet DM
– DM and mono-‐γ, W/Z, top, Higgs... • Conclusions
• Top, Boosted Jets, Di-‐boson Resonances
– Vector-‐like Tʹ′⟶ tZ/tH/bW
– X ⟶ Z semi-‐leptonic, hadronic
– Gbulk ⟶ WW, ZZ ⟶ semi-‐leptonic
2
OUTLINE
• What is “Exo,c”?
– Standard Model, standard problems
– New energy regime
– “ExoGc” deﬁned
• Resonances and “standard stuﬀ”
– Z’ and ATLAS/CMS comparison
– W’, Dijet resonance
– High ST: black holes • Top, Boosted Jets, Di-‐boson Resonances
– Vector-‐like Tʹ′⟶ tZ/tH/bW
– X ⟶ Z semi-‐leptonic, hadronic
– Gbulk ⟶ WW, ZZ ⟶ semi-‐leptonic
• Long-‐lived par,cles
– displaced jets
– HSCP
• Dark MaEer – monojet DM
– DM and mono-‐γ, W/Z, top, Higgs... • Conclusions
• Not an aEempt to cover all Exo,c results for ATLAS or CMS
– Each collaboraGon has 60-‐70 analyses; I selected some highlights – Extra apologies to ATLAS... I show more CMS results (really a CMS talk)
3
THE STANDARD MODEL
From experimental evidence and theory insight, a simple picture emerged:
The Standard “Ingredients”:
– Handful of fundamental parGcles
– ParGcles constructed by 2 or 3 quarks and only a few rules
– A few forces mediated by bosons
– Add the Higgs, to give parGcles mass
Standard Model Particles
The Standard Model has been incredibly successful in explaining all data...
…but there are problems too
4
STANDARD MODEL, STANDARD PROBLEMS
• AnGmaZer: What happened to all the an,ma.er?
• Dark MaZer: We don’t know what most of the ma.er in our world is made of!
5
STANDARD MODEL, STANDARD PROBLEMS
“Cracks” have started to appear in the Standard Model…
Many problems idenKﬁed over Kme
-‐ No explanaGon of masses, coupling constants
-‐ Why three families?
-‐ Gravity not included
-‐ The “hierarchy” problem, ﬁne tuning…
-‐ What is the Dark Energy?
…and yet it explains the data
The Standard Model isn’t so much wrong as it is incomplete
6
EFFECTIVE THEORIES... AND SCALE
• Fundamental theory may be hiding at shorter distances (higher energies)
• ~1900 we reached the atomic scale – 10-‐8 cm ≈ ħ2/e2me
– Quantum Mechanics, Quantum Electrodynamics
• ~1950 we reached strong interacGon scale – 10-‐13 cm ≈ Mexp[-‐8π2gs2(M)b0]
– QCD; Quarks, Gluons
• 2010 we reach (and exceeded) the EWK scale – 10-‐17 cm, the TeV scale
– EWK phase transiGon; W, Z, e… acquire mass
– v = (√2GF)-‐1/2 ≈ 246 GeV ← Higgs VEV
Expect lots of interes,ng stuﬀ at 13 TeV!
7
ACCELERATOR ADVANCES
• Each advance is a revoluKon… but sadly only once or twice per generaKon
– Previous energy record-‐holder (Tevatron) started in 1983 – 30 years ago
– LEP at CERN stopped in 2000 – 14 years ago
The jump to 13 TeV will be a huge advance for BSM searches
8
DETECTORS AND DISCOVERIES
1910
1920
1930
1940
1950
positron
neutron
pion
kaon
Cloud Chambers
1960
1970
1980
1990
J/Ψ
hyperons
anG-‐proton
resonances
Emulsions
2000
top
upsilon
W, Z
Wire Chambers
Bubble Chambers
Silicon Don’t underes,mate the role of new technology, techniques, triggers...
9
THE FOUR MAIN LHC EXPERIMENTS
ATLAS
ALICE
CMS
LHCB
10
BSM AND EXOTICA: WHAT IS “EXOTIC”?
• ExoGca/ExoGcs is an old term (and physics admin grouping), but with new purpose:
Comprehensive search of the HEP parameter space for new physics
• Exo,ca covers the full range of new phenomena searches
– generally no set map or guide (as in Supersymmetry or Higgs) – at ﬁrst, race to cover as much territory as possible (signatures, models) – then work on depth: more “general” searches, more complete coverage
• Beyond the Standard Model (BSM), but ozen no set framework as in SUSY
– ExoGca/ExoGcs use models as moGvaGon and sanity check
– Not just “crazy stuﬀ” or lezovers; ExoGca is now the highest priority for LHC’s Run 2 11
THE HIERARCHY PROBLEM
• ImplicaKons of Higgs as a scalar
– radiaGve correcGons to self-‐energy are divergent
– maybe we are missing a new (fermion/scalar/vector) degree of freedom?
• Supersymmetry: – sparGcles cancel parGcle contribuGons
– well-‐studied but so far undetected
• Higgs is a composite: – strongly-‐coupled BSM, yielding vector-‐like q
– mulG-‐jet resonances from heavy gluons
• Extra Dimensions: – Higgs is a vector in 5D
– moGvates LED searches, KK excitaGons Low-‐mass Higgs causes tensions, but also mo,vates new physics at ~TeV
12
RESONANCES AND OTHER “USUAL SUSPECTS”:
Z’, W’, DIJETS...
Maybe the new physics really s,cks out...or hides under a lot of jets (QCD)?
13
NEW ENERGY REGIMES
• Each advance in energy makes new discovery possible
Multiplicity
• Many historic examples of discovery from “bumps” in the mass spectra pp à X
multiplicity
S [(GeV)2]
14
DILEPTON RESONANCE SEARCH: TRIGGER
ATLAS
• ee channel
– Diphoton trigger
– ET > 35 GeV and ET > 25 GeV
• μμ channel
– Single muon triggers – ET > 24 GeV or ET > 36 GeV CMS
• ee channel
– Dielectron trigger
– Both clusters with ET > 33 GeV
• μμ channel
– Single muon trigger
– ET > 40 GeV
15
DILEPTON RESONANCE SEARCH: ELECTRONS
ATLAS
• Single electron threshold
– ET1 > 40 GeV
– ET2 > 30 GeV
• Suppress jets faking e’s
– Icalo0.2 < 0.7%·∙ET + 5 GeV (leading)
– Icalo0.2 < 2.2%·∙ET + 6 GeV (subleading)
A x ε = 73% (m = 2 TeV) CMS
• Single electron threshold
– ET1 > 35 GeV
– ET2 > 35 GeV
• Suppress jets faking e’s
– Itracker0.3 < 5 GeV – Icalo0.3 < 3%·∙ET A x ε = 67% (m = 2.5 TeV) 16
DILEPTON RESONANCE SEARCH: MUONS
ATLAS
• Single muon triggers
– pT > 25 GeV
– |η|< 2.4
CMS
• Single muon trigger
– pT > 45 GeV
– |η|< 2.4
• Suppress cosmic rays
• Suppress cosmic rays
– |d0| < 0.2 mm
– |z0-‐z(vertex)|< 1 mm
– |d0| < 0.2 mm
– |z0-‐z(vertex)|< 24 cm
• Suppress jets faking μ’s
• Suppress jets faking μ’s
– ∑pT(∆R<0.3) < 5%·∙pT
• Require opposite charge
– ∑pT(∆R<0.3) < 10%·∙pT
– |z0-‐z(vertex)|< 0.2mm
• Require opposite charge
A x ε = 46% (m = 2 TeV)
A x ε = 80% (m = 2.5 TeV)
17
DILEPTON RESONANCE SEARCH: BACKGROUNDS
• SM Drell-‐Yan: γ*/Z-‐> l+l-‐
– shape taken from Monte Carlo
– normalisaGon taken from Z peak in data
• t-‐tbar:
– where Z goes to e+e-‐, µ+µ-‐
– est. from MC, cross-‐checked in data
– also includes Z-‐>ττ, WW, WZ
• Jet Background (for ee):
– di-‐jet, W+jet events where the jets are misidenGﬁed as electrons/muons
• Cosmic Ray Background (for µµ):
– muons from cosmic rays
– esGmated <0.1 event azer vertex and angular diﬀerence requirements
...Start taking data and what do we see?
18
19
ca
r
i
c
e
12
d
IN
0
i
2
l
s
h
c
r
Ma
• Many new models have Z-‐like narrow resonances decaying to dileptons
Z’
2011 DATA?
[hep-ex 1206.1849]
• InteresGng features in dilepton spectra
– around 2σ each for CMS & ATLAS in e+μ
– similar in scale to 2011 Higgs excess
Worth watching in 2012’s 8 TeV data...
[ATLAS-CONF-2012-007]
20
DILEPTON RESONANCE SEARCH
• Event selecGon [ATLAS arXiv:1405.4123 , CMS EXO-12-061]
– CMS: ET (e1,e2) > 35 GeV, pT (μ1,μ2) > 45 GeV, plus isolaGon criteria
– ATLAS: ET (e1,e2) > (40,30) GeV, pT (μ1,μ2) > 25 GeV, plus isolaGon criteria
• Backgrounds – Z/γ*, Z, tW, VV, Z → ττ, mulGjets with ≥1 jet reconstructed as lepton
– esGmated by funcGonal ﬁt
No obvious excess observed in 2012 data
CMS
21
DILEPTON RESONANCE (Z’) SEARCH
• Both experiments analysed full 8 TeV datasets, combined ee and μμ channels
• No excess; limits set for a variety of narrow resonances (Z’SSM, Z’ψ, etc.)
M(Z’SSM) expected
CMS
> 2.96 TeV
ATLAS
> 2.87 TeV
observed
> 2.96 TeV
> 2.90 TeV
Excess in 2011 data just below 1 TeV all but gone in 2012
22
ATLAS AND CMS DIFFERENCES?
ATLAS
CMS
• Uses signal templates for Z’ limits
• Use narrow resonance window • Loss of sensiGvity at high masses (parton luminosiGes)
– Cross secGon upper limits less model dependent
– Give outside world descripGon of what was done • Cross secGon limits model-‐speciﬁc
B [pb]
• narrow resonance G* has no rise:
1
ATLAS Preliminary
s = 8 TeV
G*
ll
10-1
10-3
10-4
ee, µµ:
10-5
0.5
L dt = 20 fb
1
• Not sensiGve to parton luminosiGes
Expected limit
Expected ± 1
Expected ± 2
Observed limit
k/ MPl = 0.1
k/ MPl = 0.05
k/ MPl = 0.03
k/ MPl = 0.01
10-2
• Generic resonance search
-1
1.5
2
2.5
3
• Take signal shapes within ±40% of the mass peak into account to compute theory curves
3.5
Big diﬀerence in eﬃciency and approach... small diﬀerence in limit
MG* [TeV]
23
EXTRA DIMENSIONS IN DILEPTONS (CMS)
[CMS EXO-12-027, CMS EXO-12-031]
Limit on Ms [TeV]
CMS Preliminary
CMS ee+µµ(8TeV,20fb-1)
Atlas ee+µµ+γ γ (7TeV,5.0fb-1)
CMS ee+µµ+γ γ (7TeV,2.0fb-1)
CMS γ γ (7TeV,34pb-1)
DØ ee+γ γ (1.96TeV, 1.05fb-1)
6
5
4
3
2
1
0
MS (ADD) at LO
95% CL limits
CMS dimuon
CMS dielectron
Combined:
Combined limits in HLZ convenKon at NLO (K=1.3)
2
Lumi.
[“-‐1]
20.6
19.6
20.6+19.6
3
δ=3
Exp. [TeV]
4.34
4.62
4.76
4
5
δ=3
Obs. [TeV]
4.33
4.64
4.77
6
δ=6
Exp. [TeV]
3.07
3.27
3.37
7
nED
δ=6
Obs. [TeV]
3.06
3.28
3.37
ΛT (GRW)
[TeV] (GRW)
3.64
3.90
4.01
24
SEARCH FOR W’ ➞ lν
[CMS PAS EXO-12-060, ATLAS-CONF-2014-017]
Events / 1 GeV
• Search for a new heavy gauge boson W' decaying to a charged lepton (µ or e) and ν
CMS Preliminary
∫ L dt = 20 fb-1
s = 8 TeV
7
10
106
105
W' → µ ν M=2500 GeV
W' → µ ν M=500 GeV
104
W→µν
QCD
tt +single top
W → τν
DY → µµ
DY → ττ
Diboson
data
3
10
2
10
• Many models possible
right-‐handed W' bosons with standard-‐model couplings
lez-‐handed W' bosons including interference Kaluza-‐Klein W'KK-‐states in split-‐UED
Excited chiral boson (W*)
• Event SelecGon and Backgrounds
– back-‐to-‐back isolated lepton and ETmiss
– Plot transverse mass of lν system
– backgrounds from W, QCD, Z+single t, DY, VV
No signiﬁcant excess observed
muon
1
-1
10
10-2
10-3
500
1000
1500
2000
2500
MT [GeV]
Ratio data/MC
–
–
–
–
syst uncer.
10
10
8
6
4
2
0
500
1000
1500
2000
2500
electron
25
SEARCH FOR W’ ➞ lν
σ × B [fb]
[CMS PAS EXO-12-060, ATLAS-CONF-2014-017]
CMS preliminary, 20 fb-1, 2012,
s = 8 TeV
Observed 95% CL limit
Observed 95% CL limit W' → eν
Observed 95% CL limit W' → µ ν
Expected 95% CL limit
Expected 95% CL limit ± 1 σ
Expected 95% CL limit ± 2 σ
SSM W' NNLO
PDF uncertainty
W KK with µ = 10 TeV NNLO
W KK with µ = 0.05 TeV NNLO
104
103
miss
e + ET
102
8 TeV 2012
miss
, µ+E
T
10
1
500
1000 1500 2000 2500 3000 3500 4000
MW' [GeV]
M(W’SSM) 95% CL
Luminosity
Expected
Observed
ATLAS e+µ, 2012
20
> 3.19 TeV
> 3.27 TeV
CMS e+µ, 2012
20
> 3.37 TeV
> 3.35 TeV
26
SEARCH FOR DIJET RESONANCES
[ATLAS-CONF-2012-148]
[CMS PAS EXO-12-059]
CMS Preliminary
• Search for dijet resonance in smoothly falling mass spectrum
– leading jet mass mjj > 0.9-‐1 TeV from trigger and other constraints
– Background esGmated from smooth funcGonal ﬁt
27
SEARCH FOR DIJET RESONANCES
[CMS PAS EXO-12-016]
[ATLAS-CONF-2012-110]
CMS Preliminary
M(q*) 95% CL
ATLAS 2011
CMS 2011
ATLAS 2012
CMS 2012
Luminosity
4.8
5.0
13.0
19.6
Expected
> 3.09 TeV
> 3.27 TeV
> 3.70 TeV
> 3.75 TeV
Observed
> 3.55 TeV
> 3.05 TeV
> 3.84 TeV
> 3.50 TeV
28
HIGH MULTIPLICITY, LARGE ST & BLACK HOLES
•
[arXiv:1303:5338, EXO-12-009]
Search for microscopic Black Holes in 12 “-‐1 of 8 TeV data
– HypotheGcal BH would evaporate into many high-‐pt. objects – EsGmate by ST, the pT sum of physics objects with pT > 50 GeV
• Main background of QCD esGmated by ﬁt to n=2 distribuGon
– Normalised for each mulGplicity bin separately at ST = 1.8–2.2 TeV
– Model-‐independent limits vs ST and mulGplicity Black Hole limits around 5 TeV, also model-‐independent limits on high ST
σ(S > STmin) × A (pb)
CMS s = 8 TeV
-1
L = 12.1 fb
Multiplicity N ≥ 4
Observed
Expected ± 1σ
Expected ± 2σ
T
10-1
10
-2
10
-3
10-4
2000
3000
4000
5000
STmin (GeV)
29
8-JET EVENT, ST = 3 TEV
[arXiv:1303:5338, EXO-12-009]
Many interes,ng events found!
30
TOP, BOOSTED JETS & DIBOSON RESONANCES
New physics might decay to t or make resonance w/ heavy par,cles (t, W, Z, H)
31
VECTOR-LIKE T′⟶ tZ/tH/bW (CMS)
[CMS arXiv:1311.7667]
• Combined informaGon from single lepton, SS and OS dilepton, trilepton (+jets)
• Separate bins by W-‐tags, #jets, #b-‐jets, HT, MET, lepton pT, 3rd/4th jet pT
–
–
–
–
Opposite-‐Sign targe,ng tZtZ: on-‐Z, ≥5 jets, ≥2 b-‐jets, HT>500 GeV, ST>1000 GeV
Opposite-‐Sign targe,ng bWbW: oﬀ-‐Z, 2-‐3 jets, HT>300 GeV, ST>900 GeV
Same-‐Sign targe,ng tZ or tH: ≥3 jets, HT>500 GeV, ST>700 GeV + lepton ﬂavor
Mul,lepton category targe,ng tZ or tH: ≥3 jets, HT>500 GeV, ST>700 GeV + lepton ﬂavor
32
VECTOR-LIKE T′⟶ tZ/tH/bW (CMS)
[CMS arXiv:1311.7667]
• Combine all channels to get limits
– At lez: speciﬁc BR assumpGon of BR(T’→bW/tH/tZ)=50/25/25%
– At right: limits for all possible BR
Limits on the mass of Tʹ′ between 687 and 782 GeV
33
HEAVY TOP-LIKE QUARKS TO bW (ATLAS)
• W+jets and QCD use data-‐
driven esGmates
ATLAS Preliminary
L dt = 14.3 fb -1
140
Data ( s = 8 TeV)
TT (600) Chiral
TT (600) Singlet
tt
Non-t t
Total BG uncert.
120
100
Events / 150 GeV
Events / 150 GeV
• TT → bWlepbWhad → lvbjjb → l+4j+MET
[ATLAS-CONF-2013-060]
loose
80
ATLAS Preliminary
L dt = 14.3 fb -1
Data ( s = 8 TeV)
45
TT (600) Chiral
TT (600) Singlet
40
tt
Non-t t
Total BG uncert.
35
30
tight
25
20
60
15
40
10
Data / BG
Data / BG
0
1.5
1
0.5
100 200 300 400 500 600 700 800 900 1000
0
100 200 300 400 500 600 700 800 900 1000
ATLAS Preliminary
Theory (approx. NNLO prediction ±1 )
95% CL expected limit
mreco [GeV]
TT) [pb]
102
95% CL expected limit ±1
(pp
102
ATLAS Preliminary
Theory (approx. NNLO prediction ±1 )
95% CL expected limit
95% CL expected limit ±1
10
95% CL expected limit ±2
95% CL expected limit ±2
95% CL observed limit
TT
1
95% CL observed limit
Wb+X
10-2
Wb+X
10-1
s = 8 TeV
10-2
-1
Ldt = 14.3 fb
300
TT
1
10-1
Combined bW+tH limits on singlet T are mT > 670 GeV
2
1
mreco [GeV]
10
• Tight: minΔR(l,b) > 1.4, minΔR(Whad,b) > 1.4 0
3
(pp
• Loose: > 1 Whad, HT > 800, pT(b1) > 160, pT(b2) > 80, ΔR(l,MET) < 1.2
5
0
TT) [pb]
• Require 1 e or µ, > 1 b, > 4 jets, MET > 20 GeV
20
400
500
-1
Ldt = 14.3 fb
SU(2) singlet
600
700
s = 8 TeV
800
900
mT [GeV]
300
400
500
Chiral
600
700
800
900
mT [GeV]
34
X ⟶ o RESONANCE (CMS)
– Top-‐tagging: requirements on # of subjets, jet mass, minimum pair-‐wise mass (W)
– 2 jets, Cambridge-‐Aachen with R=0.8
– Scale factor measured in orthogonal muon+jets sample
Events / (5 GeV/c2)
• SelecGon and tagging for hadronic: [CMS arXiv:1309.2030]
-1
CMS Preliminary, s = 8 TeV, 19.6 fb
1800
1600
mDATA
= 84.3 ± 0.3 GeV/c2
W
1400
mMC
W
= 83.7 ± 0.2 GeV/c2
1200
1000
Data
tt
W+Jets
Non-W MJ
Z+jets
Single Top
Data fit
MC fit
800
600
• Similar approach for semileptonic
400
200
Limits on M(GKK) < 2.5 TeV, M(Z’) < 2.7 TeV
0
0
20
40
60
80 100 120 140 160 180 200
CMS Preliminary, s = 8 TeV, 19.6 fb-1
103
95% CL Limit on σ(pp → Z' → tt) (pb)
Events / (50 GeV/c2)
Hadronic W Jet Mass (GeV/c2)
Data
Non-Top Multijet
SM tt
1 TeV RS KK gluon
2 TeV RS KK gluon
3 TeV RS KK gluon
102
10
1
500
1000
1500
2000
2500
3000
tt Invariant Mass (GeV/c2)
CMS Preliminary, s = 8 TeV, 19.6 fb-1
combined limits
10% Width Z'
Expected Limit
Observed Limit
± 1σ
± 2σ
Topcolor Z' × 1.3, 10% Width
(Harris, et. al.)
10
1
10-1
10-2
1000
1200
1400
1600
1800
2000
2200
2400
2600
2800
3000
Z' Mass (GeV/c2)
35
HIGH-MASS DIBOSON RESONANCE SEARCHES
W’/ρTC ⟶ WZ ⟶ 3l + MET
[CMS EXO-‐12-‐025, ATLAS-‐CONF-‐2014-‐015]
lepton
+ MET
boosted
Z ⟶ µµ
Gbulk ⟶ WW ⟶ l + jet + MET
lepton
+ MET
boosted
W jet
boosted
Z jet
boosted
W jet
boosted
W/Z
boosted
W/Z
[CMS arXiv:1405.3447, ATLAS-‐CONF-‐2013-‐074]
Gbulk ⟶ ZZ ⟶ 2l + 2jets
[CMS arXiv:1405.3447, ATLAS-‐CONF-‐2013-‐074]
GRS ⟶ WW/ZZ and W’ ⟶ WZ
[CMS arXiv:1405.1994]
...and many more searches underway
36
SEMILEPTONIC WW, ZZ (CMS)
g
CMS Preliminary, 19.5 fb-1 at s=8TeV, W→ µν
• Search for WW (or ZZ) W G
resonance at high mass ⌫
1000
q
W
– RaGo of 2-‐to-‐1 jets: τ2/τ1 = τ21
q
WW/WZ/ZZ
Single Top
tt
W+jets
data
Events / 0.03
• IdenGfy boosted W-‐jets g
with “N-‐subješness” [CMS arXiv:1405.1337]
`
800
~
Bulk Graviton M=1.5TeV k=0.2 (×6×104)
600
400
200
– N-‐subješness: τ21 < 0.5 for high purity, and 0.5 < τ21 < 0.75 for low 0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
τ21
• Study performance of “W-‐tagging” in data
– derive data/MC scale factor (SF) for each analysis
– error on “substructure SF” ⟶ systemaGc on signal
• Study merged hadronic W's from Z
– boosted enough to merge jets from W – not so boosted that the b quark also merges
37
SEMILEPTONIC WW, ZZ (CMS)
[CMS arXiv:1405.1337]
• Measure of dominant W+jets backgrounds taken from data – Side-‐band region Mjet=[40,65] GeV
– W signal region Mjet=[65,105] GeV
– W+jets: MWW obtained from scaled Mjet sidebands
• Limits set on bulk graviton producGon Gmes BR
– 700 “ for 0.6 TeV mass
– 10 “ for 2.5 TeV mass
µ
µv
ee
combined limits
38
LONG-LIVED PARTICLES
Maybe the new physics has a long life,me, and has been missed!
39
DISPLACED JETS (CMS)
[CMS EXO-12-038]
• Massive long-‐lived parGcles can decay to (displaced) jets
– Split SUSY, RPV SUSY, Gauge Mediated SUSY, Hidden Valley models, etc.
– gg ⟶ H ⟶ XX ⟶ (qq) (qq)
– MH = [200, 400, 1000] GeV, MX = [50, 150, 350] GeV, cτX = [3, 30, 300] cm
• Search for events with dijets from a common, displaced vertex
Data
QCD
H(1000)→ 2X(350) cτ =35cm
H(400) → 2X(150) cτ =40cm
H(200) → 2X(50) cτ =20cm
5
10
CMS Preliminary
∫
-1
L dt = 17 pb , s = 8 TeV
104
3
10
102
10
1
Data/QCD
•
dijets / bin
– Trigger: events with HT > 300 GeV and ≥ 2 jets with small fracGon of prompt tracks
– Oﬄine: form mulGvariate discriminant based on vertex track mulGplicity, fracGon of tracks with posiGve d0, and variables from a dedicated track clustering algorithm
2
4
6
8
10
12
14
16
2
4
6
8
10
12
14
16
1.5
1
0.5
Track Multiplicity
Discriminant
Vertex Track Multiplicity
40
DISPLACED JETS (CMS)
[CMS EXO-12-038]
• Background predicGon using ABCD technique: jet1, jet2, secondary vertex details
• Search using “cut & count” technique opGmised for LXY < 20 cm and > 20 cm
• For X0 mean proper lifeGmes of 0.1 to 200 cm, limits typically 0.3−300 “.
Number of Candidates
< 20 cm(low)
1
< 0.15
> 0.9
1.60 ± 0.26(stat.) ± 0.51(syst.)
2
Table 1:
Predicted background and the number
of observed candidates for optimised
selections.
CMS Preliminary
CMS Preliminary
CMS Preliminary
∫ L dt = 18.6 fb , s = 8 TeV
-1
observed background
102
predicted background
∫ L dt = 18.6 fb , s = 8 TeV
-1
102
observed background
predicted background
10
10
∫ L dt = 18.6 fb ,
-1
-1
10
10-2
s = 8 TeV
mH = 1000 GeV
mX = 350 GeV
Obs. Limit
Exp. Limit
Exp. ± 1σ
Exp. ± 2σ
1
Lxy < 20 cm
Lxy > 20 cm
Significance
1
Significance
> 20 cm(high)
1
< 0.09
> 0.8
1.14 ± 0.15(stat.) ± 0.52(syst.)
1
σ B2 [pb] (95% CL)
Number of Candidates
Lxy
prompt tracks
prompt energy fraction
vertex/cluster disc.
expected background
observed
2
0
-2
0.01
0.1
0.3
0.5
0.7
0.9
2
0
-2
0.01
Vertex/Cluster Discriminant
.
10-3
0.1
0.3
0.5
0.7
10
0.9
Vertex/Cluster Discriminant
.
102
cτ [cm]
41
LONG-LIVED CHARGED PARTICLES (CMS)
[CMS EXO-12-026]
• Heavy, (quasi-‐)stable, also charged: slow (β<1), high dE/dx, long Gme-‐of-‐ﬂight
• stau benchmark model:
– |Q=e| in GMSB (SPS7)
– e/3 ≤ |Q| ≤ 8e pair producGon (neutral under SU(2)L)
R0
R+
• gluino (spit SUSY) or stop (large gluino masses limit) benchmark
– form R-‐hadrons containing a massive parton, – uncertainty from hadronizaGon (fracGon of gluino balls?) and charge ﬂipping
– electric charge can change while interacGng with the detector • SelecGon
– basic selecGon: pT > 45 GeV, |η| < 2.1, |dxy| and |dz|< 0.5 cm, very loose isolaGon, etc.
– Track pT : inner tracker transverse momentum
– Muon 1/β : measured by muon system – Track Ias : incompaGbility of the track energy loss w.r.t MIP expected dE/dx
42
Q=1 HSCP
Q≠1 HSCP
[CMS EXO-12-026]
HSCP unchanged - Tracker + TOF
Multiply charged - violet
HSCP becoming neutral - Tracker-only
Fractionally
charged - red
HSCP neutral in tracker - Muon-only
43
HSCP - BACKGROUNDS AND RESULTS
• ABCD-‐technique; pT, dE/dx and 1/β variables
–
–
–
–
–
Tk-‐Only Tk+TOF Mu-‐Only mulG. charged frac. charged [CMS EXO-12-026]
pT +dE/dx
pT +dE/dx +1/β
pT +1/β
dE/dx +1/β
pT +dE/dx
• Tk and Tk+TOF: predict the mass from dE/dx
44
HSCP - LIMITS
[CMS EXO-12-026]
• First CMS limits on gluino fully hadronizing into gluino balls (f=100%) MGluino > 1322 GeV, MStop > 935 GeV
45
DARK MATTER & ISR TAGGING
Maybe the new physics can explain the puzzle of Dark MaEer!
46
PRODUCTION OF DARK MATTER AT THE LHC
• Search for evidence of pair-‐producKon of Dark Maoer parKcles (χ)
q
χ
Production at Colliders
q
χ
• Dark Maoer producKon gives missing transverse energy (MET)
4
• Photons (or jets from a gluon) can be radiated from quarks, giving “mono”photon/jet 4plus MET: ini,al-‐state radia,on (ISR)
q¯
q¯
¯
q
Monophoton + MET
¯
q
Monojet + MET
47
DARK MATTER AND ADD FROM MONOJETS
[ATLAS-CONF-12-147, CMS EXO-12-048]
• Pair-‐produced Dark MaZer or Extra Dimensions
– Search for missing energy and radiated jet
– Similar searches in monophoton and other channels
• Monojet SelecGon for CMS (similar for ATLAS):
• Backgrounds from Data-‐Driven and MC – Measure Z + jets -‐-‐> predict Z(νν) + jets
– Measure W + jets -‐-‐> predict W(lν) + jets
– smaller backgrounds from top, QCD, non-‐collision
Events / 25 GeV
– Leading jet pT > ~120 GeV
– topological cuts to reduce QCD, e.g. Δϕ(j1,j2)<2.5
– veto events with isolated leptons
107
Z→ ν ν
CMS Preliminary
6
10
s = 8 TeV
tt
t
∫ L dt = 19.5 fb
-1
5
10
W →lν
QCD
-
Z→l+l
104
ADD MD= 2 TeV, δ = 3
103
UNP dU=1.7, ΛU = 2 TeV
DM Λ = 0.9 TeV, Mχ = 1 GeV
Data
102
• Best limits with ETmiss > 350–400 GeV
10
1
200
300
400
500
600
700
800 900 1000
Emiss
[GeV]48
T
49
LARGE EXTRA DIMENSIONS FROM MONOJETS
[ATLAS-CONF-12-147, CMS EXO-12-048]
MD (TeV/c2)
Large Extra Dimensions: Arkani-‐
Hamed, Dimopoulos, Dvali (ADD)
8
CMS Preliminary
7
∫L dt = 19.5 fb ,
-1
s=8 TeV
CMS Monojet (LO) 8 TeV, 19.5 fb-1
6
ATLAS Monojet (LO) 8 TeV, 10 fb-1
CMS Monojet (LO) 7 TeV, 5 fb-1
5
LEP
CDF
4
D∅
3
2
1
0
2
3
4
5
6
δ
MD (ADD) at LO
95% CL limits
ATLAS Monojet
CMS Monojet
√s
[TeV]
8
8
Lumi
[“.-‐1]
10.5
19.5
δ=3
Exp. [TeV]
3.39
3.94
δ=3
Obs. [TeV]
3.16
3.96
δ=6
Exp. [TeV]
2.69
2.95
δ=6
Obs. [TeV]
2.58
2.94
50
DARK MATTER AND MONOJETS
[CMS EXO-12-048]
• Pair-‐producGon of DM (χ) characterized by a contact interacGon eﬀecGve theory
• Limits compared to direct-‐detecGon experiments in (decepGvely) simple plots 10-36
CMS Preliminary
10-37
10-38
CMS, s = 7 TeV, 5.1 fb-1
10-39
CMS, s = 8 TeV, 19.5 fb-1
-40
10
C
-41
N
o Ge
11
T 20
012
IMPLE 2
10
S
10-42
C
-43
20 1
OU P P
2
S II
CDM
10
10-44
N100
XENO
-45
µ
10
10-46
χ-Nucleon Cross Section [cm2]
χ-Nucleon Cross Section [cm2]
• ATLAS & CMS generaGng comparable results
(χγ µχ)(qγ q)
Spin Independent, Vector Operator
1
10
Λ2
2
10
3
10
2
Mχ [GeV/c ]
10-36
10-37
12
E 20
L
P
M
SI
12
P P 20
C OU
+
W
W
K
r
Supe
10-38
10-39
CMS, s = 7 TeV, 5.1 fb-1
-40
10
-
+
eW W
b
u
C
Ice
CMS, s = 8 TeV, 19.5 fb-1
-41
10
10-42
10-43
10-44
CMS Preliminary
-45
10
10-46
Spin Dependent, Axial-vector operator
1
10
102
(χγ µγ χ)(qγ µγ q)
5
5
Λ2
3
10
Mχ [GeV/c251]
MONO-EVERYTHING!
4
4
q¯
• In last two years:
q¯
– Hundreds of citaGons for collider DM
– Hundreds of phenomenology papers
¯
– “ISR tagging” established technique for all new parGcle searches (not just DM)
q
¯
q
Monojet
Monophoton
Figure 1: Dark matter production in association
Figurewith
1: Dark
a single
matter
jet inproduction
a hadron collider.
in association with a single jet in a hadro
3.1.
Dark matter pair production through aDark
diagram
matter
likepair
figure
production
1 is one through
of the leading
a diagram
channels
like figure 1 is one of th
for dark matter searches at hadron colliders
for dark
[3, 4].
matter
The searches
signal would
at hadron
manifest
colliders
itself [3,
as an
4]. excess
The signal would manifest
/ T ) events
/ T ) events which
of jets plus missing energy (j + E
of jets
over
plus
themissing
Standard
energy
Model
(j +
background,
E
over the
consists
Standard Model backgrou
inv ⌫)
mainly of (Z ! ⌫⌫) + j and (W ! `inv ⌫)mainly
+ j final
of (Z
states.
! ⌫⌫)
In +
the
j and
latter
(Wcase
! `the
charged
+ j final
lepton
states.
` isIn the latter case the
/ T final
/ T fina
lost, as indicated by the superscript “inv”.
lost,Experimental
as indicated by
studies
the superscript
of j + E
“inv”.
states
Experimental
have been studies of j + E
performed by CDF [22], CMS [23] and ATLAS
performed
[24, by
25],CDF
mostly
[22],inCMS
the context
[23] andofATLAS
Extra Dimensions.
[24, 25], mostly in the context of
Our analysis will, for the most part, be based
Our analysis
on the ATLAS
will, forsearch
the most
[25]part,
which
belooked
based for
on the
monoATLAS search [25] whic
jets in 1 fb 1 of data, although we will also
jets in
compare
1 fb 1 to
of the
data,
earlier
although
CMSwe
analysis
will also
[23],
compare
which used
to the earlier CMS analys
36 pb 1 of integrated luminosity. The 36
ATLAS
pb 1 search
of integrated
containsluminosity.
three separate
The ATLAS
analyses search
based contains
on
three separate
successively harder pT cuts, the major selection
successively
criteria
harder
from
pT each
cuts, analysis
the major
that
selection
we apply
criteria
in ourfrom each analysis tha
analysis are given below.3
analysis are given below.3
MonoZ
q¯
q
q
W/Z
MonoW (Monolepton)
g
t
/ T > 120 GeV,
/ T GeV,
LowPT Selection requires E
LowPT
one jet
Selection
with pTrequires
(j1 ) > 120
E
> 120|⌘(j
GeV,
one2, jet
andwith
events
pT (j1 ) > 120 GeV, |⌘(j1
1 )| <
are vetoed if they contain a second jet with
are vetoed
pT (j2 ) if> they
30 GeV
contain
and a|⌘(j
second
4.5.with pT (j2 ) > 30 GeV and |⌘(j2 )|
2 )| < jet
χ
χ
/ T > 220 GeV,
/ TGeV,
HighPT Selection requires E
HighPT
one jet
Selection
with pTrequires
(j1 ) > 250
E
> 220|⌘(j
GeV,
one
2, jet
andwith
events
pT (j1 ) > 250 GeV, |⌘(j
1 )| <
are vetoed if there is a second jet withare
|⌘(jvetoed
if there
and with
is a second
either pjet
60 GeV
4.5 and with either pT
2 )| < 4.5
2 ) > |⌘(j
2 )| < or
T (jwith
/ T ) < 0.5. Any further jets with |⌘(j
/<T )4.5
(j2 , E
(j22)|
,E
< must
0.5. Any
havefurther
pT (j3 ) jets
< 30with
GeV.
|⌘(j2 )| < 4.5 must have pT (j3 ) <
¯
q
MonoW/Z (hadronic)
Comparing Various Mono-Jet Analyses
3.1. Comparing Various Mono-Jet Analyses
g
/ T > 300
/T >
veryHighPT Selection requires E
veryHighPT
GeV, one jet
Selection
with prequires
E
GeV,
300 |⌘(j
GeV,
< 2,jet
and
with pT (j1 ) > 350 GeV
1 )| one
T (j1 ) > 350
events are vetoed if there is a second jetevents
with |⌘(j
are2 )|
vetoed
< 4.5ifand
there
with
is aeither
second
pT jet
(j2 )with
> 60|⌘(j
GeV
2 )| < 4.5 and with eithe
/
/
or
(j2 , E T ) < 0.5. Any further jets with
or |⌘(j
(j22)|
, E<T )4.5
< must
0.5. Any
havefurther
pT (j3 ) jets
< 30with
GeV.
|⌘(j2 )| < 4.5 must
52 have pT (j3
t
ttbar InDM
MonoTop
all cases events are vetoed if they contain
In allany
cases
hard
events
leptons,
are vetoed
definediffor
they
electrons
containasany
|⌘(e)|
hard
< leptons,
2.47
defined for electro
e 1: Dark matter production in association with a single jet in a hadron collider.
MONOPHOTON DARK MATTER (CMS)
[CMS EXO-12-047]
• Monophoton to Dark Maoer – single photon plus signiﬁcant MET
– aggressive isolaGon-‐based cleanup to ensure purity
– backgrounds from physics (W, Z) and halo
• Strong DM limits from eﬀecKve ﬁeld theory
53
MONOLEPTON DARK MATTER (CMS)
[CMS EXO-13-004]
• Dark Maoer producKon with a W
– W recoiling against pair-‐produced DM – vector-‐ and axial-‐vector couplings considered
– interference eﬀects parameterised by ξ (W+ diagram at right) 106
105
104
103
102
10
1
-1
10
10-2
10-3
10-4
10-5
µ + Emiss
Mχ = 300 GeV Λ = 200 GeV
Spin Independent
DM ξ = +1
T
-1
∫ L dt = 20 fb
W → lν
s = 8 TeV
t t +single top
QCD
DY
DM ξ = -1
DM ξ = 0
Diboson
data
syst uncer.
CMS preliminary 2012 20 fb-1 s = 8 TeV
10-30
10-31
10-32
Observed limit
Expected limit
Expected ± 1 σ
-33
10
Expected ± 2 σ
10-34 Limit in 90 C.L.
Spin Independent
10-35 electron + muon ξ = +1
10-36
CMS Preliminary 2012 20 fb-1 s = 8 TeV
χ-proton σ (cm2)
Events / 1 GeV
CMS Preliminary
χ-nucleon σ (cm2)
• Limits can be quite strong (interference)
CMS monojet 2012
Xenon 100 2012
COUPP 2012
SIMPLE 2012
CoGeNT 2011
CDMSII 2011
CDMSII 2010
10-38
10-40
10-42
1500
2000
2500
MT (GeV)
Expected limit for ξ=+1
10-36
Observed limit for ξ=-1
Observed limit for ξ=0
Observed limit for ξ=+1
10-37
10-40
10-41
1000
Spin Independent
10-39
10-39
500
Expected limit for ξ=0
10-38
10-37
10-43
Expected limit for ξ=-1
10-35
10-41
1
10
102
103
Mχ (GeV)
1
10
102
103
Mχ (GeV)
54
MONO W/Z HADRONIC (ATLAS)
• ATLAS analysis looks for a radiated hadronic W or Z (boosted topology)
[ATLAS arXiv1309.4017v2]
• Also sensiGve to WH and ZH, where H ➝ χ χ
55
DARK MATTER IN TOP QUARK PAIRS (CMS)
[CMS B2G-13-004]
• Select top quark pairs in di-‐lepton events
– Exactly two leptons, two or more jets, MET > 320
– Cuts on scalar sum of leptons & jets, opening angles
g
χ
χ
• Scalar coupling, four-‐fermion contact interacKon – Limits set on scale (M✳︎), translated to limits on σ
– σ > 0.09 (0.24) pb excluded for Mχ of 50 (1000) GeV t
g
t
56
MONOTOP DARK MATTER (CMS)
• Event SelecGon
– Three jets, with j2>60 GeV and j3>40, one tagged b-‐jet
– Veto events with j4 > 35 GeV or e(μ) > 20(10) GeV – M(j1j2j3) < 250 GeV, MET> 350 GeV [CMS B2G-12-022]
χ • Results
– Excellent agreement with data
– DM coupling set to 0.1 for q=u/d [arXiv:1106.199]
– Exclude scalar (vector) DM masses below 327 (655) GeV
χ 57
HIGGS “PORTAL” TO DARK MATTER
• DM can couple to the Higgs sector; H ➝ χ χ [CMS arXiv:1404.1344, ATLAS arXiv1402.3244]
– Limits on branching fracGon of Higgs to “invisible” parGcles used for limits on DM
– Can be scalar, vector or fermionic couplings
– Limits only up to DM mass Mχ < MH/2
• First results from ATLAS, CMS set strong bounds on Higgs couplings to DM
58
CMS EXOTICA 95% CL E
LQ1, β=0.5
LQ1, β=1.0
IMITS E
LQ2, β=0.5
LQ2, β=1.0
LQ3 (bν), Q=±1/3, β=0.0
LQ3 (bτ), Q=±2/3 or ±4/3, β=1.0
stop (bτ)
XCLUSION L
q* (qg), dijet
q* (qW)
q* (qZ)
q* , dijet pair
q* , boosted Z
e*, Λ = 2 TeV
μ*, Λ = 2 TeV
Z’SSM (ee, µµ)
Z’SSM (ττ)
Z’ (tt hadronic) width=1.2%
Z’ (dijet)
Z’ (tt lep+jet) width=1.2%
Z’SSM (ll) fbb=0.2
G (dijet)
G (ttbar hadronic)
G (jet+MET) k/M = 0.2
G (γγ) k/M = 0.1
G (Z(ll)Z(qq)) k/M = 0.1
W’ (lν)
W’ (dijet)
W’ (td)
W’→ WZ(leptonic)
WR’ (tb)
WR, MNR=MWR/2
WKK μ = 10 TeV
ρTC, πTC > 700 GeV
String Resonances (qg)
s8 Resonance (gg)
E6 diquarks (qq)
Axigluon/Coloron (qqbar)
gluino, 3jet, RPV
gluino, Stopped Gluino
stop, HSCP
stop, Stopped Gluino
stau, HSCP, GMSB
hyper-K, hyper-ρ=1.2 TeV
neutralino, cτ<50cm
1
2
3
4
5
LeptoQuarks
0
Compositeness
0
(T V)
6
Heavy
Resonances
1
b’ → tW, (3l, 2l) + b-jet
q’, b’/t’ degenerate, Vtb=1
b’ → tW, l+jets
B’ → bZ (100%)
T’ → tZ (100%)
t’ → bW (100%), l+jets
t’ → bW (100%), l+l
C.I. Λ , Χ analysis, Λ+ LL/RR
C.I. Λ , Χ analysis, Λ- LL/RR
C.I., µµ, destructve LLIM
C.I., µµ, constructive LLIM
C.I., single e (HnCM)
C.I., single µ (HnCM)
C.I., incl. jet, destructive
C.I., incl. jet, constructive
Sh. Rahatlou
0
1
2
3
4
Long
Lived
1
2
3
4
0
6
4
5
6
1
2
3
4
5
6
Contact
Interactions
Ms, γγ, HLZ, nED = 3
Ms, γγ, HLZ, nED = 6
Ms, ll, HLZ, nED = 3
Ms, ll, HLZ, nED = 6
MD, monojet, nED = 3
MD, monojet, nED = 6
MD, mono-γ, nED = 3
MD, mono-γ, nED = 6
5
6
MBH, rotating, MD=3TeV, nED = 2
MBH, non-rot, MD=3TeV, nED = 2
MBH, boil. remn., MD=3TeV, nED = 2
MBH, stable remn., MD=3TeV, nED = 2
MBH, Quantum BH, MD=3TeV, nED = 2
5
3
4th
Generation
0
0
2
5
10
15
Extra Dimensions
& Black Holes
0
1
2
3
4
51
59
6
60
CONCLUSIONS
• The LHC has an extremely acKve programme of “ExoKc” searches • Results presented today include highlights from:
– Resonances in Z’, W’, dijets
– Top, boosted jets & diboson resonances
– New long-‐lived parGcles
– Dark maZer & ISR tagging
• More than 100 results out now... many more results available on the web:
– hZps://twiki.cern.ch/twiki/bin/view/CMSPublic/PhysicsResultsEXO & B2G
– hZps://twiki.cern.ch/twiki/bin/view/AtlasPublic/ExoGcsPublicResults
More results on the way
– leaving no stone unturned!
61
62
JET SUBSTRUCTURE TECHNIQUES
• Mass Drop: idenGfy subjets [arXiv:0802.2470]
j2
• Filtering: recluster consGtuents of j1, j2 [arXiv:0802.2470]
• Trimming: uses kt algorithm to idenGfy and cut subjets [arXiv:0912.1342]
63
JET SUBSTRUCTURE TECHNIQUES
• Pruning: cut sozer or wider consGtuents during jet reconstrucGon [arXiv:0912.0033] • N-‐subješness: [arXiv:1101.2268]
– Measure to what degree a jet can be considered to be composed of N-‐subjets
– Force a jet algorithm to produce N subjets
– The N-‐subješness characterizes how close to these jets the pT is distributed
• Q-‐jets: [arXiv:1201:1914]
– Instead of clustering according to dij (as in CA), cluster at each algorithm step randomly according to a probability distribuGon of P = exp(-‐αdij) – Get a probability distribuGon for the jet substructure instead of just one quanGty – Discriminator: volaGlity (~RMS) of the jet mass
64

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