Searches for physics beyond the Standard Model at CMS

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Carmen Diez Pardos for the CMS collaboration

CIEMAT (Madrid)

III CPAN days, Barcelona

2-4 November 2011

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Outline

1 Introduction

2 Heavy Resonances

3 Heavy long-lived Particles

4 4th Generation Quarks

5 Outlook

C. Diez Pardos (CIEMAT) CPAN III, 2 Nov 2011 2/31

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Introduction

.

2010/2011 have been very exciting and productive for exotica searches We present most recent results: New analysis with 2011 data and updates (∼1 fb −1 ) of 2010 analysis

Complete information about all results:

https://twiki.cern.ch/twiki/bin/view/CMSPublic/PhysicsResultsEXO This talk with not cover SUSY searches

(https://twiki.cern.ch/twiki/bin/view/CMSPublic/PhysicsResults/SUS), see G. G´ omez’s CMS Plenary talk, Thursday.

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Search for Heavy Resonances

Predicted by numerous extensions of the Standard Model:

GUT-inspired theories, Little Higgs Technicolor

Randall-Sundrum Extra Dimensions model. It has two free parameters mass of the first graviton excitation

coupling k/M

Pl

, k is the curvature of the extra dimension, M

Pl

reduce effective Planck scale

Experimental challenge: understand detector performance (resolution, efficiency) at very high momentum

New particles would be observed as a bump, excess in the mass spectrum

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Dilepton Resonances CMS-EXO-11-019

Models used as benchmark: Randall-Sundrum graviton excitation, SSM Z

⁰

, Z’

_Ψ

predicted by grand unified theories

Signature: two isolated electrons or muons, explicit requirement of opposite sign for the muon channel

Search for a resonance in dilepton invariant mass spectrum

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Dilepton Resonances

µµ ee

) [GeV]

µ- µ+ m(

200 400 600 800 1000 1200

Events / 5 GeV

10-3 10-2 10-1 1 10 102 103 104 105

DATA µ- µ+

→ γ* Z/

+ other prompt leptons t

t jets

L dt = 1.1 fb-1

∫

= 7 TeV s CMS preliminary

) [GeV]

ee m(

200 400 600 800 1000 1200

Events / 5 GeV

10-3 10-2 10-1 1 10 102 103 104 105

DATA e- e+

→ γ* Z/

+ other prompt leptons t

t jets (data)

L dt = 1.1 fb-1

∫

= 7 TeV s CMS preliminary

Obtain limit in the ratio between the new gauge boson cross-section and the Z SM cross-section

R

σ

=

^σ(pp→Zσ(pp→Z+X→ll+X)⁰^+X→ll+X)

500 1000 1500 2000

0 0.1 0.2 0.3 0.4

M [GeV]

-4 10⋅σR

median expected 68% expected 95% expected Z'SSM Z'Ψ

Pl=0.1 M KK k/

G

=0.05 MPl KK k/

G 95% C.L. limit dt = 1.1fb-1

∫

L

CMS preliminary, ee+µ⁺µ^-

Z

⁰_SSM

: 1940 GeV G

_KK

(k/M

_Pl

=0.05):

1450 GeV

G

_KK

(k/M

_Pl

=0.10):

1780 GeV Z

⁰_ψ

: 1620 GeV

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Heavy Resonance: Diphoton channel EXO-11-038

Looked for RS gravitons via resonances in the diphoton channel G

KK

→ γγ: lower limit on the mass set at 1.7 TeV (k/M

Pl

= 0.1)

[GeV]

γ Mγ 200 300 400 500 600 700 800 900 1000

Entries/20 GeV

10-3 10-2 10-1 1 10 102

Observed Diphoton γ+jet Dijet Syst. Uncertainty

CMS Preliminary at 7 TeV 1.1 fb-1

[GeV]

γ Mγ 200 300 400 500 600 700 800 900 1000

Entries/20 GeV

10-3 10-2 10-1 1 10 102

[GeV]

M

1

600 800 1000 120014001600 18002000

[pb] σ RS graviton

10-2

10-1

median expected 68% expected 95% expected = 0.10 k~ GKK

95% CL limit CMS Preliminary

at 7 TeV 1.1 fb-1

Also limits on the effective Planck scale (in TeV) in extra dimensions (ADD scenario)

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Dijet resonances 10.1016/j.PhysLetB.2011.09.015 High sensitivity to strongly produced

new resonances predicted in numerous models: string phenomena, excited quarks, colorons, diquarks

Looking for resonances above expectation from

phenomenological fit to the data

1000 1500 2000 2500 3000 3500 4000

/dm (pb/GeV)σd

10-5 10-4 10-3 10-2 10-1 1 10

/ ndf

χ2 27.51 / 28

Prob 0.4907

p0 3.238e-05 ± 1.86e-05 p1 7.181 ± 0.5794 p2 5.847 ± 0.4157 p3 0.08448 ± 0.08538

/ ndf

χ2 27.51 / 28

Prob 0.4907

p0 3.238e-05 ± 1.86e-05 p1 7.181 ± 0.5794 p2 5.847 ± 0.4157 p3 0.08448 ± 0.08538

-1) CMS (1.0 fb Fit

QCD Pythia + CMS Simulation JES Uncertainty Excited Quark String Resonance

= 7 TeV s

| < 1.3 η

∆

| < 2.5, | η

| Wide Jets

S (1.8 TeV)

S (2.6 TeV) q* (1.5 TeV)

q* (2.3 TeV)

Dijet Mass (GeV) 1000 1500 2000 2500 3000 3500 4000

Significance

-2 -1 0 1 2

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Model independent cross-section limits

95% CL upper limits on σ×BR×A for dijet resonances of type gluon-gluon, quark-gluon and quark-quark.

These upper limits are compared to the theoretical predictions for seven resonance models.

95% CL Mass Limit (TeV) using CTEQ6L Model Observed Expected

String 4.0 3.9

q* 2.49 2.68

Axigluon 2.47 2.66

E

6

diquark 3.52 3.28

W

⁰

1.51 1.40

Probing the quark structure up to 4 TeV

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Z 0 → t ¯ t

Search in the semileptonic (t¯ t → WbWb → qqbµνb) and all hadronic decay channel (t ¯ t → WbWb → qqbqqb).

Tops are boosted for high mass Z

⁰

, their products either partially or fully merged into one jet. Developed dedicated algorithms for jet-reconstruction for M

t¯t

≥1 TeV.

2] [GeV/c

t

Mt

0 500 1000 1500 2000 2500 3000

2event yield / 100 GeV/c

0 500 1000 1500 2000 2500 3000 3500

t QCD t lν

W→ -

+l l

* → Z/γ Single-Top QCD multijet Uncertainty CMS data 2011 L = 1.14/fb

CMS preliminary = 7TeV s

p: 0.510 χ2

KS p: 1.000,

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Semileptonic EXO-11-055 and All-Hadronic EXO-11-006

Exclusion limits on SSM Z

⁰

, KK and topcolor models

Semileptonic: Z

⁰

topcolor excluded in mass regions 850-935 GeV, 960-1060 GeV, sub-pb limits set on σ(pp → Z

⁰

→ t¯ t ) for masses above 1.35 TeV

All hadronic: KK gluon excluded 1.0-1.5 TeV, subpicobarn limits to Z

⁰

masses above 1.1 TeV

1000 1500 2000 2500 3000

M

_Z0

[GeV/ c

²

]

10^-1

10⁰ 10¹ 10²

lim it o n σ (p p

→

Z

0→

t¯t ) [p b]

^L⁼¹^.¹⁴^fb⁻¹ CMS preliminary, ^ps=7 TeV median expected limit observed limit (95% C.L.) central 1σ expected limit central 2σ expected limit Topcolor Z⁰, 3.0% width, Harris et al.

Topcolor Z⁰, 1.2% width, Harris et al.

2) Invariant Mass (TeV/c t

t

1 1.5 2 2.5 3

) (pb)t t→ BR(Z' ×Z'σUpper Limit

10-1

1 10

102 ^at^s^{= 7 TeV}

CMS Preliminary, 886 pb-1 Combined type 1+1 & 1+2

Observed (95% CL) Expected (95% CL)

Expected σ

± 1 Expected σ

± 2 KK Gluon, Agashe et al Topcolor Z', 3.0% width, Harris et al Topcolor Z', 1.2% width, Harris et al

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W 0 Searches

Left-Right symmetry of electroweak interactions: Extend the SM gauge group to include RH interactions.

Technicolor.

General extensions of the SM gauge group, as Little Higgs models

W

⁰

→ l ν W

⁰

/ρ

TC

→ WZ → l νll W

R

→ lW

^∗

→ l(jjl)

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W 0 leptonic (µ, e ) channels EXO-11-024

Signature: 1 isolated high p

T

lepton + missing transverse energy, E

_T^miss

, look for a jacobian peak in the transverse mass spectrum

M

T

= q

2(p

^l_T

· c)E

_T^miss

(1 − cos ∆φ

l,ν

)

[GeV]

M

T 200 400 600 800 1000 1200 1400

Events / 10 GeV

10-2

10-1

1 10 102

103

104

105

106

107 ^W^→^µ^ν

WW, WZ, ZZ + single-top t t QCD

µ µ

→ Z

ν τ

→ W

τ τ

→ Z Data

=1.5 TeV) W' (mW'

CMS Preliminary L dt = 1.13 fb-1

∫

= 7 TeV s

ν µ

→ W'

overflow bin

W' mass (GeV)

1400 1600 1800 2000 2200 2400 ) (pb)ν + µ e / → BR(W' .σ

10-3

10-2

10-1

CMS Preliminary = 7 TeV s

95% Observed Limit Electron 1.03 fb-1 95% Observed Limit Muon 1.13 fb-1 95% Observed Combined 95% Expected Combined Theoretical Cross Section

W' mass (GeV)

1400 1600 1800 2000 2200 2400 ) (pb)ν + µ e / → BR(W' .σ

10-3

10-2

10-1

W

⁰

with SM-like couplings is excluded below M

W⁰

=2.27 TeV

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WZ Resonances EXO-11-041

W

⁰

or ρ

TC

to WZ

All leptonic channel (W → lν, Z → ll) Reconstruct M

WZ

by constraining m

W

(GeV) MWZ

0 200 400 600 800 1000 1200

Events / 10 GeV

10-2 10-1 1 10

102CMS Preliminary 2011 s = 7 TeV

L dt = 1.15 fb-1

Data

∫

W+Jets

VV tt

Z+Jets WZ→3lν W' 600

(GeV) MWZ

300 400 500 600 700 800 900

BR (pb)⋅ σ

10-3 10-2

10-1 W' Limit = 784 GeV

CMS Preliminary 2011 s = 7 TeV

L dt = 1.15 fb-1

∫

Obs. Limit Exp. Limit

σ

± 1 σ

± 2 σW'

Sequential SM: M

_W0

>784 GeV Technicolor: M

ρ

> 384 GeV

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W 0 → lN EXO-11-002

Search for W

⁰

decaying to a lepton plus a right-handed (heavy) neutrino Benchmark: LR symmetric models

Final state: two (same-flavour) muons or electrons plus two jets W

_R⁰

→ lN → l (lW

_R^∗

) → l (ljj)

jj) [GeV]

µ µ M(

0 500 1000 1500 2000

Events/80 GeV

0 5 10 15 20

Z+Jets Top Other backgrounds Data

µjj µ

→ µN R→ W

= 7 TeV s -1 at 204.16 pb

CMS Preliminary

[GeV]

WR

M 800 1000 1200 1400 1600 [GeV]µNM

0 200 400 600 800 1000

1200 Observed

Expected WR

> M Nµ

M

Excluded by Tevatron

CMS Preliminary at 7 TeV 240 pb-1

[GeV]

WR

M 800 1000 1200 1400 1600 [GeV]eNM

0 200 400 600 800 1000

1200 Observed

Expected WR

> M Ne

M

Excluded by Tevatron

CMS Preliminary at 7 TeV 240 pb-1

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Heavy long-lived Particles

2] HSCP Mass [GeV/c

500 1000

HSCP Stopping Probability per Event

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

CMS Simulation g~

~g Stopped gluinos,

~t

~t Stopped stops,

Predicted by many new physics scenarios Some flavours of SUSY

Hidden valley models GUT’s

Split SUSY

Charged heavy particles: Slow moving particles will lose E at a higher rate than MIP. If hadron-like, can stop in the detector.

Two complementary methods:

High momentum tracks with high dE/dX.

Stopped particles, decay product signals out-of-synch. w.r.t. bunch crossing (β <0.4).

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Direct Search for HSCP EXO-11-022

Look for the distinctive signature of a high momentum particle with an anomalously large rate of energy loss through ionization (dE/dx) and an anomalously long time-of-flight (TOF).

Limits on the production cross-section for stau, stop and gluino, translated into the mass of the particle

m

stau

> 293 GeV m

stop

> 829 GeV m

_gluino

> 885 GeV

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Search for Stopped HSCP EXO-11-020

If long-lived gluinos (stops) are produced at CMS will hadronise into ’R-hadrons’ (˜ g g, ˜ g q¯ q,

˜

g qqq states).

These stopped R-hadrons may decay during time intervals when there are no pp collisions.

Time profile analysis

HSCP stops in the hadronic calorimeter, its decay produces large energy deposit outside collision window

Look for signal without collisions: No beam in the machine and between bunch trains

Counting experiment

Hypothesis on lifetime from 75ns to 10

⁶

s:

set limits on σ× stopping probability over 13 orders of magnitude in τ

HSCP

. Result independent of models of R-hadron formation and nuclear int.

HSCP [s]

τ 10-710^-610^-510^-410^-310^-210^-1 1 1010²10³10⁴10⁵10⁶

Model Independent Cross-section [pb]

10-1 1 10

CMS Preliminary 2011 L dt = 886 pb-1

∫

s-1 cm-2 = 1.3 x 1033 inst Lmax

= 7 TeV s

95% C.L. Limits:

=400 GeV/c2 χ∼0 2, m

=500 GeV/c g~ Gluino : m

=100 GeV/c2 χ∼0 2, m

=300 GeV/c

~t Stop : m

No excess observed, set limits on HSCP lifetime for a given mass (or viceversa)

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Search for 4th Generation quarks

Flavour physics: It could explain some observed discrepancies It is not excluded by EWK precision measurements

New CP source for Baryogenesis

Search for production of t

⁰

t ¯

⁰

, b

⁰

b ¯

⁰

t

⁰

b, b

⁰

t

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Heavy top-like quark EXO-11-050/051

Search for the production of t

⁰

t ¯

⁰

→ WbWb t

⁰

→ Wb: top-like signal (l+jets, dilepton), but heavier

Experimental challenge: large t¯ t background

> 170 GeV/c2 ) for Ml1b1 (GeV/c2 Ml2b2

0 100 200 300 400 500

Events

10-2 10-1 1 10 102

Data

(dileptonic) t t

Other backgrounds

= 350 GeV/c2 , Mt' t' t' CMS Preliminary

=7 TeV s at 1.14 fb-1

µ µ/e µ Events with ee/

Signal Region

3500 400 450 500

1 2 3

[GeV]

Mt'

[pb]σ 95% expected

68% expected median expected 95% CL observed

THEORY

t'

CMS preliminary CL_S: e+jets (573pb^-1), µ+jets (821pb^-1)

2) (GeV/c Mt'

400 500 600

') pbt t'→ (pp σ

10-1

1 10

=7 TeV -1s CMS Preliminary 1.14 fb

NLO Theory Expected Limits 95% CLs

Observed Limits 95% CLs

σ

± 1 CLs

σ

± 2 CLs

l+jets: m

t⁰

>450 GeV dileptons: m

t⁰

>422 GeV

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Heavy Bottom-Like Quarks EXO-11-036

Search for production of b

⁰

b ¯

⁰

→ tW

⁻

tW

⁺

→ bW

⁺

W

⁻

bW ¯

⁻

W

⁺

Signature: 3-lepton or same signed-dileptons + ≥ 1 b-jet Higher mass than top quark and more jets than top pair decays b’ excluded below 495 GeV

NJets

0 2 4 6 8 10

Events

10-1

1 10 102

data Mb' 400 GeV/c²

t

t tt+W(Z)

Single-top W→lν l-

l+

→

Z diboson

CMS 2011 Preliminary 1.14 fb-1

same-sign dilepton

2] [GeV/c Mb'

350 400 450 500 550

') [pb]b b'→(pp σ

10-1

1 10

P

rediction expected limit

observed limit

> 495 GeV/c2 Limit at 95% CL: Mb'

σ 2

σ 1 = 7 TeV s -1 CMS 2011 Preliminary 1.14 fb

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Inclusive Search for 4th Generation Quarks EXO-11-054

Inclusive search for t’ and b’ quarks, produced singly or in pairs

Muon + jets channel: Signature a high p

T

isolated muon, E

_T^miss

and at least 1 b-tag jet

Classify events according to number of hadronically decaying Ws and b-tags Assume simplified model where m

t⁰

= m

b⁰

and one free paramenter in the CKM4

For minimal offdiagonal mixing (A∼1), observed lower mass limit 490 GeV

HT (GeV)

200 300 400 500 600 700 800 900

Events/50 GeV

0 20 40 60 80 100 120 140 160 180 200 220

= 7TeV -1s CMS Preliminary L = 1.1fb

2B_0W

data t t W+Z single top t' pair (400) (x5) t' single (400) (x5) b' pair (400) (x5) b' single (400) (x5)

A

0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

)2 (GeV/cb' = mt'm

350 400 450 500 550

600CMS Preliminary L = 1.1fb^-1 s = 7TeV

> 0.77 @ 95% C.L. (Tevatron)tbV

expected limit 95% C.L.

observed limit 95% C.L.

σ

± 1

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CMS Grand Summary (as of PIC2011, thanks to S. Rahatlou)

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Summary and outlook

In this talk we presented results with integrated luminosity of ∼1 fb

⁻¹

.

Rich program of searches for physics beyond the SM, setting stringent limits to many benchmark models.

Unfortunately, New Physics was not ”around the corner”.

Experimental challenges as we enter further the Multi-TeV regime TeV leptons

Boosted objects

More complex signatures Both the LHC and CMS are performing very well, the total luminosity recorded in 2011 amounts to more than 5 fb

⁻¹

, analysis of these data ongoing.

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BACK UP

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Excited leptons: Motivation

The Standard Model lepton mass hierarchy can be explained by the existence of lepton substructure

Leptons made up of bound states of 3 fermions or a fermion and a boson that can be excited and then decay to ordinary leptons

Search for the production of an excited lepton (e*/µ*) in association with a SM Model lepton via novel contact interactions (scale determined by Λ).

l

^∗

decays via the EWK interactions resulting in a final state of two high-E

T

leptons and one high-E

T

γ

The decay width for other decay modes taken into account: BR(l*→lγ)=25%

for low M

l^∗

/Λ

Two theory parameters: Λ and M

l^∗

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Excited Leptons: Limit setting

2) (GeV/c γ µmax M

100 200 300 400 500 600 700 800 9001000 2Events / 20 GeV/c

10-3 10-2 10-1 1

10 ^Data_µ_µ_γ

backgrounds γ Fake

backgrounds µ Fake Signals CMS Preliminary 7 TeV 36 pb-1

100 200 300 400 500 600 700 800 9001000 10-3

10-2 10-1 1 10

100 200 300 400 500 600 700 800 9001000 10-3

10-2 10-1 1 10

2) (GeV/c γ e Mmax

100 200 300 400 500 600 700 800 9001000 2Events / 20 GeV/c

10-3 10-2 10-1 1

10 ^Data_ee_γ

backgrounds γ Fake Fake e backgrounds Signals CMS Preliminary 7 TeV 36 pb-1

100 200 300 400 500 600 700 800 9001000 10-3

10-2 10-1 1 10

100 200 300 400 500 600 700 800 9001000 10-3

10-2 10-1 1 10

2) (TeV/c µ* M

0.2 0.4 0.6 0.8 1 1.2

(TeV)Λ

1 1.5 2 2.5 3 3.5 4 4.5 5

2) (TeV/c µ* M

0.2 0.4 0.6 0.8 1 1.2

(TeV)Λ

1 1.5 2 2.5 3 3.5 4 4.5 5

CMS Preliminary 7 TeV 36 pb-1

CMS Excluded 95% CL µ*

µ

→ pp*→µ+γ µ

D0 Excluded 95% CL

2) (TeV/c Me*

0.2 0.4 0.6 0.8 1 1.2

(TeV)Λ

1 1.5 2 2.5 3 3.5 4 4.5 5

2) (TeV/c Me*

0.2 0.4 0.6 0.8 1 1.2

(TeV)Λ

1 1.5 2 2.5 3 3.5 4 4.5 5

CMS Preliminary 7 TeV 36 pb-1

CMS Excluded 95% CL

→ee*

pp→e+γ e*

D0 Excluded 95% CL

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T → tZ ZFCNC processes 1109.4985 (hep-ex)

Flavour-changing neutral current t’ decay, in trilepton channel

N(Jets)

0 2 4 6 8 10

Events

10

-1

1 10 10

2

10

3

data

2) (350GeV/c T T

+W,Z t t W/Z/diboson

t t

= 7 TeV s

-1

CMS 1.14 fb

2

] [GeV/c M

T

250 300 350 400 450 500 550

X) [pb] T T → (pp σ

10-1

1 10

Theory

> 475 GeV/c2

Limit at 95% CL: MT

= 7 TeV s

-1 CMS 1.14 fb

observed limit 1 σ expected limit 2 σ

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Search for monojets EXO-11-041

Large ED (ADD scenario), also split SUSY

Final states with missing transverse energy plus single-jet

) [GeV/c]

(Jet

1

p

T

0 100 200 300 400 500 600 700 800

Events / 25 GeV/c

1 10 10

2

10

3

10

4

10

5

10

6 ADD MD²^δ²

ν ν

→ Z

ν

→l W

t t QCD

l-

l+

→ Z Data

CMS Preliminary

=7 TeV s

-1 at L dt = 1.1 fb

∫

(TeV) M

D

1 1.5 2 2.5 3 3.5 4

(pb) σ

10-1

1 10 102

δ =2 ADD,

95% CL Expected limits 95% CL Observed limits Theor. prediction (LO) Theor. prediction (NLO)

CMS Preliminary

=1.1 fb-1

=7 TeV, Lint

s

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ED with monophoton Final State EXO-11-058

Large ED (ADD scenario), similarity to monojet: search for a photon and nothing else

(TeV) M

D

1 1.2 1.4 1.6 1.8 2

Cross section (fb)

10 10

2

10

3

95% CL Obs. Limit 95% CL Exp. Limit

Exp. Limit σ

±1 Exp. Limit σ

±2

CMS Preliminary s = 7 TeV Ldt = 1.14 fb-1

∫

n=4, Theory NLO n=4, Theory LO n=6, Theory NLO n=6, Theory LO

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Black holes EXO-11-071

Microscopic BH decaying through Hawking radiation

Large uncertainty on models due to our ignorance of quantum gravity

(TeV) M

D

1.5 2 2.5 3 3.5

( T e V )

min BH

Excluded M

4.2 4.4 4.6 4.8 5

BlackMax Non-Rotating Rotating

CMS Preliminary = 7 TeV, 1.09 fb

-1

s

n = 2 n = 4 n = 6