sergei shmatov, search for extra dimensions.., npd ras, moscow, november 23-27, 20091 search for...

Sergei Shmatov, Search for Extra Dimensions.., NPD RAS, Moscow, November 23-27, 2009 1

Search for Extra Dimensions with CMS Search for Extra Dimensions with CMS Detector at the LHCDetector at the LHC

Sergei ShmatovJoint Institute for Nuclear Research,

Dubna

for CMS Collaborations

Theoretical Motivations Models Considered Signals and Uncertainties Discovery limits for ED (LED, TeV-1 ED, RS, UED)

Model Discrimination Conclusions

Theoretical Motivations Models Considered Signals and Uncertainties Discovery limits for ED (LED, TeV-1 ED, RS, UED)

Model Discrimination Conclusions


Theoretical MotivationsTheoretical Motivations Hierarchy Problem: Gravity/EW ~ 1019/102 GeV? Why gravitational

Interaction is so weak?

Yukawa hierachy (explanation of mass patterns for quarks and leptons)

Unification of interactions Number of Generations (why 3?)

Ways to solve the “naturalness” problem:

Supersymmetry assumes symmetry between fermionic and bosonic fields EW and strong interactions are unified at 1016 GeV must be broken at low energy (? TeV) will be probably found at LHC

Hierarchy is fixed (theory is stabilized), but is not solved (two energy scales still

remain) … Can not yet describe Gravity, evolution of Universe …

Technicolor: confinement problem of strong coupled resonance masses

Compositeness: arbitrariness with a new energy scale Extra Dimensions

Hierarchy Problem: Gravity/EW ~ 1019/102 GeV? Why gravitational Interaction is so weak?

Yukawa hierachy (explanation of mass patterns for quarks and leptons)

Unification of interactions Number of Generations (why 3?)

Ways to solve the “naturalness” problem:

Supersymmetry assumes symmetry between fermionic and bosonic fields EW and strong interactions are unified at 1016 GeV must be broken at low energy (? TeV) will be probably found at LHC

Hierarchy is fixed (theory is stabilized), but is not solved (two energy scales still

remain) … Can not yet describe Gravity, evolution of Universe …

Technicolor: confinement problem of strong coupled resonance masses

Compositeness: arbitrariness with a new energy scale Extra Dimensions


Model ConsideredModel Considered Large flat Extra-Dimensions (ADD model)

Extra dimensions are flat and could be as large as a few m SM particles restricted to 3D brane only accessible to gravity

Randall-Sundrum (RS1 – two branes) Small extra spatial dimensions

Curved bulk space (AdS5 - slice)

Well separated graviton mass spectrum

TeV-1 Extra dimension Model Bosons could also propagate in the bulk Fermions are localized at the same (opposite) orbifold point: destructive

(constructive) interference between SM gauge bosons and KK excitations

Universal Extra Dimensions All SM particles propagate in Extra Dimensions often embedded in large Extra Dimensions

Large flat Extra-Dimensions (ADD model) Extra dimensions are flat and could be as large as a few m SM particles restricted to 3D brane only accessible to gravity

Randall-Sundrum (RS1 – two branes) Small extra spatial dimensions

Curved bulk space (AdS5 - slice)

Well separated graviton mass spectrum

TeV-1 Extra dimension Model Bosons could also propagate in the bulk Fermions are localized at the same (opposite) orbifold point: destructive

(constructive) interference between SM gauge bosons and KK excitations

Universal Extra Dimensions All SM particles propagate in Extra Dimensions often embedded in large Extra Dimensions


Di-lepton, di-jets and di-photon resonance states (new particles)

in RS1-model (RS1-graviton) and TeV-1 extra dimension model (ZKK)

Di-leptons, di-jets continuum modifications (virtual graviton production in ADD)

Single Jets/Single Photons + Missing ET (direct graviton production in ADD)

Single Leptons + missing ET in WKK decays in TeV-1 extra dimension model (WKK)

Back-to-back energetic jets + Missing ET (UED)

4 jets + 4 leptons + Missing ET (mUED)

Di-lepton, di-jets and di-photon resonance states (new particles)

in RS1-model (RS1-graviton) and TeV-1 extra dimension model (ZKK)

Di-leptons, di-jets continuum modifications (virtual graviton production in ADD)

Single Jets/Single Photons + Missing ET (direct graviton production in ADD)

Single Leptons + missing ET in WKK decays in TeV-1 extra dimension model (WKK)

Back-to-back energetic jets + Missing ET (UED)

4 jets + 4 leptons + Missing ET (mUED)

Experimental SignalsExperimental Signals


Total weight 12 500 tOverall diameter 15.00 mOverall length 21.6 mMagnetic field 4 Tesla

Total weight 12 500 tOverall diameter 15.00 mOverall length 21.6 mMagnetic field 4 Tesla

Large general-purpose particle physics detector

Compact Muon SolenoidCompact Muon Solenoid

Detector subsystems are designed to measure:the energy and momentum of photons, electrons, muons, jets, missing ET up to a few TeV


Experimental UncertaintiesExperimental Uncertainties

Energy MisCalibration performance of e//hadron energy reconstruction.

Misalignment effect increase of the mass residuals by around 30%

Drift time and drift velocities

Magnetic and gravitational field effects can cause a scale shift in a mass resolution by 5-10%

Pile-up mass residuals increase by around 0.1–0.2 %

Background uncertainties (variations of the bg. shape) a drop of about 10-15% in the significance values

Trigger and reconstruction acceptance uncertainties

Energy MisCalibration performance of e//hadron energy reconstruction.

Misalignment effect increase of the mass residuals by around 30%

Drift time and drift velocities

Magnetic and gravitational field effects can cause a scale shift in a mass resolution by 5-10%

Pile-up mass residuals increase by around 0.1–0.2 %

Background uncertainties (variations of the bg. shape) a drop of about 10-15% in the significance values

Trigger and reconstruction acceptance uncertainties


Theoretical UncertaintiesTheoretical Uncertainties

QCD and EW high-order corrections (K factors)

Parton Distribution Functions (PDF)

Hard process scale (Q2)

Cut efficiency, significance estimators..

QCD and EW high-order corrections (K factors)

Parton Distribution Functions (PDF)

Hard process scale (Q2)

Cut efficiency, significance estimators..


ADD ModelADD ModelN.Arkani-Hamed, S.Dimopoulos, G.Dvali (ADD scenario),Phys.Lett. B429(1998), Nuc.Phys.B544(1999)

The real World is multi-dimensional: n flat - Euclidian - extra spatial dimensions, the maximal

total number of dimensions is 3(our) + 6(extra)=9

The fundamental scale is not planckian: MD ~ TeV

We (all of SM forces) live on 3D brane (there is another “parallel” hidden World)

Only gravitons are multi-dimensional

N.Arkani-Hamed, S.Dimopoulos, G.Dvali (ADD scenario),Phys.Lett. B429(1998), Nuc.Phys.B544(1999)

The real World is multi-dimensional: n flat - Euclidian - extra spatial dimensions, the maximal

total number of dimensions is 3(our) + 6(extra)=9


We (all of SM forces) live on 3D brane (there is another “parallel” hidden World)

Only gravitons are multi-dimensional

A “Parallel” World

Our World

Excess above di-lepton continuum!

Graviton contributions to SM processes Real graviton production

Jets + missing ET, γ + missing ET

llqq llgg

9

ADD: model restrictions from measurements of the gravitational potential n = 1 excluded by solar system (verification of the Newton’s law up to R < 0.19

mm) from supernova SN1987 (graviton emission speeds up the supernova

cooling): MD > 30 TeV (n = 2) , 4 TeV (n = 3)

from energy spectrum of the diffuse gamma-ray background (CDG) due to GKK γγ: MD > 110 TeV (n = 2) , 5 TeV (n = 3)

from measurements of the gravitational potential n = 1 excluded by solar system (verification of the Newton’s law up to R < 0.19

mm) from supernova SN1987 (graviton emission speeds up the supernova

cooling): MD > 30 TeV (n = 2) , 4 TeV (n = 3)

from energy spectrum of the diffuse gamma-ray background (CDG) due to GKK γγ: MD > 110 TeV (n = 2) , 5 TeV (n = 3)

http://www-cdf.fnal.gov/physics/exotic/r2a/20071213.gammamet/LonelyPhotons/photonmet.html http://www-cdf.fnal.gov/physics/exotic/r2a/20071213.gammamet/LonelyPhotons/photonmet.html

PRL 101:181602 (2008) PRL 101:181602 (2008) PRL 97:171802 (2006) PRL 97:171802 (2006)

http://www-cdf.fnal.gov/physics/exotic/r2a/20071213.gammamet/LonelyPhotons/photonmet.html

http://www-cdf.fnal.gov/physics/exotic/r2a/20071213.gammamet/LonelyPhotons/photonmet.html


ADD Discovery limitADD Discovery limitReal graviton production (momojets): jets + missins ET

CMS PAS EXO-09-013CMS PAS EXO-09-013

CMS-PAS-EXO-08-001CMS-PAS-EXO-08-001

14 TeV@100pb-1

Discovery reach:MD = 3.58 (2.62) TeV for = 2 (4)

Discovery reach:MD = 3.1 (2.3) TeV for = 2 (4)

10 TeV@200pb-1

Real graviton production (photons + missins ET)

MMDD= = 1 1 TeV for 0.1-0.2 fbTeV for 0.1-0.2 fb--

11

1.5-2 1.5-2 TeV for 1 fbTeV for 1 fb-1-1

2- 2.5 2- 2.5 TeV for 10 fbTeV for 10 fb--

11

3- 3.5 3- 3.5 TeV for 60 fbTeV for 60 fb--

11

CMS NOTE 2006/092CMS NOTE 2006/092


Virtual graviton production (dimuons)

ADD Discovery limit @ 14 TeVADD Discovery limit @ 14 TeV

1 fb-1: 3.9-5.5 ТеV for n=6..310 fb-1: 4.8-7.2 ТеV for n=6..3100 fb-1: 5.7-8.3 ТеV for n=6..3300 fb-1: 5.9-8.8 ТеV for n=6..3

CMS PTDR 2006CMS PTDR 2006

Confidence limits for

two muons in the final state

PYTHIA + CTEQ6L, LO + K=1.30

Full (GEANT-4) simulation/reco + L1 + HLT(riger)

Theoretical uncert.

Misalignment, trigger and off-line reco inefficiency, acceptance due to PDF


Virtual graviton production (diphotons)

ADD Discovery limit @ 10 TeVADD Discovery limit @ 10 TeV



RS1 ModelRS1 ModelL.Randall, R.Sundrum (RS1 scenario), PRL83 3370 (1999)

L.Randall, R.Sundrum (RS1 scenario), PRL83 3370 (1999)

5D curve space with AdS5 slice: two 3(brane)+1(extra)+time!

Signals:

Narrow, high-mass resonance states in di-lepton, di-jet, di-photon events:

Signals:

Narrow, high-mass resonance states in di-lepton, di-jet, di-photon events:

jetjet,,,eeGgg,qq KK CDF: PRL 102, 091805 (2009)CDF: PRL 102, 091805 (2009)


RS1 Discovery Limit @ 14 TeVRS1 Discovery Limit @ 14 TeV

two muons/electrons in the final state

Bckg: Drell-Yan/ZZ/WW/ZW/ttbar

PYTHIA/CTEQ6L

LO + K=1.30 both for signal and DY

Full (GEANT-4) and fast simulation/reco

Viable L1 + HLT(riger) cuts

Theoretical uncert.

Misalignment, trigger and off-line reco inefficiency, pile-up

Di-lepton statesCMS PTDR 2006CMS PTDR 2006


GG11μμ++μμ--

GG11ee++ee--

c=0.1100 fb-1

c=0.01100 fb-1


Bckg: QCD hadronic jets

L1 + HLT(riger) cuts

RS1 Discovery Limit @ 14 TeVRS1 Discovery Limit @ 14 TeV

two photons in the final state

Bckg: prompt di-photons, QCD hadronic jets and gamma+jet events, Drell-Yan e+e-

PYTHIA/CTEQ5L

LO for signal, LO + K-factors for bckg.

Fast simulation/reco + a few points with full GEANT-4 MC

Viable L1 + HLT(riger) cuts

Theoretical uncert.

Preselection inefficiency

Di-photon states CMS PTDR 2006CMS PTDR 2006

GG11

Di-jet states

55 Discovered Mass: 0.7-0.8 TeV/c Discovered Mass: 0.7-0.8 TeV/c22


c=0.1


RS1 Discovery Limit @ 10 TeVRS1 Discovery Limit @ 10 TeVDi-photon states

Dielectron states




TeVTeV-1-1 Extra Dimension Model Extra Dimension ModelI. Antoniadis, PLB246 377 (1990)

Multi-dimensional space with orbifolding (5D in the simplest case, n=1)


Gauge bosons can travel in the bulk

Fermion-gauge boson couplings can be exponentially suppressed for higher KK-modes

Fundamental fermions can be localized at the same (M1) or opposite (M2) points of orbifold destructive or constructive interference with SM model

I. Antoniadis, PLB246 377 (1990)



Gauge bosons can travel in the bulk

Fermion-gauge boson couplings can be exponentially suppressed for higher KK-modes

Fundamental fermions can be localized at the same (M1) or opposite (M2) points of orbifold destructive or constructive interference with SM model

me+e- (GeV)

ppZ1/1e+e-


5 discovery limit of

(M1 model)

CMS PTDR 2006

Di-electron states (ZKK decays)

TeVTeV-1-1 ED Discovery Limits @ 14 TeV ED Discovery Limits @ 14 TeV

two electrons in the final state

Bckg: Drell-Yan/ZZ/WW/ ZW/ttabr

PYTHIA/PHOTOS with CTEQ61M

LO + K=1.30 for signals, LO + K-factors for bckg.

Full (GEANT-4) simulation/reco

L1 + HLT(riger) cuts

Theoretical uncert.

Low luminosities pile-up



The model parameters: compactificaton radius R, cut-off scale , mh

All particles can travel into the bulk

KK parity conservation -> the lightest massive KK particle (LKP) is stable (dark matter candidate).

mass degeneration except if radiative corrections included


The model parameters: compactificaton radius R, cut-off scale , mh

All particles can travel into the bulk

KK parity conservation -> the lightest massive KK particle (LKP) is stable (dark matter candidate).

mass degeneration except if radiative corrections included

600

570

g1

Q1

Z1

L1

1

SM brane is endowed with a finite thickness in the ED

Gravity-matter interactions break KK number conservation:

● 1st level KK states decay to G+SM.

● If radiative corrections -> mass degeneracy is broken and and leptons are produced.

SM brane is endowed with a finite thickness in the ED

Gravity-matter interactions break KK number conservation:

● 1st level KK states decay to G+SM.

● If radiative corrections -> mass degeneracy is broken and and leptons are produced.

Universal Extra DimensionsUniversal Extra DimensionsStandard UED

Thick brane


UEDUED Discovery Limit @ 14 TeVDiscovery Limit @ 14 TeVStandard UED

4 leptons in the final state + missing pT

Bckg: ttbar + n jets (n = 0,1,2), 4 b-quarks, ZZ, Zbbar

CompHEP for signal and PYTHIA for bckgr. with CTEQ5L

Full simulation/reco + L1 + HLT(riger) cuts

Theoretical and exp. uncert.

11

l

Geo accepL1,HLT2 OSSF4 ISOb-tag vetopT

l<ET

miss

Z veto

QQ 11q

p pgg 11QQ 11 q

ZZ11q LL11

l

gg11

LL11

l

11

l

ZZ11

q

T

T

T

PjetslLKPqlQQpp

PjetslLKPqlQgpp

PjetslLKPqlggpp

24224

34234

44244

11

11

11

CMS-CR-2006/062CMS AN 2006/008


Spin-1 States: Z from extended gauge models, ZKK

Spin-2 States: RS1-graviton Method: unbinned likelihood ratio statistics incorporating the angles in of the decay products the Collins-Soper farme (R.Cousins et al. JHEP11 (2005) 046). The statististical technique has been applied to fully simu/reco events.

Spin-1/Spin-2 DiscriminationSpin-1/Spin-2 Discrimination

Angular distributions


Z’ vs RS1-graviton

Z-model(mZ=1,5 TeV,168 fb-1)

RS1 graviton(mZ=1,5 TeV,c=0.1, 134 fb-1)


ConclusionsConclusions

CMS analyses cover a large part of different hypotheses proposed tosolve a number of problems of Standard Model

The discovery potential of both experiments makes it possible to investigate if extradimensions really exist within various ED scenarios at a few TeV scale:

Large Extra-Dimensions (ADD model) Randall-Sundrum (RS1) TeV-1 Extra dimension Model Universal Extra Dimensions

The performance of detector systems allows to perform searches in the differentchannels

A proper energy, momentum angular reconstruction for high-energy leptons and jets, Et measurement b-tagging An identification of prompt photons

New results are expected at the start-up LHC @ 10 TeV(integrated luminosity ~ 0.1-0.2 fb-1)

Many analyses are out of this talk: Black Holes, Bulk Scalars, Singlet Neutrino etc.

CMS analyses cover a large part of different hypotheses proposed tosolve a number of problems of Standard Model

The discovery potential of both experiments makes it possible to investigate if extradimensions really exist within various ED scenarios at a few TeV scale:

Large Extra-Dimensions (ADD model) Randall-Sundrum (RS1) TeV-1 Extra dimension Model Universal Extra Dimensions

The performance of detector systems allows to perform searches in the differentchannels

A proper energy, momentum angular reconstruction for high-energy leptons and jets, Et measurement b-tagging An identification of prompt photons

New results are expected at the start-up LHC @ 10 TeV(integrated luminosity ~ 0.1-0.2 fb-1)

Many analyses are out of this talk: Black Holes, Bulk Scalars, Singlet Neutrino etc.


Backup slides


LHC Expectations @ 14 TeVLHC Expectations @ 14 TeV

Model Mass reach Integrated Luminosity (fb-1)

Systematic uncertainties

ADD Direct GKK MD~ 1.5-1.0 TeV, n = 3-6 1 Theor.

ADD Virtual GKK MD~ 4.3 - 3 TeV, n = 3-6

MD~ 5 - 4 TeV, n = 3-6

0.1

1

Theor.+Exp.

RS1di-electrons

di-photons

di-muons

di-jets

MG1~1.35- 3.3 TeV, c=0.01-0.1

MG1~1.31- 3.47 TeV, c=0.01-0.1

MG1~0.8- 2.3 TeV, c=0.01-0.1

MG1~0.7- 0.8 TeV, c=0.1

10

10

1

0.1

Theor.+Exp.

(only stat. for di-jets)

TeV-1 (ZKK(1)) Mz1 < 5 TeV 1 Theor.

UED

4 leptons

R-1 ~ 600 GeV 1.0 Theor.+Exp.

Thick brane R-1 = 1.3 TeV 6 pb-1

sergei shmatov, search for extra dimensions.., npd ras, moscow, november 23-27, 20091 search for...

Documents

model extra dimensions

extra dimension model

extra dimension model

npd ras

rs1model rs1graviton

large flat extradimensions

single leptons missing

et ued