田中 礼三郎
岡山大学大学院自然科学研究科「LHCが切り拓く新しい素粒子物理学」
ICEPP 2008年3月28日­29日

Contents
1.
2.
3.
4.
5.
6.
•

Electroweak Symmetry Breaking
Object identiﬁcation (e/γ,μ,τ)Standard Model predictions
Ź and RS-graviton discovery potential
Ẃ, Di-photons, Di-jets
Summary
References––––ATLAS CSC Notes (to be submitted soon)
CMS Physics TDR Vol.I, II CERN-LHCC-2006-001, CERN-LHCC-2006-021
CDF PRL99(2007)171802, PRL99(2007)171801, PRL96(2006)211802,PRL95(2005)252001, PRL95(2005)131801, PRL92(2004)121802.
D0 PRL100(2008)091802, PRL95(2005)091801

2008.3.28

2

1. Electroweak Symmetry Breaking (EWSB)
Extended Gauge Symmetry
Little Higgs, Higgsless, Left-Right Symmetric Model
Higgs-Gauge Unification
J.Lykken, Physics at LHC (Vienna)

SUSY(m)SUGRA
GMSB
AMSB
MirageSplit SUSY
RPV…

Extra-Dimension
LED(ADD)
Randall-Sundrum
Universal ED(KK)…

Dynamical Symmetry Breaking
Strong EWSB, Chiral Lagrangian, Technicolor,
Composite Higgs, Top-quark Condensation
Exotics: Compositeness, Lepto-quarks, Monopole …

Precision
EW data3ADD
Ex. Direct Graviton production at LHC

ADDL. Vacavant, I. Hinchliffe, J.Phys.G27(2001)1839- Large ﬂat compactiﬁed extra dimensions⇒ conjecture:- SM particles localized in 4D brane- gravity propagates in the bulk ofcf. SUSY → Multi-jets

higher dimension
100fb-1

Uncertainty in σ(Z+jets)
will lower the reach4

Randall-Sundrum
Golden channel: G(1)  e+e-LLEEATLAS, e+e-, L=100 fb-1
mG= 1.5 TeV, c = 0.01
Signal:• from gluon fusion
1 – cos4θ*• from quark annihilation1 – 3cos2θ* + 4cos4θ*AdS(5D)KK graviton excitations G(k)• scale Λπ• coupling & width determined by:c = k/MPl• 0.01 < k/MPl < 0.1• mass spectrum:mn = k xn exp(-kπrc)

Spin-1 (Z ‘):
1 + cos2θ*Drell-Yan SM

B.C. Allanach, et al., JHEP09(2000)019, ibid.12(2002)039
5

KK graviton of RS

J.L. Hewett, M. Spiropulu, Ann.Rev.Nucl.Part.Sci.52 (2002) 397-424.
2008.3.28

6

Kaluza-Klein, Randall-Sundrum
KaluzaとKleinの論文の和訳
Th. Kaluza 「物理学の統一問題について」
素粒子論研究 Vol.67, No.5 (1983) 270-276, 清水, 牟田, 山岡
 O. Klein「量子論と五次元相対論」
素粒子論研究 Vol.68, No.3 (1983) 125-135, 清水, 牟田

T.D.Lee and L.Randall in ATLAS Pit

Th. Kaluza

O. Klein

ATLAS eNews, Sep.2007
2008.3.28

7

Duality
Not a easy question when excess is observed.
Q) Is it a Randall-Sundrum graviton mode or a Z´ ?
Q) Is it extra dimensions (ex. UED) or SUSY ?
Example: Drell-Yan di-leptons pp→γ/Z0→l+lNew physics possibilities,• New gauge bosons: ZʼCMS– SSM, E6, SO(10), Left-Right,…

••••Little Higgs: AH, ZH
Large Extra-Dimension(ADD): G(KK)
Randall-Sundrum: G(K)…
8Supersymmetry vs Extra-Dimension
Universal Extra-Dimension scenario

Typical mSUGRA scenario

Use spin !
LHC - Higgs, squark/gluinosquarkneutralino
Higgs chargino
slepton

B.C.Allanach et al., Eur.Phys.J.C25(2002)113

H-C.Cheng et al.,Phys.Rev.D66(2002)036005, ibid. 056006
9

Search Topologies
Dilepton,dijet,
diphotonresonancesZ´, RS ED, ZKK
in TeV‐1 ,Li=le Higgs

Dilepton, dijet
con@nuum
modiﬁca@on
ADD graviton
exchange,contact
interac@ons

Single lepton+ missing ET
W´, Li=leHiggs, WKK
in TeV‐1

Mul@lepton+ mul@jet
Technicolor,
Li=lestHiggs,
Lepto‐quark

2008.3.28

Dilepton+dijetHeavy
neutrinofrom right‐
handed W,
Lepto‐quark

Same‐sign
dileptons
Technicolor,charged Higgs,
SUSY

Single photon+ missing ET
ADD direct
gravitonemission,
GMSB
gravi@noHigh
mul@plicity,sphericial
Microscopic
Black Hole10

2. Object identiﬁcation (e/γ,μ,τ)• Electron ID performance for 1TeV Ź→e+e– pT > 50GeV/c, |η|<2.5– Eﬃciency ~ 80% for “loose cut” (minimal criteria).
– Energy resolution ΔE/E~1% (crack region~5%).
– Charge mis-assign 1-5% for pT = 100GeV/c ‒ 1TeV/c.
ATLAS

2008.3.28

ATLAS

11

Eﬃciency ~ 95%“Tag and Prove” method
use Z→μ+μtag =one combined muonprobe= inner detector track

Efficiency• Muon Identiﬁcation
1TeV Ź→μ+μ-ATLAS

2008.3.28

12

Muon Momentum Resolution and pT distribution
Calibration & alignment are critical at high pT
Oliver Kortner (MPI), HCP2006 (Duke, May 22-26, 2006)

Muon spectrometer TDR (CERN/LHCC 97-22)

Muon chamber: overall sagitta measurement precision ~ 45µm
pT=1TeV/c ; sagitta=500µm → ΔpT/pT ~ 45µm * pT [TeV/c] / 500µm ~ 10%2006.5.31

TeV Energy Muons in Z'‐>mu+mu‐13

1TeV µ+ Geant4

D. Naito (Okayama)

Cu: r =8.96g/cm3

PDG
D. E. Groom et al., Atomic Data and Nuclear Data Table 78,183-356(2001)

Landau fit

14

G*/Ź→e+e- vs G*/Ź→μ+μCMS

CMS

PartonlevelDetectorlevelZ´

G*Z´G. Azuelos, G. Polesello, Eur.Phys.J.C39S2 (2005) 1-11.

Electron is the discovery channel, though µ+µ- and τ+τ- are also important.
2008.3.28

15

3. Standard Model predictions
Background in di-lepton search– Drell-Yan ‒ irreducible– Jet, photon etc. ‒ reducible• Inclusive jets
• W/Z+jets, W/Z+photon• …

– Rejection factor
CDF• R(e-jet)=104• R(e-γ)=10ATLAS
e+e-2008.3.28

16

Drell-Yan backgroundParametrized fitting
ATLAS

ATLAS
exp(−2.2M 0.3 )€CMS

ps : pdf of signal = convoluiton of Breit - Wigner with Gaussianpb : pdf of Drell - Yan background
fs = N s /( N s + N b )2008.3.28€18

Systematic uncertainties• Theoretical calculations– Higher-order QCD corrections ΔKQCD= 0.05
NNLO
• CMS KQCD
= 1.35 for Drell-Yan and Ź, but K(Mll,η,pT,…)– Higher-order electroweak corrections (NLO) ΔKEW= 0.10
– Parton distribution functions (PDF)– Hardprocess scale: renormalization(μR) and€factorization(μF) scale, s/2 < μ < 2 s• Imperfect knowledge of the detector– Alignment, calibration, magnetic ﬁeld etc.

• Uncertainties in the ﬁtting procedure– Background shape (← low mass control region in real data)– Functional form of PDFʼs– Mass resolution
2008.3.28

19

Drell-Yan background study
CMSCMSCMS
Theoretical uncertainty > Experimental

2008.3.28

20

CDF
Z´→e+e-

4. Ź discovery
potential
CMS
５σ significance

ATLAS
Z´→e+e-2008.3.28

Z´→µ+µMisalignment included21

RS graviton
CDF

ATLAS

CMS

2008.3.28

22

Discriminating Z´ and RS-graviton

CMS

B.C. Allanach, et al., JHEP09(2000)019, ibid.12(2002)039
2008.3.28

23

5. W´, Di-photons, Di-jets
W´CMSW´

2008.3.28

24

2008.3.28

25

Di-jetCDF
D0parametrization
NLO QCD smeared with jet resolution

CMSCMS
2 TeV Z´

2008.3.28

26

6. Summary• LHC will probe the origin of the EWSB.
• Challenge– Theoretical uncertainties dominate over experimental ones.
• QCD scale factor, PDF, EW rad. Corr.

– Experimental challenge• Detector calibration, alignment, fake rate,…
• Background shape with control sample.

• Discovery potential– RS Graviton with coupling c=k/MPl• MG*=1.5TeV for c=0.01, 3.5TeV for c=0.1(L=10fb-1)– Ź• MŹ=1TeV(L=0.1fb-1), 3TeV(L=10fb-1), 5TeV(L=0.1-1ab-1)– Spin study helps to disentangle diﬀerent models.

• Not covered, but spin-0 sector (radion) also studied.
2008.3.28

27

backup2008.3.28

28

Drell-Yan NLO EW radiative correction

2008.3.28

29