1. Prospects for TeV Scale New Physics at LHC
Reisaburo Tanaka
(Okayama University)
On behalf of ATLAS-Japan
KEK Theory Meeting 2006
March 2-4, 2006

2. Prospects for TeV Scale New Physics at LHC
4. Supersymmetry
Large cross section via strong interaction
Easy discovery M~1TeV within 1 month ?
SUSY Scale
２０％ accuracy（L=10fb-1, mSUGRA）
Missing ET is important （calibrate with Z→ll+jets)
Signal
Missing ET + high pt jets + Leptons
(Model indep. Analysis, R-parity conserv.)
J.G. Branson et al., Eur.Phys.J.direct C4(2002)N1
Prospects for TeV Scale New Physics at LHC

3. Prospects for TeV Scale New Physics at LHC
Gluino/squark are produced copiously,
“Cascade decay” follows after.
SUSY event topology
(Gravity- mediation + R-parity) 　
High
Stop,sbottom --->
High PT leptons
+ multi-jets b-jets
τ-jets
ETmiss should be controlled in multi-jets topology (N>=4).
High Pt multi-jets are important to estimate SM background contributions and SUSY reconstruction.
Prospects for TeV Scale New Physics at LHC

4. mSUGRA discovery potential
No EWSB
High Lum. 3 year run (L=300fb-1)
M2.5TeV
Cold Dark Matter
1 week run is enough.
WMAP <Ωmh2<0.129
1 year run (L=10fb-1) M2TeV
1 month run (L=1fb-1)
　　　 〜1.5TeV 5 discovery
LEP & Tevatron region
Prospects for TeV Scale New Physics at LHC

5. Prospects for TeV Scale New Physics at LHC
ME-PS Matching
PS(Pythia)
1. Collinear and soft regions are covered with Parton Shower Pythia(6.2). Pt ordering is applied.
2. ME-PS matching is performed to remove double counts:
No-Shower branching probability is given by pQCD:　 Sudakov factorΔ:
Two major methods exist:
(A) CKKW: Events is reweight with Sudakov factor (product of Δ for all line)
(B) MLM: veto is applied after shower evolution PS
Prospects for TeV Scale New Physics at LHC
F. Krauss et al., Phys.Rev.D70(2004)114009

6. No lepton mode One Lepton mode
S.Asai et al., ATLAS Preliminary
Count /400GeV/10fb-1
Effective Mass(GeV) = mET + ΣPT(4jets)
(1) One lepton mode gives clean discovery.
(2) Top is dominant background.　
(1) Background increases by factor 2-4 than the PS prediction depending on Meff.
(2) Slope becomes more gentle, and similar to the signal <-- important Point
Prospects for TeV Scale New Physics at LHC

7. Prospects for TeV Scale New Physics at LHC
Tile barrel
Tile extended barrel
LAr forward calorimeter (FCAL)
LAr hadronic
end-cap (HEC)
LAr EM end-cap (EMEC)
LAr EM barrel
Lots of materials
Crack ||=
Detector Material
ATLAS preliminary
T.Sasaki (U.Tokyo) et al.
Missing Ex resolution
 (GeV)
Crack +20% worse
All eta
∑Et (GeV)
Prospects for TeV Scale New Physics at LHC

8. Prospects for TeV Scale New Physics at LHC
Mass Reconstruction
　kinematical endpoint
Bottomup Reconstruction
B.C. Allanach et al., JHEP 0009(2000)004
Sharp Edge
Mllmax
Generally under-constrained. Determine mass with help of models.
Can determine model independently if 2-body decay chain continues 3 times.
Large tanβ means more cascade and , b.
Strong model dependence.
Mass uncertainty mostly from LSP’s momentum.
Determination of spin or Br are difficult.　
Prospects for TeV Scale New Physics at LHC

9. Synergy between LHC and ILC
Typical mSUGRA scenario
Universal Extra-Dimension scenario
Use spin !
H-C.Cheng et al.,
Phys.Rev.D66(2002)036005, ibid
B.C.Allanach et al., Eur.Phys.J.C25(2002)113
squark
LHC
Higgs
neutralino
chargino
slepton
ILC
LHC - Higgs, squark/gluino
ILC - Higgs, neutralino/chargino, slepton
Split supersymmetry: R-hadrons in ATLAS
A.C. Kraan et al., hep-ex/
Prospects for TeV Scale New Physics at LHC

10. Testing the underlying theory
Determination of SUSY model parametres
C.G. Lester, M.A. Parker, M.J. White, JHEP 0601(2006)080
SUSY “inverse map” LHC signatures  theoretical models
N. Arkani-Hamed et al., hep-ph/
Cross sections
Meff
Nlepton …
Markov chain sampling technique
Kinematics
Endpoints(mass)
Inclusive
Signature
Exclusive
Signature
Easy for theory
15 dimensional parametrization
1808 LHC observables
Prospects for TeV Scale New Physics at LHC

11. Prospects for TeV Scale New Physics at LHC
7. Summary
Discovery first !
LHC is capable to find new particles (SUSY, ED, Z’ etc. ) up to 2-3 TeV (up to ~10TeV with interference effect).
Model discrimination / parametre determination under study.
Experimental issues: commissioning/calibration
Needs to understand SM bkg from data and tuned MC.
Tools: t, b, W/Z and even Higgs!
We do hope major breakthrough in HEP (SUSY, ED etc.)
Important decision in 2010 about HEP’s future…
Prospects for TeV Scale New Physics at LHC