1. Dilepton/Diphoton CSC activities
Samir Ferrag
University of Glasgow
ATLAS UK physics meeting, Durham, 9-11/01/2008

2. Introduction Big number of the Exotic Models
Exotic CSC notes: Encompassing all final state topologies to maximise the number of Exotic models to be tested simultaneously. 5 notes investigated
We want it to be one of the first ATLAS Publications:
”Dileptons & Diphotons at high mass”
2 sides: Understand the Standard Model before looking for BSM
Standard Model side: “Drell-Yan”
Uncertainties from theory PDF,mfact,mren
Corrections: K Factors, EW corrections…
. Backgrounds: WW, tt, tt, ECal linearity, charge mis-id, W+jet, g-conversion
Draw the uncertainty band of SM prediction and any deviation of this band signs new physics
Exotic side
S-channel resonances: Z’ ZH,ZKK G
Virtual exchange of gravitons
Leptoquarks, Leptogluons, Heavy scalars (Graviscalar, radion, heavy higgs..)
If the first year collected luminosity will not be enough to discover new physics
Limits on the different models will be included
Wiki page: outdated

3. Status of the CSC note CSC note written Post-note activities:
Strategy:
Detector  Standard Model New Physics
Specificities.
High energy performance and trigger investigated regarding the note and there is no reference notes for all of them (electrons, muons, taus and photons)
Special exercise: grouping many new physics: G*, Technicolor and Z’…
Post-note activities:
Refine the CSC note
Still lot of analysis tasks to do (long list)
Many updates has been shown since we froze the draft

4. Contents of the CSC note

5. Post CSC…
Electrons:
Contamination:
Jet electron, photonelectron
Lack of efficiencies at high energy
Reported in the note and meeting
Need to develop the eID at high pt
Linearity:
Efficiency measurement from data
Photons:
Electron  Photo contamination
Muons:
Contamination
Linearity
Trigger:
Menu and rates for L=1033,
What should we use to tag dileptons ?
2e15i, combined e60+ simply high deposit ?…
What are the trigger rates on s,b
Improve the trigger menu (or slice):
Is it e60 or something else (High Pt deposit)..
Uncertainties: first attempt but need more investigations & agreement with others:
Higher order corrections (EW, QCD, N**LL)
Linearity
Alignment
Efficiencies
Luminosity
Backgrounds:
Top, WW, W+jet, tautau, gamma conversion
Fake rate: jet jet, gamma+jet
Exotics:
Statistical methods for resonances: S>>B
ee:
Z’, G*, ADD graviton,heavy scalars, LQ, LG, technicolor
mumu:
Z’, G*, heavy scalars, LQ, LG, technicolor
Tautau:
Photon-photon:
G*, heavy scalars, Excited quarks.
Disentangling the underlying models

6. Note Contents: Performances and Trigger (briefly!)

7. Electrons reconstruction
J. Morel, F. Ledroit

8. Muon reconstruction efficiencies
Performances:
MC based method
data based (TP ) extrapolated at high Pt
Charge MisID
Effect at high Pt:
Radiation effects more important than minimum ionization effects
E. Thompson, J. Love, S. Willocq & J. Butler

9. Alignment in muon reconstruction
6 degrees of freedom x,y,z,
8 configurations are investigated. Each one obtained by performing a random translation on the 6 variables using a gaussian of : 40,100,…,1000
Nominal configuration corresponds to 40 
C. Helsens & CEA

10. Performances: photons
High energy photons from Gravitons in RS model
Contamination from jets < 10-3
H. Hadvand, B. Kahoe, K. Dinda

11.  High Pt  from Z’ decay
Efficiencies after removing the overlaping electrons and muons
Hadronic taus
T. Vickey, Z. Czyczula

12. Trigger: egamma Matthew’s talk M. Tamsett, A. De Santo
X. del Popolo, M. T. Dova
Matthew’s talk

13. Trigger: muons L1 trigger:
K. Black
L1 trigger:
Barrel: incomplete trigger coverage regarding high precision chambers ()
Structure and Feet ()

14. Trigger: 
T. Vickey, Z. Czyczula

15. Note Contents: Uncertainties on the Standard Model

16. Limits of the Standard Model
PDF uncertainties:
CTEQ PDF sets
Generator and Reconstructed level
mll,,*…
QCD NLO…K-Factor
Factorisation and QCD renormalisation scale
To be completed by the work presented this morning
F. Heinmann, S. Ferrag

17. Uncertainties: summary

18. Note Contents: Search of New Physics

19. Z’ee Exotic physics probed:
Higher gauge groups, Extra-Dimensions, Dynamic breaking symmetry (Little Higgs)
fit based approach
Same parameterization for ee and signals
BW(m,1)*Landau(m,2)
Parameterization works for both e and 
CLs method used for sensitivity estimation
Combining e and m channels to be done
L. Flores

20. G* ee Exotic: Extra-dimensions in Randall-Sundrum geometry
N. Zhou
Exotic: Extra-dimensions in
Randall-Sundrum geometry
Non parameterized CLs method
(mclimit code by T. Junk)

21. Z’tt
T. Vickey, Z. Czyczula
Complete analysis including Drell-Yan, Di-jets, tt, Z+jets, W+jets, but only Z’ 600 GeV
In the CSC note:
Only lep-had was investigated
MET Object-Based
Updates:
lep-lep and had-had 1 fb-1
Combined sensitivity
MET RefFinal used
lep-lep:
b-tagging required to lower the tt background
Only visible mass is reconstructed (low stat at 1fb-1)

22. Z’tt II Had-had channel:
Promising channel
1fb-1 using visible mass only
Event counting:
S/sqrt(B)
Low statistics in full simulation for all backgrounds  difficult to estimate systematics
T. Vickey, Z. Czyczula

23. Exotics: G*  Exotic physics: ExtraDimensions in
Randall-Sundrum geometry
Sensitivity using Event counting:
S=2(Sqrt(S+B)-Sqrt(B))
H. Hadvand, B. Kahoe, K. Dinda

24. Technicolor in  Probed Exotics: Technicolor Snow Mass Models
J. Butler, J. Love
Probed Exotics: Technicolor Snow Mass Models
T,T,T
Statistics:
Event Counting
Non parameterized CLs
Bayesian methods (D0)

25. Conclusion Dilepton/Diphoton CSC:
Big number of Exotic models to be tested (or excluded!) simultaneously.
We want it to be one of the first ATLAS Publications:
”Dileptons & Diphotons at high mass”
Draft of the CSC note written:
Detector performances, Standard Model and search of Exotics
All the works inside has been developed for the CSC note
Post-note activities:
Still lot of analysis tasks to do (long list)
Many updates has been shown the last meeting
UK contribution