DileptonDiphoton CSC activities Samir Ferrag University of Glasgow

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

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, fact, ren Corrections: K Factors, EW corrections… . Backgrounds: WW, 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: https: //twiki. cern. ch/twiki/bin/view/Atlas/Dilep. Diphoton. Res. CSCNote…completely outdated

Status of the CSC note • CSC note written – 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

Contents of the CSC note

Post CSC… • Electrons: – – • Photons: – – • Efficiency measurement from data • Electron Photo contamination Linearity: Muons: – – – • Contamination: • Jet electron, photon electron Lack of efficiencies at high energy • Reported in the note and meeting • Need to develop the e. ID at high pt Linearity: Efficiency measurement from data Contamination Linearity Trigger: – Menu and rates for L=1033, • What should we use to tag dileptons ? – 2 e 15 i, combined e 60+ simply high deposit ? … – What are the trigger rates on s, b – Improve the trigger menu (or slice): • Is it e 60 or something else (High Pt deposit). . – Efficiency measurement from data • Uncertainties: first attempt but need more • Backgrounds: investigations & agreement with others: – Higher order corrections (EW, QCD, N**LL) – Linearity – Alignment – Efficiencies – Luminosity – – • Top, WW, W+jet, tautau, gamma conversion Fake rate: 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: • Z’, G*, heavy scalars, LQ, LG, technicolor Photon-photon: • G*, heavy scalars, Excited quarks. Disentangling the underlying models

Note Contents: Performances and Trigger (briefly!)

Electrons reconstruction J. Morel, F. Ledroit

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

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

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

• High Pt from Z’ decay • Efficiencies after removing the overlaping electrons and muons • Hadronic taus T. Vickey, Z. Czyczula

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

Trigger: muons • L 1 trigger: – Barrel: incomplete trigger coverage regarding high precision chambers ( ) – Structure and Feet ( ) K. Black

Trigger: T. Vickey, Z. Czyczula

Note Contents: Uncertainties on the Standard Model

Limits of the Standard Model • PDF uncertainties: – CTEQ 6 40+1 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

Uncertainties: summary

Note Contents: Search of New Physics

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

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

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

Z’ II • Had-had channel: – Promising channel – Sensitivity @ 1 fb-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

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

Technicolor in • Probed Exotics: Technicolor Snow Mass Models – T, T, T • Statistics: – Event Counting – Non parameterized CLs – Bayesian methods (D 0) J. Butler, J. Love

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