Update on high pT electrons study presented last meeting

1. 10 July 2007 Update on high pT electrons study presented last meeting Julien MOREL CSC note – diphoton dilepton

2. outline • Update on the electron study presented last meeting • Problem with the 1mm bug • Impact on linearity, resolution • Impact on selection efficiency • Preliminary results for the dileptonpairs • Selection efficiency • Resolution for different part of the detector

3. Data set and Athena version • Weused: • Athena version : 12.0.6 • Process : Z’e+e-at 1TeV (Mll > 500 GeV), c model from E6 • Cross section = 376.5 fb • 7250 Z’ • On lastmeeting slides, I show a bad electron linearity. In fact, using dq2, I can find different data-set with different TID. • These data-set give different results for instance for the electron linearity.

4. pT resolution and linearity ( Data set tid009428 ) Data Set : trig1_misal1_csc11.005605.Zprime_ee_pythia_chi1000.merge.AOD.v12000604_tid009428._00005.pool.root.1 trig1_misal1_csc11.005605.Zprime_ee_pythia_chi1000.merge.AOD.v12000604_tid009428._00004.pool.root.5 trig1_misal1_csc11.005605.Zprime_ee_pythia_chi1000.merge.AOD.v12000604_tid009428._00003.pool.root.5 trig1_misal1_csc11.005605.Zprime_ee_pythia_chi1000.merge.AOD.v12000604_tid009428._00001.pool.root.1 Usingthis data, the electronlinearity looks bad(~2.5%). This data set is NOT corrected for the 1mm bug Central Resolution = (1 ± 0.04) % Linearity = (2.3 ± 0.04) % Crack Resolution = (4.2 ± 0.05) % Linearity = (7.5 ± 0.05) % Forward Resolution = (1.3 ± 0.01) % Linearity = (2.8 ± 0.01) %

5. pT resolution and linearity ( Data set tid010014 ) Data Set : trig1_misal1_csc11.005605.Zprime_ee_pythia_chi1000.merge.AOD.v12000604_tid010014._00001.pool.root.2 trig1_misal1_csc11.005605.Zprime_ee_pythia_chi1000.merge.AOD.v12000604_tid010014._00002.pool.root.3 trig1_misal1_csc11.005605.Zprime_ee_pythia_chi1000.merge.AOD.v12000604_tid010014._00004.pool.root.3 trig1_misal1_csc11.005605.Zprime_ee_pythia_chi1000.merge.AOD.v12000604_tid010014._00005.pool.root.2 Central Resolution = (1 ± 0.02) % Linearity = (-0.06 ± 0.02) % Crack Resolution = (4 ± 0.5) % Linearity = (6 ± 0.05) % Forward Resolution = (1.3 ± 0.01) % Linearity = (0.1 ± 0.1) % “Ok, I see that tid=9428 was aborted, because it lacked the correction flag. The tid=10014 should be OK, since correction have been applied.” Rashid Mehdiyev MC coordinator

6. Pierre-antoine sent a list with the problematic data-set 5667  VBF -> WW ->jj ll5115 Drell-Yan (mumu)5114 Drell-Yan (ee)5116 Drell-Yan (tautau)5665  VBF -> WW ->jj ll5631 LQ ee-jets5605 Z'(E6)->ee 1TeV5607 Z'(SM-like)->tautau 600 GeV5166 Z(->ll)+4j (QED diagrams)5201 ttbar5372 H++->ee/mumu5374 H++->tautau 5623 Graviton (G*)->diphotons M=500 GeV5370 H++->ee/mumu5661 Excited quarks5620 Graviton (G*)->ee M=500 GeV5375 H++->tautau5371 H++->ee/mumu5373 H++->tautau6682 M(LQ) = 1200 GeV LQ -> mu c  channel 5622 Graviton (G*)->tautau M=500 GeV5950 WZ fusion -> W(jj)Z(ll) if you urgently need to use one of this temporary dataset USE THE LATEST (with highest XXXX number) Otherwise wait for the non _tid dataset which will be filled with the correct data.

7. Impact on energy distribution for electron coming from Z’ at 1 TeV 1 TeV Z’ induce a pic at 500 GeV tid010014 - 1mm Bug corrected tid009428 - 1mm Bug not corrected Pic at 500 GeV Pic below 500 GeV E (GeV)

8. Impact on pTdistribution for electron coming from Z’ at 1 TeV Cut at 500 GeV in the dilepton invariant mass tid010014 - 1mm Bug corrected Pic below 500 GeV Pic at 500 GeV tid009428 - 1mm Bug not corrected pT (GeV) Other distributions are not really affected and are the same as last meeting

9. Electron selection efficiency as a function of j, h, and pTare not very affected Versus pT : Average efficiency value around 60% Identification based on TRT and E/P are the main sources of loss and increase with pT Versus j : Flat efficiency in Phi Versus h : Crack around 1.4 – 1.5

10. Selection efficiency as a function of h, and pTfor loose and medium electron Selection efficiency around 0.8 for medium electrons In the Z’ reconstruction we will use medium electrons

11. Dilepton invariant mass spectrum 1 TeV Z’ Generation level Reconstruction level Mll (GeV)

12. Z’ Selection effeciency Average efficiency around 50% We use medium electrons With opposite charge We have to refine the selection efficiency : add isolation and back to back criteria Selection efficiency Dilepton invariant mass (GeV)

13. Z‘ mass resolution and linearity Good reconstruction Resolution = (0.7 ± 0.02) % Linearity = (0.06 ± 0.02) % Long tail on the right due to the crack contribution

14. Resolution and linearity for different parts of the detector Resolution = (0.82 ± 0.02) % Linearity = (0.07 ± 0.02) % Resolution = (0.84 ± 0.03) % Linearity = (0.15 ± 0.04) % Poor reconstruction if one of the electron goes in the crack but it concern few events

15. Twiki page • I don’t show all the electron plots, but you can find them on the Twiki page : • https://twiki.cern.ch/twiki/bin/view/Atlas/DilepDiphotListOfPlots • Z’ plots have to be completed and consolidated. We will put them soon on the wiki page • If you are using root via a compiled c++ code, you may be interested in utils.cc, utils.h (link on the Twiki page) to use the “ATLAS style macro”. • This is a compilable version of the rootlogon.c and utils.h. • In your C++ code, you just have to put : • Include “utils.h” • ATLAS_STYLE::SetStyle(); //…replaces the rootlogon.C • gROOT->SetStyle("ATLAS"); • gROOT->ForceStyle();

16. outlook • To do • Use the full available Z’ statistic. • 7250 Z’c + Z’ SSM ? • Look at the linearity and resolution dependence on pT, h, j. Need a lot of statistic (add the high mass DY sample). • More dileptonresults coming soon • (efficiency versus dileptonmass for uubarand ddbar separately) …