Update on high pT electrons study presented last meeting

LPSC - Grenoble Julien MOREL 1Study of high pT electrons from Z’

introduction Resolution & linearity Kinematics Efficiency Preliminary Z’ results Outlook

Update on high pT electrons study presented last meetingUpdate on high pT electrons study presented last meeting

Julien MOREL

CSC note – diphoton dilepton

10 July 2007



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Update on the electron study presented last meeting 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 dilepton pairsPreliminary results for the dilepton pairs•Selection efficiency•Resolution for different part of the detector



Data set and Athena versionData set and Athena version

We used We used ::

Athena versionAthena version : 12.0.6

ProcessProcess : Z’e+e- at 1TeV (Mll > 500 GeV), model from E6 model from E6

Cross sectionCross section = 376.5 fb

7250 Z’7250 Z’

On lOn last meeting slides, I show a bad electron linearity. In fact, using dq2, I can ast meeting slides, I show a bad electron linearity. In fact, using dq2, I can find different data-set with different TID.find different data-set with different TID.

These data-set give different results for instance for the electron linearity.These data-set give different results for instance for the electron linearity.



pT resolution and linearity ( Data set ( Data set tid009428tid009428 ) )

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) %

1.4 1.4 1.5 1.5 2.5

Data SetData Set : trig1_misal1_csc11.005605.Zprime_ee_pythia_chi1000.merge.AOD.v12000604_tid009428._00005.pool.root.1trig1_misal1_csc11.005605.Zprime_ee_pythia_chi1000.merge.AOD.v12000604_tid009428._00004.pool.root.5trig1_misal1_csc11.005605.Zprime_ee_pythia_chi1000.merge.AOD.v12000604_tid009428._00003.pool.root.5trig1_misal1_csc11.005605.Zprime_ee_pythia_chi1000.merge.AOD.v12000604_tid009428._00001.pool.root.1

UsingUsing thisthis data, the data, the electronelectron linearitylinearity looks looks bad bad (~2.5%)(~2.5%).. This data set is NOT corrected for the 1mm bug This data set is NOT corrected for the 1mm bug



pT resolution and linearity ( Data set ( Data set tid010014tid010014 ) )

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) %

1.4 1.4 1.5 1.5 2.5

Data Set :Data Set :trig1_misal1_csc11.005605.Zprime_ee_pythia_chi1000.merge.AOD.v12000604_tid010014._00001.pool.root.2trig1_misal1_csc11.005605.Zprime_ee_pythia_chi1000.merge.AOD.v12000604_tid010014._00002.pool.root.3trig1_misal1_csc11.005605.Zprime_ee_pythia_chi1000.merge.AOD.v12000604_tid010014._00004.pool.root.3trig1_misal1_csc11.005605.Zprime_ee_pythia_chi1000.merge.AOD.v12000604_tid010014._00005.pool.root.2

“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



Pierre-antoine sent a list with the problematic data-setPierre-antoine sent a list with the problematic data-set

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 channel5622 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.

5667 VBF -> WW ->jj ll5115 Drell-Yan (mumu)5114 Drell-Yan (ee)5116 Drell-Yan (tautau)5665 VBF -> WW ->jj ll5631 LQ ee-jets

5605 Z'(E6)->ee 1TeV5607 Z'(SM-like)->tautau 600 GeV5166 Z(->ll)+4j (QED diagrams)5201 ttbar5372 H++->ee/mumu5374 H++->tautau



Impact on energy distribution for electron coming from Z’ at 1 TeVImpact on energy distribution for electron coming from Z’ at 1 TeV

E (GeV)

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



Impact on pImpact on pT T distribution for electron coming from Z’ at 1 TeVdistribution for electron coming from Z’ at 1 TeV

pT (GeV)

Cut at 500 GeV in the dilepton invariant mass

Pic at 500 GeVPic below 500 GeV

Other distributions are not really affected and are the same as last meeting

tid010014 - 1mm Bug corrected

tid009428 - 1mm Bug not corrected



Electron selection efficiency as a function of Electron selection efficiency as a function of and pand pT T are not very are not very

affected affected

Flat efficiency in Phi

Average efficiency value around 60%

Identification based on TRT and E/P are the main sources of loss and increase with pT

Crack around 1.4 – 1.5

Versus pT :

Versus : Versus :



Selection efficiency as a function of Selection efficiency as a function of and pand pT T for loose and medium for loose and medium

electronelectron

Selection efficiency around 0.8 for medium electronsIn the Z’ reconstruction we will use medium electrons



Dilepton invariant mass spectrumDilepton invariant mass spectrum

1 TeV Z’

Generation levelReconstruction level

Mll (GeV)



Z’ Selection effeciencyZ’ Selection effeciency

Dilepton invariant mass (GeV)

Sel

ectio

n ef

fici

ency

Average efficiencyaround 50%

We use medium electronsWith opposite charge

We have to refine the selection efficiency :

add isolation and back to back criteria



Z‘ mass resolution and linearityZ‘ 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



Resolution and linearity for different parts of the detectorResolution 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



Twiki pageTwiki 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.CgROOT->SetStyle("ATLAS");gROOT->ForceStyle();



outlookoutlook

To do To do

Use the full available Z’ statistic.• 7250 Z’ + Z’ SSM ?

Look at the linearity and resolution dependence on pT, , . Need a lot of statistic (add the high mass DY sample).

More dilepton results coming soon (efficiency versus dilepton mass for uubar and ddbar separately) …

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Update on high pT electrons study presented last meeting