Post on 20-Dec-2015
11-July-2008 ALICE EMCAL PPR Meeting 1
Working Group 4 Summary/Plans
Coordinators:
J.L. Klay (Cal Poly) and M. Heinz (Yale)
Contributing Members:
Ken Read (Tennessee)
Josh Hamblen (Tennessee)
Irakli Martashvili (Tennessee)
Ben Rizzo (Creighton)
Postdoc (Creighton)
Sebastien Gadrat (Grenoble) Brandon Boswell (Cal Poly)
Christopher Brown (Cal Poly)(Mostly) Summer
“Not available” after 01-Oct-2008
August-November
Coordination only after 01-Oct-2008
after 15-August
11-July-2008 ALICE EMCAL PPR Meeting 2
Simulations completed for CD-2
• Electron, W and B-jet rates (PYTHIA only)• Electron and Hadron Background rates (PYTHIA only)
– Including photon conversions (full detector included, no reco)
• Electron track-matching and PID (Full simulation + Full reconstruction)– Efficiency and e/h discrimination
• Preliminary DVM technique for semi-leptonic decays– Background rejection
• Preliminary W-jet rejection
Reasonably final:
Good start, but need more effort:
Note: Noise, other sim parameters have changed since CD-2 simulations. We may want to re-do everything with latest version of AliRoot, newer cuts, etc
11-July-2008 ALICE EMCAL PPR Meeting 3
Electron rates
L=0.5mb-1, 1yr =106 s, Pb-Pb scaling
~5000 B-electrons
*This plot should be redone
Need to double-check that these rates agree with
MNR NLO
11-July-2008 ALICE EMCAL PPR Meeting 4
Conversion backgrounds
<10% convert before TRD/TOF R~428cm
Start of EMCAL:
(~20% reduction)
Track-matching cut eliminates these
11-July-2008 ALICE EMCAL PPR Meeting 5
Electron/Hadron Ratios
Need a minimum factor of 400 hadron rejection
*This plot should be redone
11-July-2008 ALICE EMCAL PPR Meeting 6
Track-Cluster matching
~90% track-cluster matching efficiency
Matched particles (mostly hadrons)
*Should be revisited
**Re-check efficiency in PYTHIA and HIJING
PYTHIA
11-July-2008 ALICE EMCAL PPR Meeting 7
Electron ID: p/E
What is the status of testbeam e/h?
11-July-2008 ALICE EMCAL PPR Meeting 8
Electron ID: summary
For pT>10 GeV/c, pion rejection is well above the factor 400 needed
High efficiency
*Add a few more efficiency curves?
*Should be re-done
11-July-2008 ALICE EMCAL PPR Meeting 9
B-Jet Rates
Expect several hundred 80 GeV B-jets per year
Should make annual statistics plot similar to electron rates
11-July-2008 ALICE EMCAL PPR Meeting 10
Displaced Vertex Method
• The method pursued here has previously been used by CDF to identify secondary vertices from semi-leptonic decays.
• Breakdown of method:– Find a high-pt electron trigger
particle in EMCAL– Pair with all charged hadrons within
a cone of radius dR.– Reconstruct “approximate” (average
between B-D decay) secondary vertex and apply more cuts to reduce backgrounds from other leptonic decays.
– Plot Lxy distribution and obtain B-contribution from positive/negative imbalance
D0
B-
e-
K/e
Pe+K
r
PrimVtx
SecVtx
Lxy= r .pe+k / |pe+k|
Lxy
CDF Phys.Rev.D66 (2002))
11-July-2008 ALICE EMCAL PPR Meeting 11
Signal vs. Backgrounds
• Electron pT-cut > 10 GeV/c• Min. 6 ITS-hits on both electron/hadron track• Inv mass of (elec-kaon) mass > 1.7 GeV• Pair DCA < 200 m• B-Tag = |Lxy| > 600 m
Bottom Signal
Backgrounds
Cuts used for analysis
11-July-2008 ALICE EMCAL PPR Meeting 12
Efficiencies
All sources
B-jets
Dalitz
ConversionsCharm
B-jets
B-jets B-jets
More stats needed, higher pT
11-July-2008 ALICE EMCAL PPR Meeting 13
W backgrounds
pT pT
EMCAL Acceptance EMCAL Acceptance
B-jet electrons W electrons
So far only a qualitative look
~10x higher stats
11-July-2008 ALICE EMCAL PPR Meeting 14
DVM Comparison: B-jet vs WB-jets W
Standard cuts
Standard cuts +Minv> 1.7 GeV(charm rejection)
Standard cuts +Minv> 1.7 GeV + Max ITS-hits
Blue = right - leftMore
statistics needed
11-July-2008 ALICE EMCAL PPR Meeting 15
DVM results
After applying DVM cuts the signal efficiency is ~30-40%, whereas the backgrounds are factor ~100 suppressed.
Electrons from all sources (before DVM method)
Electrons from all sources (after DVM method)
11-July-2008 ALICE EMCAL PPR Meeting 16
What’s needed for PPR• Revisit rate calculations with higher statistics• Re-check e-ID with newer AliRoot• Electron and Electron-Jet Trigger
– Rates and backgrounds?
• Electron Spectra/RAA studies– Investigate electron heavy meson (Charm/Bottom) correspondence in AA– Compare to TPC alone and TPC+TRD vs. with EMCAL
• D/B Spectra/RAA studies– DVM method for B-mesons through e+D– Displaced vertex reconstruction of B through J/psi+K– Compare to electron RAA
• B-jet studies – DVM B-jet selection
• Effect of mis-identified electron/hadrons?
– W rejection – Study of alternative tagging methods/algorithms– Combine DVM method and electron ID with JETAN
• Cone and FastJet objects• FF performance for B-jets• Effect of mis-identified B-jets on FF
Effect of mis-identified electron/hadrons?
11-July-2008 ALICE EMCAL PPR Meeting 17
Preliminary work matrixTask Tools Manpower Statistics
Revisit rates
(higher stats)
PYTHIA + Material ---kinematics info
0.5 person 100k x 15 jet pT bins
Re-check e-ID (track-matching, p/E)
PYTHIA/HIJING + Full simulation
0.5 person Single e, 0 10k x ~10 pT ranges
100k x 15 jet pT bins + 10k HIJING bkg
Electron and E-Jet trigger
(rates/bkg)
PYTHIA/HIJING + AliEMCALTrigger, HLT
Trigger Group?
100k x 15 jet pT bins + 10k HIJING bkg
Electron spectra/RAA
(eB/D corresp., compare to TPC and TPC+TRD)
PYTHIA + Full simulation
1 person 100k x 15 jet pT bins
100k x ~5 pThard bins each of MSEL4 and MSEL5
D/B Spectra/RAA
(e+D, J/Psi+K, mis-ID)PYTHIA + Full simulation
1-2 people 100k x 15 jet pT bins
100k x ~5 pThard bins each of MSEL4 and MSEL5
B-jets (DVM,W,JETAN reco, FF, other tag methods)
PYTHIA/HIJING + Full simulation
2-3 people 100k x ~5 pThard bins each of MSEL4 and MSEL5
50-100k W-boson decays
10k HIJING bkg
11-July-2008 ALICE EMCAL PPR Meeting 18
ALICE Grid resources available• PDC08 simulations used a few different AliRoot versions
– http://pcalimonitor.cern.ch/job_details.jsp
– EMCAL was in for all of these runs
– At Offline week we were encouraged to submit requests• CPU is not a problem• Storage for our files is the major issue
– Do we have grid-accessible space at pdsf/LLNL?
v4-11-Rev-02
v4-10-Rev-02
v4-10-Rev-02
v4-11-Rev-02
v4-12-Rev-02
v4-13-Rev-02