2008.07.07 Pre-shower1 < 5MeV cut study

Ilya Selyuzhenkov July 07, 2008

Data sets:

• pp2006 - STAR 2006 pp longitudinal data (~ 3.164 pb^1) after applying gamma-jet isolation cuts.
• gamma-jet - data-driven Pythia gamma-jet sample (~170K events). Partonic pt range 5-35 GeV.
• QCD jets - data-driven Pythia QCD jets sample (~4M events). Partonic pt range 3-65 GeV.

Figure 1: Correlation between 3x3 cluster energy in pre-shower2 vs. pre-shower1 layers

 

Figure 1a: Distribution of the 3x3 cluster energy in pre-shower1 layer (zoom in for Epre1<0.03 region)
(pp2006 data vs. MC gamma-jet and QCD events)

 

Figure 2: Shower shapes after pre-shower1 < 5MeV cut.
Shapes are narrower than those without pre1 cut (see Fig. 2)

 

 

Figure 3: Gamma pt distribution with pre-shower1 < 5MeV cut.
Compare with distribution withoud pre-shower1 (Fig. 3)

 

Sided residual (before and after pre-shower1 < 5MeV cut)

Figure 4: Fitted peak vs. maximum sided residual (no pre-shower1 cuts)
Only points for pp2006 data are shown.

 

Figure 5: Fitted peak vs. maximum sided residual (after pre-shower1 < 5MeV cut).
Only points for pp2006 data are shown.
Note that distribution for pre1>0,pre2>0 case are narrower
compared to that in Fig.4 (without pre-shower1 cuts).

 

Figure 6: Distribution of maximum sided residual with pre-shower1 < 5MeV cut.

2008.07.16 Gamma-gamma invariant mass cut study

Ilya Selyuzhenkov July 16, 2008

Three data sets:

• pp2006 - STAR 2006 pp longitudinal data (~ 3.164 pb^1) after applying gamma-jet isolation cuts.
• gamma-jet - data-driven Pythia gamma-jet sample (~170K events). Partonic pt range 5-35 GeV.
• QCD jets - data-driven Pythia QCD jets sample (~4M events). Partonic pt range 3-65 GeV.

My simple gamma-gamma finder is trying to
find a second peaks (clusters) in each SMD u and v planes,
match u and v plane high strip intersections,
and calculate the invaraint mass from associated tower energies (3x3 cluster)
according to the energy sharing between SMD clusters.

Figure 1: Gamma-gamma invariant mass plot.
Only pp2006 data are shown: black: no pt cuts, red: gamma pt>7GeV and jet pt>5 GeV.
Clear pi0 peak in the [0.1,0.2] invariant mass region.
Same data on the log scale

 

Gamma pt distributions

Figure 2: Gamma pt distribution (no inv mass cuts).

 

Figure 3: Gamma pt distribution (m_invMass<0.11 or no second peak found).
This cut improves signal to background ratio.

 

Figure 4: Gamma pt distribution (m_invMass>0.11).
Mostly background events.

 

Shower shapes

Figure 5: Shower shapes (no pre1 and no invMass cuts).
Good match between shapes in case of no energy in pre-shower1 layer (pre1=0 case).

 

Figure 6: Shower shapes (pre1<5MeV, no invMass cuts).
For pre1&2>0 case shapes getting closer to ech other, but still do not match.

 

Figure 7: Shower shapes (cuts: pre1<5MeV, invMass<0.11 or no second peak found).
Note, the surprising agreement between eta-meson shapes (blue) and data (black).

 

Gamma-gamma invariant mass plots

Figure 8: Invariant mass distribution (MC vs. pp2006 data): no pre1 cut

 

Figure 9: Invariant mass distribution (MC vs. pp2006 data): pre1<5MeV
Left side is the same as in Figure 8

 

Figure 10: Invariant mass distribution (MC vs. pp2006 data): pre1>5MeV
Left side plot is empty, since there is no events with [pre1=0 and pre1>5MeV]

2008.07.22 Photons from eta-meson: library QA

Ilya Selyuzhenkov July 22, 2008

Shower shapes

Figure 1: Shower shapes: no energy cuts, only 12 strips from peak (left u-plane, right v-plane).

Figure 1a: Shower shapes: no energy cuts, 150 strips from peak (left u-plane, right v-plane).

 

Figure 2: Shower shapes Energy>8GeV (left u-plane, right v-plane).

 

Figure 3: Shower shapes Energy<=8GeV (left u-plane, right v-plane).

 

One dimensional distributions

Figure 4: Tower energy.

 

Figure 5: Post-shower energy.

 

Figure 6: Pre-shower1 energy.

 

Figure 7: Pre-shower2 energy.

 

Figure 8: Number of library candidates per sector.

 

Correlation plots

Figure 9: Transverse momentum vs. energy.

 

Figure 10: Distance from center of the detector vs. energy.

 

Figure 11: x:y position.

 

Figure 12: u- vs. v-plane position.

2008.07.29 Shower shape comparison with new dd-library bins

Ilya Selyuzhenkov July 29, 2008

Data sets:

• pp2006 - STAR 2006 pp longitudinal data (~ 3.164 pb^1) after applying gamma-jet isolation cuts.
• gamma-jet - data-driven Pythia gamma-jet sample (~170K events). Partonic pt range 5-35 GeV.
• QCD jets - data-driven Pythia QCD jets sample (~4M events). Partonic pt range 3-65 GeV.

 

Latest data-driven shower shape replacement library:

• Four pre-shower bins: pre1,2=0, pre1=0,pre2>0 pre1<4MeV, pre1>=4MeV
• plus two energy bins (E<8GeV, E>=8GeV)

 

Figure 1: Shower shapes for u-plane [12 strips]
Shower shapes for the library are for the E>8GeV bin.

 

Figure 2: Shower shapes for v-plane [12 strips]

 

Figure 3: Shower shapes for u-plane [expanded to 40 strips]

 

Figure 4: Shower shapes for v-plane [expanded to 40 strips]