# 2009.05.03 LDA: varying pt and eta cut

### Cut optimization with Fisher's LDA classifier

ROOT implementation for LDA:

### Application for cuts optimization in the gamma-jet analysis

LDA configuration: default

LDA input parameters Set0:

**Set0**:- Energy fraction in 3x3 cluster within a r=0.7 radius:

**E_3x3/E_0.7** - Photon-jet pt balance:

**[pt_gamma-pt_jet]/pt_gamma** - Number of charge tracks within r=0.7 around gamma candidate:

**Ncharge** - Number of Endcap towersL fired within r=0.7 around gamma candidate:

**NtowBarrel** - Number of Barrel towers fired within r=0.7 around gamma candidate

**NtowEndcap**

- Energy fraction in 3x3 cluster within a r=0.7 radius:
**Set1:****All from Set0**- Shower shape analysis: distance to 80% cut line:

**distance to cut line**

**Set2:****All from Set1**- Energy fraction in E_2x1 and E_2x2 witin E_3x3:

**E_2x1/E_2x2**and**E_2x2/E_3x3**

**Set3:****All from Set2**- Energy in post-shower layer under 3x3 tower patch:

**E_post^3x3**

The number of strips in SMD u or v planes is required to be greater than 3

Pre-shower sorting (energy in tiles under 3x3 tower patch):

- pre1=0, pre2=0
- pre1=0, pre2>0
- 0 < pre1 < 0.004
- 0.004 < pre1 < 0.01
- pre1 < 0.01
- pre1 >= 0.01

Photon pt and rapidity cuts:

- pt>7GeV
- pt>8GeV
- pt>9GeV
- pt>10GeV
- detector eta <1.4 (pt>7GeV)
- detector eta > 1.4 (pt>7GeV)

**Figure 0:** photon pt distribution for pre-shower1<0.01

**Colour coding**:

black pp2006 data, red gamma-jet MC, green QCD MC, blue gamma-jet+QCD

### LDA Set0

**Figure 1:** LDA discriminant with Set0: Data to Monte-Carlo comparison (pt>7GeV cut)

Right plot for each pre-shower condition shows the ratio of pp2006 data to sum of the Monte-Carlo samples

**Colour coding**:

black pp2006 data, red gamma-jet MC, green QCD MC, blue gamma-jet+QCD

**Figure 2:** efficiency, purity, rejection vs. LDA discriminant (pt>7GeV cut)

**Figure 3:** rejection vs. efficiency

**Figure 4:** purity vs. efficiency

**Figure 5:** purity vs. rejection

### LDA Set1

**Figure 6:** LDA discriminant with Set1: Data to Monte-Carlo comparison

**Figure 7:** rejection vs. efficiency

**Figure 8:** purity vs. efficiency

**Figure 9:** purity vs. rejection (click link to see the figure)

### LDA Set2

**Figure 10:** rejection vs. efficiency (click link to see the figure)

**Figure 11:** purity vs. efficiency

**Figure 12:** purity vs. rejection (click link to see the figure)

### LDA Set3

**Figure 13:** rejection vs. efficiency (click link to see the figure)

**Figure 14:** purity vs. efficiency

**Figure 15:** purity vs. rejection (click link to see the figure)

- Printer-friendly version
- Login or register to post comments