ROOT implementation for LDA:

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

**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

**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)

**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)

**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)

ROOT implementation for LDA:

LDA configuration: default

LDA input parameters Set0:

**Set4 (link for results with LDA Set0-Set3)**:- 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** - Shower shape analysis: distance to 80% cut line:

**distance to cut line** - Energy fraction in E_2x1 and E_2x2 witin E_3x3:

**E_2x1/E_2x2**and**E_2x2/E_3x3** - Energy in post-shower layer under 3x3 tower patch:

**E_post^3x3** - Tower energy in 3x3 patch:

**E_tow^3x3** - SMD-u energy in 25 central strips:

**E_smd-u^25** - SMD-v energy in 25 central strips:

**E_smd-v^25** - SMD-v peak energy (in 5 central strips):

**E_peak**

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

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

**Integrated yields per pre-shower bin**:

sample | total integral | pre1=0,pre2=0 | pre1=0, pre2>0 | 0 < pre1 < 0.004 | 0.004 < pre1 < 0.01 | pre1 < 0.01 | pre1 >= 0.01 |

photon-jet |
2.5640e+03 | 3.5034e+02 | 5.2041e+02 | 5.6741e+02 | 5.2619e+02 | 1.9644e+03 | 5.9994e+02 |

QCD |
5.6345e+04 | 1.3515e+03 | 4.3010e+03 | 1.2289e+04 | 1.5759e+04 | 3.3701e+04 | 2.2644e+04 |

pp2006 |
6.2811e+04 | 6.8000e+02 | 2.4310e+03 | 1.2195e+04 | 1.6766e+04 | 3.2072e+04 | 3.0739e+04 |

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 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:** rejection vs. efficiency

**Figure 3:** purity vs. efficiency

**Figure 4:** purity vs. rejection

**Figure 5:** Correlation matrix (pt>7GeV cut)

pre1=0, pre2=0

pre1=0, pre2>0

0 < pre1 < 0.004

0.004 < pre1 < 0.01

pre1 < 0.01

pre1 >= 0.01

For this post LDA input parameters Set4 has been used

LDA for various pre-shower bins is trained independetly,

and later results with pre-shower1<0.01 are combined.

There are a set of plots for various photon pt cuts (pt> 7, 8, 9 10 GeV)

and with different selection of cutoff for LDA

(either based on purity or efficiency).

Number in brackets shows the total yield for the sample.

Link to all plots (16 total) as a single pdf file

**Figure 1:** pt > 7GeV, efficiency@70

**Figure 2:** pt > 7GeV, purity@35

**Figure 3:** pt > 7GeV, purity@40

**Figure 4:** pt > 7GeV, purity@25 (Note: very similar to results with efficiency@70)

**Figure 5:** pt > 9GeV, efficiency@70

**Figure 6:** pt > 9GeV, purity@35

**Figure 7:** pt > 10GeV, efficiency@70

**Figure 8:** pt > 10GeV, purity@40

(analysis status update for Spin PWG)

Slides in pdf format:

For this post LDA results with Set1 and Set2 has been used

Note, that LDA for various pre-shower bins is trained independetly

pdf-links with results for **pre1=0 and pre2=0** (pre-shower bin 1):

- before LDA cut (figures are not sorted)
- after LDA cut @70% efficiency for Set 2 (figures are not sorted)

Figures below are for **0.004<pre-shower1<0.01** (pre-shower bin 4).

Photon pt cut: pt> 7, pre-shower bin: 0.004 < pre1 < 0.01

LDA cut with efficiency @ 70%

What is added in Set2 compared to Set1:

smaller cluster size information (r2x1, r2x2), post-shower energy

**Figure 1:** r2x1

before LDA cut

LDA cut for Set1

LDA cut for Set2

**Figure 2:** r2x2

before LDA cut

LDA cut for Set1

LDA cut for Set2

**Figure 3:** r3x3

before LDA cut

LDA cut for Set1

LDA cut for Set2

**Figure 4:** Residual distance

before LDA cut

LDA cut for Set1

LDA cut for Set2

Note: Only plos for LDA cut @70 efficiency for Set2 are shown

**Figure :** number of charge particles around photon

**Figure 5:** number of EEMC tower around photon

**Figure 6:** number of BEMC tower around photon

**Figure 7:** photon-jet pt balance

**Figure 8:** SMD energy in 5 centrapl strips

**Figure 9:** SMD energy in 25 central strips: u and v plane separately (plot for V plane)

**Figure 13:** tower energy in r=0.7 radius

**Figure 14:** 3x3 pre-shower1 energy

**Figure 15:** 3x3 pre-shower2 energy

**Figure 16:** 3x3 post-shower energy

**Title:**

"Photon-jet coincidence measurements

in polarized pp collisions at sqrt{s}=200GeV

with the STAR Endcap Calorimeter"

- Presentation in pdf format
- Older versions: 0, 1, 2 3, 4, 5, open office file: odp
- Submitted abstract
- Conference link: CIPANP 2009