# 2008.11.11 Yields vs. analysis cuts

Ilya Selyuzhenkov *November 11, 2008*

Data sets:

**pp2006**- STAR 2006 pp longitudinal data (~ 3.164 pb^1)

after applying gamma-jet isolation cuts (**R_cluster > 0.9**is used below).**gamma-jet[gamma-filtered]**- data-driven Prompt Photon [p6410EemcGammaFilter] events.

Partonic pt range 2-25 GeV.**QCD jets[gamma-filtered]**- data-driven QCD [p6410EemcGammaFilter] events.

Partonic pt range 2-25 GeV.

**Figure 1:** Reconstructed gamma pt for di-jet events and

Geant cuts: pt_gamma[Geant] > 7GeV and 1.05 < eta_gamma[Geant] < 2.0

Total integral for the histogram is: **N_total = 5284**

(after weighting different partonic pt bins and scaled to 3.164pb^-1).

Compare with number from Jim Sowinski study for

Endcap East+West gamma-jet and pt>7 GeV: **N_Jim = 5472**

( Jim's numbers are scaled to 3.164pb^-1 : [2539+5936]*3.164/4.9)

**Figure 2:** Reconstructed jet pt for di-jet events and the same cuts as in Fig. 1

### Yield vs. various analysis cuts

List of cuts (sorted by bin number in Figs. 2 and 3):

**N_events**: total number of di-jet events found by the jet-finder**cos(phi_gamma - phi_jet) < -0.8**: gamma-jet opposite in phi**R_{3x3cluster} > 0.9**: Energy in 3x3 cluster of EEMC tower to the total jet energy**R_EM^jet < 0.9**: neutral energy fraction cut for on away side jet**N_ch=0**: no charge tracks associated with a gamma candidate**N_bTow = 0**: no barrel towers associated with a gamma candidate (gamma in the endcap)**N_(5-strip cluster)^u > 2**: minimum number of strips in EEMC SMD u-plane cluster around peak**N_(5-strip cluster)^v > 2**: minimum number of strips in EEMC SMD v-plane cluster around peak**gamma-algo fail**: my algorithm failed to match tower with SMD uv-intersection, etc...**Tow:SMD match**: SMD uv-intersection has a tower which is not in a 3x3 cluster

**Figure 3:** Number of accepted events vs. various analysis cuts

The starting number of events (shown in first bin of the plots) is

the number of di-jets with reconstructed gamma_pt>7 GeV and jet_pt>5 GeV

upper left: cuts applied independently

upper right: cuts applied sequentially

lower left: ratio of pp2006 data vs. MC sum of gamma-jet and QCD-jets events (cuts applied independently)

lower right:ratio of pp2006 data vs. MC sum of gamma-jet and QCD jets events (cuts applied sequentially)

**Figure 4:** Number of accepted events vs. various analysis cuts

Data from Fig. 3 (upper plots) scaled to the initial number of events from first bin:

left: cuts applied independently

right: cuts applied sequentially

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