# Dielectron Analysis Status - PowerPoint PPT Presentation

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Dielectron Analysis Status. WIS 21-Aug-14. Normalization. Get the normalization factors for the like sign spectra: Get in integrals of the normalized like sign spectra: Get the normalization factor for the unlike sign spectrum:. Normalization I. Normalization II. HIJING (~0-10% central).

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Dielectron Analysis Status

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## Dielectron Analysis Status

WIS

21-Aug-14

### Normalization

• Get the normalization factors for the like sign spectra:

• Get in integrals of the normalized like sign spectra:

• Get the normalization factor for the unlike sign spectrum:

Normalization I.

Normalization II.

### HIJING (~0-10% central)

• Compare the combinatorial background from SAME event with the combinatorial background from MIXED event

• How do we select the combinatorial background from SAME event:

vert1!=vert2

(both legs are coming from different space points)

OR

vert1==vert2 && vertr1==0 && vertr2==0

(both legs are coming from exactly zero – these are pi+ and pi-)

### HIJING (~0-10% central)

• Applying the Normalization II:

-> the ratio of the combinatorics from the SAME and the MIXED is:

0.9898 +/- 0.0003

### HIJING (~0-10% central)

• Applying the Normalization I:

-> the ratio of the combinatorics from the SAME and the MIXED is 1

### HIJING to DATA

-> Assuming the results from HIJING are correct we apply normalization I. to the data

• Standards CA eID is applied

• DC ghost track rejected

• RICH ghost event rejected

• Normalization done after CA and ghost cuts

• HBD cuts applied later

• In the following slides the data set is ~1B events

### Cabana Boy settings

//CabanaBoy *cb = new CabanaBoy(10,8,1,"ULMM_DataTrack");

CabanaBoy *cb = new CabanaBoy(10,8,6,"ULMM_DataTrack"); cb->setPoolType(CabanaBoy::AkibaPools);cb->setPoolDepth(100);cb->setFastMom(false);cb->setZVertexMax(20.0);//cb->setReactionPlaneSelectionType(CabanaBoy::ReactionPlaneNotUsed);

cb->setReactionPlaneSelectionType(CabanaBoy::ReactionPlaneRun7RXNEllipticSN); cb->setCentralitySelectionType(CabanaBoy::CentralityTypeRun10AuAu200);

• Other settings

• CA eID cuts

• no HBD cuts applied

• Ghost events rejected

### Nlike/Blike , S+- (0 < centrality < 10)

CA + ghost rej.

CA + ghost rej. + HBD (matching)

CA + ghost rej. + HBD (matching)

+ S/D rejection

### Nlike/Blike , S+- (10 < centrality < 20)

CA + ghost rej.

CA + ghost rej. + HBD (matching)

CA + ghost rej. + HBD (matching)

+ S/D rejection

### Nlike/Blike , S+- (20 < centrality < 40)

CA + ghost rej.

CA + ghost rej. + HBD (matching)

CA + ghost rej. + HBD (matching)

+ S/D rejection

### Nlike/Blike , S+- (40 < centrality < 92)

CA + ghost rej.

CA + ghost rej. + HBD (matching)

CA + ghost rej. + HBD (matching)

+ S/D rejection

### Applying strong eID cuts

• eID cuts:

• n0 > 3

• sqrt(emcsdphi*emcsdphi + emcsdz*emcsdz) < 2

• dep > -1 [#]

• chi2/npe0 < 5

• disp < 4

• prob > 0.05

• |zed| < 75

• In the following slides the data set is ~2B events

### Nlike/Blike , S+- (0 < centrality < 10)

CA + ghost rej.

CA + ghost rej. + HBD (matching)

CA + ghost rej. + HBD (matching)

+ S/D rejection

### Nlike/Blike , S+- (10 < centrality < 20)

CA + ghost rej.

CA + ghost rej. + HBD (matching)

CA + ghost rej. + HBD (matching)

+ S/D rejection

### Nlike/Blike , S+- (20 < centrality < 40)

CA + ghost rej.

CA + ghost rej. + HBD (matching)

CA + ghost rej. + HBD (matching)

+ S/D rejection

### Nlike/Blike , S+- (40 < centrality < 92)

CA + ghost rej.

CA + ghost rej. + HBD (matching)

CA + ghost rej. + HBD (matching)

+ S/D rejection

### Summary

• There is some correlation in like sign?

• It is masked by the combinatorics in the central, but becomes visible in the peripheral?

• The like-sign ratio looks flat for the central and the normalization is reasonble?

• Should we apply some kind of “jet-free region” normalization for the peripheral?

• Will try to study peripheral events in HIJING