Charge particle correlation analysis
This presentation is the property of its rightful owner.
Sponsored Links
1 / 21

γ -charge particle correlation analysis PowerPoint PPT Presentation


  • 91 Views
  • Uploaded on
  • Presentation posted in: General

γ -charge particle correlation analysis. Prithwish Tribedy , Arindam Roy (VECC). Motivation. 1. The charged particles are measured from the FTPC and photons from the PMD at forward rapidity. Correlation between productions of charged and neutral pions have been studied at top RHIC energy.

Download Presentation

γ -charge particle correlation analysis

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Charge particle correlation analysis

γ-charge particle correlation analysis

PrithwishTribedy, Arindam Roy

(VECC)


Charge particle correlation analysis

Motivation

1. The charged particles are measured from the FTPC and photons from the PMD at forward rapidity. Correlation between productions of charged and neutral pions have been studied at top RHIC energy.

2.The energy dependence of the isospin fluctuation of pions in BES would be an interesting study in the context of phase transitions .


Issues addressed in the following presentation

Issues addressed in the following presentation :

  • AuAu 200 GeV Run 7- Run 10 comparison

  • PMD – FTPC West correlation


Charge particle correlation analysis

QA plots & data cleanup


Run 10 data

Run 10 data

<ηch>

<Nγ>

<Nch>

<φch>

<ηγ>

<φγ>

1 sigma cut applied to remove outlier runs

<DCAch>

<pT ch>

<nCellγ>


Charge particle correlation analysis

Checking consistency with Run10 data

Run 10: AuAu200

Prod: P08ic

Stlib: SL10K

st_pmdftp_

Events : 3.5 M

Centrality: ReMultCorr

Bad Runs : Alex-Hiroshi list

+ PMD-FTPC list

|Vz|<5 cm

|vpd(Vz)-TPC(Vz)|<4 cm

All standard cuts of PMD-FTPC


Charge particle correlation analysis

Removing bad events for PMD using cuts of CPV (standard technique)


Charge particle correlation analysis

The PMD bad events are removed by putting a cut on cpvfrac (= cpvadc/cpvcluster)

We use cpvfrac >1.8 for our analysis


Charge particle correlation analysis

Some more cleanup

Using #primary vertex cut.

npV=1  better cleanup


Charge particle correlation analysis

Looks clean except for

peripheral events.


Charge particle correlation analysis

Run7-Run10 looks consistent

Some difference may be due to some bad-events in the peripheral collisions.


Charge particle correlation analysis

PMD & FTPC East – FTPC West comparison

Issue 1 : Difference in multiplicity even in same acceptance (Run10 is better )

Run 7

~40%

Difference

In multiplicity

Run 10


Charge particle correlation analysis

PMD & FTPC East – FTPC West comparison

Issue 2 : Contamination effect makes direct comparison misleading

  • GEANT Simulation shows 30% of the photons might contain different contamination in the same coverage which can’t be completely removed.

  • So some of the photons from PMD include FTPCE tracks. So PMD-FTPCE correlation will be more than PMD-FTPCW.

Common

coverage

<NPMD> = α <NFTPCE> + εγ <Nγ>

<NPMD> and <NFTPCE> are average measured multiplicities from PMD and FTPC East.

<Nγ> is actual photon multiplicity in the coverage considered, εγis photon detection efficiency.

α Unknown contamination factor.

FTPC W


Charge particle correlation analysis

Correlation of PMD with East and West FTPC : comparison

It can be easily shown that the contamination will affect not only the same side correlation

but also the opposite side correlation in different way.

One can’t get rid of the unknown contamination factor by algebraic manipulation.


Charge particle correlation analysis

Correlation of PMD with East and West FTPC : comparison from Run10 data

  • ΔCorrWest-East

  • = Correlation (FTPCW-PMD)

  • Correlation

  • (FTPCE-PMD)

  • Depending on the value of unknown contamination factor it is not possible to conclude which side has more correlation.


Charge particle correlation analysis

Summary

Run10 comparison:

Run7-Run10 data are consistent, although some cleanup issues still remain with Run10 data.

PMD-FTPCW (away-side) correlation:

-It is hard to make a conclusion by comparing PMD-FTPCW and PMD-FTPCE correlation.

-The difference in correlation between FTPCEast and FTPCWest

depends on the unknown contamination factor, alpha. Higher correlation with FTPCWest would have indicated interesting physics signal where as higher correlation with FTPCEast would indicate dominance of resonance and jets etc.


Backup slides

Backup slides


Results for the observable dyn

Results for the observable νdyn

Results for Top energy

(systematic error bars are included)

Energy and centrality dependence of the observable νdyn

νdyn is a measure of dynamical fluctuation, non-zero νdyn dynamical fluctuation

Non-zero νdyn is observed over wide range of centrality and energy.


Charge particle correlation analysis

Observation :

(charge-dependence)

γ-ch fluctuation result is very different from positive-negative

charge fluctuation.


Charge particle correlation analysis

Generic

expectation

DCC expectation

Observable r_{m,1} shows :

Deviation from Poisson is small, result is consistent with particle production from equilibrated matter. (hydrodynamic evolution).


  • Login