Correla(on of Neutral and Charge par(cle using PMD Ankhi Roy Indian - - PowerPoint PPT Presentation

Correla(on of Neutral and Charge par(cle using PMD

Ankhi Roy Indian Ins(tute of Technology Indore ALICE-India Collabora(on Mee(ng VECC, Kolkata 15th -17th March, 2017

Plan of My Talk Ø Physics Mo(va(on Ø PMD Detector Ø Purity and Efficiency Calcula(on Ø Data Analysis and Simula(on Ø Future Plan

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Physics Mo(va(on

• One of the goals of Heavy ion collision is to study the proper(es of a

strongly interac(ng QGP (sQGP) through its phase transi(on to Hadron gas (HG).

• Phase transi(on is associated with de-confinement transi(on and chiral Phase

transi(on

• De-confinement transi(on expected to reveal through fluctua(on of conserved

quan((es like net charge, strangeness and baryon number.

• Dynamical fluctua(on of neutral to charge pion ra(o is one of the observables to

study Chiral Phase Transi(on.

• Possibility of the forma(on of Disoriented Chiral Condensate (DCC) during transi(on

from symmetric chiral phase to broken phase.

• Forma(on and decay of DCC could lead to a dis(nct distribu(on of neutral pion

compared to generic produc(on of pions under isospin symmetry.

• This will appear as an(-correla(on between the yield of charged and neutral pion .

[1] L. Adamczyk..P. Tribedy et al , ( STAR Collabora(on), Physical Review C 91,035905 (2015)

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Nch: Charge par(cle mul(plicity, Nγ: photon mul(plicity ωch: Charge par(cle mul(plicity fluctua(on

ωγ : Photon mul(plicity fluctua(on

Corr γ-ch : Scaled correla(on of charge par(cle and photon mul(plicity r1,1= Corr γ-ch/ωch

When r=1

Observables for the correla(on studies :

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Data Sets Used for the Analysis

√SNN Data Pass MC AOD/ ESD Trigger pp 2.76 TeV LHC11a Pass3_w ith_SDD LHC11h5a (Pythia_ Perugia0) LHC13d17b (Phojet) ESD kMB

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Previous ALICE-India Presenta(on : I had presented my analysis with pb-pb 2.76 TeV data. Now I have started the same analysis with pp data.

PMD Detector Detector used for this analysis : ² PMD : 2.3 < η < 3.9 ü Preshower – photon ü CPV – charge pion

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Preshower Plane CPV Plane

Preshower Plane

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ADC distribu(on

• No. of Cells of Cluster

Purity and Efficiency Calcula(on of Photon from Preshower Efficiency = Ndet /Ninc Purity = Ndet/Nlike Ninc= Number of Incident photons in Preshower Ndet= Number of clusters in Preshower above threshold condi(on with track PID=22 Nlike= Number of Clusters in Preshower plane above threshold condi(on

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Incident Photon Detected Photon

Det=0 Track pid =22 Det=0 Trackpid =22 Ncell > 1 Adc > 432

Efficiency of Photon in Preshower Plane

Efficiency

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Ncell>1

Purity of Photon in Preshower plane Photon-like

Detected Photon Purity

Det=0 Adc>432 Ncell>1 Det=0 Adc>432 Ncell>1 Trackpid=22

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Ncell>>1

CPV

Ncell=1 ADC distribu(on

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Purity and Efficiency Calcula(on of Charged pion from CPV Efficiency = Ndet /Ninc Purity = Ndet/Nlike Ninc= Number of Incident charge pion in CPV Ndet= Number of clusters in CPV with threshold condi(on and track PID=+211 or -211 Nlike= Number of Clusters in CPV plane with threshold condi(on

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Efficiency of Charged pion in CPV Plane

Incident Charge Pion Detected Charge Pion Det =1 Track Pid= +211/-211 Det =1 ADC< 432 Ncell =1 Trackpid = +211/-211

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Efficiency vs ADC threshold Ncell=1

Purity of Charged pion in CPV Plane Charge Pion like Detected Charge Pion Det=1 Ncell=1 Adc>432 Det=1 Ncell=1 Adc>432 Trackpid=+211/-211

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Ncell=1

Comparison of Efficiency and Purity between Preshower and CPV

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ADC Efficiency Purity 50 0.53 0.47 72 0.50 0.48 144 0.44 0.50 216 0.38 0.52 288 0.33 0.53 360 0.29 0.55 432 0.25 0.56 504 0.21 0.58 576 0.18 0.60 648 0.16 0.61 Preshower Plane ADC Efficienc y Purity 50 0.12 0.56 72 0.25 0.55 108 0.40 0.54 144 0.54 0.52 180 0.62 0.51 216 0.66 0.50 288 0.72 0.50 360 0.76 0.50 432 0.78 0.50 504 0.79 0.50 576 0.80 0.50 CPV Plane Threshold condi(on for neutral and charge par(cle selected in such a way that efficiency and purity remain same.

Basic Cuts for the analysis-

• -10 cm < Vz < 10 cm
• Same eta-phi coverage of CPV and Preshower plane
• Preshower ( det==0):

ncell > 1 and adc > 432

• CPV (det==1):
• ncell =1 and adc < 72

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Common Coverage of Preshower and CPV

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Comparison of data and simula(on

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Simula(on : Pythia-Perugia Data –pp@2.76TeV Nch

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Data Data

Simula(on

Simula(on

Comparison of data and simula(on

Neutral Par(cle Mul(plicity Charge Par(cle Mul(plicity

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TPC Mul(plicity 0-10 TPC Mul(plicity 10-20 TPC Mul(plicity 20-30 TPC Mul(plicity 30-40

Comparison of Mean photon mul(plicity in different tpc mul(plicity range

Ngamma Ngamma Ngamma Ngamma

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Comparison of mean chrage mul(plicity in different tpc mul(plicity range

Nch Nch Nch Nch TPC Mul(plicity 0-10 TPC Mul(plicity 20-30 TPC Mul(plicity 10-20 TPC Mul(plicity 30-40

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Charge Mul(plicity Fluctua(on Photon Mul(plicity fluctua(on

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Challenges in this Analysis :

• Not all gammas come from pi0
• Not all charged tracks are from pi+ or pi-
• Conversion Probability of gamma
• Efficiency and purity are dependent on adc threshold
• Realis(c Simula(on

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Preshower Preshower+CPV

Method to Reject Charge hit treated as photon in Preshower plane using CPV

• Selected Ngamma

(Adc> 430 and Ncell>1)

• Projected back that cluster

in CPV plane and searched whether there is any hit in circle of certain radius

• If there is no cluster, selected

them as Ngamma, otherwise rejected

R=4cm

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Future Plan

• Understand the photon conversion

probability

• Need to work on the CPV plane

Summary:

• Performed Purity and Efficiency calcula(on
• Started analysis with pp data

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Acknowledgements:

• Sidharth, Sanjib, Sinjini, Rathijit
• Dr. Subhahsis Charopadhyay