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 15 th -17 th 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 2

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) 3

Observables for the correla(on studies : N ch : Charge par(cle mul(plicity, N γ : photon mul(plicity ω ch : Charge par(cle mul(plicity fluctua(on ω γ : Photon mul(plicity fluctua(on Corr γ-ch : Scaled correla(on of charge par(cle and photon mul(plicity When r=1 r 1,1 = Corr γ-ch /ω ch 4

Data Sets Used for the Analysis √S NN Data Pass MC AOD/ Trigger ESD pp 2.76 LHC11a Pass3_w LHC11h5a ESD kMB TeV ith_SDD (Pythia_ Perugia0) LHC13d17b (Phojet) 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. 5

PMD Detector Detector used for this analysis : ² PMD : 2.3 < η < 3.9 ü Preshower – photon ü CPV – charge pion 6

Preshower Plane CPV Plane 7

Preshower Plane ADC distribu(on No. of Cells of Cluster 8

Purity and Efficiency Calcula(on of Photon from Preshower Efficiency = N det /N inc Purity = N det /N like N inc = Number of Incident photons in Preshower N det = Number of clusters in Preshower above threshold condi(on with track PID=22 N like = Number of Clusters in Preshower plane above threshold condi(on 9

Efficiency of Photon in Preshower Plane Detected Photon Incident Photon Det=0 Track pid =22 Det=0 Trackpid =22 Ncell > 1 Adc > 432 Ncell>1 Efficiency 10

Purity of Photon in Preshower plane Detected Photon Photon-like Det=0 Det=0 Adc>432 Adc>432 Ncell>1 Ncell>1 Trackpid=22 Purity Ncell>>1 11

CPV Ncell=1 ADC distribu(on 12

Purity and Efficiency Calcula(on of Charged pion from CPV Efficiency = N det /N inc Purity = N det /N like N inc = Number of Incident charge pion in CPV N det = Number of clusters in CPV with threshold condi(on and track PID=+211 or -211 N like = Number of Clusters in CPV plane with threshold condi(on 13

Efficiency of Charged pion in CPV Plane Detected Charge Pion Incident Charge Pion Det =1 Det =1 ADC< 432 Track Pid= +211/-211 Ncell =1 Trackpid = +211/-211 Ncell=1 Efficiency vs ADC threshold 14

Purity of Charged pion in CPV Plane Detected Charge Pion Charge Pion like Det=1 Det=1 Ncell=1 Ncell=1 Adc>432 Adc>432 Trackpid=+211/-211 Ncell=1 15

Comparison of Efficiency and Purity between Preshower and CPV CPV Plane Preshower Plane ADC Efficienc Purity ADC Efficiency Purity y 50 0.53 0.47 50 0.12 0.56 72 0.50 0.48 72 0.25 0.55 144 0.44 0.50 108 0.40 0.54 216 0.38 0.52 144 0.54 0.52 288 0.33 0.53 180 0.62 0.51 360 0.29 0.55 216 0.66 0.50 432 0.25 0.56 288 0.72 0.50 504 0.21 0.58 360 0.76 0.50 576 0.18 0.60 432 0.78 0.50 648 0.16 0.61 504 0.79 0.50 576 0.80 0.50 Threshold condi(on for neutral and charge par(cle selected in such a way that efficiency 16 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 17

Common Coverage of Preshower and CPV 18

Comparison of data and simula(on Simula(on : Pythia-Perugia Data – pp@2.76TeV Nch 19

Comparison of data and simula(on Neutral Par(cle Mul(plicity Charge Par(cle Mul(plicity Data Data Simula(on Simula(on 20

Comparison of Mean photon mul(plicity in different tpc mul(plicity range TPC Mul(plicity TPC Mul(plicity 10-20 0-10 Ngamma Ngamma TPC Mul(plicity TPC Mul(plicity 20-30 30-40 Ngamma Ngamma 21

Comparison of mean chrage mul(plicity in different tpc mul(plicity range TPC Mul(plicity TPC Mul(plicity 0-10 10-20 Nch Nch TPC Mul(plicity TPC Mul(plicity 20-30 30-40 Nch Nch 22

Photon Mul(plicity fluctua(on Charge Mul(plicity Fluctua(on 23

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 • 24

Method to Reject Charge hit treated as photon in Preshower plane using CPV Selected Ngamma • Preshower (Adc> 430 and Ncell>1) Preshower+CPV • Projected back that cluster in CPV plane and searched R=4cm whether there is any hit in circle of certain radius • If there is no cluster, selected them as Ngamma, otherwise rejected 25

Summary: Performed Purity and Efficiency calcula(on • Started analysis with pp data • Future Plan • Understand the photon conversion probability • Need to work on the CPV plane 26

Acknowledgements: • Sidharth, Sanjib, Sinjini, Rathijit • Dr. Subhahsis Charopadhyay 27