Azimuthally differential pion femtoscopy relative to the second - PowerPoint PPT Presentation

1 Azimuthally differential pion femtoscopy relative to the second harmonic in Pb-Pb collisions at √ s NN = 2.76 TeV from ALICE Mohammad Saleh - Wayne State University on behalf of the ALICE Collaboration US LHC Users Association Meeting, Nov 3, 2017

Outline 2 ¨ Introduction ¨ ALICE at the LHC ¨ Azimuthal HBT: ¤ second harmonic PRL 118 , 222301 (2017) ¤ third harmonic Not included in this presentation ¨ Summary Mohammad Saleh US-LHC Meeting 11/03/2017

3 Introduction: Heavy Ion Collisions Mohammad Saleh US-LHC Meeting 11/03/2017

Introduction: Heavy Ion Collision 4 arXiv:1702.01612 Hard QGP: Quark Gluon Plasma Initial Not included in this presentation collisions and hydrodynamic expansion state Hadron freeze-out

Introduction: Heavy Ion Collisions 5 arXiv:1702.01612 Hard QGP: Quark Gluon Plasma Initial Not included in this presentation collisions and hydrodynamic expansion state Hadron freeze-out We measure the We want to correlations study the between identified particles QGP

6 Experimental setup Mohammad Saleh US-LHC Meeting 11/03/2017

7 ALICE at the LHC V0 TPC CENTRALITY % TOF Centrality: V0 multiplicity, Centrality: 0-50% ¨ Main tracking device: Time Projection Chamber (TPC), ¨ 100% Particle identification (PID): TPC (d E /d x ) & TOF (time of ¨ flight), pions were used in this analysis Mohammad Saleh US-LHC Meeting 11/03/2017

8 Analysis Methods Mohammad Saleh US-LHC Meeting 11/03/2017

��� HBT 9 ¨ HBT : Hanbury Brown and Twiss, measured the angular diameter of Sirius ¨ A very powerful tool to study the source space-time extension in heavy-ion collisions Theory Experiment ¨ Bowler and Sinyukov: C ( � q ) = N [(1 − � ) + � K ( q inv )(1 + G ( � Fitting q ))] � q | 2 − q 2 q 0 = E 1 − E 2 | � q inv = 0 A(q) is the measured (same-event) pair distribution in relative momentum � q = � p 1 − � p 2 B(q) is the measured (mixed-event) N : normalization; K : Coulomb correction; pair distribution in relative momentum λ : chaoticity . Our goal is to estimate G(q), the source function Mohammad Saleh US-LHC Meeting 11/03/2017

��� 3D HBT radii 10 ¨ Gaussian parametrization of the source function in the out-side-long system q ) = exp( − q 2 out R 2 out − q 2 side R 2 side − q 2 long R 2 long − 2 q out q side R 2 G ( � os ) � k T = ( � p T,1 + � p T,2 ) / 2 q out � � � k T q side ⊥ � � k T R out : source size along the pair transverse momentum direction R side : source size perpendicular to pair transverse momentum direction 10 R long : longitudinal size R os : out-side cross term Y. Sinyukov, R. Lednicky, S. Akkelin, J. Pluta, and B. Erazmus, Physics Letters B 432 (1998) Mohammad Saleh US-LHC Meeting 11/03/2017 S. Pratt, T. Csorgo, and J. Zimanyi,” Phys. Rev. C 42 2646–2652.

11 Azimuthal HBT w.r.t v 2 plane Initial source Initial elliptic source Mohammad Saleh US-LHC Meeting 11/03/2017

12 Azimuthal HBT w.r.t v 2 plane reaction plane Initial elliptic source v 2 plane ( 𝛀 2 ) Stronger in-plane expansion Mohammad Saleh US-LHC Meeting 11/03/2017

13 Azimuthal HBT w.r.t v 2 plane reaction plane Stronger in-plane Initial elliptic expansion elliptic Initial source flow ( v 2 ) source v 2 plane ( 𝛀 2 ) ¨ Final eccentricity can be measured by azimuthal HBT w.r.t second harmonic event plane ¤ It depends on initial eccentricity, lifetime and dynamics of the source evolution Mohammad Saleh US-LHC Meeting 11/03/2017

14 Azimuthal HBT w.r.t v 2 plane reaction plane Stronger in-plane Initial elliptic expansion elliptic Initial source flow ( v 2 ) 𝛇 2 > 0 source out-of-plane v 2 plane ( 𝛀 2 ) ¨ Final eccentricity can be measured by azimuthal HBT w.r.t second harmonic event plane ¤ It depends on initial eccentricity, lifetime and dynamics of the source evolution Mohammad Saleh US-LHC Meeting 11/03/2017

15 Azimuthal HBT w.r.t v 2 plane reaction plane Stronger in-plane Initial elliptic expansion elliptic Initial source flow ( v 2 ) 𝛇 2 > 0 source out-of-plane 𝛇 2 < 0 v 2 plane ( 𝛀 2 ) in-plane ¨ Final eccentricity can be measured by azimuthal HBT w.r.t second harmonic event plane ¤ It depends on initial eccentricity, lifetime and dynamics of the source evolution Mohammad Saleh US-LHC Meeting 11/03/2017

16 Azimuthal HBT w.r.t v 2 plane reaction plane Stronger in-plane Initial elliptic expansion elliptic Initial source flow ( v 2 ) 𝛇 2 > 0 source out-of-plane 𝛇 2 < 0 v 2 plane ( 𝛀 2 ) in-plane 𝛇 final ? ¨ Final eccentricity can be measured by azimuthal HBT w.r.t second harmonic event plane ¤ It depends on initial eccentricity, lifetime and dynamics of the source evolution Mohammad Saleh US-LHC Meeting 11/03/2017

Azimuthal HBT w.r.t v 2 plane 17 reaction plane Stronger in-plane Initial elliptic expansion elliptic Initial source flow ( v 2 ) 𝛇 2 > 0 source 𝞆 pair out-of-plane 𝛇 2 < 0 v 2 plane ( 𝛀 2 ) in-plane 𝛇 final ? ¨ Final eccentricity can be measured by azimuthal HBT w.r.t second harmonic event plane ¤ It depends on initial eccentricity, lifetime and dynamics of the source evolution Mohammad Saleh US-LHC Meeting 11/03/2017

Azimuthal HBT w.r.t v 2 plane 18 reaction plane Stronger in-plane Initial elliptic expansion elliptic Initial source 𝞆 pair flow ( v 2 ) 𝛇 2 > 0 source out-of-plane 𝛇 2 < 0 v 2 plane ( 𝛀 2 ) in-plane 𝛇 final ? ¨ Final eccentricity can be measured by azimuthal HBT w.r.t second harmonic event plane ¤ It depends on initial eccentricity, lifetime and dynamics of the source evolution Mohammad Saleh US-LHC Meeting 11/03/2017

Azimuthal HBT w.r.t v 2 plane 19 reaction plane Stronger in-plane Initial elliptic expansion elliptic Initial source 𝞆 pair flow ( v 2 ) 𝛇 2 > 0 source out-of-plane 𝛇 2 < 0 v 2 plane ( 𝛀 2 ) in-plane 𝛇 final ? ¨ Final eccentricity can be measured by azimuthal HBT w.r.t second harmonic event plane ¤ It depends on initial eccentricity, lifetime and dynamics of the source evolution Mohammad Saleh US-LHC Meeting 11/03/2017

20 Results Mohammad Saleh US-LHC Meeting 11/03/2017

Results: Azimuthal HBT w.r.t v 2 plane 21 40 40 ) ) 0.4 < 2 2 0.4 < k < 0.5 GeV/ c 0.2 < k < 0.3 GeV/ c 0.4 < k < 0.5 GeV/ c T (fm ALICE 20-30% Pb-Pb s = 2.76 TeV (fm T T 0.5 < 0.5 < k < 0.7 GeV/ c 0.3 < k < 0.4 GeV/ c NN T T 30 30 side out 2 2 R R 20 20 10 10 PRL 118, 222301 (2017) π π 0 π /4 1 2 3 0 π /4 1 2 3 π /2 3 π /4 0 π /2 3 π /4 0 ϕ - Ψ (rad) - (rad) ϕ Ψ ALI − PUB − 127578 EP,2 EP,2 pair pair ¨ As the value of k T increases, the radii decrease. ¤ Space-momentum correlation =collective flow Mohammad Saleh US-LHC Meeting 11/03/2017

Results: Azimuthal HBT w.r.t v 2 plane 22 40 40 ) ) 0.4 < 2 2 0.4 < k < 0.5 GeV/ c 0.2 < k < 0.3 GeV/ c 0.4 < k < 0.5 GeV/ c T (fm ALICE 20-30% Pb-Pb s = 2.76 TeV (fm T T 0.5 < 0.5 < k < 0.7 GeV/ c 0.3 < k < 0.4 GeV/ c NN T T 30 30 side out 2 2 R R 20 20 10 10 PRL 118, 222301 (2017) π π 0 π /4 1 2 3 0 π /4 1 2 3 π /2 3 π /4 0 π /2 3 π /4 0 ϕ - Ψ (rad) - (rad) ϕ Ψ ALI − PUB − 127578 EP,2 EP,2 pair pair ¨ As the value of k T increases, the R side radii decrease. R out ¤ Space-momentum correlation =collective flow ∆ ϕ = ϕ pair − Ψ EP , 2 v 2 plane R out and R side oscillate out-of-phase ¨ Mohammad Saleh US-LHC Meeting 11/03/2017

Results: Azimuthal HBT w.r.t v 2 plane 23 40 40 ) ) 0.4 < 2 2 0.4 < k < 0.5 GeV/ c 0.2 < k < 0.3 GeV/ c 0.4 < k < 0.5 GeV/ c T (fm ALICE 20-30% Pb-Pb s = 2.76 TeV (fm T T 0.5 < 0.5 < k < 0.7 GeV/ c 0.3 < k < 0.4 GeV/ c NN T T 30 30 side out 2 2 R R 20 20 10 10 PRL 118, 222301 (2017) π π 0 π /4 1 2 3 0 π /4 1 2 3 π /2 3 π /4 0 π /2 3 π /4 0 ϕ - Ψ (rad) - (rad) ϕ Ψ ALI − PUB − 127578 EP,2 EP,2 pair pair ¨ As the value of k T increases, the R side radii decrease. R out ¤ Space-momentum correlation =collective flow ∆ ϕ = ϕ pair − Ψ EP , 2 v 2 plane R out and R side oscillate out-of-phase ¨ Mohammad Saleh US-LHC Meeting 11/03/2017

24 Results: Azimuthal HBT w.r.t v 2 plane ) 2 (fm side 2 R ϕ - Ψ (rad) EP,2 pair Final source Initial source Mohammad Saleh US-LHC Meeting 11/03/2017