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
US LHC Users Association Meeting, Nov 3, 2017
¨ Introduction ¨ ALICE at the LHC ¨ Azimuthal HBT:
¤second harmonic ¤third harmonic
¨ Summary
PRL 118, 222301 (2017)
Mohammad Saleh US-LHC Meeting 11/03/2017
Mohammad Saleh US-LHC Meeting 11/03/2017
arXiv:1702.01612
Hard collisions Initial state QGP: Quark Gluon Plasma and hydrodynamic expansion Hadron freeze-out
arXiv:1702.01612
Hard collisions Initial state QGP: Quark Gluon Plasma and hydrodynamic expansion Hadron freeze-out
Mohammad Saleh US-LHC Meeting 11/03/2017
¨
Centrality: V0 multiplicity, Centrality: 0-50%
¨
Main tracking device: Time Projection Chamber (TPC),
¨
Particle identification (PID): TPC (dE/dx) & TOF (time of flight), pions were used in this analysis TOF V0 TPC
CENTRALITY %
Mohammad Saleh US-LHC Meeting 11/03/2017
Mohammad Saleh US-LHC Meeting 11/03/2017
¨ 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
B(q) is the measured (mixed-event) pair distribution in relative momentum . A(q) is the measured (same-event) pair distribution in relative momentum
Fitting
C( q) = N[(1 − ) + K(qinv)(1 + G( q))]
N: normalization; K: Coulomb correction; λ: chaoticity
p1 − p2 q0 = E1 − E2 qinv =
q|2 − q2
Mohammad Saleh US-LHC Meeting 11/03/2017
10
sideR2 side − q2 longR2 long − 2qoutqsideR2
pT,1 + pT,2)/2
kT
kT
Rout: source size along the pair transverse momentum direction Rside: source size perpendicular to pair transverse momentum direction Rlong: longitudinal size Ros: out-side cross term
¨ Gaussian parametrization of the source
Mohammad Saleh US-LHC Meeting 11/03/2017
Initial source
Mohammad Saleh US-LHC Meeting 11/03/2017
Initial elliptic source
Mohammad Saleh US-LHC Meeting 11/03/2017
Stronger in-plane expansion elliptic flow (v2) Initial elliptic source
v2 plane (𝛀2)
¨ Final eccentricity can be measured by azimuthal HBT w.r.t
¤ It depends on initial eccentricity, lifetime and dynamics of the source
evolution
reaction plane
Initial source
Mohammad Saleh US-LHC Meeting 11/03/2017
v2 plane (𝛀2)
reaction plane
𝛇2 > 0
Initial source
¨ Final eccentricity can be measured by azimuthal HBT w.r.t
¤ It depends on initial eccentricity, lifetime and dynamics of the source
evolution
Stronger in-plane expansion elliptic flow (v2) Initial elliptic source
Mohammad Saleh US-LHC Meeting 11/03/2017
v2 plane (𝛀2)
reaction plane
Initial source
¨ Final eccentricity can be measured by azimuthal HBT w.r.t
¤ It depends on initial eccentricity, lifetime and dynamics of the source
evolution 𝛇2 > 0
𝛇2 < 0
in-plane
Stronger in-plane expansion elliptic flow (v2) Initial elliptic source
Mohammad Saleh US-LHC Meeting 11/03/2017
v2 plane (𝛀2)
reaction plane
𝛇2 > 0
Initial source
𝛇2 < 0
in-plane
¨ Final eccentricity can be measured by azimuthal HBT w.r.t
¤ It depends on initial eccentricity, lifetime and dynamics of the source
evolution
Stronger in-plane expansion elliptic flow (v2) Initial elliptic source
Mohammad Saleh US-LHC Meeting 11/03/2017
𝞆pair
v2 plane (𝛀2)
reaction plane
𝛇2 > 0
Initial source
𝛇2 < 0
in-plane
¨ Final eccentricity can be measured by azimuthal HBT w.r.t
¤ It depends on initial eccentricity, lifetime and dynamics of the source
evolution
Stronger in-plane expansion elliptic flow (v2) Initial elliptic source
Mohammad Saleh US-LHC Meeting 11/03/2017
𝞆pair
v2 plane (𝛀2)
reaction plane
𝛇2 > 0
Initial source
𝛇2 < 0
in-plane
¨ Final eccentricity can be measured by azimuthal HBT w.r.t
¤ It depends on initial eccentricity, lifetime and dynamics of the source
evolution
Stronger in-plane expansion elliptic flow (v2) Initial elliptic source
Mohammad Saleh US-LHC Meeting 11/03/2017
𝞆pair
v2 plane (𝛀2)
reaction plane
𝛇2 > 0
Initial source
𝛇2 < 0
in-plane
¨ Final eccentricity can be measured by azimuthal HBT w.r.t
¤ It depends on initial eccentricity, lifetime and dynamics of the source
evolution
Stronger in-plane expansion elliptic flow (v2) Initial elliptic source
Mohammad Saleh US-LHC Meeting 11/03/2017
Mohammad Saleh US-LHC Meeting 11/03/2017
(rad)
EP,2
Ψ
ϕ
1 2 3)
2
(fm
2
R
10 20 30 40
/4 π /2 π /4 π 3 π
(rad)
EP,2
Ψ
ϕ
1 2 3)
2
(fm
side 2
R
10 20 30 40
= 2.76 TeV
NN
s ALICE 20-30% Pb-Pb
/4 π /2 π /4 π 3 π
¨ As the value of kT increases, the
radii decrease.
¤ Space-momentum correlation
=collective flow
c < 0.3 GeV/
T
k 0.2 < c < 0.5 GeV/
T
k 0.4 < c < 0.4 GeV/
T
k 0.3 < c < 0.5 GeV/
T
k 0.4 < c < 0.7 GeV/
T
k 0.5 <
0.4 < 0.5 <
ALI−PUB−127578
Mohammad Saleh US-LHC Meeting 11/03/2017
PRL 118, 222301 (2017)
(rad)
EP,2
Ψ
ϕ
1 2 3)
2
(fm
side 2
R
10 20 30 40
= 2.76 TeV
NN
s ALICE 20-30% Pb-Pb
/4 π /2 π /4 π 3 π
(rad)
EP,2
Ψ
ϕ
1 2 3)
2
(fm
2
R
10 20 30 40
/4 π /2 π /4 π 3 π
c < 0.3 GeV/
T
k 0.2 < ¨
Rout and Rside oscillate out-of-phase
∆ϕ = ϕpair − ΨEP,2
v2 plane ¨ As the value of kT increases, the
radii decrease.
¤ Space-momentum correlation
=collective flow Rside Rout
c < 0.5 GeV/
T
k 0.4 < c < 0.4 GeV/
T
k 0.3 < c < 0.5 GeV/
T
k 0.4 < c < 0.7 GeV/
T
k 0.5 <
0.4 < 0.5 <
ALI−PUB−127578
Mohammad Saleh US-LHC Meeting 11/03/2017
PRL 118, 222301 (2017)
(rad)
EP,2
Ψ
ϕ
1 2 3)
2
(fm
2
R
10 20 30 40
/4 π /2 π /4 π 3 π
(rad)
EP,2
Ψ
ϕ
1 2 3)
2
(fm
side 2
R
10 20 30 40
= 2.76 TeV
NN
s ALICE 20-30% Pb-Pb
/4 π /2 π /4 π 3 π
¨
Rout and Rside oscillate out-of-phase
∆ϕ = ϕpair − ΨEP,2
v2 plane ¨ As the value of kT increases, the
radii decrease.
¤ Space-momentum correlation
=collective flow Rside Rout
c < 0.3 GeV/
T
k 0.2 < c < 0.5 GeV/
T
k 0.4 < c < 0.4 GeV/
T
k 0.3 < c < 0.5 GeV/
T
k 0.4 < c < 0.7 GeV/
T
k 0.5 <
0.4 < 0.5 <
ALI−PUB−127578
Mohammad Saleh US-LHC Meeting 11/03/2017
PRL 118, 222301 (2017)
Initial source
2
side 2
EP,2
Mohammad Saleh US-LHC Meeting 11/03/2017
٭
Final eccentricity is smaller than the initial eccentricity, but remains positive (still out-of-plane extended)
init
ε
0.1 0.2 0.3 0.4
2 side,0
R /
2 side,2
R 2
0.05 0.1 0.15 0.2 0.25
final
ε =
init
ε
Hydro ALICE Pb-Pb 2.76 TeV c < 0.3 GeV/
T
k 0.2 < c < 0.4 GeV/
T
k 0.3 < c < 0.5 GeV/
T
k 0.4 < c < 0.7 GeV/
T
k 0.5 < STAR Au-Au 200 GeV c < 0.6 GeV/
T
k 0.15 < PHENIX Au-Au 200 GeV c < 2.0 GeV/
T
k 0.2 <
f i n a l
ε =
i n i t
ε
c Hydro ALICE Pb-Pb 2.76 TeV c < 0.3 GeV/
T
k 0.2 < c < 0.4 GeV/
T
k 0.3 < c < 0.5 GeV/
T
k 0.4 < c < 0.7 GeV/
T
k 0.5 < PHENIX Au-Au 200 GeV c < 2.0 GeV/
T
k 0.2 < PHENIX Au-Au 200 GeV
𝛇final > 0
Final source 0 < 𝛇final (LHC) < 𝛇final (RHIC) < 𝛇initial
ALI−PUB−127590
Initial source
Mohammad Saleh US-LHC Meeting 11/03/2017
PRL 118, 222301 (2017)
3+1D hydro calculations from: P. Bozek, “Phys. Rev. C89,258,044904(2014)
Final source
The lines connect the hydro points
The 3+1D hydro calculations agree qualitatively but predict a more isotropic final source
init
ε
0.1 0.2 0.3 0.4
2 side,0
R /
2 side,2
R 2
0.05 0.1 0.15 0.2 0.25
final
ε =
init
ε
Hydro ALICE Pb-Pb 2.76 TeV c < 0.3 GeV/
T
k 0.2 < c < 0.4 GeV/
T
k 0.3 < c < 0.5 GeV/
T
k 0.4 < c < 0.7 GeV/
T
k 0.5 <
final
ε =
init
ε
ALI−PUB−127590
𝛇final > 0
Initial source
Mohammad Saleh US-LHC Meeting 11/03/2017
PRL 118, 222301 (2017)
¨ Azimuthal HBT w.r.t v2 plane:
¤ Final eccentricity is smaller than the initial eccentricity, but remains positive (still
¤ The 3+1D hydro calculations for final eccentricity agree qualitatively but predict a
more isotropic final source CERN Courier, April issue PRL publication
Mohammad Saleh US-LHC Meeting 11/03/2017
Mohammad Saleh US-LHC Meeting 11/03/2017
Mohammad Saleh US-LHC Meeting 11/03/2017
¨ Average radii are larger for more central collisions
¨ Rout, Rside, and
Rlong have clear centrality and kT dependence
¨ 3+1D Hydro
agrees qualitatively with ALICE data points
Centrality(%)
10 20 30 40
)
2
(fm
2
R
10 20 30 40 50
ALICE Pb-Pb 2.76 TeV c < 0.3 GeV/
T
k 0.2 < c < 0.4 GeV/
T
k 0.3 < c < 0.5 GeV/
T
k 0.4 < c < 0.7 GeV/
T
k 0.5 <
Centrality(%)
10 20 30 40
)
2
(fm
2 side,0
R
10 20 30 40
Centrality(%)
10 20 30 40
)
2
(fm
2 long,0
R
20 40 60 80
Centrality(%)
10 20 30 40
)
2
(fm
2
R
0.5 − 0.5 1 1.5
3+1D Hydro Pb-Pb 2.76 TeV c < 0.3 GeV/
T
k 0.2 < c < 0.4 GeV/
T
k 0.3 < c < 0.5 GeV/
T
k 0.4 < c < 0.7 GeV/
T
k 0.5 <
ALI−PUB−127582
arXiv:1702.01612
Mohammad Saleh US-LHC Meeting 11/03/2017
¨
For non-expanding source: triangular flow (v3) Triangular flow leads to Radii oscillations
Final source shape Initial geometry no Rside oscillations should be observed w.r.t 𝛀3
Radii oscillations will confirm the collective nature of triangular flow
AMPT model: B. Zhang, C. M. Ko, B. -A. Li, Z. -w. Lin, Phys. Rev. C61, 067901 (2000)
Expected by
Mohammad Saleh US-LHC Meeting 11/03/2017
Mohammad Saleh US-LHC Meeting 11/03/2017 ¨ Rout and Rside oscillate in-phase ¨ Radii oscillations were observed for all centralities
ALI-PREL-116562
Amplitudes of the relative radii oscillations for Rout agree qualitatively with hydro while Rside and Ros agree quantitatively
*3+1D hydro calculations from: P. Bozek, “Phys. Rev. C89,258,044904(2014)
ALI-PREL-121785 ALI−PREL−121773 ALI−PREL−121789
Mohammad Saleh US-LHC Meeting 11/03/2017
Toy model shows in-phase oscillations of Rout and Rside for kT > 0.6 GeV
Toy model: C. J. Plumberg, C. Shen, and U. Heinz, Phys. Rev. C 88 (2013)
Toy Model
Mohammad Saleh, XII WPCF 2017
Triangular flow dominated case (𝛇3=0)
Centrality %
10 20 30 40 50
)
2
(fm
side,3 2
R
1 − 0.5 − 0.5
Centrality %
10 20 30 40 50
)
2
(fm
2
R
1 − 0.5 − 0.5
Initial triangular deformation is washed-out, or even reversed.
c < 0.3 GeV/
T
k 0.2 < c < 0.4 GeV/
T
k 0.3 < c < 0.5 GeV/
T
k 0.4 < c < 0.7 GeV/
T
k 0.5 < c < 0.3 GeV/
T
k 0.2 < c < 0.4 GeV/
T
k 0.3 < c < 0.5 GeV/
T
k 0.4 < c < 0.7 GeV/
T
k 0.5 < c < 0.3 GeV/
T
k 0.2 < c < 0.4 GeV/
T
k 0.3 < c < 0.5 GeV/
T
k 0.4 < c < 0.7 GeV/
T
k 0.5 < c < 0.3 GeV/
T
k 0.2 < c < 0.4 GeV/
T
k 0.3 < c < 0.5 GeV/
T
k 0.4 < c < 0.7 GeV/
T
k 0.5 < c < 0.3 GeV/
T
k 0.2 < c < 0.4 GeV/
T
k 0.3 < c < 0.5 GeV/
T
k 0.4 < c < 0.7 GeV/
T
k 0.5 < c < 0.3 GeV/
T
k 0.2 < c < 0.4 GeV/
T
k 0.3 < c < 0.5 GeV/
T
k 0.4 < c < 0.7 GeV/
T
k 0.5 < = 2.76 TeV
NN
s Pb-Pb ALICE Preliminary
0.005 0.01
0.05 0.1 a3 ρ
3
Centrality
0-5% 5-10% 10-20% 20-30% 30-40% 40-50%
Mohammad Saleh US-LHC Meeting 11/03/2017