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HBT
10

.. 2015


-
ALICE LHC- QGP, QGP
1 fm/c 5 fm/c 10 fm/c 50 fm/c









" "

- . p+, p+Pb Pb+Pb .


Evolution time scale from STAR data
?
Chemical freeze out Resonance survival

Rlo
dN/dt

Rout, Rside
ng

1 fm/c

5 fm/c

10 fm/c

20 fm/c

time

STAR QM Talk: F. Retiere

Kinetic freeze out


HBT -
Bose-Einstien ­ FSI ­

10/31/12

Dragos Velicanu

Hot Quarks 2012





HBT
· 1956 R. Hambury-Brown and R.Q. Twiss (HBT) , - . [R. Hambury-Brown and R.Q. Twiss, Nature 178 (1956) 1046]
1960 G. Goldhaber, S. Goldhaber, W. Lee and A. Pais, - .
[G.Goldhaber et al., Phys. Rev. 120 (1960) 300]

·

:

p( k1 , k2 ) C ( q) 1 exp[ ( q R ) 2 ] p( k1 ) p( k2 )
k2: 4- (4-vector) ; 0 < < 1

where: ·q: · k1, ·R: ·:



2R pp

QS - FSI ­ , .



2- - q pi p j

CF (q, k )

N 2 ( pi , p j )

2 2 CF (q, k ) 1 (k ) exp ( Rin vqin v )
2 qin v q 2

1D :

N1 ( pi ) N 2 ( p j )

kT 1 / 2( pi p j )

CF (q ) 1

strength of correlations

3D

Decomp qLong : qOut : qSide :

ose q into components: in beam direction in direction of transverse momentum qLong & qOut
2 out 2 Rside q

@2-[
2 side 2 2 2 Rlong qlong Rout ,long

2 CF ( p1 , p2 ) 1 ( Rout q


qout qlong )


Femtoscopy: usually used parametrizations

correlation strength, inv ), R, Gaussian radius in Pair Rest Frame (PRF) 1d- analysis is only sensitive to the system size averaged over all directions ;
2

C(q) = 1+exp(-Rinv2q

C(q) = 1+exp(-Ro2qo2 ­Rs2qs2 -Rl2ql2 ),
where both R and q are in Longitudinally Co-Moving Frame (LCMS)

long beam; out transverse pair velocity vt; side normal to out and long
3D- analysis Rside sensitive to geometrical transverse size. Rlong sensitive to time of freeze-out. Rout / Rside ~ sensitive to emission duration.


K±K± , K0sK0s and pp in Pb­Pb at LHC
PID via +- decay channel (purity95%) - up to 2 GeV/c Strong FSI and QS lead to femtoscopic effect, both included in the fit (Lednicky &Lyuboshitz model, Sov.J.Nucl.Phys. 35(1982)770) No Coulomb suppression

Neutral kaons:

Charged kaons:
QS and Coulomb repulsion PID: TPC+TOF pT range up to 1.5 GeV/c Bowler-Sinyukov fit C(qinv) = (1 - ) + K(qinv)(1 + exp( -R2 qinv2), K(qinv) - Coulomb function,

Protons:
QS, Coulomb and Strong FSI PID: TPC+TOF Wide correlation effect reproduced by residual correlations from p.


RHIC data

kT 0-30% ( RHIC). Rout/Rside 1


ALICE - Phys.Lett.B696:328-337,2011

Heavy Ions STAR and ALICE, 200 and 2760 GeV

· All the expected trends are observed:
­ Overall increase of the radii as compared to RHIC ­ Strong dependence of the radii on kT ­ Rout/Rside ratio even smaller than the one at RHIC

04/11/2011

P. Boek,Phys.Rev. C83 (2011) 044910 3D relativistic viscous hydrodynamics. The viscosity and the EoS are the same as used for RHIC. 12


Femtoscopy with identied charged hadrons in pp, pPb, and peripheral PbPb collisions in CMS


ALICE p+p STAR AuAu
· Heavy-ion data at ultrarelativistic energies show dN/d1 / 3 scaling · ALICE p+p does grow linearly with dN/d1 / 3, but not with the same offset and slope as heavy-ions · Comparison at same dN/d possible for the first time · Violation of the scaling shows that initial geometry does play a role in the final freeze-out shape

ALICE - arXiv:1101.3665

04/11/2011

14



ALICE - Phys.Lett.B696:328-337,2011

· Clear increase of the emitting region size and the system lifetime between the largest system to date (cenrtal full energy RHIC) and the central LHC. This means that the "quark-gluon plasma", if produced, lives longer and in a significantly bigger volume. · The dependence with energy follows the multiplicity scaling ­ this will be tested in more detail with the full centrality dependence from ALICE

ALICE - Phys.Lett.B696:328-337,2011

04/11/2011

Particle correlations - Luca Perrozzi SM@LHC

15


Comparing to models
· The hydrodynamic models which were extensively tuned to reproduce the RHIC data work also at the LHC · It is still not trivial to simultaneously reproduce the overall magnitude of the radii and the change between RHIC and the LHC. Only the models which introduce all the features important at RHIC (initial flow, cross-over phase transition, realistic equation of state, full inclusion of resonances) continue to work at the LHC.

ALICE - Phys.Lett.B696:328-337,2011

04/11/2011

Particle correlations - Luca Perrozzi SM@LHC

16


HBT in pp, pA and AA
Rsize
1/3

Jan Fiete Grosse-Oetringhaus (ALICE), QM2014, Nucl.Phys. A931(2014) 22.

3 1


, 10 / . RHIC LHC .

- - - ?


(. 10)
1. ?

2 LHC RHIC?