Title: Azimuthallysensitive HBT in STAR
1Azimuthally-sensitive HBT in STAR
Mike Lisa Ohio State University
- Motivation
- Noncentral collision dynamics
- Azimuthally-sensitive interferometry previous
results - STAR results
- Hydrodynamic predictions for RHIC and LHC
- Summary
2Central collision dynamics _at_ RHIC
- Hydrodynamics reproduces p-space aspects of
particle emission up to pT2GeV/c (99 of
particles)? hopes of exploring the early, dense
stage
Heinz Kolb, hep-th/0204061
3Central collision dynamics _at_ RHIC
- Hydrodynamics reproduces p-space aspects of
particle emission up to pT2GeV/c (99 of
particles)? hopes of exploring the early, dense
stage
- x-space is poorly reproduced
- model source lives too long and disintegrates too
slowly? - Correct dynamics signatures with wrong space-time
dynamics?
- Turn to richer dynamics of non-central collisions
for more detailed information
Heinz Kolb, hep-th/0204061
4Noncentral collision dynamics
hydro evolution
- Dynamical models
- x-anisotropy in entrance channel ? p-space
anisotropy at freezeout - magnitude depends on system response to pressure
5Effect of dilute stage
hydro evolution
- hydro reproduces v2(pT,m) (details!) _at_ RHIC for
pT lt 1.0 GeV/c - system response ? EoS
- early thermalization indicated
- dilute hadronic stage (RQMD)
- little effect on v2 _at_ RHIC
Teaney, Lauret, Shuryak, nucl-th/0110037
6Effect of dilute stage
hydro evolution
- hydro reproduces v2(pT,m) (details!) _at_ RHIC for
pT lt 1.5 GeV/c - system response ? EoS
- early thermalization indicated
- dilute hadronic stage (RQMD)
- little effect on v2 _at_ RHIC
- significant (bad) effect on HBT radii
calculation Soff, Bass, Dumitru, PRL 2001
7Effect of dilute stage
hydro evolution
- hydro reproduces v2(pT,m) (details!) _at_ RHIC for
pT lt 1.5 GeV/c - system response ? EoS
- early thermalization indicated
- dilute hadronic stage (RQMD)
- little effect on v2 _at_ RHIC
- significant (bad) effect on HBT radii
- related to timescale? - need more info
Teaney, Lauret, Shuryak, nucl-th/0110037
8Effect of dilute stage
hydro evolution
- hydro reproduces v2(pT,m) (details!) _at_ RHIC for
pT lt 1.5 GeV/c - system response ? EoS
- early thermalization indicated
- dilute hadronic stage (RQMD)
- little effect on v2 _at_ RHIC
- significant (bad) effect on HBT radii
- related to timescale? - need more info
- qualitative change of freezeout shape!!
- important piece of the puzzle!
Teaney, Lauret, Shuryak, nucl-th/0110037
9Possible to see via HBT relative to reaction
plane?
- for out-of-plane-extended source, expect
- large Rside at 0?
- small Rside at 90?
2nd-order oscillation
Rs2 no flow expectation
fp
10Traditional HBT - cylindrical sources
Decompose q into components qLong in beam
direction qOut in direction of transverse
momentum qSide ? qLong qOut
(beam is into board)
11 Anisotropic sources? Six HBT radii vs f
- explicit and implicit (xmxn(f)) dependence on f
Wiedemann, PRC57 266 (1998).
12Symmetries of the emission function
Heinz, Hummel, MAL, Wiedemann, nucl-th/0207003
13Fourier expansion of HBT radii _at_ Y0
Insert symmetry constraints of spatial
correlation tensor into Wiedemann relations
and combine with explicit F-dependence
Note These most general forms of the Fourier
expansions for the HBT radii are preserved when
averaging the correlation function over a finite,
symmetric window around Y0. Relations between
the Fourier coefficients reveal interplay between
flow and geometry, and can help disentangle space
and time
Heinz, Hummel, MAL, Wiedemann, nucl-th/0207003
14Anisotropic HBT results _at_ AGS (?s2 AGeV)
AuAu 2 AGeV E895, PLB 496 1 (2000)
xside
xout
K
fp 0
- strong oscillations observed
- lines predictions for static (tilted)
out-of-plane extended source ? consistent with
initial overlap geometry
15Meaning of Ro2(f) and Rs2(f) are clearWhat about
Ros2(f) ?
AuAu 2 AGeV E895, PLB 496 1 (2000)
fp 0
fp 45
- Ros2(f) quantifies correlation between xout and
xside - No correlation (tilt) b/t between xout and xside
at fp0 (or 90)
- Strong (positive) correlation when fp45
- Phase of Ros2(f) oscillation reveals orientation
of extended source
16Indirect indications of x-space anisotropy _at_ RHIC
- v2(pT,m) globally well-fit by hydro-inspired
blast-wave
temperature, radial flow consistent with fits to
spectra
?
anisotropy of flow boost
spatial anisotropy (out-of-plane extended)
STAR, PRL 87 182301 (2001)
17STAR data AuAu 130 GeV minbias
- significant oscillations observed
- blastwave with same parameters as used to
describe spectra v2(pT,m) - additional parameters
- R 11 fm
- ? 2 fm/c !!
preliminary
18STAR data AuAu 130 GeV minbias
no spatial anisotropy
- significant oscillations observed
- blastwave with same parameters as used to
describe spectra v2(pT,m) - additional parameters
- R 11 fm
- ? 2 fm/c !!
preliminary
- both flow anisotropy and source shape contribute
to oscillations, but - geometry dominates dynamics
- freezeout source out-of-plane extended? fast
freeze-out timescale !
19Azimuthal HBT hydro predictions
- RHIC (T0340 MeV _at_ t00.6 fm)
- Out-of-plane-extended source (but flips with
hadronic afterburner) - flow geometry work together to produce HBT
oscillations - oscillations stable with KT
(note RO/RS puzzle persists)
Heinz Kolb, hep-th/0204061
20Azimuthal HBT hydro predictions
- RHIC (T0340 MeV _at_ t00.6 fm)
- Out-of-plane-extended source (but flips with
hadronic afterburner) - flow geometry work together to produce HBT
oscillations - oscillations stable with KT
- LHC (T02.0 GeV _at_ t00.1 fm)
- In-plane-extended source (!)
- HBT oscillations reflect competition between
geometry, flow - low KT geometry
- high KT flow
sign flip
Heinz Kolb, hep-th/0204061
21HBT(f) Results 200 GeV
- Oscillations similar to those measured _at_ 130GeV
- 20x more statistics ?explore systematics in
centrality, kT - much more to come
STAR PRELIMINARY
22Summary
- Quantitative understanding of bulk dynamics
crucial to extracting real physics at RHIC - p-space - measurements well-reproduced by models
- anisotropy ? system response to compression (EoS)
- probe via v2(pT,m)
- x-space - generally not well-reproduced
- anisotropy ? evolution, timescale information,
geometry / flow interplay - Azimuthally-sensitive HBT correlating quantum
correlation with bulk correlation - reconstruction of full 3D source geometry
- Freezeout geometry out-of-plane extended
- early (and fast) particle emission !
- consistent with blast-wave parameterization of
v2(pT,m), spectra, R(pT), K-p - With more detailed information, RHIC HBT puzzle
deepens - what about hadronic rescattering stage? - must
occur, or? - does hydro reproduce ?t? or not??
- right source shape via oscillations, but misses
RL(mT) - Models of bulk dynamics severely
(over?)constrained