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PW2. Femtoscopy. Femtoscopy at the highest energies: Expectations and directions at the LHC. Mike Lisa Ohio State University. Outline. Femtoscopic expectations @ LHC NNUS: systematic extrapolation of existing systematics naïve CGC cascade HRM: microscopic hadronic rescattering model - PowerPoint PPT Presentation
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malisa - SPHIC - Catania Italy - Sept 2006 1
Femtoscopy at the highest energies:Expectations and directions at the LHC
Mike Lisa
Ohio State University
malisa - SPHIC - Catania Italy - Sept 2006 2
Outline• Femtoscopic expectations @ LHC
• NNUS: systematic extrapolation of existing systematics• naïve• CGC
• cascade• HRM: microscopic hadronic rescattering model• AMPT: HIJING+parton cascade+string frag+hadronic cascade
• hydro• scales• shapes
• p+p• Pythia (+HRM, jets)• Black holes
• Some directions at LHC
• Summary
malisa - SPHIC - Catania Italy - Sept 2006 3
Femtoscopic information
€
C r P
ab(r q ) = d3 ′
r r ⋅Sr
P
ab( ′ r r )∫ ⋅ φ(
r ′ q ,r ′ r )
2
xa
xb
pa
pbxa
xb
pa
pb
€
Sr P
ab( ′ r r ) =
r x a -
r x b( ) distribution
φ(r ′ q ,r ′ r ) = (a,b) relative wavefctn
know/assume source distrib extract interaction (scat. length..)
know/assume relative wavefunction extract spatial distributions
OR
malisa - SPHIC - Catania Italy - Sept 2006 4
Microexplosions Femtoexplosions
s 0.1 J 1 J
1017 J/m3 5 GeV/fm3 = 1036 J/m3
T 106 K 200 MeV = 1012 K
rate 1018 K/sec 1035 K/s
• energy quickly deposited• enter plasma phase• expand hydrodynamically• cool back to original phase• do geometric “postmortem” & infer momentum
malisa - SPHIC - Catania Italy - Sept 2006 5
Microexplosions Femtoexplosions
s 0.1 J 1 J
1017 J/m3 5 GeV/fm3 = 1036 J/m3
T 106 K 200 MeV = 1012 K
rate 1018 K/sec 1035 K/s
• energy quickly deposited• enter plasma phase• expand hydrodynamically• cool back to original phase• do geometric “postmortem” & infer momentum
malisa - SPHIC - Catania Italy - Sept 2006 6
Baseline: 20-year-old systematic program
• Pion HBT @ Bevalac: “largely confirming nuclear dimensions”• Since 90’s: increasingly detailed understanding and study w/ high stats
T 1 2 sysˆHBT( ;p , y, b ,b,ms ,m ,A )
r
y
|b|
pT0
2
4
6
8
10
12
14
16
18
20
1985 1990 1995 2000 2005 2010
Year
#
Heinz/JacakWiedemann/Heinz
Csorgo
Tomasik/Wiedemann
Lisa/Pratt/Solts/Wiedemann
Experimental HBT Refereed Journal Publications
malisa - SPHIC - Catania Italy - Sept 2006 7
R(√SNN, b, Npart, A, B, y, mT, , PID)
€
R i mT( ) =′ R i
mTα i
fast region
fast region
malisa - SPHIC - Catania Italy - Sept 2006 8
R(√SNN, b, Npart, A, B, mT, y, , PID)
PRL 87 082301 (2001)PRL 93 012301 (2004)PRC 71 044906 (2005)
PRC 71 044906 (2005)
PRL 93 012301 ‘04
Spectra
v2
HBT
malisa - SPHIC - Catania Italy - Sept 2006 9
€
R i mT( ) =′ R i
mTα i
R(√SNN, b, Npart, A, B, y, mT, , PID)
Z. Chajecki, QM05
malisa - SPHIC - Catania Italy - Sept 2006 10
R(√SNN, b, Npart, A, B, mT, y, , PID)
PRL 87 082301 (2001)PRL 93 012301 (2004)PRC 71 044906 (2005)
PRC 71 044906 (2005)
PRL 93 012301 ‘04
D. Flierl, PhD thesis 2002
Spectra
v2
HBT
PRL 91 262301 (2003)
emission region
K emission region
malisa - SPHIC - Catania Italy - Sept 2006 11
R(√SNN, b, Npart, A, B, mT, y, , PID)
PRL 87 082301 (2001)PRL 93 012301 (2004)PRC 71 044906 (2005)
PRC 71 044906 (2005)
PRL 93 012301 ‘04
D. Flierl, PhD thesis 2002
Spectra
v2
HBT
PRL 91 262301 (2003)
emission region
K emission region
STAR, PRL 2004
MAL,Pratt Soltz,Wiedemann nucl-ex/0505014
+ - K+ K- K0S p p
p
p
K0S
K-
K+
-
+
Full program just startedEvolution with energy?
malisa - SPHIC - Catania Italy - Sept 2006 12
€
R i mT( ) =′ R i
mTα i
R(√SNN, b, Npart, A, B, y, mT, , PID)
Z. Chajecki, QM05
QuickTime™ and aTIFF (LZW) decompressor
are needed to see this picture.
MAL, Pratt, Soltz, Wiedemann nucl-ex/0505014 STAR, PRL 2004
malisa - SPHIC - Catania Italy - Sept 2006 13
€
R i mT( ) =′ R i
mTα i
R(√SNN, b, Npart, A, B, y, mT, , PID)
Z. Chajecki, QM05
QuickTime™ and aTIFF (LZW) decompressor
are needed to see this picture.
MAL, Pratt, Soltz, Wiedemann nucl-ex/0505014 STAR, PRL 2004
MAL,Pratt Soltz,Wiedemann nucl-ex/0505014
Naïve (?) : multiplicity dominance continues @ LHC(though two unexplored areas...)
Little dataShape Evolution with energy?
malisa - SPHIC - Catania Italy - Sept 2006 14
Source imaging - inverting Koonin-Pratt equation
•Non-Gaussian source in 1D (long-known)
•imaging resolves long-range component
•STAR sees similar (see talk of M. Bysterský
•Resonances? [check size scaling]
PHENIX nucl-ex/0605032
€
C r P
ab(r q ) = d3 ′
r r ⋅Sr
P
ab( ′ r r )∫ ⋅ φ(
r ′ q ,r ′ r )
2
€
Sr P
ab( ′ r r ) =
r x a -
r x b( ) distribution
φ(r ′ q ,r ′ r ) = (a,b) relative wavefctn
malisa - SPHIC - Catania Italy - Sept 2006 15
€
R i mT( ) =′ R i
mTα i
R(√SNN, b, Npart, A, B, y, mT, , PID)
Z. Chajecki, QM05
QuickTime™ and aTIFF (LZW) decompressor
are needed to see this picture.
MAL, Pratt, Soltz, Wiedemann nucl-ex/0505014 STAR, PRL 2004
MAL,Pratt Soltz,Wiedemann nucl-ex/0505014
Naïve (?) : multiplicity dominance continues @ LHC(though two unexplored areas...)
Little dataShape Evolution with energy?
malisa - SPHIC - Catania Italy - Sept 2006 16PHOBOS White Paper: NPA 757, 28
1000 5.5 TeV
5
6
6.4 = RHICx1.6
malisa - SPHIC - Catania Italy - Sept 2006 17
Multiplicity sets scale: all else fixed
MAL,Pratt Soltz,Wiedemann nucl-ex/0505014
PHOBOS White Paper: NPA 757, 28
1000 5.5 TeV
5
6
6.4 = RHICx1.6
malisa - SPHIC - Catania Italy - Sept 2006 18
Multiplicity sets scale: all else fixed
• PHOBOS-based extrapolation:• RLHC / RRHIC = (1.6)1/3 = 1.17
PHOBOS White Paper: NPA 757, 28
1000 5.5 TeV
5
6
6.4 = RHICx1.6
malisa - SPHIC - Catania Italy - Sept 2006 19
Multiplicity sets scale: all else fixed
• PHOBOS-based extrapolation:• RLHC / RRHIC = (1.6)1/3 = 1.17
• CGC prediction of multiplicity
• RLHC / RRHIC = (11/3.6)1/3 = 31/3 = 1.45
Kharzeev, Levin & Nardi NPA747 609 (2005)
malisa - SPHIC - Catania Italy - Sept 2006 20
Beyond multiplicity
• PHOBOS-based extrapolation:• RLHC / RRHIC = (1.6)1/3 = 1.17
• CGC prediction of multiplicity
• RLHC / RRHIC = (11/3.6)1/3 = 31/3 = 1.45
• Humanic Rescattering Model
• “real” model predicting dN/d and HBT
• (dN/d[LHC] / dN/d[RHIC])1/3 ~ 1.9
dN
/d
T. Humanic,Int.J.Mod.Phys.E15197(2006)
malisa - SPHIC - Catania Italy - Sept 2006 21
Beyond multiplicity
Rlo
ng (
fm)
dN
/dt
• PHOBOS-based extrapolation:• RLHC / RRHIC = (1.6)1/3 = 1.17
• CGC prediction of multiplicity
• RLHC / RRHIC = (11/3.6)1/3 = 31/3 = 1.45
• Humanic Rescattering Model
• “real” model predicting dN/d and HBT
• (dN/d[LHC] / dN/d[RHIC])1/3 ~ 1.9
• LHC / RHIC = 2 :: (recall Rlong~~ )
• dynamic effect
• Rlong[LHC] / Rlong[RHIC] ~ 1.5-2
• all are connected??
T. Humanic,Int.J.Mod.Phys.E15197(2006)
malisa - SPHIC - Catania Italy - Sept 2006 22
Beyond multiplicity
• PHOBOS-based extrapolation:• RLHC / RRHIC = (1.6)1/3 = 1.17
• CGC prediction of multiplicity
• RLHC / RRHIC = (11/3.6)1/3 = 31/3 = 1.45
• Humanic Rescattering Model
• “real” model predicting dN/d and HBT
• (dN/d[LHC] / dN/d[RHIC])1/3 ~ 1.9
• LHC / RHIC = 2 :: (recall Rlong~~ )
• dynamic effect
• Rlong[LHC] / Rlong[RHIC] ~ 2
• all are connected?
• RS, RO larger, but not a simple factor
T. Humanic,Int.J.Mod.Phys.E15197(2006)
malisa - SPHIC - Catania Italy - Sept 2006 23
Beyond multiplicity
• PHOBOS-based extrapolation:• RLHC / RRHIC = (1.6)1/3 = 1.17
• CGC prediction of multiplicity
• RLHC / RRHIC = (11/3.6)1/3 = 31/3 = 1.45
• Humanic Rescattering Model
• “real” model predicting dN/d and HBT
• (dN/d[LHC] / dN/d[RHIC])1/3 ~ 1.9
• LHC / RHIC = 2 :: (recall Rlong~~ )
• dynamic effect
• Rlong[LHC] / Rlong[RHIC] ~ 2
• all are connected?
• RS, RO larger, but not a simple factor
• steeper pT-dep due to more flow?
• dynamic effect
T. Humanic,Int.J.Mod.Phys.E15197(2006)
malisa - SPHIC - Catania Italy - Sept 2006 24
hydro
• does not do as well as
cascades, but nevertheless
we’ll look next for guidance...
Cascade / Hydro models versus RHIC data
cascade
• AMPT does ~Ok- needs string melting
& 6-10 mb parton
malisa - SPHIC - Catania Italy - Sept 2006 25
AMPT @ LHC
• All radii increase• ~10% for transverse• ~30% for long
• RO/RS [LHC] < RO/RS [RHIC]
• But... RHIC radii too large in this configuration of model ???
C.M. Ko; WPCF Sept. 2006
malisa - SPHIC - Catania Italy - Sept 2006 26
Hydro predictions I: Scales
• Neglecting flow, to cool to C[QGP] :
C = 0(C /0)3/4
• Cno flow[RHIC] = 6 fm/c
• Cno flow[LHC] = 20 fm/c
Eskola et al PRC72044904 (2005)
initial conditions frompQCD+saturation
malisa - SPHIC - Catania Italy - Sept 2006 27
• Neglecting flow, to cool to C[QGP] :
C = 0(C /0)3/4
• Cno flow[RHIC] = 6 fm/c
• Cno flow[LHC] = 20 fm/c
• Much larger flow @LHC• signif. reduction of timescale @ LHC
[similar to RHIC]
• larger transverse size @ FO
Eskola et al PRC72044904 (2005)
Hydro predictions I: Scales
malisa - SPHIC - Catania Italy - Sept 2006 28
• Neglecting flow, to cool to C[QGP] :
C = 0(C /0)3/4
• Cno flow[RHIC] = 6 fm/c
• Cno flow[LHC] = 20 fm/c
• Much larger flow @LHC• signif. reduction of timescale @ LHC
[similar to RHIC]
• larger transverse size @ FO
• No HBT prediction per se, but...
• RL[LHC] / RL[RHIC] ~ 1.1 ÷ 1.2
• RS[LHC] / RS[RHIC] ~ 1.5 ÷ 2
• (different than HRM)
• steeper pT-dependence
Eskola et al PRC72044904 (2005)
Hydro predictions I: Scales
malisa - SPHIC - Catania Italy - Sept 2006 29
• Neglecting flow, to cool to C[QGP] :
C = 0(C /0)3/4
• Cno flow[RHIC] = 6 fm/c
• Cno flow[LHC] = 20 fm/c
• Much larger flow @LHC• signif. reduction of timescale @ LHC
[similar to RHIC]
• larger transverse size @ FO
• No HBT prediction per se, but...
• RL[LHC] / RL[RHIC] ~ 1.1 ÷ 1.2
• RS[LHC] / RS[RHIC] ~ 1.5 ÷ 2
• (different than HRM)
• steeper pT-dependence
• Consistent w/ independent hydrofor non-central collisions
Eskola et al PRC72044904 (2005)
Hydro predictions I: Scales
Heinz&Kolb, PLB542 216 (2002)
(LHC)
malisa - SPHIC - Catania Italy - Sept 2006 30
• easy prediction: importance of -dep measurements will continue @ LHC
• asHBT• probes timescale & dynamics• non-trivial (& incomplete!) excitation fctn
Hydro predictions II: Shapes
E895 2 GeVPLB496 1 (2000)
STAR 200 GeV
PRL93 012301 (‘04)
O’H
ara
, e
t a
l, S
cie
nce
29
8 2
17
9 (
20
02
)
malisa - SPHIC - Catania Italy - Sept 2006 31
• easy prediction: importance of -dep measurements will continue @ LHC
• asHBT• probes timescale & dynamics• non-trivial (& incomplete!) excitation fctn
• hydro @ RHIC• misses scale (well-known)• impressive agreement on -dep
Hydro predictions II: Shapes
STAR PRL93 012301 (2004)Heinz&Kolb, PLB542 216 (2002)
“RHIC”
malisa - SPHIC - Catania Italy - Sept 2006 32
• easy prediction: importance of -dep measurements will continue @ LHC
• asHBT• probes timescale & dynamics• non-trivial (& incomplete!) excitation fctn
• hydro @ RHIC• misses scale (well-known)• impressive agreement on -dep
• prediction @ LHC• sign change in shape & oscillations
Hydro predictions II: Shapes
Heinz&Kolb, PLB542 216 (2002)
“RHIC”
Heinz&Kolb, PLB542 216 (2002)
“IPES” (LHC)
malisa - SPHIC - Catania Italy - Sept 2006 33
• easy prediction: importance of -dep measurements will continue @ LHC
• asHBT• probes timescale & dynamics• non-trivial (& incomplete!) excitation fctn
• hydro @ RHIC• misses scale (well-known)• impressive agreement on -dep
• prediction @ LHC• sign change in shape & oscillations
• qualitatively different kT dependence (*)
Hydro predictions II: Shapes
Heinz&Kolb, PLB542 216 (2002)
“RHIC”
Heinz&Kolb, PLB542 216 (2002)
“IPES” (LHC)
* simple formula will not work @ LHC
€
≈2RS,2
2
RS,02
F. R
etiè
re &
MA
L P
RC70
044
907
(200
4)
malisa - SPHIC - Catania Italy - Sept 2006 34
p+p: a short diversion and “practice,” or a crucial question?
• “minimalist” physics• Momenta & parentage from PYTHIA• space by hand: x= “1 fm” + p/E
• pT-dep from x-p correlations
• resonances• formation time • some from rescatt
• mult dep from rescatt only
i-th particle
Initial “disk” of radius r
T. Humanic, presentationto ALICE PW2 (March 2006)
malisa - SPHIC - Catania Italy - Sept 2006 35
p+p: a short diversion and “practice,” or a crucial question?
• “minimalist” physics• Momenta & parentage from PYTHIA• space by hand: x= “1 fm” + p/E
• pT-dep from x-p correlations
• resonances• formation time • some from rescatt
• mult dep from rescatt only
• R(dN/d) space-time properties of jet fragmentation/hadronization? [fundamental]
• prediction of pT-dependence needed to test
whether hard processes are really dominant here
pp
jet
jet
Paic and SkowronskiJ. Phys. G31 1045 (2005)
see also Csorgo & Zajchep-ph/0412243 (ISMD04)
malisa - SPHIC - Catania Italy - Sept 2006 36
p+p: a short diversion and “practice,” or a crucial question?
• “minimalist” physics• Momenta & parentage from PYTHIA• space by hand: x= “1 fm” + p/E
• pT-dep from x-p correlations
• resonances• formation time • some from rescatt
• mult dep from rescatt only
• R(dN/d) space-time properties of jet fragmentation/hadronization? [fundamental]
• prediction of pT-dependence needed to test
whether hard processes are really dominant here
• Black Holes / extra dimensions at LHC p+p ?• may be copiously produced (depending on mass)• look for long lifetimes (if d large) in high mult
events ???• even more fundamental, but expectations unclear
[prelim from T. Humanic: small effect on HBT...]
Hossenfelder, H
ofmann, B
leicher, Stocker
Phys.R
ev. D66 (2002) 101502
Humanic, Koch, Stocker hep-ph/0607097
malisa - SPHIC - Catania Italy - Sept 2006 37
STAR preliminary
mT (GeV) mT (GeV)
Z. Chajecki WPCF05
femtoscopy in p+p @ STAR
• p+p and A+A measured in same experiment
• great opportunity to compare physics
• what causes pT-dependence in p+p?
• same cause as in A+A?
malisa - SPHIC - Catania Italy - Sept 2006 38
Surprising („puzzling”) scaling
HBT radii scale with pp
Scary coincidence or something deeper?
pp, dAu, CuCu - STAR preliminary
Ratio of (AuAu, CuCu, dAu) HBT radii by pp
• p+p and A+A measured in same experiment
• great opportunity to compare physics
• what causes pT-dependence in p+p?
• same cause as in A+A?
!! But !! major issues with nontrivialinterplay non-femtoscopic correlations
malisa - SPHIC - Catania Italy - Sept 2006 39
5
as before (same pT dep etc)but scale by ~17%
as before (same pT dep etc)but scale by ~45%
NNUS: naive extrapolation HRM and AMPT
RL (50-100% 30%increase)[dynamics / chemistry / both ??]
RO,S • smaller increase (~30% 10%)• higher flow steeper pT dep
hydro
RL small increase (~30%)[huge flow rapid cooling short ]
RO,S : huge flow • larger increase (~60%)• steeper pT dep
shape inversion; oscillation sign flip
p+p
pp
jet
jet
• signif pT dep• R increase w/ mult
• R increase w/ mult• other details??
• very large RO in high mult??
plats principaux
boissonsentrées
le menu des espérances au LHC
malisa - SPHIC - Catania Italy - Sept 2006 40
“Inverting the femtoscopic paradigm”
• First-ever p-, p-, p- correlations
• Consistency from baryon sector for flow-generated x-p correlations
• Extraction of real/imaginary p-, p- scattering lengths from CF !!• important new physics direction• “invert the femtoscopic paradigm”• c.f. K0-K0 / p-p
• possible effect of residual correlations - could not reliably calculate (for now...)• significant technical effort (and
more information) required
STAR, accepted to Phys Rev
malisa - SPHIC - Catania Italy - Sept 2006 41
• p+p - very interesting in itself!• understanding non-femtoscopic correlations crucial
• Beyond Gaussian imaging (3D)• see M. Bystersky
• shape inversion?• correlate femtoscopy with global event plane
• non-id systematics• including “exotica”
• will seriously need to understand correlated feed-down• see talk of H. Gos• a “complication” and a new source of information !
• hadronic physics - extracing phaseshifts• turning the problem around
nouvelles directions
malisa - SPHIC - Catania Italy - Sept 2006 42
THE END
malisa - SPHIC - Catania Italy - Sept 2006 43
references• RHIC-tested predictions for low-pT and high-pT hadron spectra
in nearly central Pb+Pb collisions at the LHC• Eskola et al hep-ph/0506049; PRC72044904 (2005)• hydro predictions for spectra• no HBT per se, but timescales and sizes of freezeout at
LHC versus RHIC are shown• Emission angle dependent pion interferometry at RHIC and
beyond• Heinz and Kolb PLB542 216 (2002)• RHIC and LHC predictions for asHBT from hydro
• Signatures for Black Hole production from hadronic observables at the Large Hadron Collider
• Humanic, Koch, Stocker hep-ph/0607097• surprisingly, no HBT, but discussion of possible BH
formation, rates, and how to trigger on them (high-mult: will it follow multiplicity systematics if physics changes so much??)
• Femtoscopy in heavy ion collisions: Wherefore, whence, and whither?
• Lisa nucl-ex/0506049 (WPCF05)• systematics and PHOBOS-extrapolation-based “prediction”
for LHC• Color Glass Condensate at the LHC: hadron multiplicities in pp,
pA and AA collisions• Kharzeev, Levin & Nardi; NPA747 609 (2005)• not HBT, but multiplicity predictions, which of course can
be coupled to HBT multiplicity systematics
• Hanbury-Brown-Twiss interferometry with identical bosons in relativistic heavy ion collisions: Comparisons with hadronic scattering models
• Humanic, Int.J.Mod.Phys.E15:197-236,2006; nucl-th/0510049
• Tom’s review article; contains LHC predictions
For proton-proton collisions:• Signatures for Black Hole production from hadronic
observables at the Large Hadron Collider• Humanic, Koch, Stocker hep-ph/0607097• surprisingly, no HBT, but discussion of possible BH
formation, rates, and how to trigger on them (high-mult: will it follow multiplicity systematics if physics changes so much??)
• Quasi-stable black holes at LHC• Hossenfieder, Hoffman, Bleicher, Stocker
hep-ph/0109085; Phys.Rev. D66 (2002) 101502• VERY nice plot of lifetime versus number of dimensions
• Pion HBT for LHC p+p collisions using a simple causality model
• Humanic, ppt presentation at PW2 meeting March 06• Pythia and HRM - nice, simple calculations showing pT
dep from simple formation time effect• Effect of hard processes on momentum correlations in pp
and ppbar collisions• Paic and Skowronski; J. Phys. G31 1045 (2005)• from size and mult dep, make a connection to space-
time properties of jet fragmentation• unfortunately, no pT prediction
malisa - SPHIC - Catania Italy - Sept 2006 44
Why can’t HBT be
more like v2?
malisa - SPHIC - Catania Italy - Sept 2006 45
STAR preliminary
v2 excitation functionpT-integrated
NA49: Phys.Rev. C68 (2003) 034903
slide of Raimond Snellings HIF 2003
Why can’t HBT be more like v2...?
malisa - SPHIC - Catania Italy - Sept 2006 46
Why can’t HBT be more like v2...?• v2(pT) very similar
• <pt> 158 A GeV ≈ 400 MeV/c
• <pt> 200 GeV ≈ 500 MeV/c
• Integrated v2 mainly driven by <pt>
• Note: In comparison SPS data the slight difference in centrality and systematic uncertainties, about 1.5% are
not plotted
STAR Preliminary
NA49: Phys.Rev. C68 (2003) 034903; CERES: nucl-ex/0303014
slide of Raimond Snellings HIF 2003
v2(pt) SPS-RHIC
malisa - SPHIC - Catania Italy - Sept 2006 47
Why can’t HBT be more like v2...?It can!.....Just gotta look in less detail!
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