Expectations for Femtoscopy at the LHC
Mike Lisa
Ohio State University
malisa - WPCF - Sao Paulo, Brazil - Sept 2006
1
Outline
• Femtoscopic expectations @ LHC
• NNUS: systematic extrapolation of multiplicity systematic
• naïve
• CGC
• HRM: microscopic hadronic rescattering model
• hydro
• scales
• shapes
• p+p
• Pythia (+HRM, jets)
• Black holes
• Summary
• Some foci of the experimental program
malisa - WPCF - Sao Paulo, Brazil - Sept 2006
2
Baseline: 20-year-old systematic program
ˆ
HBT( s ;p T , y, b ,b,m
1 ,m2 ,Asys )
Experimental HBT Refereed Journal Publications
y
20
Heinz/Jacak
Wiedemann/Heinz
Csorgo
18
16
Tomasik/
Wiedemann
14
#
12
|b|
Lisa/Pratt/
Solts/Wiedemann
10
8
6
4
2
0
1985
pT
1990
1995
2000
2005
2010
Year
• Pion HBT @ Bevalac: “largely confirming nuclear dimensions”
• Since 90’s: increasingly detailed understanding and study w/ high stats
malisa - WPCF - Sao Paulo, Brazil - Sept 2006
3
R(√SNN, b, Npart, A, B, y, mT, , PID)
R i mT  
Ri
mTi

malisa - WPCF - Sao Paulo, Brazil - Sept 2006
4
R(√SNN, b, Npart, A, B, y, mT, , PID)
R i mT  

malisa - WPCF - Sao Paulo, Brazil - Sept 2006
Ri
mTi
Z. Chajecki, QM05
5
R(√SNN, b, Npart, A, B, y, mT, , PID)
STAR, PRL 2004
MAL, Pratt, Soltz, Wiedemann nucl-ex/0505014
QuickTime™ and a
TIFF (LZW) decompressor
are needed to see this picture.
R i mT  

malisa - WPCF - Sao Paulo, Brazil - Sept 2006
Ri
mTi
Z. Chajecki, QM05
6
R(√SNN, b, Npart, A, B, y, mT, , PID)
STAR, PRL 2004
MAL, Pratt, Soltz, Wiedemann nucl-ex/0505014
QuickTime™ and a
TIFF (LZW) decompressor
are needed to see this picture.
R i mT  
Ri
mTi
MAL,Pratt Soltz,Wiedemann nucl-ex/0505014

malisa - WPCF - Sao Paulo, Brazil - Sept 2006
Z. Chajecki, QM05
7
R(√SNN, b, Npart, A, B, y, mT, , PID)
+
-
K+
K-
K0
p
p
S



MAL, Pratt, Soltz, Wiedemann nucl-ex/0505014 


STAR, PRL 2004






p




p






K0
QuickTime™ and a
TIFF (LZW) decompressor
are needed to see this picture.

S
R
R i mTK  ii
m
K+ T



 QM05


Z. Chajecki,
-

+
Full program just started
MAL,Pratt Soltz,Wiedemann nucl-ex/0505014
Evolution with energy?

Little data
Shape Evolution with energy?
Naïve (?) : multiplicity dominance continues @ LHC
(though two unexplored areas...)
malisa - WPCF - Sao Paulo, Brazil - Sept 2006
8
LHC = RHIC++
6.4 = RHICx1.6
6
5
MAL,Pratt Soltz,Wiedemann nucl-ex/0505014
1000
5.5 TeV
PHOBOS White Paper: NPA 757, 28
Naïve (?) : multiplicity dominance continues @ LHC
(though two unexplored areas...)
malisa - WPCF - Sao Paulo, Brazil - Sept 2006
9
Multiplicity sets scale: all else fixed
6.4 = RHICx1.6
6
5
MAL,Pratt Soltz,Wiedemann nucl-ex/0505014
1000
5.5 TeV
PHOBOS White Paper: NPA 757, 28
malisa - WPCF - Sao Paulo, Brazil - Sept 2006
10
Multiplicity sets scale: all else fixed
6.4 = RHICx1.6
• PHOBOS-based extrapolation:
6
• RLHC / RRHIC = (1.6)1/3 = 1.17
5
1000
5.5 TeV
PHOBOS White Paper: NPA 757, 28
malisa - WPCF - Sao Paulo, Brazil - Sept 2006
11
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
malisa - WPCF - Sao Paulo, Brazil - Sept 2006
Kharzeev, Levin & Nardi NPA747 609 (2005)
12
Beyond multiplicity
T. Humanic,
Int.J.Mod.Phys.E15197(2006)
• PHOBOS-based extrapolation:
• RLHC / RRHIC = (1.6)1/3 = 1.17
• RLHC / RRHIC = (11/3.6)1/3 = 31/3 = 1.45
dN/d
• CGC prediction of multiplicity
• Humanic Rescattering Model
• “real” model predicting dN/d and HBT
• (dN/d[LHC] / dN/d[RHIC])1/3 ~ 1.9
malisa - WPCF - Sao Paulo, Brazil - Sept 2006
13
• PHOBOS-based extrapolation:
• RLHC / RRHIC = (1.6)1/3 = 1.17
T. Humanic,
Int.J.Mod.Phys.E15197(2006)
dN/dt
Beyond multiplicity
• CGC prediction of multiplicity
• RLHC / RRHIC = (11/3.6)1/3 = 31/3 = 1.45
• “real” model predicting dN/d and HBT
• (dN/d[LHC] / dN/d[RHIC])1/3 ~ 1.9
• LHC / RHIC = 2 :: (recall Rlong~~ )
Rlong (fm)
• Humanic Rescattering Model
• dynamic effect
• Rlong[LHC] / Rlong[RHIC] ~ 2
• all are connected??
malisa - WPCF - Sao Paulo, Brazil - Sept 2006
14
Beyond multiplicity
T. Humanic,
Int.J.Mod.Phys.E15197(2006)
• 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
malisa - WPCF - Sao Paulo, Brazil - Sept 2006
15
Beyond multiplicity
T. Humanic,
Int.J.Mod.Phys.E15197(2006)
• 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?
malisa -• WPCF
- Sao Paulo,
dynamic
effectBrazil - Sept 2006
16
Eskola et al PRC72044904 (2005)
Hydro predictions I: Scales
• Neglecting flow, to cool to C[QGP] :
C = 0(C /0)3/4
• Cno flow[RHIC] = 6 fm/c
initial conditions from
pQCD+saturation
• Cno flow[LHC] = 20 fm/c
malisa - WPCF - Sao Paulo, Brazil - Sept 2006
17
Eskola et al PRC72044904 (2005)
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
• Much larger flow @LHC
• signif. reduction of timescale @ LHC
[similar to RHIC]
• larger transverse size @ FO
malisa - WPCF - Sao Paulo, Brazil - Sept 2006
18
Eskola et al PRC72044904 (2005)
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
• 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
malisa - WPCF - Sao Paulo, Brazil - Sept 2006
19
Eskola et al PRC72044904 (2005)
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
• Much larger flow @LHC
• signif. reduction of timescale @ LHC
[similar to RHIC]
• larger transverse size @ FO
• No HBT prediction per se, but...
Heinz&Kolb, PLB542 216 (2002)
• RL[LHC] / RL[RHIC] ~ 1.1 ÷ 1.2
• RS[LHC] / RS[RHIC] ~ 1.5 ÷ 2
• (different than HRM)
• steeper pT-dependence
• Consistent w/ independent hydro
for non-central collisions
malisa - WPCF - Sao Paulo, Brazil - Sept 2006
20
Hydro predictions II: Shapes
• easy prediction: importance of -dep
measurements will continue @ LHC
• asHBT
O’Hara, et al, Science 298 2179 (2002)
• probes timescale & dynamics
• non-trivial (& incomplete!) excitation fctn
malisa - WPCF - Sao Paulo, Brazil - Sept 2006
E895 2 GeV
PLB496 1 (2000)
STAR 200 GeV
PRL93 012301 (‘04)
21
Hydro predictions II: Shapes
• 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
“RHIC”
malisa - WPCF - Sao Paulo, Brazil
- Sept
2006
Heinz&Kolb,
PLB542
216 (2002)
STAR PRL93 012301 (2004)
22
Hydro predictions II: Shapes
• 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
“RHIC”
PLB542 216 (2002)
malisa - WPCF - Sao Heinz&Kolb,
Paulo, Brazil
- Sept 2006
“IPES” (LHC)
Heinz&Kolb, PLB542 216 (2002)
23
• 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 (*)
“RHIC”
F. Retière & MAL PRC70 044907 (2004)
Hydro predictions II: Shapes
* simple formula will not work @ LHC   2
“IPES” (LHC)
2
R S,2
2
R S,0

PLB542 216 (2002)
malisa - WPCF - Sao Heinz&Kolb,
Paulo, Brazil
- Sept 2006
Heinz&Kolb, PLB542 216 (2002)
24
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, presentation
to ALICE PW2 (March 2006)
malisa - WPCF - Sao Paulo, Brazil - Sept 2006
25
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
jet
p
p
jet
• 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
Paic and Skowronski
J. Phys. G31 1045 (2005)
see also Csorgo & Zajc
hep-ph/0412243 (ISMD04)
malisa - WPCF - Sao Paulo, Brazil - Sept 2006
26
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
• 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...]
malisa - WPCF - Sao Paulo, Brazil - Sept 2006
Hossenfelder, Hofmann, Bleicher, Stocker
Phys.Rev. D66 (2002) 101502
• Black Holes / extra dimensions at LHC p+p ?
Humanic, Koch, Stocker hep-ph/0607097
27
le menu des espérances au LHC
boissons
entrées
hydro
p+p
jet
p
jet
p
• signif pT dep
• R increase w/ mult
RL small increase (~30%)
[huge flow  rapid cooling  short ]
• R increase w/ mult
• other details??
RO,S : huge flow 
• larger increase (~60%)
• steeper pT dep
• very large RO in high mult??
shape inversion; oscillation sign flip
plats principaux
NNUS: naive extrapolation
5
as before (same pT dep etc)
but scale by ~17%
as before (same pT dep etc)
but scale by ~45%
malisa - WPCF - Sao Paulo, Brazil - Sept 2006
HRM
RL scales with mult (x2 increase)
[dynamics / chemistry / both ??]
RO,S
• smaller increase (~30%)
• higher flow  steeper pT dep
28
THE END
malisa - WPCF - Sao Paulo, Brazil - Sept 2006
29
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
malisa - WPCF - Sao Paulo, Brazil - Sept 2006
• 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; nuclth/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 hepph/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 spacetime properties of jet fragmentation
• unfortunately, no pT prediction
30