Expectations for Femtoscopy at the LHC

malisa - WPCF - Sao Paulo, Brazil - Sept 2006 1

Expectations for Femtoscopy at the LHC

Mike Lisa

Ohio State University


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


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


R(√SNN, b, Npart, A, B, y, mT, , PID)

€

R i mT( ) =′ R i

mTα i


€

R i mT( ) =′ R i

mTα i


Z. Chajecki, QM05


€

R i mT( ) =′ R i

mTα i


Z. Chajecki, QM05

QuickTime™ and aTIFF (LZW) decompressor

are needed to see this picture.

MAL, Pratt, Soltz, Wiedemann nucl-ex/0505014 STAR, PRL 2004


€

R i mT( ) =′ R i

mTα i


Z. Chajecki, QM05



MAL, Pratt, Soltz, Wiedemann nucl-ex/0505014 STAR, PRL 2004

MAL,Pratt Soltz,Wiedemann nucl-ex/0505014


€

R i mT( ) =′ R i

mTα i


Z. Chajecki, QM05



MAL, Pratt, Soltz, Wiedemann nucl-ex/0505014STAR, PRL 2004


+ - K+ K- K0S p p

p

p

K0S

K-

K+

-

+

Full program just startedEvolution with energy?

Little dataShape Evolution with energy?

Naïve (?) : multiplicity dominance continues @ LHC(though two unexplored areas...)


LHC = RHIC++


PHOBOS White Paper: NPA 757, 28

1000 5.5 TeV

5

6

6.4 = RHICx1.6

Naïve (?) : multiplicity dominance continues @ LHC(though two unexplored areas...)


Multiplicity sets scale: all else fixed



1000 5.5 TeV

5

6

6.4 = RHICx1.6



• PHOBOS-based extrapolation:• RLHC / RRHIC = (1.6)1/3 = 1.17


1000 5.5 TeV

5

6

6.4 = RHICx1.6




• CGC prediction of multiplicity

• RLHC / RRHIC = (11/3.6)1/3 = 31/3 = 1.45

Kharzeev, Levin & Nardi NPA747 609 (2005)


Beyond 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)


Beyond multiplicity

Rlo

ng (

fm)

dN

/dt



• RLHC / RRHIC = (11/3.6)1/3 = 31/3 = 1.45



• (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??



Beyond multiplicity



• RLHC / RRHIC = (11/3.6)1/3 = 31/3 = 1.45



• (dN/d[LHC] / dN/d[RHIC])1/3 ~ 1.9


• dynamic effect


• all are connected?

• RS, RO larger, but not a simple factor



Beyond multiplicity



• RLHC / RRHIC = (11/3.6)1/3 = 31/3 = 1.45



• (dN/d[LHC] / dN/d[RHIC])1/3 ~ 1.9


• dynamic effect


• all are connected?

• RS, RO larger, but not a simple factor

• steeper pT-dep due to more flow?

• dynamic effect



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



C = 0(C /0)3/4



• Much larger flow @LHC• signif. reduction of timescale @ LHC

[similar to RHIC]

• larger transverse size @ FO





C = 0(C /0)3/4




[similar to RHIC]


• 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





C = 0(C /0)3/4




[similar to RHIC]


• 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



Heinz&Kolb, PLB542 216 (2002)

(LHC)


• 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

)




• hydro @ RHIC• misses scale (well-known)• impressive agreement on -dep


STAR PRL93 012301 (2004)Heinz&Kolb, PLB542 216 (2002)

“RHIC”





• prediction @ LHC• sign change in shape & oscillations



“RHIC”


“IPES” (LHC)





• prediction @ LHC• sign change in shape & oscillations

• qualitatively different kT dependence (*)



“RHIC”


“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)


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)







• 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)







• 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


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

RL scales with mult (x2 increase)[dynamics / chemistry / both ??]

RO,S • smaller increase (~30%)• 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


THE END


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

Expectations for Femtoscopy at the LHC

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