Mike Lisa - ISMD, Berkeley - August A menu of expectations for femtoscopy* 1.0 at LHC/ALICE Mike Lisa Ohio State University *femtoscopy (fem-ta-skö-pee) noun The measurement of spatial scales at the fermi level. Non-trivially related to the “HBT effect” invented to measure stellar scales

Mike Lisa - ISMD, Berkeley - August Outline Brief motivation / review Model expectations for H.I. collisions [  mostly] The importance of femtoscopy in p+p collisions A menu

Mike Lisa - ISMD, Berkeley - August MicroexplosionsFemtoexplosions ss0.1  J 1  J  J/m 3 5 GeV/fm 3 = J/m 3 T10 6 K200 MeV = K rate10 18 K/sec10 35 K/s fast energy deposition  plasma  hydro expansion  cooling to original phase do geometric “postmortem” & infer momentum

Mike Lisa - ISMD, Berkeley - August MicroexplosionsFemtoexplosions ss0.1  J 1  J  J/m 3 5 GeV/fm 3 = J/m 3 T10 6 K200 MeV = K rate10 18 K/sec10 35 K/s fast energy deposition  plasma  hydro expansion  cooling to original phase do geometric “postmortem” & infer momentum

Mike Lisa - ISMD, Berkeley - August MicroexplosionsFemtoexplosions ss0.1  J 1  J  J/m 3 5 GeV/fm 3 = J/m 3 T10 6 K200 MeV = K rate10 18 K/sec10 35 K/s fast energy deposition  plasma  hydro expansion  cooling to original phase do geometric “postmortem” & infer momentum measure explosive pattern of the thermalized bulk matter (low-pT) B2B jets? access to bulk properties (EoS) driving dynamics

Mike Lisa - ISMD, Berkeley - August Spectra v2v2 HBT measure explosive pattern of the thermalized bulk matter (low-pT) hydro expectation (off-center collision) collective p T component: m*v T

Mike Lisa - ISMD, Berkeley - August Spectra v2v2 HBT measure explosive pattern of the thermalized bulk matter (low-pT) “elliptic flow”

Mike Lisa - ISMD, Berkeley - August Spectra v2v2 HBT measure explosive pattern of the thermalized bulk matter (low-pT) femtoscopy probes x-p substructure

Mike Lisa - ISMD, Berkeley - August hydro ideal fluid dynamics At RHIC: Explosive signature sensitive to physics in models cascade Boltzmann models - collisions between particles 3 talks later What might we expect at LHC?

Mike Lisa - ISMD, Berkeley - August “All” soft-physics observables at RHIC (& often SPS/AGS) are multiplicity-driven S. Manly (PHOBOS) QM05 H. Caines (STAR) QM05 NA57 (open) STAR (filled) NA57 (open) STAR (filled) G. Westfall, WPCF 2007 E-by-E fluctuation in K/  MAL,Pratt Soltz,Wiedemann nucl-ex/ Entropy dominance?

Mike Lisa - ISMD, Berkeley - August PHOBOS White Paper: NPA 757, TeV = RHICx1.6

Mike Lisa - ISMD, Berkeley - August NNUS*: Multiplicity sets scale: all else fixed PHOBOS-based extrapolation: R LHC / R RHIC = (1.6) 1/3 = 1.17 PHOBOS White Paper: NPA 757, TeV = RHICx1.6 * NNUS = Nothing New Under the Sun

Mike Lisa - ISMD, Berkeley - August NNUS*: Multiplicity sets scale: all else fixed PHOBOS-based extrapolation: R LHC / R RHIC = (1.6) 1/3 = 1.17 CGC prediction of multiplicity R LHC / R RHIC = (11/3.6) 1/3 = 3 1/3 = 1.45 Kharzeev, Levin & Nardi NPA (2005)

Mike Lisa - ISMD, Berkeley - August NNUS*: Multiplicity sets scale: all else fixed PHOBOS-based extrapolation: R LHC / R RHIC = (1.6) 1/3 = 1.17 CGC prediction of multiplicity R LHC / R RHIC = (11/3.6) 1/3 = 3 1/3 = 1.45 R <~ 11 fm [low pT pions generate largest separation distribution]

Mike Lisa - ISMD, Berkeley - August STAR PRC (2005) NNUS*: Multiplicity sets scale: all else fixed PHOBOS-based extrapolation: R LHC / R RHIC = (1.6) 1/3 = 1.17 CGC prediction of multiplicity R LHC / R RHIC = (11/3.6) 1/3 = 3 1/3 = 1.45 R <~ 11 fm well within experimental reach R fit ~ 1/  (  q 2  )  q ~ 1 MeV/c q min ~ 2 MeV/c ALICE PPR (vol 2): J. Phys G. Part. Nucl. Phys (2006) Access to low-q -> high R

Mike Lisa - ISMD, Berkeley - August Access to long-range non-Gaussian tail Generalized imaging* fit probes long-R / low-q access to resonance tail small below  s ~ 10 GeV LHC should be ~RHIC (... and/or “other” tails...) details beyond gross size Brown, Soltz, Newby, Kisiel nucl-th/ PHENIX, PRL 98, (2007), * c.f. talks of P. Danielewicz & P. Chung

Mike Lisa - ISMD, Berkeley - August Physics from (Gaussian) scales - dynamic models Boltzmann models particle rescattering thermalization not assumed typically “hard” EoS softening must be put in by hand (“string melting” etc) Hydrodynamic models thermalization / “perfect fluid” EoS varied. Typically a “soft point” used

Mike Lisa - ISMD, Berkeley - August Boltzmann-type models Humanic/Hadron Rescattering Model “real” model predicting flow & HBT (dN/d  [LHC] / dN/d  [RHIC] ) 1/3 ~ 1.9 dN/d  T. Humanic, Int.J.Mod.Phys.E15197(2006)

Mike Lisa - ISMD, Berkeley - August Boltzmann-type models R long (fm) dN/dt Humanic/Hadron Rescattering Model “real” model predicting flow & HBT (dN/d  [LHC] / dN/d  [RHIC] ) 1/3 ~ 1.9  LHC /  RHIC = 2 :: (recall R long~ ~  ) dynamic effect R long [LHC] / R long [RHIC] ~ 2 all are connected?? T. Humanic, Int.J.Mod.Phys.E15197(2006)

Mike Lisa - ISMD, Berkeley - August Boltzmann-type models Humanic/Hadron Rescattering Model “real” model predicting flow & HBT (dN/d  [LHC] / dN/d  [RHIC] ) 1/3 ~ 1.9  LHC /  RHIC = 2 :: (recall R long~ ~  ) dynamic effect R long [LHC] / R long [RHIC] ~ 2 all are connected? R S, R O larger, but not a simple factor T. Humanic, Int.J.Mod.Phys.E15197(2006)

Mike Lisa - ISMD, Berkeley - August Boltzmann-type models Humanic/Hadron Rescattering Model “real” model predicting flow & HBT (dN/d  [LHC] / dN/d  [RHIC] ) 1/3 ~ 1.9  LHC /  RHIC = 2 :: (recall R long~ ~  ) dynamic effect R long [LHC] / R long [RHIC] ~ 2 all are connected? R S, R O larger, but not a simple factor steeper p T -dep due to more flow? dynamic effect Hard EoS rescattering models: dynamic effects superimposed on chemistry similar for AMPD C.M. Ko; WPCF06 T. Humanic, Int.J.Mod.Phys.E15197(2006)

Mike Lisa - ISMD, Berkeley - August Hydro predictions I: Scales Neglecting flow, to cool to  C [QGP] :  C =  0 (  C /  0 ) 3/4  C no flow [RHIC] = 6 fm/c  C no flow [LHC] = 20 fm/c Eskola et al PRC (2005) initial conditions from pQCD+saturation

Mike Lisa - ISMD, Berkeley - August Neglecting flow, to cool to  C [QGP] :  C =  0 (  C /  0 ) 3/4  C no flow [RHIC] = 6 fm/c  C no flow [LHC] = 20 fm/c Much larger signif. reduction of LHC [similar to RHIC] larger transverse FO Eskola et al PRC (2005) Hydro predictions I: Scales

Mike Lisa - ISMD, Berkeley - August Neglecting flow, to cool to  C [QGP] :  C =  0 (  C /  0 ) 3/4  C no flow [RHIC] = 6 fm/c  C no flow [LHC] = 20 fm/c Much larger signif. reduction of LHC [similar to RHIC] larger transverse FO No HBT prediction per se, but... R L [LHC] / R L [RHIC] ~ 1.1 ÷ 1.2 R S [LHC] / R S [RHIC] ~ 1.5 ÷ 2 (different than HRM) steeper p T -dependence Eskola et al PRC (2005) Hydro predictions I: Scales

Mike Lisa - ISMD, Berkeley - August Neglecting flow, to cool to  C [QGP] :  C =  0 (  C /  0 ) 3/4  C no flow [RHIC] = 6 fm/c  C no flow [LHC] = 20 fm/c Much larger signif. reduction of LHC [similar to RHIC] larger transverse FO No HBT prediction per se, but... R L [LHC] / R L [RHIC] ~ 1.1 ÷ 1.2 R S [LHC] / R S [RHIC] ~ 1.5 ÷ 2 (different than HRM) steeper p T -dependence Consistent w/ independent hydro for non-central collisions Eskola et al PRC (2005) Hydro predictions I: Scales Heinz&Kolb, PLB (2002) (LHC)

Mike Lisa - ISMD, Berkeley - August easy prediction: importance of  -dep measurements will LHC RP resolution at least as good as STAR asHBT measures source shape at freezeout Hydro predictions II: Shapes STAR 200 GeV PRL (‘04) ALICE PPR (vol 2): J. Phys G. Part. Nucl. Phys (2006)

Mike Lisa - ISMD, Berkeley - August easy prediction: importance of  -dep measurements will LHC RP resolution at least as good as STAR asHBT measures source shape at freezeout probes timescale & dynamics non-trivial (& incomplete!) excitation fctn Hydro predictions II: Shapes E895 2 GeV PLB496 1 (2000) STAR 200 GeV PRL (‘04) O’Hara, et al, Science (2002) 

Mike Lisa - ISMD, Berkeley - August easy prediction: importance of  -dep measurements will LHC RP resolution at least as good as STAR asHBT measures source shape at freezeout probes timescale & dynamics non-trivial (& incomplete!) excitation fctn RHIC misses scale (well-known) impressive agreement on  -dep Hydro predictions II: Shapes STAR PRL (2004) Heinz&Kolb, PLB (2002) “RHIC” 

Mike Lisa - ISMD, Berkeley - August easy prediction: importance of  -dep measurements will LHC RP resolution at least as good as STAR asHBT measures source shape at freezeout probes timescale & dynamics non-trivial (& incomplete!) excitation fctn RHIC misses scale (well-known) impressive agreement on  -dep LHC sign change in shape & oscillations Hydro predictions II: Shapes Heinz&Kolb, PLB (2002) “RHIC” Heinz&Kolb, PLB (2002) “IPES” (LHC) Sign flip in oscillations reflects transition to in-plane geometry (more flow, more time) 

Mike Lisa - ISMD, Berkeley - August p+p: A clear reference system?

Mike Lisa - ISMD, Berkeley - August e+e- (and p+p,  +p...) -- “similar” HBT radii high-quality/stats data sparse diversity of methods corrections coordinate systems jet axis in e+e-... mixing... physics? OPAL e+e- -> Z July 2007 CERN-PH-EP/

Mike Lisa - ISMD, Berkeley - August e+e- (and p+p,  +p...) -- “similar” HBT radii high-quality/stats data sparse diversity of methods corrections coordinate systems jet axis in e+e-... mixing... physics of “x-p” correlations in very small systems? strings? jets? pythia + rescattering? else? i-th particle Initial “disk” of radius r talk by T. Humanic L. Lonnblad - WPCF2007 Paic and Skowronski J. Phys. G (2005) see also Csorgo & Zajc hep-ph/ (ISMD04) pT signal?

Mike Lisa - ISMD, Berkeley - August STAR preliminary m T (GeV) Z. Chajecki WPCF05 Caution: femtoscopy in STAR p+p and A+A measured in same experiment with same method great opportunity to compare physics what causes p T -dependence in p+p? same cause as in A+A??

Mike Lisa - ISMD, Berkeley - August 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 with same method great opportunity to compare physics what causes p T -dependence in p+p? same cause as in A+A? !! But !! significant issues with nontrivial interplay non-femtoscopic correlations (restricted phasespace) - should be less of a problem at LHC - [see talk of T. Humanic] A. Białasz (ISMD): I personally feel that its solution may provide new insight into the hadronization process of QCD

Mike Lisa - ISMD, Berkeley - August as before (same p T dep etc) but scale by ~17% as before (same p T dep etc) but scale by ~45% NNUS: naive extrapolation HRM and AMPT R L (50-100% 30%increase) [dynamics / chemistry / both ??] R O,S smaller increase (~30% 10%) higher flow  steeper p T dep plats principaux boissonsentrées le menu des espérances au LHC hydro R L small increase (~30%) [huge flow  rapid cooling  short  ] R O,S : huge flow  larger increase (~60%) steeper p T dep shape inversion; oscillation sign flip large tilt for central region? p+p p p jet signif p T dep R increase w/ mult other details?? very large R O in high mult?? p+p “=“ A+A ???

Mike Lisa - ISMD, Berkeley - August

Mike Lisa - ISMD, Berkeley - August ++ -- K+K+ K-K- K0SK0S p pp  ++ --  -  K+K+  K-K-  --K0SK0S  p pp     R(√S NN, b, N part, A, B, m T, y, , PID 1, PID 2 ) Does lock pattern break? extract phaseshifts (inversion of K-P paradigm) p+p in multiplicity classes [esp very low multiplicity] HBT relative to jets in p+p and A+A excitation function  -  (direct  yield)

Mike Lisa - ISMD, Berkeley - August The end (...finally...)

Mike Lisa - ISMD, Berkeley - August ALICE PPR2 plots

Mike Lisa - ISMD, Berkeley - August Relative momentum resolution ITS+TPC tracks 2 MeV/c (-> 100 fm, for scale only...) del-qside small since azim. angle well-known qout probes sagitta resolution heavier particles less bending -> smaller sagitta -> worse resolution but due to mT scaling, worse resolution is OK :-) ALICE PPR (vol 2): J. Phys G. Part. Nucl. Phys (2006)

Mike Lisa - ISMD, Berkeley - August Track merging effects in the TPC merging -> ~0.3 fm bias in HBT radius determination for 8 fm source less impt for smaller sources less impt if Coulomb FSI included (?) impact on imaging (non-Gaussian shapes) (?) merging correlated in qo-qs (can mimic “tilted source”) requiring separation in TPC helps remove effect, but convergence is slow ALICE PPR (vol 2): J. Phys G. Part. Nucl. Phys (2006)

Mike Lisa - ISMD, Berkeley - August The ITS helps remove merging effects Ros = 0 as figure of merit Cutting on ITS separation reduces bias to ~ fm ALICE PPR (vol 2): J. Phys G. Part. Nucl. Phys (2006) “similar triangles” : qmin/pT = separationMin/radius

Mike Lisa - ISMD, Berkeley - August Momentum resolution correction “Triple-ratio” correction first (?) used by NA44 uses single-particle resolution (assumed known) to smear “ideal” CF rapid convergence ALICE PPR (vol 2): J. Phys G. Part. Nucl. Phys (2006) method of NA44/E895/STAR/...

Mike Lisa - ISMD, Berkeley - August HBT radii : “out versus in” good to ~15 fm ALICE PPR (vol 2): J. Phys G. Part. Nucl. Phys (2006)

Mike Lisa - ISMD, Berkeley - August Event-by-event femtoscopy in Pb+Pb ALICE PPR (vol 2): J. Phys G. Part. Nucl. Phys (2006)

Mike Lisa - ISMD, Berkeley - August reactionplane resolution At least as good as RHIC/STAR ALICE PPR (vol 2): J. Phys G. Part. Nucl. Phys (2006) Plot from T. Hirano 2005