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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
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PW2 Femtoscopy Femtoscopy at the highest energies:Expectations and directions at the LHC Mike Lisa Ohio State University malisa - SPHIC - Catania Italy - Sept 2006
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
pa pa pb pb xa xa xb xb know/assume source distrib extract interaction (scat. length..) know/assume relative wavefunction extract spatial distributions OR Femtoscopic information malisa - SPHIC - Catania Italy - Sept 2006
energy quickly deposited • enter plasma phase • expand hydrodynamically • cool back to original phase • do geometric “postmortem” & infer momentum malisa - SPHIC - Catania Italy - Sept 2006
energy quickly deposited • enter plasma phase • expand hydrodynamically • cool back to original phase • do geometric “postmortem” & infer momentum malisa - SPHIC - Catania Italy - Sept 2006
y |b| pT Baseline: 20-year-old systematic program • Pion HBT @ Bevalac: “largely confirming nuclear dimensions” • Since 90’s: increasingly detailed understanding and study w/ high stats malisa - SPHIC - Catania Italy - Sept 2006
fast region fast region R(√SNN, b, Npart, A, B, y, mT, ,PID) malisa - SPHIC - Catania Italy - Sept 2006
PRC 71 044906 (2005) Spectra v2 HBT PRL 87 082301 (2001) PRL 93 012301 (2004) PRC 71 044906 (2005) PRL 93 012301 ‘04 R(√SNN, b, Npart, A, B, mT, y, ,PID) malisa - SPHIC - Catania Italy - Sept 2006
R(√SNN, b, Npart, A, B, y, mT, ,PID) Z. Chajecki, QM05 malisa - SPHIC - Catania Italy - Sept 2006
PRC 71 044906 (2005) D. Flierl, PhD thesis 2002 Spectra v2 PRL 91 262301 (2003) HBT emission region PRL 87 082301 (2001) PRL 93 012301 (2004) PRC 71 044906 (2005) K emission region PRL 93 012301 ‘04 R(√SNN, b, Npart, A, B, mT, y, ,PID) malisa - SPHIC - Catania Italy - Sept 2006
PRC 71 044906 (2005) D. Flierl, PhD thesis 2002 Spectra v2 PRL 91 262301 (2003) HBT emission region PRL 87 082301 (2001) PRL 93 012301 (2004) PRC 71 044906 (2005) K emission region PRL 93 012301 ‘04 R(√SNN, b, Npart, A, B, mT, y, ,PID) STAR, PRL 2004 Full program just started Evolution with energy? MAL,Pratt Soltz,Wiedemann nucl-ex/0505014 malisa - SPHIC - Catania Italy - Sept 2006
STAR, PRL 2004 MAL, Pratt, Soltz, Wiedemann nucl-ex/0505014 R(√SNN, b, Npart, A, B, y, mT, ,PID) Z. Chajecki, QM05 malisa - SPHIC - Catania Italy - Sept 2006
MAL,Pratt Soltz,Wiedemann nucl-ex/0505014 R(√SNN, b, Npart, A, B, y, mT, ,PID) STAR, PRL 2004 MAL, Pratt, Soltz, Wiedemann nucl-ex/0505014 Z. Chajecki, QM05 Little data Shape Evolution with energy? Naïve (?) : multiplicity dominance continues @ LHC (though two unexplored areas...) malisa - SPHIC - Catania Italy - Sept 2006
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 malisa - SPHIC - Catania Italy - Sept 2006
MAL,Pratt Soltz,Wiedemann nucl-ex/0505014 R(√SNN, b, Npart, A, B, y, mT, ,PID) STAR, PRL 2004 MAL, Pratt, Soltz, Wiedemann nucl-ex/0505014 Z. Chajecki, QM05 Little data Shape Evolution with energy? Naïve (?) : multiplicity dominance continues @ LHC (though two unexplored areas...) malisa - SPHIC - Catania Italy - Sept 2006
6 5 5.5 TeV 1000 6.4 = RHICx1.6 PHOBOS White Paper: NPA 757, 28 malisa - SPHIC - Catania Italy - Sept 2006
6.4 = RHICx1.6 6 5 MAL,Pratt Soltz,Wiedemann nucl-ex/0505014 PHOBOS White Paper: NPA 757, 28 5.5 TeV 1000 Multiplicity sets scale: all else fixed malisa - SPHIC - Catania Italy - Sept 2006
6.4 = RHICx1.6 6 5 PHOBOS White Paper: NPA 757, 28 5.5 TeV 1000 Multiplicity sets scale: all else fixed • PHOBOS-based extrapolation: • RLHC / RRHIC = (1.6)1/3 = 1.17 malisa - SPHIC - Catania Italy - Sept 2006
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 - SPHIC - Catania Italy - Sept 2006 Kharzeev, Levin & Nardi NPA747 609 (2005)
dN/d 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 malisa - SPHIC - Catania Italy - Sept 2006
dN/dt Rlong (fm) 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] ~ 1.5-2 • all are connected?? malisa - SPHIC - Catania Italy - Sept 2006
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 - SPHIC - Catania Italy - Sept 2006
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? • dynamic effect malisa - SPHIC - Catania Italy - Sept 2006
hydro cascade • does not do as well ascascades, but neverthelesswe’ll look next for guidance... • AMPT does ~Ok • needs string melting& 6-10 mb parton Cascade / Hydro models versus RHIC data malisa - SPHIC - Catania Italy - Sept 2006
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
Eskola et al PRC72044904 (2005) initial conditions from pQCD+saturation 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 malisa - SPHIC - Catania Italy - Sept 2006
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 - SPHIC - Catania Italy - Sept 2006
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 - SPHIC - Catania Italy - Sept 2006
Eskola et al PRC72044904 (2005) Heinz&Kolb, PLB542 216 (2002) 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 • Consistent w/ independent hydrofor non-central collisions (LHC) malisa - SPHIC - Catania Italy - Sept 2006
PLB496 1 (2000) E895 2 GeV STAR 200 GeV O’Hara, et al, Science 298 2179 (2002) PRL93 012301 (‘04) Hydro predictions II: Shapes • easy prediction: importance of -dep measurements will continue @ LHC • asHBT • probes timescale & dynamics • non-trivial (& incomplete!) excitation fctn malisa - SPHIC - Catania Italy - Sept 2006
“RHIC” STAR PRL93 012301 (2004) Heinz&Kolb, PLB542 216 (2002) 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 malisa - SPHIC - Catania Italy - Sept 2006
“RHIC” “IPES” (LHC) Heinz&Kolb, PLB542 216 (2002) Heinz&Kolb, PLB542 216 (2002) 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 malisa - SPHIC - Catania Italy - Sept 2006
F. Retière & MAL PRC70 044907 (2004) “RHIC” “IPES” (LHC) * simple formula will not work @ LHC Heinz&Kolb, PLB542 216 (2002) Heinz&Kolb, PLB542 216 (2002) 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 • qualitatively different kT dependence (*) malisa - SPHIC - Catania Italy - Sept 2006
i-th particle Initial “disk” of radius r 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 T. Humanic, presentation to ALICE PW2 (March 2006) malisa - SPHIC - Catania Italy - Sept 2006
jet p p jet 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 Paic and Skowronski J. Phys. G311045 (2005) see also Csorgo & Zajc hep-ph/0412243 (ISMD04) malisa - SPHIC - Catania Italy - Sept 2006
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...] Humanic, Koch, Stocker hep-ph/0607097 Hossenfelder, Hofmann, Bleicher, Stocker Phys.Rev. D66 (2002) 101502 malisa - SPHIC - Catania Italy - Sept 2006
STAR preliminary mT (GeV) mT (GeV) femtoscopy in p+p @ STAR Z. Chajecki WPCF05 • 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
Ratio of (AuAu, CuCu, dAu) HBT radii by pp pp, dAu, CuCu - STAR preliminary Surprising („puzzling”) scaling !! But !! major issues with nontrivial interplay non-femtoscopic correlations • 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? HBT radii scale with pp Scary coincidence or something deeper? malisa - SPHIC - Catania Italy - Sept 2006
le menu des espérances au LHC p+p NNUS: naive extrapolation • signif pT dep • R increase w/ mult as before (same pT dep etc) but scale by ~17% • R increase w/ mult • other details?? 5 as before(same pT dep etc) but scale by ~45% • very large RO in high mult?? hydro HRM andAMPT jet RL (50-100%30%increase) [dynamics / chemistry / both ??] RL small increase (~30%) [huge flow rapid cooling short ] • RO,S • smaller increase (~30% 10%) • higher flow steeper pT dep p p • RO,S : huge flow • larger increase (~60%) • steeper pT dep jet shape inversion; oscillation sign flip boissons entrées plats principaux malisa - SPHIC - Catania Italy - Sept 2006
“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
nouvelles directions • 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 malisa - SPHIC - Catania Italy - Sept 2006
THE END malisa - SPHIC - Catania Italy - Sept 2006
references • 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 • 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 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. G311045 (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
Why can’t HBT be more like v2? malisa - SPHIC - Catania Italy - Sept 2006
STAR preliminary Why can’t HBT be more like v2...? pT-integrated v2 excitation function NA49: Phys.Rev. C68 (2003) 034903 slide of Raimond Snellings HIF 2003 malisa - SPHIC - Catania Italy - Sept 2006
Why can’t HBT be more like v2...? v2(pt) SPS-RHIC • 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 malisa - SPHIC - Catania Italy - Sept 2006
Why can’t HBT be more like v2...? It can! ..... Just gotta look in less detail! malisa - SPHIC - Catania Italy - Sept 2006