Rencontres de Moriond QCD 4 Klaus Werner Subatech, Nantes - Flow in p-pb collisions at 5 TeV? K.W. in collaboration with B. Guiot, Iu. Karpenko, T. Pierog
Rencontres de Moriond QCD 4 Klaus Werner Subatech, Nantes - Ultimate goal? Determining properties of the quark gluon plasma (in high energy collisions) Which tool? Observables related to hydrodynamic flow Which systems? Heavy ions, but not only
Rencontres de Moriond QCD 4 Klaus Werner Subatech, Nantes - Signatures of flow?
Rencontres de Moriond QCD 4 Klaus Werner Subatech, Nantes - Ridges & flow harmonics Ridges appear in R = N trigg dn d φ η p.4. assoc T R.-. GeV/c p trigg T.-4. GeV/c due to initial azimuthal anisotropies (longitudinally invariant).. - -.5 - -.5.5 η EPOS.74.5 - φ 4
Rencontres de Moriond QCD 4 Klaus Werner Subatech, Nantes -4 Particle spectra affected by radial flow dn/d dy - - - π K p Λ ppb 5TeV -5% 4 EPOS.76 string decay (dotted) hydro (solid) => mass effect
Rencontres de Moriond QCD 4 Klaus Werner Subatech, Nantes -5 Recent LHC data
Rencontres de Moriond QCD 4 Klaus Werner Subatech, Nantes -6 ppb at 5.TeV CMS arxiv:7.44 Strong variation of shape with multiplicity for kaon and even more for proton pt spectra (flow like)
Rencontres de Moriond QCD 4 Klaus Werner Subatech, Nantes -7 ppb at 5.TeV ALICE Phys.Lett. B79 () 9, arxiv:. ridge & significant v as in in PbPb...
Rencontres de Moriond QCD 4 Klaus Werner Subatech, Nantes -8 ppb at 5.TeV ALICE arxiv:7.7 v.8.6.4...8.6.4. ALICE π K p 4 mass splitting of v!!! pt one of the highlights in heavy ion collisions...
Rencontres de Moriond QCD 4 Klaus Werner Subatech, Nantes -9 ppb data, interpreted in terms of hydrodynamic flow
Rencontres de Moriond QCD 4 Klaus Werner Subatech, Nantes - EPOS, B. Guiot, Y. Karpenko, T. Pierog, K. Werner arxix:7.479,arxiv:., Initial conditions: Gribov-Regge multiple scattering approach, elementary object = Pomeron = parton ladder, using saturation scale Q s N part ŝ λ Core-corona approach to separate fluid and jet hadrons Viscous hydrodynamic expansion, η/s =.8 Statistical hadronization, final state hadronic cascade see also P. Bozek, W. Broniowski, arxiv:4.44 and A. Bzdak, B. Schenke, P. Tribedy, R. Venugopalan, arxiv:4.4
Rencontres de Moriond QCD 4 Klaus Werner Subatech, Nantes - EPOS IC: Marriage pqcd+grt+energy sharing (Drescher, Hladik, Ostapchenko, Pierog, and Werner, Phys. Rept. 5, ) σ tot = cut P uncut P A cut G uncut G B } {{ } dσ exclusive cut Pom : G = ŝ Im {FT {T }}(ŝ, b), T = iŝ σ hard(ŝ) exp(r hardt) Nonlinear effects considered via saturation scale Q s N part ŝ λ
Rencontres de Moriond QCD 4 Klaus Werner Subatech, Nantes - σ tot = A d b B j= i= d b A i dzi A ρ A ( (b A i ) + (zi A) ) d b B j dzj B ρ B ( (b B j ) + (zj B) ) AB ( mk... ( δ Σmk ) dx + k,µ dx k,µ m l m AB l AB k= µ= AB ( m k G(x + k,µ m k! l k!, x k,µ, s, b + b A π(k) b B τ(k) ) k= A i= l k λ= ( µ= G( x + k,λ, x k,λ, s, b + b A π(k) b B τ(k) ) ) π(k)=i x + k,µ, π(k)=i x + k,λ ) α B j= ( l k λ= τ(k)=j d x + k,λ d x k,λ x k,µ τ(k)=j ) { x k,λ ) α }
Rencontres de Moriond QCD 4 Klaus Werner Subatech, Nantes - The hydrodynamic equations (Israel-Stewart formulation) in arbitrary coordinate system (implemented/solved by Yuri Karpenko), always η/s =.8, ζ/s = ;ν T µν = ν T µν + Γ µ νλ T νλ + Γ ν νλt µλ = γ ( t + v i i )π µν = πµν π µν NS + I π µν τ π γ ( t + v i i ) Π = Π Π NS τ Π + I Π T µν = ǫu µ u ν (p + Π) µν + π µν, ;ν denotes a covariant derivative, µν = g µν u µ u ν is the projector orthogonal to u µ, π µν and Π are the shear stress tensor and bulk pressure, respectively. π µν NS = η( µλ ;λ u ν + νλ ;λ u µ ) η µν ;λ u λ Π NS = ζ ;λ u λ I µν π = 4 πµν ;γ u γ [u ν π µβ + u µ π νβ ]u λ ;λ u β I Π = 4 Π ;γu γ
Rencontres de Moriond QCD 4 Klaus Werner Subatech, Nantes -4 EPOS: Pomeron => parton ladder => flux tube (kinky string) y (fm).5.5 -.5 - -.5 String segments with high pt escape => corona, the others form the core = initial condition for hydro ppb 5TeV 8 Pomerons depending on the local string density η =. -.5 - -.5.5.5 x (fm) dn/d dy - - - -4 pions x protons corona ppb 5TeV -4% core EPOS.76 4 6 pt
Rencontres de Moriond QCD 4 Klaus Werner Subatech, Nantes -5 We will compare EPOS with ppb data and also with EPOS LHC LHC tune of EPOS.99, : same GR, but uses parameterized flow T. Pierog et al, arxiv:6.54 AMPT Parton + hadron cascade Z.-W. Lin, C. M. Ko, B.-A. Li, B. Zhang and S. Pal, Phys. Rev. C 7, 649 (5). QGSJET GR approach, No flow S. Ostapchenko, Phys. Rev. D74 (6) 46
Rencontres de Moriond QCD 4 Klaus Werner Subatech, Nantes -6 dn/d (normalized) dn/d (normalized) 4.5 4.5.5.5.5 5 4 π QGSJETII-4 CMS.5.5 π EPOS LHC CMS.5.5 dn/d (normalized) dn/d (normalized) 5 4 4.5 4.5.5.5.5 π AMPT CMS.5.5 π EPOS.76 CMS.5.5 Little change with <N_tracks> for pions CMS 4 multiplicity classes: <N_tracks> : 8, 84, 6, 5 (in η <.4)
Rencontres de Moriond QCD 4 Klaus Werner Subatech, Nantes -7 dn/d (normalized) dn/d (normalized) 4.5 4.5.5.5.5 4.5.5.5.5 K QGSJETII-4 CMS.5.5 K EPOS LHC CMS.5.5 dn/d (normalized) dn/d (normalized) 4.5 4.5.5.5.5 4.5.5.5.5 K AMPT CMS.5.5 K EPOS.76 CMS.5.5 Kaon spectra change with <N_tracks> in EPOS: more and more flow contribution
Rencontres de Moriond QCD 4 Klaus Werner Subatech, Nantes -8 dn/d (normalized) 4.5.5.5.5 p QGSJETII-4 CMS.5.5 dn/d (normalized) 4.5.5.5.5 p AMPT CMS.5.5 dn/d (normalized).5.5.5.5 p EPOS LHC CMS.5.5 dn/d (normalized).5.5.5.5 p EPOS.76 CMS.5.5 Strong variation of proton spectra => flow helps
Rencontres de Moriond QCD 4 Klaus Werner Subatech, Nantes -9 ALICE arxiv:7.6796 Two multiplicity classes: -5%, 6-8% (in.8 < η lab < 5.) Useful : ratios (Λ/K) ratio. Λ / Ks ppb 5.TeV data ALICE.8.6.4. -5% 6-8% 4 5 6 Significant variation of lambda/k like in PbPb
ratio ratio Rencontres de Moriond QCD 4 Klaus Werner Subatech, Nantes -..8.6.4...8.6.4. Λ / Ks ppb 5.TeV data ALICE QGSJETII-4 4 5 6 Λ / Ks ppb 5.TeV data ALICE EPOS LHC -5% 6-8% 4 5 6 ratio ratio..8.6.4...8.6.4. Λ / Ks ppb 5.TeV data ALICE AMPT -5% 6-8% 4 5 6 Λ / Ks ppb 5.TeV data ALICE EPOS.76-5% 6-8% 4 5 6 again, flow already needed for low multiplicity (even in pp!) => flow peak
Rencontres de Moriond QCD 4 Klaus Werner Subatech, Nantes - Ridges in pa ALICE, arxiv:., arxiv:7.7 p assoc T.-. GeV/c p trigg T.-4. GeV/c R.4... ALICE - -.5 - -.5.5 η EPOS.74.5 - φ 4
Rencontres de Moriond QCD 4 Klaus Werner Subatech, Nantes - Central - peripheral (to get rid of jets) assoc p T.-. GeV/c p trigg T.-4. GeV/c R.78.76.74.7 - -.5 η - -.5.5.5 - φ 4 ALICE EPOS.74
Rencontres de Moriond QCD 4 Klaus Werner Subatech, Nantes - Identified particle v v.8.6.4...8.6.4. ALICE π K p 4 pt mass splitting, as in PbPb!!!
Rencontres de Moriond QCD 4 Klaus Werner Subatech, Nantes -4 ppb in EPOS Pomerons (number and positions) characterize geometry (P. number multiplicity) random azimuthal asymmetry => asymmetric flow seen at higher pt for heavier ptls Robust results y (fm).5.5 -.5 - -.5 ppb 5TeV 8 Pomerons η =. -.5 - -.5.5.5 x (fm)
Rencontres de Moriond QCD 4 Klaus Werner Subatech, Nantes -5 v for π, K, p clearly differ v.4...8.6.4. EPOS.74 π K p ALICE π K p.5.5.5 mass splitting, due to flow
Rencontres de Moriond QCD 4 Klaus Werner Subatech, Nantes -6 Summary Analyzing pt-spectra, ratios, and dihadrons correlations for identified hadrons: ppb looks very much like a hydrodynamically expanding system (more clean than PbPb, where hydro and minijets heavily interact, as well as the final hadrons among themselves) v.4...8.6.4. EPOS.74 π K p ALICE π K p.5.5.5
Rencontres de Moriond QCD 4 Klaus Werner Subatech, Nantes -7 ALICE arxiv:.77