ALICE physics. with focus on activities from the Dutch groups. Marco van Leeuwen, Nikhef, Utrecht University and CERN

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1 ALICE hysics with focus on activities from the Dutch grous Marco van Leeuwen, Nikhef, Utrecht University and CERN NuPECC meeting, 6-7 March, Amsterdam

Meet the grou Comosition 7 staff 6 ostdocs PhD students Analysis/hysics involvement: Flow, collective effects Photons Heavy flavour High- and jets Detector involvement: Silicon Stri Detector (current

2 Meet the grou Comosition 7 staff 6 ostdocs PhD students Analysis/hysics involvement: Flow, collective effects Photons Heavy flavour High- and jets Detector involvement: Silicon Stri Detector (current IS) IS ugrade FOCAL: Si-W EMCal develoment Large imact on hysics ublications Organisational roles in ALICE: PWG convener(s), PAG coordinators, Editorial board, Conference Committee membershi, Physics Coordinator

3 Quick word on funding Four main sources of funding: Permanent staff funded by Nikhef, Utrecht University NwO rogram funding : research ostdocs+phd students (a few ositions) NwO Big : investment funding for detector construction and comuting; common with other LHC exeriments Personal grants (NwO/ERC): other PhD students + ostdocs (majority) 3

4 Heavy ion collisions Heavy-ion collisions roduce quasi-thermal QCD matter Dominated by soft artons ~ ~ -3 MeV Bulk observables Study hadrons roduced by the QGP yically < - GeV

5 Heavy ion collisions Heavy-ion collisions roduce quasi-thermal QCD matter Dominated by soft artons ~ ~ -3 MeV Bulk observables Study hadrons roduced by the QGP yically < - GeV Hard robes Hard-scatterings roduce quasi-free artons Probe medium through energy loss > 5 GeV

6 Heavy ion collisions Heavy-ion collisions roduce quasi-thermal QCD matter Dominated by soft artons ~ ~ -3 MeV Bulk observables Study hadrons roduced by the QGP yically < - GeV Hard robes Hard-scatterings roduce quasi-free artons Probe medium through energy loss > 5 GeV wo basic aroaches to learn about the QGP ) Bulk observables ) Hard robes

7 Direct hotons Direct/decay hoton double ratio Direct hoton sectra R γ % Pb-Pb s NN =.76 ev ALICE NLO QCD PDF: CEQ6M5 FF: GRV JEPHOX PDF: C, FF: BFG JEPHOX npdf: EPS9, FF: BFG (all scaled by N coll ) -% Pb-Pb s NN =.76 ev ALICE NLO QCD PDF: CEQ6M5 FF: GRV JEPHOX PDF: C, FF: BFG JEPHOX npdf: EPS9, FF: BFG (all scaled by N coll ) N γ d c ) - (GeV dir dy d Pb-Pb s NN =.76 ev -% ALICE -% ALICE -8% ALICE A ex(- / eff ) -% -% arxiv: % Pb-Pb s NN =.76 ev ALICE NLO QCD PDF: CEQ6M5 FF: GRV JEPHOX PDF: C, FF: BFG JEPHOX npdf: EPS9, FF: BFG (all scaled by N coll ) N ev. π x. (GeV/c) x Main exected sources: High : hard scattering; quark-gluon Comton rocess Low : thermal radiation Excess at low in central collisions indicates thermal hoton roduction init ~ - MeV 3 ALI PUB Paquet et al. arxiv: Linnyk et al. arxiv: x Chatterjee et al. v. Hees et al. PRC 85() 69 NPA 933(5) 56 + JHEP 35(3) (GeV/c) 5

8 Identified article sectra and radial flow Proton momentum distribution - dy) (GeV/c) N/(d d % x 5-% x 7 -% x -3% x 5 3-% x -5% x 3 5-6% x 6-7% x 7-8% x 8-9% ALICE Preliminary Pb-Pb s NN 8 6 = 5. ev 3 5 ALI PREL 9 Uncertainties: stat. (bars), sys. (boxes) 6 8 (GeV/c) Large range in using different detector systems 6

9 Identified article sectra and radial flow - dy) (GeV/c) N/(d d Proton momentum distribution ALI PREL (GeV/c) % x 5-% x 7 -% x -3% x 5 3-% x -5% x 3 5-6% x 6-7% x 7-8% x 8-9% ALICE Preliminary Pb-Pb Uncertainties: stat. (bars), sys. (boxes) s NN 8 6 = 5. ev (GeV) kin Global Blast-Wave fit to π (.5- GeV/c), K (.-.5 GeV/c), (.3-3. GeV/c) ALICE Preliminary,, s = 7 ev ALICE, -Pb, s = 5. ev ALICE, Pb-Pb, s NN =.76 ev ALICE Preliminary, Pb-Pb, s NN = 5. ev exansion velocity β ALI-PREL-5 Radial exansion model: blast wave Large range in using different detector systems 6

10 Identified article sectra and radial flow - dy) (GeV/c) N/(d d Proton momentum distribution ALI PREL (GeV/c) % x 5-% x 7 -% x -3% x 5 3-% x -5% x 3 5-6% x 6-7% x 7-8% x 8-9% ALICE Preliminary Pb-Pb Uncertainties: stat. (bars), sys. (boxes) s NN 8 6 = 5. ev Large range in using different detector systems (GeV) kin Global Blast-Wave fit to π (.5- GeV/c), K (.-.5 GeV/c), (.3-3. GeV/c) ALICE Preliminary,, s = 7 ev ALICE, -Pb, s = 5. ev ALICE, Pb-Pb, s NN =.76 ev ALICE Preliminary, Pb-Pb, s NN = 5. ev exansion velocity β ALI-PREL-5 Radial exansion model: blast wave Largest exansion velocities observed in the laboratory achieved in Run ( snn = 5. ev).66 times the seed of light! 6

11 Azimuthal anisotroy: initial and final states MC event: location of nucleons Characterise shae by angular moments: 7

12 Azimuthal anisotroy: initial and final states MC event: location of nucleons Characterise shae by angular moments: 7

13 Azimuthal anisotroy: initial and final states MC event: location of nucleons Characterise shae by angular moments: 7

14 Azimuthal anisotroy: initial and final states MC event: location of nucleons Characterise shae by angular moments: 7

15 Azimuthal anisotroy: initial and final states MC event: location of nucleons Characterise shae by angular moments: 7

16 Azimuthal anisotroy: initial and final states MC event: location of nucleons Characterise shae by angular moments: Initial state satial anisotroies εn are transferred into final state momentum anisotroies vn by ressure gradients, flow of the Quark Gluon Plasma 7

17 Azimuthal anisotroy: initial and final states 5 5 MC event: location of nucleons 5 5 Characterise shae by angular moments: Initial state satial anisotroies εn are transferred into final state momentum anisotroies vn by ressure gradients, flow of the Quark Gluon Plasma Azimuthal distribution single event (ϕ) (GeV/c) ρ ch C( φ) Pb-Pb s NN =.76 ev Single event.5 < < 5 GeV/c, η <.9, track track ρ (ϕ) ch ρ ρ (+v cos([ϕ-ψ ])) EP, ρ (+v cos(3[ϕ-ψ ])) 3 EP, 3 ALICE ϕ (rad) Sum over many events Centrality -%, η <.8 η > v,3,,5 {, η > }. <. < t,trig t,assoc < 3. <. - 3 φ (rad.) ALICE, PLB 753, 5 ALICE PRL. 7, 33 7

18 Anisotroic flow ALICE results iebe-vishnu.5 K K v 3. ± π ± + ± π ± + -%.5 v 3. Pb-Pb s NN =.76 ev -3%.5.5 v {SP, η >.9} I PUB ± ± π K Ks φ - + Ξ +Ξ ALICE -3% Pb-Pb + Λ+ Λ - + Ω +Ω s NN =.76 ev 6 (GeV/c) JHEP6, (GeV/c) % (GeV/c).5.5 Mass-deendence of v measures flow velocity ests hydrodynamical descrition, freeze-out models. v 3 v 3 v 3 v 3 v 3 v (GeV/c) ALICE iebe-vishnu -%. ± ± π.5 π K ± K ± (GeV/c) 3-% (GeV/c) v 3 v (GeV/c) v3 v 3 v 3 v 3 v v v v v v v v ALICE iebe-vishnu -% ± ± π (GeV/c) Pb-Pb s π NN K ± =.76 ev K ± -3% % arxiv: (GeV/c) (GeV/c).5 ALICE iebe-vishnu -%. (GeV/c) ± ±.5 π.5 π K ± K ± (GeV/c) 3-% % (GeV/c) +... v (GeV/c). (GeV/c) % (GeV/c) (GeV/c).. (GeV/c) v (GeV/c) v v v v v v

19 Charge deendence of directed flow Fast moving sectator matter generates large magnetic field odd v Pb-Pb ALICE Preliminary - s = 5. ev 5-%.8 µb NN >. GeV/c + v - v. V. Voronyuk et al, arxiv: ALI-PREL-968 bars: stat. err. boxes (filled/emty): syst. err. (corr./uncorr.) η Charge deendence of v measures the magnetic field (Lorentz and Hall effect) 9

odd v.8.6... 3 Pb-Pb ALICE Preliminary - s = 5.

boxes (filled/emty): syst. err. (corr./uncorr.

20 Charge deendence of directed flow Fast moving sectator matter generates large magnetic field odd v Pb-Pb ALICE Preliminary - s = 5. ev 5-%.8 µb NN >. GeV/c + v - v. V. Voronyuk et al, arxiv: ALI-PREL-968 bars: stat. err. boxes (filled/emty): syst. err. (corr./uncorr.) η Charge deendence of v measures the magnetic field (Lorentz and Hall effect) 9

21 Direct hoton v γ v.8 Inclusive and decay hoton v. ALICE reliminary γ,decay v -% Pb-Pb, V event lane s NN =.76 ev γ,incl v γ,dir v. Direct hoton v ALICE reliminary -% Pb-Pb, s NN =.76 ev V event lane decay + NLO. Phys.Rev. D5 (99) 9-96 decay + NLO + thermal (Shen et al.) arxiv:38.. decay + NLO + thermal (Holoainen et al.) Phys.Rev. C8 () (GeV/c) ALI PREL ALI PREL 7595 ALICE reliminary NLO (Vogelsang) + thermal (Shen et al.) NLO (Vogelsang) + thermal (Holoainen et al.) PHSD(O. Linnyk et al.) 3 5 (GeV/c) hermal direct hotons roduced early in collision sensitive to time evolution of QGP

22 Direct hoton v γ v.8 Inclusive and decay hoton v. ALICE reliminary γ,decay v -% Pb-Pb, V event lane s NN =.76 ev γ,incl v γ,dir v. Direct hoton v ALICE reliminary -% Pb-Pb, s NN =.76 ev V event lane decay + NLO. Phys.Rev. D5 (99) 9-96 decay + NLO + thermal (Shen et al.) arxiv:38.. decay + NLO + thermal (Holoainen et al.) Phys.Rev. C8 () (GeV/c) ALI PREL ALI PREL 7595 ALICE reliminary NLO (Vogelsang) + thermal (Shen et al.) NLO (Vogelsang) + thermal (Holoainen et al.) PHSD(O. Linnyk et al.) 3 5 (GeV/c) hermal direct hotons roduced early in collision sensitive to time evolution of QGP Direct hoton v larger than exected yield and v are related: early emission: large yield, small v late emission: small yield, large v

23 Heavy-ion-like effects in ( and) -Pb collisions

24 wo-article correlations in and Pb+Pb d N d η d φ air trg N Central Pb+Pb CMS L int CMS, arxiv:.358 φ = 3.9 µb - -5% - η - + low multilicity + high multilicity trig PbPb s NN =.76 ev 3. < < 3.5 GeV/c 5-% Ntrk Ntrk < 35 > -5% φ - - η < < 3 GeV 9 φ - - η. CMS, PLB 78, trigger Near side associated -5% 5-3% 3-35% d N d η d φ air N trg

25 wo-article correlations in and Pb+Pb d N d η d φ air trg N Central Pb+Pb CMS L int CMS, arxiv:.358 φ = 3.9 µb - -5% - η - + low multilicity + high multilicity trig PbPb s NN =.76 ev 3. < < 3.5 GeV/c 5-% Ntrk Ntrk < 35 > -5% φ - - η < < 3 GeV 9 φ - - η. CMS, PLB 78, trigger Near side associated -5% 5-3% 3-35% d N d η d φ air N trg 5 3 Near-side long range correlation: indicates early time origin

wo-article correlations in and Pb+Pb d N d η d φ air trg N 3.5 3 9.5 9 Central Pb+Pb CMS L int CMS, arxiv:.358 φ = 3.9 µb - -5% - η - + low multilicity + high multilicity trig PbPb s NN =.76 ev 3.

26 wo-article correlations in and Pb+Pb d N d η d φ air trg N Central Pb+Pb CMS L int CMS, arxiv:.358 φ = 3.9 µb - -5% - η - + low multilicity + high multilicity trig PbPb s NN =.76 ev 3. < < 3.5 GeV/c 5-% Ntrk Ntrk < 35 > -5% φ - - η < < 3 GeV 9 φ - - η. CMS, PLB 78, trigger Near side associated -5% 5-3% 3-35% d N d η d φ air N trg 5 3 Near-side long range correlation: indicates early time origin Seen in high-multilicity and +Pb events 8 7 6

27 Collective effects for charm in -Pb? assoc ) - - baseline (rad dn d ϕ Heavy flavour-electron-hadron correlations η (c,b) e N.7 ALICE Preliminary.6 -Pb, s = 5. ev NN η < ALI PREL 38 Baseline stat. unc. -% (c,b) e - charged article correlation <.3 < Baseline stat. unc. 6-% e < GeV/c, -.6 < y assoc < GeV/c -% VA class 6-% VA class e cms <.3 3% syst. ϕ-uncorrelated unc. % syst. unc. in ϕ < not shown 3 5 ϕ (rad) 3

28 Collective effects for charm in -Pb? assoc ) - - baseline (rad dn d ϕ Heavy flavour-electron-hadron correlations η (c,b) e N.7 ALICE Preliminary.6 -Pb, s = 5. ev NN η < ALI PREL 38 Baseline stat. unc. -% (c,b) e - charged article correlation <.3 < Baseline stat. unc. 6-% e < GeV/c, -.6 < y assoc < GeV/c -% VA class 6-% VA class e cms <.3 3% syst. ϕ-uncorrelated unc. % syst. unc. in ϕ < not shown 3 5 ϕ (rad) 3

29 Collective effects for charm in -Pb? Heavy flavour-electron-hadron correlations v from -article correlations assoc ) - - baseline (rad dn d ϕ η (c,b) e N.7 ALICE Preliminary.6 -Pb, s = 5. ev NN η < ALI PREL 38 Baseline stat. unc. -% (c,b) e - charged article correlation <.3 < Baseline stat. unc. 6-% e < GeV/c, -.6 < y assoc < GeV/c -% VA class 6-% VA class e cms <.3 3% syst. ϕ-uncorrelated unc. % syst. unc. in ϕ < not shown 3 5 ϕ (rad) 3

30 Collective effects for charm in -Pb? Heavy flavour-electron-hadron correlations v from -article correlations assoc ) - - baseline (rad dn d ϕ η (c,b) e N.7 ALICE Preliminary.6 -Pb, s = 5. ev NN η < ALI PREL 38 Baseline stat. unc. -% (c,b) e - charged article correlation <.3 < Baseline stat. unc. 6-% e < GeV/c, -.6 < y assoc < GeV/c -% VA class 6-% VA class e cms <.3 3% syst. ϕ-uncorrelated unc. % syst. unc. in ϕ < not shown 3 5 ϕ (rad) azimuthal modulation for HF electrons in -Pb collisions magnitude similar to charged hadrons and Pb-Pb Similar effect also seen for J/ψ 3

31 Collective effects for charm in -Pb? Heavy flavour-electron-hadron correlations v from -article correlations assoc ) - - baseline (rad dn d ϕ η (c,b) e N.7 ALICE Preliminary.6 -Pb, s = 5. ev NN η < ALI PREL 38 Baseline stat. unc. -% (c,b) e - charged article correlation <.3 < Baseline stat. unc. 6-% e < GeV/c, -.6 < y assoc < GeV/c -% VA class 6-% VA class e cms <.3 3% syst. ϕ-uncorrelated unc. % syst. unc. in ϕ < not shown 3 5 ϕ (rad) azimuthal modulation for HF electrons in -Pb collisions magnitude similar to charged hadrons and Pb-Pb Similar effect also seen for J/ψ How does this arise in small systems? Final state interactions? Initial state effect? 3

32 Higher : robes of the QGP R Bertens, JEWEL simulation Hard robes Hard-scatterings roduce quasi-free artons Probe medium through energy loss Exected to be dominant for > 5 GeV or so

33 Higher : robes of the QGP R Bertens, JEWEL simulation Hard robes Hard-scatterings roduce quasi-free artons Probe medium through energy loss Exected to be dominant for > 5 GeV or so

34 dn/d /π Nuclear modification: Pb+Pb Charged article sectra PbPb ALICE CMS ALAS ALICE, PLB7, 5 CMS, EPJC, 7, 95 ALAS, arxiv:5.337 /N coll Ncoll: number of binary nucleon-nucleon collisions (GeV) Energy loss R AA < 5

35 dn/d /π /N coll 7 Nuclear modification: Pb+Pb Charged article sectra PbPb ALICE CMS ALAS R AA.8.6. ALICE CMS ALAS ALICE, PLB7, 5 CMS, EPJC, 7, 95 ALAS, arxiv:5.337 Nuclear modification factor LHC s NN =,76 ev Pb+Pb -5%. (GeV) 3 5 Ncoll: number of binary nucleon-nucleon collisions (GeV) Energy loss R AA < Pb+Pb: clear suression (RAA < ): arton energy loss 5

36 dn/d /π /N coll 7 Nuclear modification: Pb+Pb Charged article sectra PbPb ALICE CMS ALAS R AA.8.6. ALICE CMS ALAS ALICE, PLB7, 5 CMS, EPJC, 7, 95 ALAS, arxiv:5.337 Nuclear modification factor LHC s NN =,76 ev Pb+Pb -5%. 3 Low : soft roduction, Nart scaling (GeV) 5 Ncoll: number of binary nucleon-nucleon collisions (GeV) Energy loss R AA < Pb+Pb: clear suression (RAA < ): arton energy loss 5

37 Nuclear modification for light and heavy flavor R AA charged articles, π ± and D mesons ALICE -% Pb-Pb, s NN =.76 ev + + Average D, D, D*, y <.5 with -extraolated reference Charged articles, η <.8 Charged ions, η < (GeV/c) ALICE, arxiv:56.66, JHEP Light and heavy flavor have similar RAA desite dead-cone effect, quark/gluon difference Current understanding: interlay of energy loss and fragmentation 6

38 Nuclear modification for light and heavy flavor R AA charged articles, π ± and D mesons ALICE -% Pb-Pb, s NN =.76 ev + + Average D, D, D*, y <.5 with -extraolated reference Charged articles, η <.8 Charged ions, η < (GeV/c) ALICE, arxiv:56.66, JHEP Light and heavy flavor have similar RAA desite dead-cone effect, quark/gluon difference Current understanding: interlay of energy loss and fragmentation R AA ALI DER 9379 D meson, non-romt J/ψ RAA Pb-Pb, 5-8%* s NN =.76 ev D mesons (ALICE) 8< <6 GeV/c, y <.5 Non-romt J/ψ (CMS Preliminary) 6.5< <3 GeV/c, y <. CMS-PAS-HIN-- (emty) filled boxes: (un)correlated syst. uncert. -5% 3-% -3% -% (*) 5-% for non-romt J/ψ Djordjevic et al. Phys.Lett.B 737 () 98 D mesons Non-romt J/ψ Non-romt J/ψ with c quark energy loss -% N art Clear difference between D mesons and J/ψ from B decays Consistent with exectation from dead cone effect Djordjevic, GLV-based, arxiv:37.7 6

39 Nuclear modification for light and heavy flavor R AA charged articles, π ± and D mesons ALICE -% Pb-Pb, s NN =.76 ev + + Average D, D, D*, y <.5 with -extraolated reference Charged articles, η <.8 Charged ions, η < (GeV/c) ALICE, arxiv:56.66, JHEP R AA ALI DER 9379 D meson, non-romt J/ψ RAA Pb-Pb, 5-8%* s NN =.76 ev D mesons (ALICE) 8< <6 GeV/c, y <.5 Non-romt J/ψ (CMS Preliminary) 6.5< <3 GeV/c, y <. CMS-PAS-HIN-- (emty) filled boxes: (un)correlated syst. uncert. -5% 3-% -3% -% (*) 5-% for non-romt J/ψ Djordjevic et al. Phys.Lett.B 737 () 98 D mesons Non-romt J/ψ Non-romt J/ψ with c quark energy loss -% N art Djordjevic, GLV-based, arxiv:37.7 Light and heavy flavor have similar RAA Clear difference between D mesons desite dead-cone effect, quark/gluon difference and J/ψ from B decays Current understanding: interlay of Consistent with exectation from energy loss and fragmentation dead cone effect Confirms radiative nature of energy loss 6

40 New results from run : 5. ev R AA ALI PREL 337 ALICE Preliminary Average D -% Pb-Pb -% Pb-Pb 3-5% Pb-Pb 3-5% Pb-Pb, D s NN s NN s NN s NN, D* = 5. ev =.76 ev, JHEP 3 (6) 8 = 5. ev Filled markers: rescaled reference + +, y <.5 =.76 ev, JHEP 3 (6) 8 Oen markers: -extraolated reference -% 3-5% (GeV/c) Charm RAA similar for.76 and 5. ev Imroved uncertainties; more to come with 8 data 7

41 New results from run : 5. ev R AA ALI PREL 337 ALICE Preliminary Average D -% Pb-Pb -% Pb-Pb 3-5% Pb-Pb 3-5% Pb-Pb, D s NN s NN s NN s NN, D* = 5. ev =.76 ev, JHEP 3 (6) 8 = 5. ev Filled markers: rescaled reference + +, y <.5 =.76 ev, JHEP 3 (6) 8 Oen markers: -extraolated reference -% 3-5% (GeV/c) Charm RAA similar for.76 and 5. ev Imroved uncertainties; more to come with 8 data owerful constraint from combination of R AA and v à sensitivity to charm diffusion coefficient 7

New results from run : 5. ev R AA.8.6...8.6.. 5 5 5 3 35 5 5 ALI PREL 337 ALICE Preliminary Average D -% Pb-Pb -% Pb-Pb 3-5% Pb-Pb 3-5% Pb-Pb, D s NN s NN s NN s NN, D* = 5. ev =.

42 New results from run : 5. ev R AA ALI PREL 337 ALICE Preliminary Average D -% Pb-Pb -% Pb-Pb 3-5% Pb-Pb 3-5% Pb-Pb, D s NN s NN s NN s NN, D* = 5. ev =.76 ev, JHEP 3 (6) 8 = 5. ev Filled markers: rescaled reference + +, y <.5 =.76 ev, JHEP 3 (6) 8 Oen markers: -extraolated reference Determine deendence of diffusion coefficient D s -% 3-5% (GeV/c) Charm RAA similar for.76 and 5. ev Imroved uncertainties; more to come with 8 data Duke grou, arxiv:7.78 owerful constraint from combination of R AA and v à sensitivity to charm diffusion coefficient 7

43 Summary/conclusion Probing the QGP with Azimuthal asymmetries: initial state geometry, viscosity of QGP and magnetic fields Correlations: article roduction and hadronisation Photons: (early stage) temerature and ressure gradients Heavy flavour: diffusion coefficient of QGP and arton energy loss; density of QGP High- and jets: arton energy loss and QCD radiation 8

44 Summary/conclusion Probing the QGP with Azimuthal asymmetries: initial state geometry, viscosity of QGP and magnetic fields Correlations: article roduction and hadronisation Photons: (early stage) temerature and ressure gradients Heavy flavour: diffusion coefficient of QGP and arton energy loss; density of QGP High- and jets: arton energy loss and QCD radiation LHC rogram robes these with unrecedented recision; quantitative constraints on key arameters; discard/confirm models 8

45 Summary/conclusion Probing the QGP with Azimuthal asymmetries: initial state geometry, viscosity of QGP and magnetic fields Correlations: article roduction and hadronisation Photons: (early stage) temerature and ressure gradients Heavy flavour: diffusion coefficient of QGP and arton energy loss; density of QGP High- and jets: arton energy loss and QCD radiation LHC rogram robes these with unrecedented recision; quantitative constraints on key arameters; discard/confirm models Run 8 and ugrades: - Imroved recision for key measurements: heavy flavour, hotons, jets, magnetic effects - Plus new ones: heavy favour baryons, magnetic effects in charm sector, etc 8

46 hank you for your attention

47 Heavy flavour mesons in -Pb Nuclear modification factor Central/eriheral ratio R Pb.6.. ALICE Preliminary Promt D mesons, -.96<y + + Average D, D, D* D Pb, =5. ev s NN <. cms CP Q ALICE Preliminary.8 Pb,.6. s NN = 5. ev + + Average D, D, D* Charged articles ALI PREL 353 CGC (Fujii-Watanabe) FONLL with EPPS6 npdf Vitev et al.: ower corr. + k broad + CNM Eloss Kang et al.: incoherent multile scattering Duke POWLANG (HL) POWLANG (lqcd) (GeV/c) Nuclear modification factor ~ No sign of final state effects ALI PREL 3683 Central: % ZN energy Periheral: 6 % ZN energy (GeV/c) Enhancement in central collisions - GeV Is this (radial) flow?

48 Flow effects in small systems Many asects of the observed ridge have a natural exlanation in hydrodynamics: Long range correlation - and 3-fold symmetries Deendence on initial geometry Many-article correlations Particle mass deendence Why would the system behave as a fluid? Is there enough time, volume to thermalise? Hydrodynamisation (isotroisation) of a dense gluon system? Partonic/hadronic rescattering? How many scatterings/what density is needed to aroximate fluid behaviour?

Neutral meson and direct photon measurement in pp and Pb Pb collisions at midrapidity with the ALICE experiment at the LHC

Neutral meson and direct photon measurement in pp and Pb Pb collisions at midrapidity with the ALICE experiment at the LHC Lucia Leardini PI Heidelberg on behalf of the ALICE Collaboration 54th International