Preview of ATLAS results Jiangyong Jia for the ATLAS Collaboration Stony Brook University and Brookhaven National Laboratory

ATLAS results in QM2017 Initial state Quarkonium Flow in large systems γ+γ scattering in UPC γγμ+μ-, γγγγ 5 TeV Charmonium 5 TeV PbPb Bottomonium 5 TeV pPb nPDFs Photo-nuclear 5 TeV Z/W production 5 TeV vn harmonics 5 TeV Longitudinal dynamics 2.76,5 TeV Flow in large systems Jet quenching Jet structure & correlation Fragmentation 2.76 & 5 TeV Dijet asymmetry 2.76 TeV Gamma-jet 5 TeV RAA of spectra Jet RAA 5 TeV Charged particle RAA 5 TeV Collectivity in small systems Incl. & azimuthal dep. HBT Ridge via 2PC Heavy-flavor muon ridge Ridge via standard cumulants Ridge via subevent cumulants FB multi. fluctuation

ATLAS results in QM2017 Initial state Quarkonium Flow in large systems γ+γ scattering in UPC γγμ+μ-, γγγγ 5 TeV - M. Dyndal (Tue) Charmonium 5 TeV PbPbJorge Lopez (Tue) Bottomonium 5 TeV pPb –J. Chen poster –S. Tapia poster nPDFs Photo-nuclear 5 TeV – A. Angerami (Tue) Z/W production 5 TeV – Z. Citron (Wed) – M.Dumancic poster vn harmonics 5 TeV–S.Mohapatra(Wed) Longitudinal dynamics 2.76,5 TeV – P. Huo poster Flow in large systems Jet quenching –S.Mohapatra(Wed) Jet structure & correlation Fragmentation 2.76 & 5 TeV Dijet asymmetry 2.76 TeV Gamma-jet 5 TeV –R. Slovak (Tue) –P. Steinberg (Wed) – L. Havener poster RAA of spectra Jet RAA 5 TeV M. Spousta (Tue) Charged particle RAA 5 TeV– R. Slovak (Tue) – A. Milov poster L. Havener poster Collectivity in small systems Incl. & azimuthal dep. HBT Ridge via 2PC Heavy-flavor muon ridge Ridge via standard cumulants Ridge via subevent cumulants FB multi. fluctuation–M. Zhou (Wed) –M. Clark (Wed) –B. Cole (Wed) –A.Trzupek (Tue) –M. Zhou (Wed) – A. Behera poster – X. Tu poster 12 talks + 11 posters

Initial state M. Dyndal (Tue) A. Angerami (Tue) Z. Citron (Wed) Photon-photon scalttering in 5 TeV PbPb CONF-2016-025, CONF-2016-111 Photonuclear dijet production in 5TeV PbPb CONF-2017-011 Z/W bosons in 5.02 TeV pPb, PbPb CONF-2016-107 CONF-2017-010 M. Dyndal (Tue) A. Angerami (Tue) Z. Citron (Wed) M.Dumancic poster

Photon-Photon scattering in UPC 5 TeV PbPb Coherent production σ enhanced by Z4 ~ 4.5x107 relative to pp Require simple final state signal w/o any other event activity Well described by LO QED (StarLight) Photon flux well calibrated cross-section ~ αem2 CONF-2016-025 Small cross-section ~ αem4 13 events observed, significance: 4.4σ (3.8σ expected) CERN-EP-2016-316 back-to-back γ (12 and 11 GeV), mγγ=24 GeV

nPDFs: γ(*)+Pbdijets+X in UPC 5 TeV PbPb 0 neutron in ZDC Covers new region of x/Q2 ! Shape described by Pythia+STARlight many neutrons in ZDC arXiv:1612.05741 Sensitive to the nPDF at low x σ measured in dijet kinematic variables Proxy for Q2 Bjorken x in Pb EΥ /Ebeam

nPDFs: Z boson in 5 TeV pPb and PbPb pPb: RpPb shows slight FB asymmetry consistent with nPDF effects. PbPb: RAA shows no modification in |y| and centrality Pb+Pb p+Pb EPS09 Z boson as “Glauber baseline” for other hard processes?

Jet quenching Jet RAA in PbPb 5 TeV CONF-2017-009 M. Spousta (Tue) L. Havener poster Jet fragmentation in 2.76/5 TeV PbPb, 5 TeV pPb arXiv:1702.00674, CONF-2017-004, CONF-2017-005 Charged hadron RAA in 5.02 TeV PbPb CONF-2017-012 R. Slovak (Tue) A. Milov poster Gamm-jet 5 TeV PbPb CONF-2016-110 P. Steinberg (Wed)

First measurement: jet RAA in 5 TeV PbPb 0-10% central jet RAA measured in 100 - 1 TeV Clear increase with pT and flattens above 200-300 GeV

First measurement: jet RAA in 5 TeV PbPb 0-10% central jet RAA measured in 100 - 1 TeV Clear increase with pT and flattens above 200-300 GeV Consistent with 2.76 TeV results, but much reduced uncertainty Thanks to the 5 TeV pp reference data taken with same detector condition

Jet RAA: rapidity evolution Double RAA ratio to quantify the suppression relative to mid-rapidity. low pT: flat with rapidity High pT: more suppression at forward rapidity first observation! Interplay between y-dependent flavor composition & spectral shape

Comparing to charged hadron RAA 5 TeV PbPb h± RAA measured 1-300 GeV, not inconsistent with flat at high pT Slightly higher than Jet RAA

Jet modification in min-bias pPb? 5 TeV Phys. Lett. B 748 (2015) 392 Previously, we observe jet RpPb is not modified ATLAS

Jet modification in min-bias pPb? 5 TeV Phys. Lett. B 748 (2015) 392 Previously, we observe jet RpPb is not modified Precision 5 TeV pp ref. data allow us to make same statement of no modification for: ATLAS Jet fragmentation function CONF-2017-004 CONF-2016-108 Charged hadron RpPb

Modification of Jet fragmentation in PbPb arXiv:1702.00674 Enhancement at low z ~20% enhancement at high z ~10-20% suppression at z~ 0.1

Compare to 5 TeV PbPb Enhancement at low z ~20% enhancement at high z arXiv:1702.00674 Enhancement at low z ~20% enhancement at high z 5 TeV ~20% suppression at z~ 0.1

Jet pT dep. of fragmentation in 5 TeV PbPb CONF-2017-005 PbPb 5.02 TeV Similar to 2.76 TeV No jet pT dependence observed

Jet quenching with γ-jet 5 TeV PbPb γ provides calibration of jet energy before quenching medium effects via xJγ= pT,jet/pT,γ and Δϕ decorrelation Central 0-10% PbPb compare to pp <xJγ> shifted towards lower value  Strong energy loss for associated jet. γ-Jet CONF-2016-110 pp Central PbPb

Jet quenching with γ-jet 5 TeV PbPb γ provides calibration of jet energy before quenching medium effects via xJγ= pT,jet/pT,γ and Δϕ decorrelation Central 0-10% PbPb compare to pp <xJγ> shifted towards lower value  Strong energy loss for associated jet. Δϕ distribution consistent with pp data  Little modification of the jet direction. γ-Jet CONF-2016-110 pp Central PbPb

Quarkonium PbPb 5.02TeV J/Ψ and Ψ(2S) CONF-2016-109 Jorge Lopez (Tue) S. Tapia poster pPb 5.02TeV J/Ψ, Ψ(2S) & Υ CONF-2015-050, CONF-2015-023 J. Chen poster

Charmonium in 5 TeV PbPb 0-80% 0-80% ATLAS measure J/Ψ and Ψ(2s) for pT>9 GeV Separate prompt, non-prompt (b feeddown) contributions via Pseudo-proper decay time J/Ψ shows strong yield suppression for both components Prompt show pT dependence, while non-prompt does not! 0-80% 0-80% Mass or flavor dependence of energy loss? Non-prompt J/Ψ RAA Prompt J/Ψ RAA

Charmonium in 5 TeV PbPb Prompt Non-prompt ATLAS measure J/Ψ and Ψ(2s) for pT>9 GeV Separate prompt, non-prompt (b feeddown) contributions via Pseudo-proper decay time J/Ψ shows strong yield suppression for both components Prompt show pT dependence, while non-prompt does not! J/Ψ and Ψ(2s) are suppressed differently Prompt: Ψ(2s) is more suppressed, smaller binding energy Non-prompt: similar since both are created outside QGP from b decay. Prompt Non-prompt

Collective flow in large system longitudinal flow decorrelations 2.76 & 5 TeV CONF-2017-003 Flow harmonics 5 TeV CONF-2016-105 S.Mohapatra(Wed) P. Huo poster

Longitudinal flow fluctuation in PbPb Particle distribution from one hydro event dN/dϕdη Flow fluctuations in longitudinal direction Both magnitude and phase fluctuate in η asymmetry EP Twist Event-by-event flow fluctuations in transverse direction p(vn,vm) p(Φn,Φm), p(Φn,Φm,ΦL) p(vn) JHEP11(2013)183 PRC 90 (2014) 024905 PRC 92 (2015) 034903

√s dependence of vn decorrelation CMS observable quantify the decorrelation between -η and η Decorrelation of v2,v3 & v4 is 10-20% stronger in 2.76 TeV Extensive set of new observables also measured p.d.f. of longitudinal decorrelation Separating vn asymmetry and event-plane twist Longitudinal decorrelation between vn and vm CONF-2017-003 S.Mohapatra(Wed) P. Huo poster

Collectivity in small systems Inclusive & azimuthal dep. HBT in 5 TeV pPb CONF-2016-027, CONF-2017-008 M. Clark (Wed) Heavy-flavor muon ridge in 8 TeV pPb CONF-2017-006 B. Cole (Wed) Ridge via standard cumulants in pp, pPb, PbPb CONF-2017-007 A.Trzupek (Tue) Ridge via subevent cumulants in pp, pPb CONF-2017-002 M. Zhou (Wed) A. Behera poster vn from two-particle corr. in pp, pPb PRL116(2016)172301, arXiv:1609.06213 X. Tu poster

pPb geometry: pion HBT correlation CONF-2016-027 Comprehensive study of the 3D source: Ro/s/l(kT,Npart, dN/dy, y). V Sensitive to modeling of initial geometry, e.g. proton color fluctuation Observe a small but significant FB-asymmtry for the source

Azimuthal dependent HBT in pPb CONF-2017-008 Event-shape engineering to further study dependence on forward q2 Many observables, e.g. Rout/Rside(ϕ-Ψ2), have been measured Smaller ratio in-plane Source expands more explosively along the event plane Qualitatively similar to A+A, consistent with hydro-picture

Long-range ridge in pp via 2PC Dijet background remove via template-fit (improved peripheral sub) PRL116 (2016)172301 arXiv: 1609.06213 Y(Δϕ)cent = FY(Δϕ)peri+Acos2Δϕ+C First 8 TeV pPb result! No dependence on √s but clear dependence on collision system

Heavy-flavor μ ridge in 8 TeV pPb Correlation of 4-6 GeV muon from c & b decay with charged particles μ-h h-h μ-h ridge smaller than h-h ridge v2μ < v2h, implication on heavy quark thermalization? Uncertainty dominated by hadron background CONF-2017-006

Long-range ridge in pp from cumulants Dijet background remove via template-fit (improved peripheral sub) PRL116 (2016)172301 arXiv: 1609.06213 Y(Δϕ)cent = FY(Δϕ)peri+Acos2Δϕ+C Multi-particle cumulant reduces non-flow in pp, but by how much? Clear bias of nonflow

Long-range collectivity via subevent cumulants arXiv:1701.03830 removes intra-jet correlations removes inter-jet correlations Standard cumulant: collimated azimuthal emission of many particles Alternative definition of collectivity? Subevent cumulant: collimated azimuthal emission of many particles from multiple, distinct η ranges

Long-range collectivity via subevent cumulants arXiv:1701.03830 removes intra-jet correlations removes inter-jet correlations pp 13 TeV standard 2subevt 4% v2 pPb 5 TeV 3subevt pPb: methods consistent for Nch>100, but split below that

Long-range collectivity via subevent cumulants arXiv:1701.03830 removes intra-jet correlations removes inter-jet correlations standard 2subevt 4% v2 pPb 5 TeV pp 5 TeV 3subevt pPb: methods consistent for Nch>100, but split below that pp: 3-subevent gives negative c2{4} in broad range of Nch First observation of c2{4}<0 in 5 TeV pp

v2{4} 3-subevent vs. v2{2} template fit pp 5 TeV pp 13 TeV pPb 5 TeV v2{4}three-subevent < v2{2}template fit as expected Fluc. of ε2 (therefore v2) is driven by fluc. of independent sources Number of sources Ns can be estimate from v2{4}/v2{2} PRL112,082301(2014)

Relate to the initial geometry Source for particle production which drives FB multiplicity fluc. 1606.08170 CONF-2017-002 Sources driving the transverse flow NS? Are these two sources related?

Summary 12 new results will be presented in 12 talks and 11 posters Comprehensive study of PbPb, pPb and pp systems 12 talks and 11 posters Provides: New information on the initial state of pPb and PbPb Detailed study of medium response to hard and soft probes in PbPb Improved understanding of collectivity in small systems https://twiki.cern.ch/twiki/bin/view/AtlasPublic/HeavyIonsPublicResults

ATLAS results in QM2017 Initial state Quarkonium Flow in large systems γ+γ scattering in UPC γγμ+μ-, γγγγ 5 TeV - M. Dyndal (Tue) Charmonium 5 TeV PbPbJorge Lopez (Tue) Bottomonium 5 TeV pPb –J. Chen poster –S. Tapia poster nPDFs Photo-nuclear 5 TeV – A. Angerami (Tue) Z/W production 5 TeV – Z. Citron (Wed) – M.Dumancic poster vn harmonics 5 TeV–S.Mohapatra(Wed) Longitudinal dynamics 2.76,5 TeV – P. Huo poster Flow in large systems Jet quenching –S.Mohapatra(Wed) Jet structure & correlation Fragmentation 2.76 & 5 TeV Dijet asymmetry 2.76 TeV Gamma-jet 5 TeV –R. Slovak (Tue) –P. Steinberg (Wed) – L. Havener poster RAA of spectra Jet RAA 5 TeV M. Spousta (Tue) Charged particle RAA 5 TeV– R. Slovak (Tue) – A. Milov poster L. Havener poster Collectivity in small systems Incl. & azimuthal dep. HBT Ridge via 2PC Heavy-flavor muon ridge Ridge via standard cumulants Ridge via subevent cumulants FB multi. fluctuation–M. Zhou (Wed) –M. Clark (Wed) –B. Cole (Wed) –A.Trzupek (Tue) –M. Zhou (Wed) – A. Behera poster – X. Tu poster 12 talks + 11 posters

BACKUP

Longitudinal dynamics Forward-backward multiplicity correlation initial system size vs η Number of sources same in pp, pPb and PbPb collisions, control by Nch.

Compare with PYTHIA8 and EPOS-LHC Tuned to dN/dη and Nch distribution via MPI Models: Over-estimate the SRC Under-estimate the LRC