SUMMARY OF RECENT RHIC RESULTS THEODORE KOBLESKY UNIVERSITY OF - PowerPoint PPT Presentation

SUMMARY OF RECENT RHIC RESULTS THEODORE KOBLESKY UNIVERSITY OF COLORADO BOULDER MPI@LHC 2016 SAN CRISTÓBAL DE LAS CASAS, CHIAPAS, MÉXICO 2016-12

2 OVERVIEW HEAVY ION COLLISION TOPICS JETS QUENCHING COLLECTIVE FLOW Theodore Koblesky MPI 2016

3 OVERVIEW HEAVY ION COLLISION TOPICS JETS QUENCHING COLLECTIVE FLOW A+A COLLISIONS SMALL SYSTEM Theodore Koblesky MPI 2016

4 HEAVY ION COLLISIONS CONTEXT QUARK GLUON PLASMA (QGP) Deconfined Quarks Theodore Koblesky MPI 2016

5 HEAVY ION COLLISIONS PHASES QUARK GLUON PLASMA EVOLUTION Pre-Equilibrium QGP Expansion Hadron Phase Deconfined Quarks Theodore Koblesky MPI 2016

6 SMALL COLLISION SYSTEMS WHY ARE SMALL SYSTEMS INTERESTING? Small systems like d+Au Au+Au collisions were were thought of as the thought to be the necessary control test to measure for the generation of QGP cold nuclear matter effects. Au Au d Au Theodore Koblesky MPI 2016

7 SMALL COLLISION SYSTEMS WHY ARE SMALL SYSTEMS INTERESTING? Small systems like d+Au Au+Au collisions were were thought of as the thought to be the necessary control test to measure for the generation of QGP cold nuclear matter effects. Au Au d Au However, recent measurements of flow and jet quenching in small systems have yielded surprising results. Small systems allow for control over the initial collision geometry. Theodore Koblesky MPI 2016

8 EXPERIMENTAL OVERVIEW RELATIVISTIC HEAVY ION COLLIDER AT BNL -2 counter circulating rings, 3.8 km circumference -Capable of running Au+Au @ 200 GeV 
 - Also small systems p,d, and 3 He+Au @ 200 GeV - There is a wealth of heavy ion collision data available taken by STAR and PHENIX Theodore Koblesky MPI 2016

9 OVERVIEW HEAVY ION COLLISION TOPICS JETS QUENCHING COLLECTIVE FLOW A+A COLLISIONS SMALL SYSTEM Theodore Koblesky MPI 2016

10 MOTIVATION FOR PARTICLE PRODUCTION MEASUREMENTS HARD SCATTERING Jets q q Theodore Koblesky MPI 2016

11 MOTIVATION FOR PARTICLE PRODUCTION MEASUREMENTS THE QGP IS OPAQUE q q QGP medium Energy loss via Gluon Bremsstrahlung Suppression in jets. Theodore Koblesky MPI 2016

12 MEASUREMENT OF PRODUCTION MODIFICATION DUE TO MEDIUM Theodore Koblesky MPI 2016

13 MEASUREMENT OF PRODUCTION MODIFICATION DUE TO MEDIUM Number of binary collisions Theodore Koblesky MPI 2016

14 MEASUREMENT OF PRODUCTION MODIFICATION DUE TO MEDIUM Number of binary collisions Glauber Monte Carlo Au+Au @ 200 GeV Projectile Target Theodore Koblesky MPI 2016

15 MEASUREMENT OF PRODUCTION MODIFICATION DUE TO MEDIUM Number of binary collisions Glauber Monte Carlo Glauber Monte Carlo Au+Au @ 200 GeV And we can relate Ncoll to charged particle multiplicity to determine centrality classes: 0 - Au+Au @ 200 GeV 100% (0% is most central) Projectile Target Measured Charged Particle Multiplicity \ Theodore Koblesky MPI 2016

R AA OF SELECTED HADRONS 16 R AA Enhanced Unmodified 1 Suppressed p T Theodore Koblesky MPI 2016

R AA OF SELECTED HADRONS 17 R AA Enhanced Unmodified 1 Au+Au @ 200 GeV For 0-10% centrality events Suppressed p T Substantial suppression across p T of hadrons This measurement is consistent with jet quenching due to the medium. Theodore Koblesky MPI 2016

18 OVERVIEW HEAVY ION COLLISION TOPICS JETS QUENCHING COLLECTIVE FLOW A+A COLLISIONS SMALL SYSTEM Theodore Koblesky MPI 2016

19 D+AU COLLISIONS d d The number of binary collisions in d+Au is much lower than in Au+Au. Theodore Koblesky MPI 2016

20 D+AU COLLISIONS d d The number of binary collisions in d+Au is much lower than in Au+Au. NOT ALL BINARY COLLISIONS ARE CREATED EQUAL Hard scattering collisions will bias the centrality of events upwards. Theodore Koblesky MPI 2016

21 CENTRALITY BIAS CORRECTION FACTORS ▸ Using the MC Glauber, we can calculate the centrality dependent bias factors Theodore Koblesky MPI 2016

22 CENTRALITY BIAS CORRECTION FACTORS ▸ Using the MC Glauber, we can calculate the centrality dependent bias factors for d+Au @ 200 GeV ▸ We can go farther to calculate the pT dependent bias factors using HIJING 
 (Heavy Ion Jet INteraction Generator) Theodore Koblesky MPI 2016

23 CENTRALITY DEPENDENT JET R DAU MODIFICATION PHENIX Collaboration. Phys. Rev. Lett. 116, 122301 (2016) PHENIX Collaboration. Phys. Rev. Lett. 116, 122301 (2016) CENTRAL Central suppression consistent 
 with energy loss models Theodore Koblesky MPI 2016

24 CENTRALITY DEPENDENT JET R DAU MODIFICATION PHENIX Collaboration. Phys. Rev. Lett. 116, 122301 (2016) PERIPHERAL CENTRAL Theodore Koblesky MPI 2016

25 CENTRALITY BIAS FACTORS AT THE LHC ▸ We can calculate the bias factors for LHC p+Pb 5.02 TeV events. ▸ The centrality bias effect is much larger at LHC energies, MPI could play a role. Theodore Koblesky MPI 2016

26 HARD SCATTERING COMPARISON ▸ Using HIJING, we can compute the number of hard scatterings per nucleon nucleon collision ▸ There is nearly an order of magnitude difference between the LHC and RHIC. Theodore Koblesky MPI 2016

27 OVERVIEW HEAVY ION COLLISION TOPICS JETS QUENCHING COLLECTIVE FLOW A+A COLLISIONS SMALL SYSTEM Theodore Koblesky MPI 2016

28 COLLECTIVE FLOW ▸ The medium becomes locally equilibrated ▸ Initial state geometric anisotropy gets translated into final state momentum anisotropy. ▸ We can measure flow by looking at the long range angular Δφ correlations in the spray of particles Theodore Koblesky MPI 2016

29 QUANTIZATION OF FLOW v N are Flow Coefficients N N N N Ψ N is the generalized participant Event Plane Theodore Koblesky MPI 2016

30 QUANTIZATION OF FLOW Au+Au Gale, Jeon, et al., Phys. Rev. Lett. 110, 012302 v N are Flow Coefficients N N N N Ψ N is the generalized participant Event Plane Pb+Pb ▸ Hydrodynamics describes the data at both energies up to the 5th harmonic order. Theodore Koblesky MPI 2016

31 OVERVIEW HEAVY ION COLLISION TOPICS JETS QUENCHING COLLECTIVE FLOW A+A COLLISIONS SMALL SYSTEM Theodore Koblesky MPI 2016

32 SMALL SYSTEM DATASETS 3 He+Au 200 GeV p+Au d+Au Theodore Koblesky MPI 2016

33 SMALL SYSTEM DATASETS 3 He+Au 200 GeV 0-5% central p+Au d+Au ε 2 is the second order initial collision eccentricity For ideal hydrodynamics: v N ε N Theodore Koblesky MPI 2016

34 SMALL SYSTEM DATASETS 3 He+Au 200 GeV 0-5% central p+Au d+Au ε 2 is the second order initial collision eccentricity For ideal hydrodynamics: v N ε N Structure of 
 Geometry 
 the proton dominated by 
 is important elliptic/triangular shape. Theodore Koblesky MPI 2016

35 SMALL SYSTEM DATASETS 3 He+Au 200 GeV 0-5% central p+Au d+Au ε 2 is the second order initial collision eccentricity For ideal hydrodynamics: v N ε N Structure of 
 Geometry 
 the proton dominated by 
 is important elliptic/triangular shape. New 2016 d+Au Beam Energy Scan (200, 62, 39, 20 GeV) dataset (not in this talk) 
 Theodore Koblesky MPI 2016

36 QUANTIZATION OF FLOW ε 2 ~ ε 2 > ε 2 p+Au 3 He+Au ▸ v2 measured across three d+Au p+Au distinct small systems v 2 ~ v 2 > v 2 d+Au 3 He+Au roughly follows Glauber ε 2 scaling. ▸ The large non-flow systematic error on the p +Au points gives it the largest errors of all 3 systems. Theodore Koblesky MPI 2016

37 THEORY COMPARISON ▸ SONIC is a model which includes: 
 -MC Glauber 
 -Viscous Hydrodynamics 
 - eta/s = 0.08 
 - Hadronic cascade at T = 170 MeV 
 - Centrality matching ▸ The data is consistent with a viscous hydrodynamic model ▸ The epsilon scaling is not perfect. Theodore Koblesky MPI 2016

38 COMPARISON TO THEORY SONIC HAS THE LARGEST AGREEMENT ▸ IP Glasma (initial conditions) + Hydro can not simultaneously agree with all three systems. ▸ AMPT (a multi transport model) uses string-melty and a tunable parton scattering cross section. 
 - Is in agreement with all three systems up to ~ 1.5 GeV 
 - Does not use viscous hydrodynamics Theodore Koblesky MPI 2016

39 SUMMARY ▸ Centrality bias factors due to hard scattering must be calculated in small systems. 
 - MPI probably plays a role in the centrality bias factors difference at the LHC in comparison to RHIC 
 ▸ Substantial flow coefficients are observed in p+Au, d+Au, and He3+Au at RHIC. 
 - These observations are consistent with hydrodynamic models. 
 - Could be evidence of QGP Theodore Koblesky MPI 2016

THANK YOU Theodore Koblesky MPI 2016

41 TEXT Theodore Koblesky MPI 2016

42 SMALL SYSTEM DATASETS DATASET INFORMATION d+Au ▸ 2008 d+Au 200 GeV 
 - delivered luminosity: 437 nb -1 3 He+Au ▸ 2014 He3+Au 200 GeV 
 - delivered luminosity: 134 nb -1 ▸ 2015 p+Au 200 GeV 
 p+Au - delivered luminosity: 1270 nb -1 ▸ New 2016 d+Au Beam Energy Scan (200, 62, 39, 20 GeV) dataset (not in this talk) 
 - delivered luminosity: (289, 44, 7.2, 19.5) nb -1 Theodore Koblesky MPI 2016