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Recent Exciting Results from PHENIX

Xiaochun He, Georgia State UniversityFor

The PHENIX Collaboration

11/14/2012

• About PHENIX• QGP Characterization

• Direct photon• Quarkonia

• Summary and Outlook

Out

line

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PHENIX Collaboration

11/14/2012

South Korea

Chonbuk National University

Ewha Womans University

Hanyang University

KAERI, Cyclotron Application Laboratory

Korea University

Myong Ji University

Seoul National University

SungKyunKwan University

Yonsei University

Japan

University of Tokyo

Hiroshima University

Advanced Science Research Center

KEK - High Energy Accelerator Research Organization

Kyoto University

Nagasaki Institute of Applied Science

RIKEN, The Institute of Physical and Chemical Research

RIKEN – BNL Research Center

Physics Department, Rikkyo University

Tokyo Institute of Technology

University of Tsukuba

P.R. ChinaChina Institute of Atomic Energy (CIAE), Beijing

Peking University, Beijing

71 Institutions from 13 Countries

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PHENIX Run Summary

RHIC-Run Year Species Energy LdtRun-1 2000 Au+Au 130 GeV 1 mb-1

Run-2 2001/2 Au+Au 200 GeV 24 mb-1

p+p 200 GeV 150 nb-1

Run-3 2002/3 d+Au 200 GeV 2.74 nb-1

p+p 200 GeV 0.35 nb-1

Run-4 2003/4 Au+Au 200 GeV 241 mb-1

Au+Au 62.4 GeV 9 mb-1

Run-5 2005 Cu+Cu 200 GeV 3 nb-1

Cu+Cu 62.4 GeV 0.19 nb-1

Cu+Cu 22.4 GeV 2.7 mb-1

Run-6 2006 p+p 200 GeV 10.7 pb-1

p+p 62.4 GeV 100 nb-1

Run-7 2007 Au+Au 200 GeV 813 mb-1

Run-8 2007/8 d+Au 200 GeV 80 nb-1

p+p 200 GeV 5.2 pb-1

Run-9 2009 p+p 200 GeV 16 pb-1

p+p 500 GeV 14 pb-1

Run-10 2010 Au+Au 200 GeV 1.3 nb-1

Au+Au 62.4 GeV 100 mb-1

Au+Au 39 GeV 40 mb-1

Au+Au 7.7 GeV 260 mb-1

Run-11 2011 p+p 500 GeV 27 pb-1

Au+Au 200 GeV 915 mb-1

Au+Au 27 GeV 5.2 mb-1

Au+Au 19.6 GeV 13.7 M

Run-12 2012 p+p 200 GeV 9.2 pb-1

p+p 510 GeV 30 pb-1

U+U 193 GeV 171 mb-1

Cu+Au 200 GeV 4.96 nb-1

11/14/2012

Better knowledge on geom

etry

New

era of heavy flavor physics

Beam-energy scan continues

Discovery and Diagnostic Period

Medium Characterization Started

• RHIC ran with many colliding species which range from p+p, d+Au, Au+Au, Cu+Cu, Cu+Au, U+U.

• RHIC ran at variety center of energies.

• RHIC beam scan program has started and will continue for years to come.

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PHENIX Detectors

11/14/2012

Central arms:hadrons, photons, Electrons:p > 0.2 GeV/c|y| < 0.35

Muon arms:muons at forward rapidityp > 2GeV/c1.2 < |y| < 2.4

Centrality measurement: We use beam beam counters together with zero degree calorimetersCentrality is mapped to Npart (Ncol) using Glauber model

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DIRECT PHOTONWhat’s new in PHENIX?

11/14/2012

PHENIX has shed light on QGP! To be more accurate, light from QGP has arrived at PHENIX.

• “Observation of direct-photon collective flow in Au+Au collisions at 200 GeV”, PRL 109, 122302 (2012), published on Sep 21, 2012

• “Measurement of direct photons on Au+Au collisions at 200 GeV”, PRL 109, 152302 (2012), published on Oct 12, 2012.

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€

Nuclear modification factor :

RAA (pT ) =(1/NAA

evt )d2NAA /dpTdyTAA d

2σ pp /dpTdy

PRL 109, 152302 (2012)

RAA is found to be consistent with unit for all centralities over the entire measured pT range!

Direct Photon RAA

11/14/2012

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Direct Photon RAA Comparison with Model Calculations

11/14/2012

PRL 109, 152302 (2012)

The model calculations that account for modifications of initial direct photon production due to modified PDF’s in Au and the different isospin effects show modest deviation from unit. They are consistent with data.

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Direct Photon Flow in Au+Au

11/14/2012

PRL 109, 122302 (2012)

The results from two independent reaction plane detectors (BBC and RXN) are very consistent, especially at pT < 5 GeV/c. At larger pT, the effects of reaction plane detector efficiencies show mild differences but don’t change the physics conclusion.

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Virtual vs Real Photon Flow

11/14/2012

We observed a substantial flow at low pT region comparable to the hadron flow. However, in contrast to hadrons, the direct-g v2 rapidly decreased with pT, and for pT > 5 GeV/c, it is consistent with zero.

PRL 109, 122302 (2012)

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QUARKONIA (FOCUSING ON J/Y)What’s new in PHENIX?

11/14/2012

Since Matsui and Satz proposed the idea of using J/ysuppression as a signal for QGP formation in 1986, lots of efforts have been put both in experiments and in theories in order to characterize the matter properties at extreme hot and dense conditions. After 26 years, the situation is not as clear as we have hoped for.

Recent results from PHENIX at 39 and 62.4 GeV in Au+Au collisions add more twists! It is imperative to disentangle the interplay among cold nuclear effects, QGP color screening, and possible regeneration.

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J/y Production vs Centrality

11/14/2012

Existing Puzzle

Forward rapidity Mid rapidity

Npart dependence of J/y RAA: less suppression at LHC compared to at RHIC in central collisions.

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J/y Production vs Energy

11/14/2012

aiXrv: 1208.2251

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Comparison with Theory

11/14/2012

aiXrv: 1208.2251

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Quantify Cold Nuclear Matter Effects

11/14/2012

High statistics d+Au data set taken in 2008 J/ψ at backward, mid, and forward rapidities as a function of

centrality, y, and (new) pT. (new) ψ' at midrapidity as a function of centrality. (new) χc at midrapidity Upsilon at backward, mid (coming soon), and forward

rapidities.

D McGlinchey - QM2012 158-14-2012

Centrality Dependence

RdAu consistent with 1 at all pT for peripheral collisions

60-88%d Au

D McGlinchey - QM2012 168-14-2012

Centrality Dependence

Increasing suppression at low-pT when moving to central events

40-60%d Au

D McGlinchey - QM2012 178-14-2012

Centrality Dependence

Increasing suppression at low-pT when moving to central events

20-40%d Au

D McGlinchey - QM2012 188-14-2012

Centrality Dependence

Increasing suppression at low-pT when moving to central events

Enhancement at high-pT at backward rapidityImplies RAA(CNM) ³ 1 at high-pT in Au+Au

0-20%d Au

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y’ RdAu

11/14/2012

• Strong suppression with increasing Ncoll

• Centrality dependence of the suppression is even stronger at the mid-rapidity.

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Cu+Au(Controlled Geometry)

11/14/2012

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OPEN HEAVY FLAVORNew era of heavy flavor physics at RHIC has started. A outlook!

11/14/2012

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Need to Know the Baseline

11/14/2012

NEW

Open heavy flavor measurements in p+p collisions

Charm cross section follows Nbin scaling from p+p to Au+Au collisions

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Help is on the way – (F)VTX

11/14/2012

VTX+FVTX

New silicon vertex trackers: VTX ( commissioned in 2011) and FVTX (commissioned 2012)

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More Outlook

• sPHENIX offers a unique opportunity to study jet-medium physics over a wide range of collision energies not accessible to LHC .

• This upgrade will provide essential complementary physics to the beam energy scan currently underway at RHIC.

11/14/2012

arXiv:1207.6378

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The Concept

11/14/2012

10 GeV/c pion showering in the hadronic calorimeter

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Future jet-TomographyIs on horizon

Summary

11/14/2012

Direct-g RAA is near zero

Thermal-g flows

Direct-g does notflow

J/y is suppressed in numerous sys.Need to pin down interplay effects.

Separating b and cIs a reality in PHENIX

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THANK YOU

11/14/2012

QM12, Washington, Aug. 13-18, 2012 28

Direct photons in d+Au and Au+Au

Itzhak Tserruya

arXiv:1208.1234B. Sahlmueler Parallel 3C

RdA is consistent with unity

Large excess of g observed in Au+Au is not due to initial state effects

Reinforce interpretation of the Au+Au excess as thermal radiation from the QGP

Direct photon v2

arXiv:1105.4126

Au+Au √sNN = 200 GeVminimum bias

• Large v2 at pT < 4 GeV/c where thermal photons dominate

• v2 consistent with 0 at high pT where prompt photons domininate

Very surprising result: large v2 implies late emission whereas thermal radiation implies early emission

Models have difficulties in reproducing simultaneously yield and v2 of photons

Poster 282 M. Csanad

Phys. Rev. Lett. 109, 122302 (2012)

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Direct photon v2 via external conversion

Independent analysis

Different systematics

pT range extended down to 0.5 GeV/c

Two independent and consistent results Important confirmation of previous v2 results

External conversions (PHENIX preliminary)arXiv:1105.4126

Poster 64, R. Petti

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U+U AND CU+AU

Newest Heavy Ion Run (Run-12) at RHIC

11/14/2012

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Global Properties

11/14/2012

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U+U vs Au+Au

11/14/2012

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J/y in CNM

11/14/2012

arxiv:1010.1246

Phys. Rev. Lett. 107 (2011) 142301

J/y are suppressed at all rapidities, in all centralities.

Model using shadowing (EPS09) + sbr

Qualitatively matches what we see, but cannot simultaneously capture the rapidity and centrality dependence.

Aud

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J/y vs. pT (peripheral and central)

11/14/2012

Aud

Weak modification in peripheral; shadowing reproduces fairly well, except to strong at forward rapidity

Stronger modification in central; shadowing alone cannot reproduce the trend

Backward rapidity: high pT EMC effect suppressionNeed Cronin-like scattering or some other physics!

-2.2 < y < -1.2 |y| < 0.35 1.2 < y < 2.2

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J/y vs. pT (0-100% centrality)

11/14/2012

arXiv:1204.0777, submitted to Phys Rev C

RdAu rises out to pT~5 GeV/c at all rapidities.

Largest disagreement with models is at backward rapidity.

Shadowing + sbr model (no Cronin) does not match the qualitative trend.

Model by Kopeliovich et al. includes Cronin and sbr prediction, qualitatively matches the pT shape.

Aud