diagnosing energy loss: phenix results on high-p t hadron spectra

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Diagnosing energy loss: PHENIX results on high-p T hadron spectra Baldo Sahlmüller, University of Münster for the PHENIX collaboration

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Diagnosing energy loss: PHENIX results on high-p T hadron spectra. Baldo Sahlmüller, University of Münster for the PHENIX collaboration. A+A. p+p. Physics Motivation: Why high-p T ?. At high energy: hard scattering cross section large Measuring high p T particle yields: - PowerPoint PPT Presentation

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Page 1: Diagnosing energy loss: PHENIX results on high-p T  hadron spectra

Diagnosing energy loss: PHENIX results on high-pT hadron spectra

Baldo Sahlmüller, University of Münster

for the PHENIX collaboration

Page 2: Diagnosing energy loss: PHENIX results on high-p T  hadron spectra

Baldo Sahlmüller Quark Matter 2006 2

Physics Motivation:Why high-pT?

• At high energy: hard scattering cross section large

• Measuring high pT particle yields:– Initial yields and pT distributions can be

predicted from p+p measurements + pQCD + cold nuclear effects

– Deviations can be attributed to the medium formed in A+A collisions

• High pT particles (leading particles of jets) as ,0 can be measured in large BGs (dNch/d ~ 700)

• Quantification with nuclear modification factor:

A+A

p+p

Page 3: Diagnosing energy loss: PHENIX results on high-p T  hadron spectra

Baldo Sahlmüller Quark Matter 2006 3

What we already know

• System size dependence at 200 GeV– Suppression up to high pT

– Consistent with dNg/dy = 1200 (Au+Au) and dNg/dy = 370 (Cu+Cu)

Questions: What happens at lower energies?

Connection towards SPS energies?

• Similar suppression for similar Npart

- Consistent with pure density and path length dependence- also: taking into account shape of nuclei

Page 4: Diagnosing energy loss: PHENIX results on high-p T  hadron spectra

Baldo Sahlmüller Quark Matter 2006 4

The PHENIX Experiment

• Measurement of , 0 via decay

• Decay ’s are measured in EMCal– 2 sectors PbGl, 6 sectors

PbSc in 2 arms– Covers ||<0.35, =180°– Granularity fine enough to

measure 0’s up to pT ~ 25 GeV/c

, 0

Page 5: Diagnosing energy loss: PHENIX results on high-p T  hadron spectra

Baldo Sahlmüller Quark Matter 2006 5

Diagnosing Heavy Ion Collisions

So far: status of investigating energy loss with high pT particle production; dependence on:

• Centrality OK• pT OK• System size (OK)

=> Next step: energy dependence

Page 6: Diagnosing energy loss: PHENIX results on high-p T  hadron spectra

Baldo Sahlmüller Quark Matter 2006 6

200 GeV

Page 7: Diagnosing energy loss: PHENIX results on high-p T  hadron spectra

Baldo Sahlmüller Quark Matter 2006 7

T

The p+p Reference

• Measurement at 200 GeV

•nucl-ex/0610036

0

=> See poster by A. Bazilevsky!

Page 8: Diagnosing energy loss: PHENIX results on high-p T  hadron spectra

Baldo Sahlmüller Quark Matter 2006 8

nucl-ex/0610036

Initial State Effects?

• New PHENIX paper on centrality dependence of 0+ in d+Au at 200 GeV

• d+Au as collision system to look for initial state effects

=> no strong initial state effects

nucl-ex/0610036

Page 9: Diagnosing energy loss: PHENIX results on high-p T  hadron spectra

Baldo Sahlmüller Quark Matter 2006 9

Au+Au at 200 GeV

• data from RHIC run 2004

=> See poster by M.L. Purschke!

Page 10: Diagnosing energy loss: PHENIX results on high-p T  hadron spectra

Baldo Sahlmüller Quark Matter 2006 10

RAA at 200 GeV

• in Au+Au

=> Suppression by a factor of 5 in central events

Page 11: Diagnosing energy loss: PHENIX results on high-p T  hadron spectra

Baldo Sahlmüller Quark Matter 2006 11

RAA at 200 GeV

• Direct , 0 and in Au+Au– Direct RAA with measured p+p reference!

=> RAA of and 0 consistent, both show suppression

=> RAA of is smaller than 1 at very high pT

0-10% central events

Page 12: Diagnosing energy loss: PHENIX results on high-p T  hadron spectra

Baldo Sahlmüller Quark Matter 2006 12

62.4 GeV

Page 13: Diagnosing energy loss: PHENIX results on high-p T  hadron spectra

Baldo Sahlmüller Quark Matter 2006 13

The p+p Reference

• p+p parameterization at 62.4 GeV: Fit to existing (ISR) data at similar energies (D.d'Enterria. J.Phys.G31, S491 (2005))

Page 14: Diagnosing energy loss: PHENIX results on high-p T  hadron spectra

Baldo Sahlmüller Quark Matter 2006 14

The p+p Reference

• Problem: data sets inconsistent => large error

new important RHIC measurement in 2006 Analysis still ongoing

Page 15: Diagnosing energy loss: PHENIX results on high-p T  hadron spectra

Baldo Sahlmüller Quark Matter 2006 15

Au+Au at 62.4 GeV

• Au+Au 0:– Suppression in central

events– Important: influence of

error in p+p reference!– Theoretical curve:

Vitev nucl-th/0404052

dNg/dy = 650-800

Page 16: Diagnosing energy loss: PHENIX results on high-p T  hadron spectra

Baldo Sahlmüller Quark Matter 2006 16

Spectra in Cu+Cu at 62.4 GeV

0

=> See poster by T. Sakaguchi!

Page 17: Diagnosing energy loss: PHENIX results on high-p T  hadron spectra

Baldo Sahlmüller Quark Matter 2006 17

RAA in Cu+Cu at 62.4 GeV

Cu+Cu0:• centrality dependent• Important: Influence of

error in p+p reference!• Centrality dependent

behavior• Enhancement in

peripheral events

• RAA smaller in central events

Page 18: Diagnosing energy loss: PHENIX results on high-p T  hadron spectra

Baldo Sahlmüller Quark Matter 2006 18

RAA vs. Npart at 62.4 GeV

• RAA integrated at high pT

• Again: Large normalization uncertainty from p+p reference

• RAA smaller towards higher Npart

• Same theoretical model as for 200 GeV data consistent within errors

Page 19: Diagnosing energy loss: PHENIX results on high-p T  hadron spectra

Baldo Sahlmüller Quark Matter 2006 19

22.4 GeV

Page 20: Diagnosing energy loss: PHENIX results on high-p T  hadron spectra

Baldo Sahlmüller Quark Matter 2006 20

The p+p Reference

• p+p parameterization at 22.4 GeV: Fit to existing data at similar energies (D.d'Enterria. J.Phys.G31, S491 (2005))

Page 21: Diagnosing energy loss: PHENIX results on high-p T  hadron spectra

Baldo Sahlmüller Quark Matter 2006 21

0 at 22.4 GeV

• Towards SPS energies: Cu+Cu at 22.4 GeV

Little centrality dependence

Page 22: Diagnosing energy loss: PHENIX results on high-p T  hadron spectra

Baldo Sahlmüller Quark Matter 2006 22

SPS and RHIC

• Same behavior for similar Npart (63 at WA98, 67.8 at PHENIX)

Blattnig parameterization used for WA98 data (S. Blattnig et. al., Phys.Rev. D62 (2000) 094030 / D. D’Enterria, Phys. Lett. B 596 (2004) 32))

Page 23: Diagnosing energy loss: PHENIX results on high-p T  hadron spectra

Baldo Sahlmüller Quark Matter 2006 23

RAA at Different Energies

• Comparison of 0 in Cu+Cu at 200, 62.4, and 22.4 GeV

– Measured the same collision species over a broad energy range

• Suppression gets larger with higher energies

Page 24: Diagnosing energy loss: PHENIX results on high-p T  hadron spectra

Baldo Sahlmüller Quark Matter 2006 24

Particle Ratio

Page 25: Diagnosing energy loss: PHENIX results on high-p T  hadron spectra

Baldo Sahlmüller Quark Matter 2006 25

Ratio in Au+Au

• Ratio /0 for different centralities in comparison with PYTHIA prediction

PYTHIA works very well in describing the ratio in heavy-ion collisions

Possible conclusion (for high pT): Suppression at partonic level, fragmentation outside medium

Page 26: Diagnosing energy loss: PHENIX results on high-p T  hadron spectra

Baldo Sahlmüller Quark Matter 2006 26

Ratio in p+p and Cu+Cu

• Ratio0

• Approximately 0.5 at high pT

• First PHENIX measurement at 62.4 GeV

p+p

Cu+Cu

nucl-ex/0611006

Page 27: Diagnosing energy loss: PHENIX results on high-p T  hadron spectra

Baldo Sahlmüller Quark Matter 2006 27

“World” data

All PHENIX data consistent with world data Ratio shows no obvious energy dependence

Page 28: Diagnosing energy loss: PHENIX results on high-p T  hadron spectra

Baldo Sahlmüller Quark Matter 2006 28

Data vs. Theory?

Page 29: Diagnosing energy loss: PHENIX results on high-p T  hadron spectra

Baldo Sahlmüller Quark Matter 2006 29

Comparing to Theories

How probable is a certain parameter in theory?

Theory: Loizides,hep-ph/0608133v2

10%)ty (Probabili

fm/cGeV 24ˆ6 22

>

≤≤ q

Taking into account errors of measurement (for a certain theory parameter):

1. vary points within 4 RMS of correlated errors, find most probable point

2. calculate probability for large number of randomly picked sets of correlated and uncorrelated errors

3. see how many of these are worse than point from step 1

Page 30: Diagnosing energy loss: PHENIX results on high-p T  hadron spectra

Baldo Sahlmüller Quark Matter 2006 30

Comparing to Theories

10%)ty (Probabili

fm/cGeV 00021000 22

>

≤≤ dydNg

another compilation…

Theory: I. Vitev,Phys.Lett.B639:38-45,2006

Page 31: Diagnosing energy loss: PHENIX results on high-p T  hadron spectra

Baldo Sahlmüller Quark Matter 2006 31

Comparing to Theories

and another compilation…

10%)ty (Probabili

1600600

>

≤≤ dydNg

Theory: William Horowitz

Page 32: Diagnosing energy loss: PHENIX results on high-p T  hadron spectra

Baldo Sahlmüller Quark Matter 2006 32

Summary

• Au+Au at 200 GeV– New measurement up to pT = 15 GeV/c– Similar suppression patterns of and0

• Cu+Cu at 62.4 GeV– Strong 0 enhancement in peripheral events– RAA gets smaller in central events

• Cu+Cu at 22 GeV– No significant centrality dependence in 0 production– Consistent with SPS results at 17.3 GeV

• Ratio 0

– Ratio 0 similar for different collision systems and energies• Results in Cu+Cu and Au+Au consistent with partonic energy

loss in the medium, fragmentation in the vacuum

Page 33: Diagnosing energy loss: PHENIX results on high-p T  hadron spectra

Baldo Sahlmüller Quark Matter 2006 33

Finally: Back to the List

So far: status of investigating energy loss with high pT particle production; dependence on:– Centrality OK– pT OK– System size (OK)

Page 34: Diagnosing energy loss: PHENIX results on high-p T  hadron spectra

Baldo Sahlmüller Quark Matter 2006 34

Finally: Back to the List

Now: status of investigating energy loss with high pT particle production; dependence on:– Centrality OK– pT OK– System size OK– Energy OK

Page 35: Diagnosing energy loss: PHENIX results on high-p T  hadron spectra

13 Countries; 62 Institutions; 550 Participants*

*as of March 2005

• Lund University, Lund, Sweden• Abilene Christian University, Abilene, Texas, USA• Brookhaven National Laboratory (BNL), Upton, NY 11973, USA• University of California - Riverside (UCR), Riverside, CA 92521, USA• University of Colorado, Boulder, CO, USA• Columbia University, Nevis Laboratories, Irvington, NY 10533, USA• Florida Institute of Technology, Melbourne, FL 32901, USA• Florida State University (FSU), Tallahassee, FL 32306, USA• Georgia State University (GSU), Atlanta, GA, 30303, USA• University of Illinois Urbana-Champaign, Urbana-Champaign, IL, USA• Iowa State University (ISU) and Ames Laboratory, Ames, IA 50011, USA• Los Alamos National Laboratory (LANL), Los Alamos, NM 87545, USA• Lawrence Livermore National Laboratory (LLNL), Livermore, CA 94550, USA• University of New Mexico, Albuquerque, New Mexico, USA• New Mexico State University, Las Cruces, New Mexico, USA• Department of Chemistry, State University of New York at Stony Brook (USB),

Stony Brook, NY 11794, USA• Department of Physics and Astronomy, State University of New York at Stony

Brook (USB), Stony Brook, NY 11794, USA• Oak Ridge National Laboratory (ORNL), Oak Ridge, TN 37831, USA• University of Tennessee (UT), Knoxville, TN 37996, USA• Vanderbilt University, Nashville, TN 37235, USA

• University of São Paulo, São Paulo, Brazil• Academia Sinica, Taipei 11529, China• China Institute of Atomic Energy (CIAE), Beijing, P. R. China• Peking University, Beijing, P. R. China• Charles University, Faculty of Mathematics and Physics, Ke Karlovu 3, 12116

Prague, Czech Republic• Czech Technical University, Faculty of Nuclear Sciences and Physical

Engineering, Brehova 7, 11519 Prague, Czech Republic• Institute of Physics, Academy of Sciences of the Czech Republic, Na

Slovance 2, 182 21 Prague, Czech Republic• Laboratoire de Physique Corpusculaire (LPC), Universite de Clermont-

Ferrand, 63 170 Aubiere, Clermont-Ferrand, France• Dapnia, CEA Saclay, Bat. 703, F-91191 Gif-sur-Yvette, France• IPN-Orsay, Universite Paris Sud, CNRS-IN2P3, BP1, F-91406 Orsay, France• Laboratoire Leprince-Ringuet, Ecole Polytechnique, CNRS-IN2P3, Route de

Saclay, F-91128 Palaiseau, France• SUBATECH, Ecòle des Mines at Nantes, F-44307 Nantes France• University of Muenster, Muenster, Germany• KFKI Research Institute for Particle and Nuclear Physics at the Hungarian

Academy of Sciences (MTA KFKI RMKI), Budapest, Hungary• Debrecen University, Debrecen, Hungary• Eövös Loránd University (ELTE), Budapest, Hungary• Banaras Hindu University, Banaras, India• Bhabha Atomic Research Centre (BARC), Bombay, India• Weizmann Institute, Rehovot, 76100, Israel• Center for Nuclear Study (CNS-Tokyo), University of Tokyo, Tanashi, Tokyo

188, Japan• Hiroshima University, Higashi-Hiroshima 739, Japan• KEK - High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba,

Ibaraki 305-0801, Japan• Kyoto University, Kyoto, Japan• Nagasaki Institute of Applied Science, Nagasaki-shi, Nagasaki, Japan• RIKEN, The Institute of Physical and Chemical Research, Wako, Saitama 351-

0198, Japan• RIKEN – BNL Research Center, Japan, located at BNL• Physics Department, Rikkyo University, 3-34-1 Nishi-Ikebukuro, Toshima,

Tokyo 171-8501, Japan• Tokyo Institute of Technology, Oh-okayama, Meguro, Tokyo 152-8551, Japan• University of Tsukuba, 1-1-1 Tennodai, Tsukuba-shi Ibaraki-ken 305-8577,

Japan• Waseda University, Tokyo, Japan• Cyclotron Application Laboratory, KAERI, Seoul, South Korea• Kangnung National University, Kangnung 210-702, South Korea• Korea University, Seoul, 136-701, Korea• Myong Ji University, Yongin City 449-728, Korea• System Electronics Laboratory, Seoul National University, Seoul, South

Korea• Yonsei University, Seoul 120-749, Korea• IHEP (Protvino), State Research Center of Russian Federation "Institute for

High Energy Physics", Protvino 142281, Russia• Joint Institute for Nuclear Research (JINR-Dubna), Dubna, Russia• Kurchatov Institute, Moscow, Russia• PNPI, Petersburg Nuclear Physics Institute, Gatchina, Leningrad region,

188300, Russia• Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State

University, Vorob'evy Gory, Moscow 119992, Russia• Saint-Petersburg State Polytechnical Univiversity, Politechnicheskayastr, 29,

St. Petersburg, 195251, Russia

Map No. 3933 Rev. 2 UNITED NATIONSAugust 1999

Department of Public InformationCartographic Section

Page 36: Diagnosing energy loss: PHENIX results on high-p T  hadron spectra

Baldo Sahlmüller Quark Matter 2006 36

Related Talks and Posters

• Talks– 2.2.5 V. S. Pantuev PHENIX measurements of reaction plane dependence of high-pT photons and pions in

Au+Au collisions– 3.1.2 Yu. Riabov Measurement of leptonic and hadronic decays of and mesons at RHIC by PHENIX – 3.2.2 M. Konno High-pT Identified Hadron Production in Au+Au and Cu+Cu Collisions at RHIC-PHENIX– 3.3.1 T. Isobe Systematic Study of High-pT Direct Photon Production with the PHENIX

Experiment at RHIC

• Posters– 1.14 M. L. Purschke Measurement of pT distributions in SNN =200 GeV Au-Au collisions at RHIC-

PHENIX– 1.18 V. Ryabov Measurements of the multi-hadron decays of and mesons in heavy ion collisions at

SNN= 200 GeV in the PHENIX experiment at RHIC– 2.38 M. Shimomura Measurement of Azimuthal Anisotropy for High-pT Charged Hadron at RHIC-

PHENIX– 2.50 T. Sakaguchi System size and energy dependence of high-pT hadron production measured with the

PHENIX experiment at RHIC– 2.51 D. Winter High-pT π0 production with respect to the reaction plane in SNN = 200 GeV Au+Au

collisions at PHENIX