the landscape of particle production: results from
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Peter Steinberg PHOBOS
The Landscape ofThe Landscape ofParticle Production:Particle Production:
Results from Results from ..
Peter SteinbergBrookhaven National Laboratory
SPSFNALRHICSppS
AGS
Peter Steinberg PHOBOS
PHOBOS Collaboration PHOBOS Collaboration 20042004
Birger Back, Mark Baker, Maarten Ballintijn, Donald Barton, Russell Betts, Abigail Bickley,
Richard Bindel, Wit Busza (Spokesperson), Alan Carroll, Zhengwei Chai, Patrick Decowski,
Edmundo Garcia, Tomasz Gburek, Nigel George, Kristjan Gulbrandsen, Stephen Gushue,
Clive Halliwell, Joshua Hamblen, Adam Harrington, Conor Henderson, David Hofman, Richard Hollis,
Roman Hołyński, Burt Holzman, Aneta Iordanova, Erik Johnson, Jay Kane, Nazim Khan, Piotr Kulinich, Chia
Ming Kuo, Willis Lin, Steven Manly, Alice Mignerey, Gerrit van Nieuwenhuizen, Rachid Nouicer, Andrzej
Olszewski, Robert Pak, Inkyu Park, Heinz Pernegger, Corey Reed, Michael Ricci,
Christof Roland, Gunther Roland, Joe Sagerer, Iouri Sedykh, Wojtek Skulski, Chadd Smith,
Peter Steinberg, George Stephans, Andrei Sukhanov, Marguerite Belt Tonjes, Adam Trzupek,
Carla Vale, Siarhei Vaurynovich, Robin Verdier, Gábor Veres, Edward Wenger, Frank Wolfs,
Barbara Wosiek, Krzysztof Woźniak, Alan Wuosmaa, Bolek Wysłouch, Jinlong Zhang
ARGONNE NATIONAL LABORATORY BROOKHAVEN NATIONAL LABORATORYINSTITUTE OF NUCLEAR PHYSICS, KRAKOW MASSACHUSETTS INSTITUTE OF TECHNOLOGY
NATIONAL CENTRAL UNIVERSITY, TAIWAN UNIVERSITY OF ILLINOIS AT CHICAGOUNIVERSITY OF MARYLAND UNIVERSITY OF ROCHESTER
Peter Steinberg PHOBOS
PHOBOS HighlightsPHOBOS Highlights
• d+Au & p+p physics• Multiplicity • Inclusive Spectra• PID
• Multiparticle Physics in Au+Au
Peter Steinberg PHOBOS
PHOBOS 2003PHOBOS 2003
Trigger & Centrality:R. Hollis
A. Iordanova
TOF & SpecTrig:C. Henderson
PCAL:C. Reed
Check out our student posters!
Several crucial upgrades for d+Au
Peter Steinberg PHOBOS
Charged-Particle Charged-Particle Multiplicities in p+p & Multiplicities in p+p &
d+Aud+Au
Peter Steinberg PHOBOS
Minimum-bias d+AuMinimum-bias d+Au
Predictions as of Oct. 2003
See R. Nouicer’s talkSee R. Nouicer’s talk
nucl-ex/0311009nucl-ex/0311009 PHOBOSPHOBOS
Peter Steinberg PHOBOS
Centrality Dependence of Centrality Dependence of d+Aud+Au
Data vs. AMPT
Centrality (%)
Npart Npart(Au) Npart(d)
0-20 15.5 13.5 2.0
20-4010.8
8.9 1.9
40-60 7.2 5.4 1.7
60-80 4.2 2.9 1.4
80-100 2.7 1.6 1.1
PHOBOS PreliminaryPHOBOS Preliminary p+p poster by J. Sagererp+p poster by J. Sagerer
Peter Steinberg PHOBOS
Participant Scaling?Participant Scaling?
Multiplicity extrapolated
to 4
Relative to p+p multiplicity at same energy, scales with Npart/2
No modification with• Beam energy
• Nuclear thickness
Peter Steinberg PHOBOS
Is NIs Npartpart Fundamental? Fundamental?
Expectations:“stopping” in d direction
“cascading” in Au direction
Why do they add up toNpart scaling so robustly?
Same effect in Au+Au
“Long-range” correlation?nucl-ex/0311009nucl-ex/0311009
Peter Steinberg PHOBOS
(p)d+Au in Different (p)d+Au in Different FramesFrames
As with Au+Au, “limiting fragmentation region” grows with energy.Shape appears to be constrained by lower-energy p+A data.Surprising over 1.5 orders of magnitude in collision energy.
Peter Steinberg PHOBOS
Can we build Au+Au with Can we build Au+Au with p+p/d+Au?p+p/d+Au?
Fundamental differencebetween p+p / d+Au & Au+Au?
e e qq
Au+Au nucl-ex/0301017Au+Au nucl-ex/0301017d+Au & p+p preliminaryd+Au & p+p preliminary
PHOBOS 200 GeVPHOBOS 200 GeV
Peter Steinberg PHOBOS
Multiparticle Physics:Multiparticle Physics:Fluctuations, HBT, Fluctuations, HBT,
FlowFlow
Peter Steinberg PHOBOS
Forward Multiparticle Physics Forward Multiparticle Physics in Au+Auin Au+Au
1 2 3 4 5-1-2-3-4-5 0
• Fluctuations & Correlations• HBT Correlations• Azimuthal asymmetries
Long-Rangevs.
Short-Rangeeffects
4 multiplicity measurements show long-range correlation
Peter Steinberg PHOBOS
Forward-Backward Forward-Backward CorrelationsCorrelations
1 2 3 4 5-1-2-3-4-5 0
F BC C
F B
K. Wozniak talk• Correlations consistent w/ UA5
• Weak rapidity dependence from
PHOBOS study for Au+Au:PHOBOS Au+Au
UA5 p+p: 2-particle clusters explain• Short-range correlations in • FB correlations
UA5 PLB123:361 (1983)
~ 1
Peter Steinberg PHOBOS
Longitudinal Dynamics Longitudinal Dynamics with HBTwith HBT
Boost
Inva
rian
t
Static Source
PHOBOS Preliminary Au+Au 200 GeV(0.1 < kT < 1.4 GeV/c)
NA49 (1998)(0.1 < kT <0.2 GeV/c)
Particles at a givenrapidity are correlated
with a sourceat the same rapidity
Similar to FB result:correlations arelocal in rapidity.
See talk by B. Holzman, poster by C.M.Kuo
1 2 3 4 5-1-2-3-4-5 0
Open symbols reflectedOpen symbols reflected
Peter Steinberg PHOBOS
Directed and Elliptic FlowDirected and Elliptic Flow
UrQMD
DirectedFlow
DirectedFlow y
y
vv11
vv11
pp
vv11
vv11
pp
vv22
Peter Steinberg PHOBOS
Elliptic Flow vs. Elliptic Flow vs. Centrality Centrality
Overall shape simple, but still unexplained 2 2
central peripheralv v
See talk by M. Belt Tonjes
Open symbols reflectedOpen symbols reflected
200 GeV
Peter Steinberg PHOBOS
Directed Flow vs. EnergyDirected Flow vs. Energy
Dramatic change of directed flow near =0
Peter Steinberg PHOBOS
““Limiting Fragmentation” Limiting Fragmentation” of vof v11
Similar directed flow relative to beam rapidity
19.6 GeV130 GeV200 GeV
PHOBOS Au+Au PreliminaryPHOBOS Au+Au Preliminary
Beamy
2
part
dN
N d
PRL91 (2003), Poster by B. BackPRL91 (2003), Poster by B. Back
' beamy
Peter Steinberg PHOBOS
Connection with Net Connection with Net Baryons?Baryons?
Peak of baryon density at AGS/SPS at ’~-1.5(Busza & Goldhaber ‘84)
BRAHMS, nucl-ex/0312023BRAHMS, nucl-ex/0312023
Peter Steinberg PHOBOS
Directed & Elliptic FlowDirected & Elliptic Flow
b
y
QM2002 200 GeV v2 3-50% 200 GeV v1 6-55%
PHOBOS PreliminaryPHOBOS Preliminary
Peter Steinberg PHOBOS
Identified Particles in Identified Particles in d+Aud+Au
Peter Steinberg PHOBOS
Ratios with dE/dx PIDRatios with dE/dx PID
A “classic” PHOBOS measurement:Two charge signs,
two bending directions…
…but now we have
p+pp+p
d+Aud+Au
Au+AuAu+Au
Peter Steinberg PHOBOS
Identified Particle RatiosIdentified Particle Ratios
p+p d+Au : No modification (cf. multiplicity)Au+Au: Additional net-baryons near =0
d+Au: nucl-ex/0309013d+Au: nucl-ex/0309013Au+Au: PRC-R67 (2003) Au+Au: PRC-R67 (2003)
Poster by A. BickleyPoster by A. Bickley
200200GeVGeV
Peter Steinberg PHOBOS
PHOBOS PHOBOS TOFTOF PID PID
See talk by G.Veres
TOF Walls
SpectrometerTrigger
StartCounter
Poster by C. Henderson
StartCounter
“SpecTrig”
TOF
Spectrometertrigger enrichedd+Au data set
Peter Steinberg PHOBOS
Particle Ratios at High-pParticle Ratios at High-pTT
p
Main difference between p and p is overall yield.Spectral shape only slightly modified vs. pT
d+Au 200 GeVd+Au 200 GeV
Peter Steinberg PHOBOS
TOF PID Spectra d+AuTOF PID Spectra d+AuPending weak-decay correction
Peter Steinberg PHOBOS
mmT T Scaling in d+Au and Scaling in d+Au and Au+AuAu+Au
PossiblemT scalingin d+Au(pending
weak corr.)
20% normalizationat 2 GeV
Subm. to PRLnucl-ex/0401006
Au+Au 200 GeVAu+Au 200 GeV
Peter Steinberg PHOBOS
d+Au Inclusive d+Au Inclusive Spectra vs. Spectra vs.
Peter Steinberg PHOBOS
Inclusive Charged Hadrons Inclusive Charged Hadrons in d+Auin d+Au
Au+Au and d+Auscale differentlyrelative to Ncoll
PHOBOS has a“forward” acceptance(& more in the future!)
0 1 2 3 4 5-1-2-3-4-5
1 /
/
d AuT
d Au p pcoll T
dN dpR
N dN dp
PRL91, 072302 (2003)PRL91, 072302 (2003)
Peter Steinberg PHOBOS
Spectra in d+Au for Spectra in d+Au for >0>0
Systematic decrease in Rd+Au with increasing Saturation of ratio also occurs at a lower pT
See poster by J. Kane
Peter Steinberg PHOBOS
-Dependence of R-Dependence of Rd+Aud+Au
Monotonic evolution from mid-rapidity to forward rapidities.BRAHMS data is a continuation of trends starting at =0
Peter Steinberg PHOBOS
The Landscape of Particle The Landscape of Particle ProductionProductionSPS
FNALRHICSppSAGS
• Multiplicity measurements • Npart scaling & limiting fragmentation • Long range correlations in ?
• Forward Multiparticle Physics in Au+Au• FB & HBT show effects local in for ||<3• First measurement of directed flow vs. & s
• Identified Particle Spectra in d+Au• PID Spectra in d+Au, Au+Au for Run-4• Proton and antiproton spectra similar
• Inclusive d+Au Charged Spectra vs. • Strong dependence interpolates between =0 and forward
Peter Steinberg PHOBOS
Backup SlidesBackup Slides
Peter Steinberg PHOBOS
Relative Yields vs. pRelative Yields vs. pTTPHOBOS d+Au 200 GeVPHOBOS d+Au 200 GeV
Peter Steinberg PHOBOS
mmTT Scaling and Scaling and StrangenessStrangeness
Factor of 2 brings K’s into line (s ~ 0.5 in pp)
Peter Steinberg PHOBOS
PHOBOS CoveragePHOBOS Coverage
0 1 2 3 4 5-1-2-3-4-5
dN/d
N Rings P Rings
Octagon Spectrometer
Nowhere to hide!
Peter Steinberg PHOBOS
Principal AxesPrincipal AxesHeavy-ion collisions dominated
by Npart fluctuations
Decouple total fromrelative fluctuations
Independently partitionedbetween P & N
N
P
P+N
P – N
P N
CP N
1C
(flipping a coin, random walk…)
Peter Steinberg PHOBOS
Forward-Backward Forward-Backward CorrelationsCorrelations
N P
1 2 3 4 5-1-2-3-4-5 0
Peter Steinberg PHOBOS
Simple ExerciseSimple ExerciseLet’s play a game:
Shift PYTHIA dN/dyby y = 1
Scale up by Npart/2
Recalculate dN/d
Similar shapes(violates energy conservation )
Peter Steinberg PHOBOS
Participant ScalingParticipant Scaling
PHOBOS QM ’02
Wounded Nucleon“Scaling”
1
2 part ppN N
1
2 part e eN N
Transition to d+Au
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