the landscape of particle production: results from

Peter Steinberg PHOBOS

The Landscape ofThe Landscape ofParticle Production:Particle Production:

Results from Results from ..

Peter SteinbergBrookhaven National Laboratory

SPSFNALRHICSppS

AGS


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


PHOBOS HighlightsPHOBOS Highlights

• d+Au & p+p physics• Multiplicity • Inclusive Spectra• PID

• Multiparticle Physics in Au+Au


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


Charged-Particle Charged-Particle Multiplicities in p+p & Multiplicities in p+p &

d+Aud+Au


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


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


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


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


(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.


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


Multiparticle Physics:Multiparticle Physics:Fluctuations, HBT, Fluctuations, HBT,

FlowFlow


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


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


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


Directed and Elliptic FlowDirected and Elliptic Flow

UrQMD

DirectedFlow

DirectedFlow y

y

vv11

vv11

pp

vv11

vv11

pp

vv22


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


Directed Flow vs. EnergyDirected Flow vs. Energy

Dramatic change of directed flow near =0


““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


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


Directed & Elliptic FlowDirected & Elliptic Flow

b

y

QM2002 200 GeV v2 3-50% 200 GeV v1 6-55%

PHOBOS PreliminaryPHOBOS Preliminary


Identified Particles in Identified Particles in d+Aud+Au


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


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


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


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


TOF PID Spectra d+AuTOF PID Spectra d+AuPending weak-decay correction


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


d+Au Inclusive d+Au Inclusive Spectra vs. Spectra vs.


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)


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


-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


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


Backup SlidesBackup Slides


Relative Yields vs. pRelative Yields vs. pTTPHOBOS d+Au 200 GeVPHOBOS d+Au 200 GeV


mmTT Scaling and Scaling and StrangenessStrangeness

Factor of 2 brings K’s into line (s ~ 0.5 in pp)


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!


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…)


Forward-Backward Forward-Backward CorrelationsCorrelations

N P

1 2 3 4 5-1-2-3-4-5 0


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 )


Participant ScalingParticipant Scaling

PHOBOS QM ’02

Wounded Nucleon“Scaling”

1

2 part ppN N

1

2 part e eN N

Transition to d+Au

the landscape of particle production: results from

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