Flow and Bose-Einstein Correlations in Au-Au Collisions at RHIC

July 18, 2002 S.Manly (PHOBOS) - QM2002 1

Flow and Bose-Einstein Correlations in Au-Au Collisions at RHIC

Probe the source dynamics through

correlations

Flow constitutes the bulk of this talk

Steven Manly (Univ. of Rochester)

For the PHOBOS Collaboration


Collaboration

ARGONNE NATIONAL LABORATORYBirger Back, Alan Wuosmaa

BROOKHAVEN NATIONAL LABORATORY Mark Baker, Donald Barton, Alan Carroll, Nigel George, Stephen Gushue, George Heintzelman, Burt Holzman, Robert Pak, Louis Remsberg, Peter Steinberg, Andrei Sukhanov

INSTITUTE OF NUCLEAR PHYSICS, KRAKOWAndrzej Budzanowski, Roman Hołyński, Jerzy Michałowski, Andrzej Olszewski, Pawel Sawicki, Marek Stodulski, Adam Trzupek, Barbara Wosiek, Krzysztof Woźniak

MASSACHUSETTS INSTITUTE OF TECHNOLOGYMaartin Ballintijn, Wit Busza (Spokesperson), Patrick Decowski, Kristjan Gulbrandsen, Conor Henderson, Jay Kane, Judith Katzy, Piotr Kulinich, Jang Woo Lee, Heinz Pernegger, Corey Reed, Christof Roland, Gunther Roland, Leslie Rosenberg, Pradeep Sarin, Stephen Steadman, George Stephans, Carla Vale, Gerrit van Nieuwenhuizen, Gábor Veres, Robin Verdier, Bernard Wadsworth, Bolek Wysłouch

NATIONAL CENTRAL UNIVERSITY, TAIWANChia Ming Kuo, Willis Lin, Jaw-Luen Tang

UNIVERSITY OF ILLINOIS AT CHICAGORussell Betts, Edmundo García, Clive Halliwell, David Hofman, Richard Hollis, Aneta Iordanova, Wojtek Kucewicz, Don McLeod, Rachid Nouicer, Michael Reuter, Joe Sagerer

UNIVERSITY OF MARYLANDAbigail Bickley, Richard Bindel, Alice Mignerey,

Marguerite Belt Tonjes

UNIVERSITY OF ROCHESTERJoshua Hamblen, Erik Johnson, Nazim Khan, Steven Manly, Inkyu Park, Wojtek Skulski, Ray Teng, Frank Wolfs


Elliptic flow

dN/d(R ) = N0 (1 + 2v1cos (R) + 2v2cos (2(R) + ... )

Determine to what extent the initial state spatial anisotropy is mapped into the final state particle production.

Sensitive to the degree of equilibration and the initial equation of state.

Affects other variables, such as HBT and spectra.


Subevent technique: correlate qqqreaction plane in one part of qqqdetector to asymmetry in qqqtrack pattern in other part of qqqdetector

Correct for imperfect reaction plane resolution

-2.0 < < -0.1

SubE (a) SubE (b)

na n

b

0.1 < < 2.0

dependence of the multiplicity

Flow: basic method


The PHOBOS Detector (2001 run)

137000 Silicon Pad Channels

1m

Spectrometer

Octagon

Vertex

Ring Counters

Paddle Trigger Counter

Cerenkov Counter


RingsN Octagon RingsP



Flow: Hit-based method nucl-ex/0205021 submitted to PRL

Select vertices offset in z, symmetric coverage in ,



Reaction plane determined by subevents in -2<<2

Select vertices offset in Z, symmetric coverage in ,




Reaction plane determined by subevents in -2<<2Elliptic flow (v2) determined for ||<5.3

Select vertices offset in Z, symmetric coverage in ,



Flow: Track-based New for QM2002!

Vertex measurement

Reaction plane determined by hits in widely separated subevent regions, symmetric in ,


Reaction plane determined by hits in widely separated subevent regions, symmetric in ,

Correlate tracks in spectrometer to reaction plane to determine v2

Flow: Track-based New for QM2002!


Hit-based analysis

• Large coverage

• Event-by-event

• Uniform acceptance in

• Separated subevents

Track-based analysis

• pt dependence

• Tracks less background sensitive

• Minimal MC dependence

• Subevents and tracks wwwidely separated in

• (Species dependence)


v2 vs. centrality and energy

Preliminary v2200

Final v2130

Hit-based result v2200

& v2130 similar

PHOBOS Au-Au

130 GeV result: nucl-ex/0205021, submitted to PRL

||<1

200

130

v 2

<Npart>


Hit and track-based results agree!

v2200 (hit)

v2200 (track)

PHOBOS Preliminary

200 GeV Au-Au

v2 vs. centrality, method comparison

||<1

trackhit

v 2

<Npart>


v2 vs. pT

v2 appears to saturate for pT>2

Similar to published results at 130 GeV (STAR, PHENIX)

PHOBOS preliminary

h+ + h-

200 GeV Au-Au

track-weighted centrality averaging

0<<1.5

(top 55%)

v 2

17% scale error


v2 vs. and energy

Preliminary v2200

Final v2130

Hit-based result

v2200 & v2

130 similar

PHOBOS Au-Au

130 GeV result: nucl-ex/0205021, submitted to PRL

v 2

200 130

<Npart>~190


PHOBOS preliminary

200 GeV Au-Au

v 2

Unambiguous large drop in v2 over broad range in

v2 -dependence


PHOBOS preliminary

200 GeV Au-Au

v 2


v2 -dependence

Know pT, multiplicity, species yield vary with and all can affect flow



v2 -dependence

Know pT, multiplicity, species yield vary with and all can affect flow

PHOBOS preliminary

h+ + h-

200 GeV Au-Au

0<<1.5v 2

recall


There is no large central plateau in the multiplicity distribution!

See talk by Mark Baker tomorrow morning and talk by Peter Steinberg in minutes in session I

dN

ch/d

’/<

Np

art>

Phobos

Systematic errors not shown

’=-ybeam


Boost invariance

at RHIC

We look forward to seeing data() from BRAHMS!

?


HBT

phase space Identified ’s

Another way to look at source dynamics ...


Data sample

PHOBOS preliminary


HBT results

2222222 21 OLLOSSLLOO RQQRQRQRQeC

- - 0.540.02 5.80.2

5.10.4 6.80.3

Rout Rside Rlong

++ 0.570.03 4.90.4 7.30.3

5.80.2

R2out-long

4.91.74.51.9

Phobos preliminary

200 GeV Au-Au15% most central events

0.15<kT<0.35

0.2<y<1.5

Systematic error on radii of 1 fm, on of 0.06


Scaling with energy -- data

For more on HBT at PHOBOS, see poster by C.M. KuoCompilation of non-PHOBOS data from C. Adler et al., Phys. Rev. Lett. 87, 082301 (2001)


Summary/parting thoughts

v2200 is little changed from v2

130

AND ...

v2(pT) appears to saturate for pT>2 GeV/c

Rout, Rside, Rlong at 200 GeV are similar to those at 130 GeV

PHOBOS analyzing flow with hits and tracks


Boost invariance


An expert is a man who has made all the mistakes, which can be made, in a very narrow field.

- Niels Bohr, recalled on his death, November 1962

More to come fromP. Steinberg - Universal behavior of charged particle production

(session I, his talk is just starting … skip the QA and go!)M. Baker - Global observations from PHOBOS

Tomorrow morning (19th)

B. Wosiek - Identified particle pt distributions (including very low pt!) Parallel session I, tomorrow night (19th)

C. Roland - Scaling of charged hadron pt distributions Parallel session I, Saturday evening (20th)

C.M. Kuo - HBT Correlations (poster)

A. Iordanova - 20 GeV Au-Au analysis (poster)

R. Hollis - 200 GeV p-p analysis (poster)

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Flow and Bose-Einstein Correlations in Au-Au Collisions at RHIC

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