# Presentation: 119261

## 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**

- S.Manly (PHOBOS) - QM2002

- July 18, 2002

##               Collaboration

**	**_**ARGONNE NATIONAL LABORATORY**_**	****Birger 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, KRAKOW**_**	****Andrzej Budzanowski, Roman Hołyński, Jerzy Michałowski, Andrzej Olszewski, Pawel Sawicki, Marek Stodulski, **
**	****	****Adam Trzupek, Barbara Wosiek, Krzysztof Woźniak**
_**	**__**MASSACHUSETTS INSTITUTE OF TECHNOLOGY**_**	****Maartin 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, TAIWAN**_**	****Chia Ming Kuo****, Willis Lin, Jaw-Luen Tang**
**	**_**UNIVERSITY OF ILLINOIS AT CHICAGO**_**	****Russell Betts, Edmundo García, Clive Halliwell, David Hofman, ****Richard Hollis****, ****Aneta Iordanova****, Wojtek Kucewicz, Don McLeod, Rachid Nouicer, Michael Reuter, ****Joe Sagerer**
**	**_**UNIVERSITY OF MARYLAND**_**	****Abigail Bickley****, ****Richard Bindel****, Alice Mignerey, **
**	****	****Marguerite Belt Tonjes**
**	**_**UNIVERSITY OF ROCHESTER**_**	****Joshua Hamblen****, ****Erik Johnson****, ****Nazim Khan****, Steven Manly, **
**	****	****Inkyu Park, Wojtek Skulski, Ray Teng, Frank Wolfs**

- S.Manly (PHOBOS) - QM2002

- July 18, 2002

## Elliptic flow

**Elliptic flow**

**dN/d(********R ****) = N****0 ****(1 + 2v****1****cos (********R****) + ****2v****2****cos (2(********R****)**** + ... ) **

- S.Manly (PHOBOS) - QM2002

- July 18, 2002

## Flow: basic method

** ****Correct for imperfect reaction plane resolution **

**Flow: basic method**

- S.Manly (PHOBOS) - QM2002

- July 18, 2002

## The PHOBOS Detector (2001 run)

**137000 Silicon Pad Channels**

**1m**

**Spectrometer**

**Octagon**

**Vertex**

**Ring Counters**

**Paddle Trigger Counter**

**Cerenkov Counter**

- S.Manly (PHOBOS) - QM2002

- July 18, 2002

## Slide 6

- S.Manly (PHOBOS) - QM2002

- July 18, 2002

## Flow: Hit-based method

**Flow: Hit-based method**

**nucl-ex/0205021 submitted to PRL**

- S.Manly (PHOBOS) - QM2002

- July 18, 2002

## Flow: Hit-based method

**Select vertices offset in Z, symmetric coverage in ********, ******

**Flow: Hit-based method**

**nucl-ex/0205021 submitted to PRL**

- S.Manly (PHOBOS) - QM2002

- July 18, 2002

## Flow: Hit-based method

**Reaction plane determined by subevents in -2<********<2**

**Select vertices offset in Z, symmetric coverage in ********, ******

**Flow: Hit-based method**

**nucl-ex/0205021 submitted to PRL**

- S.Manly (PHOBOS) - QM2002

- July 18, 2002

## Flow:  Track-based

**Flow:  Track-based**

**New for QM2002!**

- S.Manly (PHOBOS) - QM2002

- July 18, 2002

## Flow:  Track-based

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

**Flow:  Track-based**

**New for QM2002!**

- S.Manly (PHOBOS) - QM2002

- July 18, 2002

## Hit-based analysis

**Hit-based analysis**

** ****Large ******** coverage**
** ****Event-by-event**
** ****Uniform acceptance in ******
** ****Separated subevents**

**Track-based analysis**

** ****p****t ****dependence**
** ****Tracks less background       ****	****sensitive **
** ****Minimal MC dependence**
** ****Subevents and tracks    ****ww****widely separated in ******
** ****(Species dependence)**

- S.Manly (PHOBOS) - QM2002

- July 18, 2002

## v2 vs. centrality and energy

**v****2 *****vs.***** centrality and energy**

**Hit-based result  v****2****200**** & v****2****130**** similar**

***PHOBOS Au-Au***

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

**|********|<1**

**200**

**130**

**v****2**

**<N****part****>**

- S.Manly (PHOBOS) - QM2002

- July 18, 2002

**Notes:**
130 GeV errors not shown
Similar to 130 GeV results
Within errors, difficult to distinguish whether or not v2 is saturated or  scales with the increase in multiplicity as the energy increases.

## v2 vs. centrality, method comparison

**Hit and track-based results agree! **

**v****2****200 ****(hit)**

**v****2****200 ****(track)**

***PHOBOS Preliminary***
***200 GeV Au-Au***

**v****2 *****vs.***** ****centrality****, method comparison**

**|********|<1**

**track**

**hit**

**v****2**

**<N****part****>**

- S.Manly (PHOBOS) - QM2002

- July 18, 2002

**Notes:**
130 GeV errors not shown
Similar to 130 GeV results
Within errors, difficult to distinguish whether or not v2 is saturated or  scales with the increase in multiplicity as the energy increases.

## v2 vs. pT

**v****2 *****vs.***** ********p****T**

**v****2**** appears to saturate for p****T****>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***

- S.Manly (PHOBOS) - QM2002

- July 18, 2002

**Notes:**
Here we integrate over h+ and h-

## v2 vs.  and energy

**v****2 *****vs.***** ******** and energy**

**Hit-based result**
**v****2****200**** & v****2****130**** similar**

***PHOBOS Au-Au***

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

**v****2**

****

**200**

**130**

**<N****part****>~190**

- S.Manly (PHOBOS) - QM2002

- July 18, 2002

**Notes:**
Again, little changed from 130 GeV

## v2 -dependence

**v****2**** ********-dependence**

- S.Manly (PHOBOS) - QM2002

- July 18, 2002

## v2 -dependence

**Unambiguous large drop in v****2**** over broad range in ******

**v****2**** ********-dependence**

**Know p****T****, multiplicity, species yield vary with ******** and all can affect flow**

- S.Manly (PHOBOS) - QM2002

- July 18, 2002

## 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********’/<N****part****>**

***Phobos***

*Systematic errors not shown*

******’****=********-y****beam**

- S.Manly (PHOBOS) - QM2002

- July 18, 2002

## We look forward to seeing data() from BRAHMS!

**at RHIC  **

**We look forward to seeing data(********) from BRAHMS!**

- S.Manly (PHOBOS) - QM2002

- July 18, 2002

## HBT

**HBT**

****** ****phase space**

**Identified ********’s**

**Another way to look at source dynamics ...**

- S.Manly (PHOBOS) - QM2002

- July 18, 2002

## Data sample

**Data sample**

***PHOBOS preliminary***

- S.Manly (PHOBOS) - QM2002

- July 18, 2002

## HBT results

- - -

**0.54********0.02**

**5.8********0.2**

**5.1********0.4**

**6.8********0.3**

****

**R****out**

**R****side**

**R****long**

- ++

**0.57********0.03**

**4.9********0.4**

**7.3********0.3**

**5.8********0.2**

**R****2****out-long**

**4.9********1.7**

**4.5********1.9**

**Phobos preliminary**
**200 GeV Au-Au**

**15% most central events**

**0.15<k****T****<0.****35**

**0.2<y<1.5**

**Systematic error on radii of 1 fm, on ******** of 0.06**

- S.Manly (PHOBOS) - QM2002

- July 18, 2002

## Scaling with energy 

**Scaling with energy **

- -- data

**For more on HBT at PHOBOS, see poster by C.M. Kuo**

***Compilation of non-PHOBOS data from C. Adler et al., Phys. Rev. Lett. 87, 082301 (2001)***

- S.Manly (PHOBOS) - QM2002

- July 18, 2002

**Notes:**
Central , low kt bin

## Summary/parting thoughts

**v****2****200**** is little changed from v****2****130**

**AND ...**

**v****2****(p****T****) appears to saturate for p****T****>2 GeV/c**

**R****out****, R****side****, R****long**** at 200 GeV are similar to those at 130 GeV **

**PHOBOS analyzing flow with hits and tracks**

- S.Manly (PHOBOS) - QM2002

- July 18, 2002

## Slide 26

- S.Manly (PHOBOS) - QM2002

- July 18, 2002

## Slide 27

- S.Manly (PHOBOS) - QM2002

- July 18, 2002

## 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 from**

**P. 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)**

**:**

- S.Manly (PHOBOS) - QM2002

- July 18, 2002