Title: High pT identified charged hadron v2 and v4 in 200GeV AuAu collisions by the PHENIX experiment
1High pT identified charged hadron v2 and v4 in
200GeV AuAu collisions by the PHENIX experiment
- Shengli Huang
- Vanderbilt University
- for the PHENIX Collaboration
2Outline
- Observables and Motivation
- Analysis methods
- Results and Discussion
- Conclusions
3Anisotropic flow v2 and v4
Peter Kolb, PRC 68, 031902
- Azimuthal correlation with the reaction plane
- Built up in the early stage and self-quenched,
therefore supply the early information of matter
generated in the collision
4 Partonic Flow
PHENIX, PRL. 99, 052301 (2007)
baryon
meson
- Baryon and meson elliptic flow follow the number
of constituent quark scaling as a function of
KET. This indicates that partonic flow builds up
at RHIC - Where is the break point where the hydro
interfaces with jet fragmentation? - The medium density and strength of interactions
?The dynamic range of the - global partonic flow
- How about the higher order anisotropic flow such
as v4?
5V4/(v2)2 ratio
- v4 /v22 is a probe of ideal
- hydro behavior and related to
- the degree of thermalization!
- Peter Kolb, PRC 68, 031902
- R.S.Bhalerao et.al PLB 627,49
- Borghini and Ollitrault, PLB642,227
- Hydro dynamics predicts
- v4 /v22 0.5
- The identified particles
- v4/v22 ratio should provide more
- detailed information than
- that of charged hadron
6 How to Coalesce?
b) Different momentum space
a) Similar momentum space
? modification factor
L.W. Chen, C.M. Ko nucl-th 0602025
- The measurement of meson and baron v4 /v22 ratio
- will allow us to extract the partonic v4,q
/v2,q2 ratio - To test whether the partons in different momentum
- space also can recombine with each other
7PHENIX in Run 7
- Run 7
- 4.5B events and around 50 have been used
- A new Time of Flight detector (TOFw) has been
installed in - the west arm of PHENIX
- A new reaction plane detector (RxNP) has been
installed in - the 38 cm lt z lt 42 cm alone the beam
8TOFw and Aerogel Detectors
- TOFw intrinsic timing resolution is 75ps
- ?/K can be separated to 2.8 GeV/c and K/p can be
separated - to 4.5 GeV/c
- 3. Together with Aerogel detector(ACC), we can
identify the K to - pT4 GeV/c and ?, p to 7 GeV/c
9Reaction Plane Measurements
- RxNP
- Two sets of plastic
- scintillators positioned
- on either side of the
- collision vertex
- 12 segments in ?
- 2 segments in ?
- 1.0 lt ? lt 1.5
- 1.5 lt ? lt 2.8
- BBC
- 3.1lt?lt3.9
- Both detectors are away from mid-rapidity.
Smaller non-flow effect - on the reaction plane measurements
- New RxNP detector resolution is around 74 at
mid-centrality
Sqrt(2cos(2(?N-?S)))
10Mass ordering of v2 and v4
- V4 has been measured as a
- function of pT in different centrality bins for
the ?, K and p - Mass ordering has been observed for both v2 and
v4 - Consistent with the hydrodynamics
- Poster 166 A.Taranenko
11KET Scaling of v4
P166 A.Taranenko
- The v4 follows the KET scaling well for KET lt 1
GeV - The number of constituent quark scaling holds
for v4 when - KET/nq lt 1 GeV. This confirms that matter with
partonic degrees - of freedom has been generated at RHIC
12V4/(v2)2 ratio
- The ratio of v4/(v2)2 is close to
- 0.9 for the ?, K and p
- Mesons and baryons have similar
- v4/(v2)2 ratio
What can we extract from this measurement?
13Partonic Thermalization !
- Parton v4,q/(v2,q)20.5 Perfect Partonic
Liquid! - Partons in different momentum space also can
- recombine with each other
- 3. Partons interact more frequently and strongly
- with each other
14Charged ? v2
- Charged ? v2 can be measured to
- 6 GeV/c.
- The results are consistent with
- ?0 results in the overlap pT region.
- All ? v2 start to drop at pT 2.5 GeV/c
- in the different centrality bins!
15Kaon and Proton v2
- Kaon v2 can be measured to 4 GeV/c and protons v2
can be measured to 6 GeV/c - Proton v2 starts to drop at pT 4 GeV/c
16Break Point?
KET/nq(GeV)
KET/nq(GeV)
- In the centrality of 2060, the ?, K and p KET
scaling seemly begins to - break at KET/nq 1 GeV
- More statistics are required for the further
investigation - A factor 2 of Run 7 data
will come after QM08
17Conclusions
New time of flight detector(TOFw) of PHENIX runs
successfully in Run 7 with 75 ps intrinsic timing
resolution. With new TOFw and RxNP detectors, we
can measure the identified charged hadrons v2 to
pT6 GeV/c and v4 to 3 GeV/c
The number of constituent quark scaling has been
observed for v4 for KET/nq lt 1 GeV. Mesons and
bayrons have similar v4/(v2)2 ratio which is
close to 0.9 The parton v4,q/(v2,q)2 0.5
perfect partonic liquid Partonic Thermalization
The number of constituent quark scaling seemly
begins to break for v2 as KET/nq1GeV at 2060
centrality a)The interface between hydro and jet
fragmentation b)Quantitative information about
density and interaction strength