Where we are & Where to go
For PHENIX Collaboration
Yasuo Miake, Univ. of Tsukuba

First Collision at PHENIX
Machine started on March, 2000
First Collisions at PHENIX recorded on June 15th, 2000
5 Million Collisions Recorded till September, 2000

Multiplicity Distribution
Multiplicity measurement by Drift & Pad chamber
Consistent Results
Shape of distr. well explained by Glauber Model Calculation
Central collisions (Upper 6%) ;‚„‚ށ^‚„ƒΕ‚T‚S‚O
<Nparticipant>~345 from Glauber
Central Pb+Pb at SPSiγ‚“17.2 GeV/Aj‚„‚ށ^‚„ƒΕ‚S‚O‚O
‚S‚O“ increase !!

Transverse Energy Distribution
Transverse Energy by EM Cal.
Glauber Model‚Ι‚ζ‚θ•ͺ•zŒ`σ‚Μΰ–Ύ‰Β
Central Collisions (Upper 2%);‚„‚d‚s^‚„ƒΕ‚T‚V‚O‚f‚…‚u
Central Pb+Pb at SPSiγ‚“17.2 GeV/Aj‚„‚d‚s^‚„ƒΕ‚S‚O‚T‚f‚…‚u
‚S‚O“ increase !!
Estimate of energy density by Bjorken Formula;
Compared with SPS, >40% increase!

More comparison
Charged Multiplicity, ET shows ~40% increase
~50% increase if normalized with # of participants
ET/Multiplicity ratio increases slightly
‚q‚g‚h‚bGi‚„‚d‚s^‚„ƒΕj^i‚„‚ށ^‚„ƒΕ j`‚PD‚O‚T
‚r‚o‚r@Gi‚„‚d‚s^‚„ƒΕj^i‚„‚ށ^‚„ƒΕ j`‚PD‚O
Slight increase of individual pt

ƒΞ‚O measurement by EM Cal.
Photons of ƒΞ‚O¨‚QƒΑ detected
Evaluate invariant mass of all photon pair
Subtract Combinatorial Background with a Mixed Event Method

@pT distribution
Compared with CERN WA98 results
Hotter(!?) at RHIC
Tracking Results
Agree with in the error

PID by TOF
No Slewing, No adj. W. tracking
Intrinsic Resolution of 120 ps
TOF resolution of 170 ps
Has been improved to
TOF resolution of 120 ps aft. Slewing
A. Kiyomichi/T. Chujo
Capability of a lot of physics!
Particle ratios ; Chemical eq.
Y. Kwon/DJ.Kim

@pT distribution of Identified
Capability of a lot of physics!
strangeness and (net)baryon content Þ ƒΚS, ƒΚB
mean pT, variation of invariant cross section with pT Þ T
pT as function of particle species - evidence for collective motion? Þ b
Cross section for short-lived particles, such as w and f vector mesons
Need works on Tracking, Acceptance
T. Chujo
Higher pt
S. Sato

Elliptic Flow @ Phenix
iƒΣ‚P-ƒΣ2jdistribution made for all the pair
Then, normalized with Mixed Events
‚–‚‚‚‚“‚–‚Q‚Q

Beam Energy Dependence of ‚u‚Q
No structure observed
a) No phase Transition?
b) No sensitivity for the signal of phase transition?
c) Bad gSystematich comparison?
Such as,
protons vs pions
pt, rapidity regions
Need gsystematich measurements!

Goal(1);Particle Ratios
Chemical Eq. In RHIC Collisions?
@ƒΑs; Eq. in Strangeness also?
Strangeness Enhancement?
Larger enhancement for multi-strangeness?
Temperature of chemical freezeout?
Larger than 170 MeV?

Goal(2); pT distribution
Slope parameters vs mass
Freezeout Temepature
Radial flow velocity
Systematic Comparison

Where it goesc