Analysis of identified hadron spectra at PHENIX

• 20M MinBias Au+Au events– feed-down corrected for weak

decay• Central collisions

– low-pT slopes decrease with mass

– protons and pions close at high pT

• Peripheral coll’s– weaker mass dependence– similar to d+Au

200 GeV Au+Au 200 GeV d+Au and p+p•42M MinBias d+Au events at 200

GeV–88.5±4% of all events–feed-down corrections

•25M MinBias p+p events at 200 GeV–51.6±9.8% of all events–feed-down corrections

•Both similar to Au+Au peripheral

How do we learn from this?

•Nuclear modification factor

–Scale down Au+Au spectra by Ncoll, compare to p+p

•Ncoll: number of binary nucleon-nucleon collisions (from Glauber geometry), is 1 in p+p

–The ratio is the nuclear modification factor

•measures the effects of nuclear matter

•hydro: scaling rather with number of participants

•Hadron ratios

–Negative versus positive particles

•thermalization: ratio should be one (equal mass)

•case of protons: nonzero initial baryon-number

–Protons versus pions

•collective dynamics effects

•baryon yield enhancement

Nuclear modification factor

•Peripheral Au+Au similar to d+Au•Pions: suppressed in central Au+Au•Protons: significant enhancement for every collision type

•Different mechanisms present here

PRELIMINARY

Negative vs. positive ratios

• Collision species and pT independent

• Sign of thermalization• Small net baryon density small, finite B

PRELIMINARY

Proton to pion ratio

PRELIMINARY

•Peripheral Au+Au and Minimum Bias d+Au have the same behavior

•Central Au+Au p/ ratio much larger•Not in the baseline systems•Protons pushed forward to higher pT•Baryon yield enhancement: only in hot, dense nuclear matter

M. Csanád for the PHENIX Collaboration

Buda-Lund hydro

•3D expansion, symmetry•Local thermal equilibrium•Analytic expressions for the observables (no numerical simulations, but formulas)

•Reproduces known exact hydro solutions (nonrelativistic, Hubble, Bjorken limit)

•Core-halo picture

A useful analogy

•Core Sun•Halo Solar wind•T0,RHIC T0,SUN 16 million K •Tsurface,RHIC Tsurface,SUN 6000 K•RG Geometrical size•Rs Radius where T = T0/2

–(Ts=T0 Rs )

• 0 Radiation lifetime •<t> Radial flow of surface•<t'> Radial flow at r=Rs

–Note: ut2 = t

2/(1-t2)

Fireball at RHIC Fireball Sun

Buda-Lund fit results•T0>Tc by 2-5 , indication for deconfinement in

Au+Au and p+p, based on lattice QCD (Tc162MeV)

•Finite Rs at the freeze-out not phase transition, crossover

• No radial flow in p+p 1D Hubble, spectra slope T0

• 3D Hubble flow in Au+Au (1/0 ut’/Rs)

• CERN SPS also fitted, but T0<Tc there!

Big Bang vs. Little Bang•Developed Hubble-flow at RHIC and in the Universe–Universality of the Hubble expansion: u= Hr

•Hubble constant of the Universe:–H0= (71 ± 7) km/sec/Mpc

–converted to SI units: H0= (2.3 ± 0.2)×10-18 sec-1

•H in Au+Au collisions at 200 GeV –HRHIC,long = <ut’>/Rs (3.8 ± 0.4)×1022 sec-1

–HRHIC,trans = 1/0 (5.1 ± 0.1)×1022 sec-1

•Ratio of expansion rates:–HRHIC / H0 2×1040

•Approx. the ratio of the ages! –15×109 yrs vs. 7fm/c

Summary and conclusions

•p+p and d+Au data at the same energy as the “discovery energy” at RHIC, √sNN = 200 GeV–New the baseline spectra–Made a lot of comparisons possible

•Nuclear modification factor measured–d+Au similar to peripheral Au+Au–Pion suppression in central Au+Au

•Hadron ratios also measured–Indication for thermalization–p/ enhancement only in central Au+Au

•Successful Buda-Lund hydro fits–Indication of deconfinement in Au+Au and also p+p

–3D Hubble flow in Au+Au, no radial flow in p+p–Crossover, not phase transition

We thank the staff of the Collider-Accelerator and Physics Departments at BNL for their vital contributions. We acknowledge support from the Department of Energy and NSF (U.S.A.), MEXT and JSPS (Japan), CNPq and FAPESP (Brazil), NSFC (China), IN2P3/CNRS, CEA, and ARMINES (France), BMBF, DAAD, and AvH (Germany), OTKA (Hungary), DAE and DST (India), ISF (Israel), KRF and CHEP (Korea), RMIST, RAS, and RMAE (Russia), VR and KAW (Sweden), U.S. CRDF for the FSU, US-Hungarian NSF OTKA- MTA, and US-Israel BSF.