Results from RHIC. Jens Sören Lange (Frankfurt University / GSI Darmstadt) XIII ISVHECRI, Pylos, Greece, 10.09.2004

Results from RHIC.

Jens Sören Lange (Frankfurt University / GSI Darmstadt)

XIII ISVHECRI, Pylos, Greece, 10.09.2004

Jens Sören Lange Frankfurt Univ./GSI Results from RHIC XIII ISVHECRI 10.09.2004 2

Outline.

How extreme are the events ?categorization (measured properties) of RHIC Au+Au collisions

• temperature• size• energy density• matter density

and (as Gedankenexperiment) qualitative comparison to primordial universe, supernovae etc.

One specific example:

production of anti-protons, anti-deuterons and anti-Helium

in A+A collisions.


Timeline of 1 Au+Au Collision.

t~ 0 fm/c gold nuclei Lorentz contracted in laboratory frame“pancakes”hard parton scattering (quarks, gluons)

t~ 1 fm/c hot cylindert~ 4 fm/c soft partons from energy at (0,0,0)

beam remnants peaked forward/backwardt~10 fm/c freezeout: all partons particles

time scale 1 fm/c ~ 10-24 suniverse: cosmic inflation started @ t~10-34 s system already had macroscopic size.

QM (xp<h) formally induces v>c

Partonic stage Hadronic stage


=3.8 km1740 superconducting magnets

New York

RHIC


The Experiments.

LeptonsEmCal e forward/backward

silicon detector, high granularity,small in-plane acceptance

TPC large acceptance,realtime trackfinder

movable spectrometer,small forward acceptance


ZDC

Barrel EMC

Endcap EMC

Magnet B= 0.5 T

ZDC

FTPCs

Vertex Position Scintillators (TOF)

Trigger Barrel(TOF)

Time Projection Chamber

Silicon Vertex Tracker

RICH

2 m

4 m

The STAR Experiment

24 sectors x 5692 r pads x 350 t bins= 47,812,800 pixels

y1


Laser for TPC Calibration.


Au+Au Collision s=200 GeV. Cosmic Ray Collision in STAR.

~6500 tracks, ~130,000 clusters.


TPC dE/dx

dE/dx resolution on Level-3 Trigger ~11% (offline ~8%)

if charge < 0 anti-matter


Data Set.

Au+Au 130 GeV 0.7 Mill. 2000 Au+Au 200 GeV 3.2 Mill. 2001 Au+Au 19.6 GeV ~20k 2001 d+Au 200 GeV 35 Mill. 2003 pp

• un-polarized• vertical pol. > 10 Mill.• longitudinal pol. > 10 Mill. (spin flip snake)

Level-3 trigger for rare probes• Upsilon• Anti-He

2004 Au+Au 200 GeV 47.5 Mill.

30.4 Mill. centralAu+Au 62 GeV 13.3 Mill.~63 x data (BELLE+BABAR) asym !

jet


An obvious difference: topology.

Au+Au 3-dim, cylinder, infinite in z (if boost-invariant = true for ||0.5)

Universe 4-dim, infinite 3-dim all directions

Note: in the universe, a blast wave could not escape (closed).

general relativity curvatureds2~dr2/(1-k)k = 2GM/Rc2 k = 1 black hole (escape velocity c)k ~ 10-22 @ RHIC not bending space-time


The phase diagram before RHIC.

B ~ NBaryon-NAnti-Baryon B ~ Nsea/Nvalence

Primordial Universe


Where is the critical point ?

phase boundaryAllton et al.hep-lat/0204010

Tc=1603.5 MeVmb=72535 MeV=0.3-1.3 GeV/fm3

RHIC and universe: not near the critical point.no dramatic Ncharged event-by-event fluctuations expected.

hep-lat/0106002

Lattice QCD


The Temperature.

2 methods:

• T from particle yield (ratios) e.g. for hadron resonance ideal gas Ni ~ mi T This is "chemical" T~200 MeV (start of scattering phase).

• T from inverse slope of exponential fits to mT

This is "kinetic" T~100 MeV (end of scattering phase).

T

mA

dm

dN

mT

TT

exp1 22 mpm TT


The baryo-chemical potential B.

energy required to add 1 nucleon to the system_p / p ratio = 0.790.003(stat) 0.005(syst) = q

-6

q=exp(q/T) b=3q~30 MeV

insert T


RHIC chemical freeze-out temperature: T=176 MeV (130 GeV), T=177 MeV (200 GeV)

B=41 MeV (130 GeV)B=29 MeV (200 GeV)

RHIC 200 GeVRHIC 130 GeV

T=2.1·1012 K

Universe:TPlanck=1.4·1034 Kbut maybe Hagedorn-limited ~1/Rn

Primordial Universe RHIC

All cosmological estimates fromK. A. Olive, hep-ph/9404352and references therein


The Temperature (cont'd).

RHIC T=2.1·1012 KSun (core) 15.6·106 K

Supernova ~109 KPlasma fusion 55·106 KLaser fusion 4·106 K

One of the highest temperatures in the universe. Only small black holes are hotter: R=2GM/c2, kT=hc/4R

T(R=1 fm, M=1012 kg) ~ 1011 K

• Note: from s=130 GeV to s=200 GeV Although initial collision energy is increased by E=70 GeV,temperature increases only by 7 MeV10–4 of E

• RHIC and primordial universe have about the same distanceto the critical point

_


p p

mT Distributions

K0s

0.2 < pT < 2.4

STAR Preliminary

MT-M0 (GeV/c2)

Statistical error only

Central events

(top 14%)

K*0

K- (K++ K-)/2, KoK+


pT in p+p (s=200 GeV)


pT in Au+Au (s=200 GeV), different from p+p !

BRAHMS: 10% centralPHOBOS: 10%PHENIX: 5%STAR: 5%


Au+Au is not a pure superposition of p+p.

Mean pT for all charged particles

p+p <pT>=0.390 GeV/cAu+Au central <pT>=0.508 GeV/c

increase by ~30%.


Hanbury-Brown-Twiss (HBT) Interferometry pairs (bosons Bose-Einstein statistics) close in p

Universe: R(galaxy) by difference in arrival time

RHIC collisions: difference in momentum p Fourier Transform p x Correlation Function C(p)=1+ x FourierTransform[(p)]=1+ exp(- p2R2) ( for resonances)

expanding system is time-dependant R=R(t)

The Size.


Expanding Volume.

R(LONG)

R(SIDE)

R(OUT)


HBT Radii vs. s

World compilation + STAR

• Surprising: Size roughly same AGS = SPS = RHIC R<10 fm• changes with beam energy negligible <0.5 fm • R increase with centrality (~ overlap region) O.K.• Unexpected: Rout/Rside ~ 1

• short “freeze-out”

• explosive source

PRL87(2001) 082301


Rout/Rside1: Expanding Shell (“blast wave”)

R(LONG)

R(SIDE)

R(OUT)

Universe:at T~100 MeV horizon distance L~10 kmexpansion rate slower ~1019 (= 1/M2

Planck)

high wave front velocityv~(0.550.06)c

supernova SN1987av=(0.80+0.31-0.17)c(see talk DeRujula)


The Quark/Gluon Density @ t=0.

Initial and final entropy must be sameThus Ngluons (partonic stage) = Npions (hadronic stage)we count Npions

we know Rassume cylinder, lorentz-invariant rapidity yt=0 =infinite, but @ t=0.2 fm/c: = 20/fm3 = 15 x [cold Au](hadrons definitely in-existent)

What is the energy density ?we have average momentum <p>90% , so assume m, then E2=m2+p2

~ 5 GeV/fm3 = 30 x [cold Au]

better pQCD estimate: ~18 GeV/fm3 Phys. Lett. B 507(01)121 SPS ~3 GeV/fm3, predictions before RHIC start up to 30 GeV/fm3


The Matter Density.

Gold nuclear density o 2·1017 kg/m3 ~1 nucleon/fm3

RHIC ~ 15 x o

metallic hydrogen (Jupiter) ~1000 kg/m3 protons in e- seaGold atomic density (solid) ~20000 kg/m3

universe critical density 1.1·10-26 kg/m3 ~6 H atoms/m3

At RHIC density 15xo, universe was in inflationassume initial inflation mass m=25 g const. / R=10-40 1 mat start t~10-34 10118 o

at end t~10-36 10-19 o

In cosmology w/o inflation, R(asymptotic t0)~10-5 m.

in order to reach RHIC density, one must put m=3600 kg gold into it.If initial mass was less, RHIC density was never achieved.


Total collision energy at RHIC.

1 Au+Au centrals=200 GeV x 197 primary pp/nn collisions 40 TeV 6 Jouletechnically human ear sensitivity starts at 10-18 Joulebut: not all energy goes into sound (instead temperature, kinetic energy etc.)


Production of anti-protons,

anti-deuterons andanti-Helium


Anti-Matter in the Universe.

~24% of all primordial matter is He creation at t~1 s, T~0.1 MeV Where is the Anti-He ? search for primordial Anti-p,d,He

by several experiments

e.g. BESS (balloon bound) H=2.7 km

e.g. AMS (space-shuttle bound) H=320-390 km


Anti-Matter production at accelerators.

production by coalescenceZ anti-protons + N anti-neutronsoverlap wave functions(x and p small)

BA is a penalty factorfor adding one anti-nucleon

B2~10-3

(anti-deuteron)

B3~10-6

(anti-3He, anti-triton)

Pcoas~50-200 MeV

astro-physicists prefer:

nuclear physicists prefer:

conversion formula:


Incident energy spectrum at AMS orbit (= "beam")

RHIC s=200 GeV

RHIC s=130 GeV

from J. A. Simpson,Ann. Rev. Nucl. Part. Sci. 33 (1983) 33

AMS relative abundance estimate:~80% p+~20% He~0.5% heavier~2% e+~0.5% e-


AMS-01 anti-proton calibration data set.

MIR used as production "target" for anti-matter

Z=-1 tracks

MIR, ~4 daysno MIR, ~6 days

7 models

AMS-02 motivation as reported on ICHEP 2004AMS-02 motivation as reported on ICHEP 2004anti-protonsanti-protons

expected anti-p distribution at AMS-02 orbit (ISS)

anti-p from neutralino annihilation


background rejection: p/anti-p > 106

e-/anti-p ~103-104

AMS-02 estimate as reported on ICHEP 2004:AMS-02 estimate as reported on ICHEP 2004:3 years orbit, envisaged start 09/2007 3 years orbit, envisaged start 09/2007 anti-protonsanti-protons


AMS-02 estimate as reported on ICHEP 2004: AMS-02 estimate as reported on ICHEP 2004: anti-deuterons vs. anti-protonsanti-deuterons vs. anti-protons

For T<1 GeV anti-d as SUSY signal possibly more promising:• "normal" anti-d production kinematically supressed in spallation• coalescence (one needs one anti-p and one anti-n close in phasespace)

RHIC anti-d

RHIC anti-HeN(SUSY)/N(Background)


AMS-01 results.

10 days mission, ~99 Mill. reconstructed events~100 anti-p, no anti-d, no anti-He

negative chargepositive charge


Anti-deuterons and Anti-Helium at RHIC.

Note: also at RHIC no anti-matter in initial state.





anti-d






10-3

10-6




Anti-deuterons at H1/HERA.

hep-ex/0403056 p collisions at s=200 GeV (= same s as RHIC)

(e+/p 27.6/820 GeV collisions, but require scattered e+) N=45 anti-d candidates


Anti-deuteron B2 compilation.

referencepp, s= 53 GeVPcoas=67 MeVastro-ph/9705110

+6– 8

it means:anti-d productionis suppressedAu+Au vs. p+p

~factor 40


Why is B2 for A+A (thus) low ?

Is annihilation cross section changed in-medium ? but p+A AGS eperiments saw anti-p yield excess vs. p+p

E802, E878, E902nucl-ex/0107013p+Be, p+Cu, p+Aupbeam=12.3, 17.5 GeV/c

2 possible explanations given

• anti-p annihilation cross section is same as free but anti-p formation time extended (e.g. p+anti-p molecule) ~1 fm/c 4.9+-0.5 fm/c• anti-p annihilation cross section is reduced in-medium by almost a factor ~10


Keep in mind: There is another source of Anti-deuterons.

Decay of Upsilon(1S),(2S) in e+e- collisions at s=10 GeV ARGUS Phys. Lett. B157(1985)326 one of the most non-perturbative known processes ever:

a b quark fragments into a nucleus Rare BR~6·10-5

not confirmed by OPAL at s=200 GeV e+e-Z. Phys. C67(1995)2003


UNILACSIS

FRS

ESR

SIS 100/300

HESRSuperFRS

NESR

CR

RESR

GSI Darmstadt Future UpgradeFAIR - Facility for Antiproton and Ion Research

100 m

© J. Reiß (GSI)


The "new" view of the phase diagram.

M. Bleicher et al. (Frankfurt UrQMD group) new lattice results (non-zero quark masses) critical point at lower B~450 MeV closed symbols: equilibrium open symbols: non-equilibrium

GSI Upgrade

RHIC


Summary

Maybe trivial, but important:at ultra-relativistic energies, A+A is not a simple superposition of p+p(<pT> increased by ~30%).

RHIC increased anti-nuclei world data set significantly • N=6416 anti-deuterons • N=193 anti-3He• from 2004 data we expect N=2.70.3 anti-4He (would be first observation) • for first time anti-He pT spectrum and temperature• coalescence is ~factor 10 weaker than pp or p• coalescence decrease as f(s) in A+A confirmed (in p+p const.)


Summary

Maybe trivial, but important:at ultra-relativistic energies, A+A is not a simple superposition of p+p(<pT> increased by ~30%).

RHIC increased anti-nuclei world data set significantly • N=6416 anti-deuterons • N=193 anti-3He• from 2004 data we expect N=2.70.3 anti-4He (would be first observation) • for first time anti-He pT spectrum and temperature• coalescence is ~factor 10 weaker than pp or p• coalescence decrease as f(s) in A+A confirmed (in p+p const.)

Final note:As an experimental site, Pylos is much nicer than Brookhaven.(Thanks very much for the invitation !)


Additional slides for discussion



System time evolution.

RHIC = strong interaction only,universe = strong, weak and EM (e.g. neutrino re-heating)

RHIC is matter dominated all the time, universe not.

This leads to different time evolutions of the temperature. Au+Au collision, after equilibrium.

E/N~T N/V~T3~1/t

T~1/t1/3

compare to cosmological, primordial phase

T~1/t1/2 for radiation dominated universe T~1/t2/3 for matter dominated universe

turnover at T~1 eV In either case, universe cool-down (somewhat) slower.


MC for secondary anti-proton flux in atmosphere.

Huang et al., astro-ph/0305367, 0305369Cascade, 3-dim, incident p,He at H=2000 kmFor anti-protons, annihilation is only inelastic channel (~10%).

solid: 38 km, dashed: 380 km

trapped


Anti-proton (trapped) trajectories.


09/03/20004:43 am ESTrun #1247009event #10243

p1=5.099 GeV/cp2=5.458 GeV/c

m=10.457 GeV

Au+AusNN=130 GeV


Upsilon->l+l- candidates

Run 2241022 Event #4699m=10.21 GeV

Run 2243027 Event #1645m=9.68 GeV

Run 2244029 Event#1570 m=9.25 GeV

+ - candidate

Run 2244032 Event #3420m=9.38 GeV

dE/dx<1.4e-5 keV/cmPPID(lepton)<3% Drell-Yan candidate

Run 2252020 Event #8718m=10.02 GeV

= 78oAu+AusNN=200 GeV


Upsilon projection for 2004 data.

PYTHIA 6.2, k=3.0, =0.9, TPC slow simulator (e- cloud for dE/dx),identical recon. as real data, background: real +- data,EMC hadron suppression 1/200 @ lepton=90%,

L0 trigger enhancement 12.1, stat. and syst. errors shown




Hadron resonance ideal gas

Compare particle ratios to experimental data

Qi : 1 for u and d, -1 for u and d

si : 1 for s, -1 for s

gi : spin-isospin freedom

mi : particle mass

Particle density of each particle

All resonances and unstable particles are decayed

Refs. J.Rafelski PLB(1991)333J.Sollfrank et al. PRC59(1999)1637

ch : Chemical freeze-out temperatureq : light-quark chemical potentials : strangeness chemical potentials : strangeness saturation factor


Cosmological Timeline

Planck epoche 1019 GeV t~10-43 s Grand Unified Theory 1015 GeV t~10-35 s Electroweak phase transition 100 GeV t~10-11 s Quark-antiquark annihilation 1 GeV t~10-6 s Baryon freeze-out 200 MeV Neutrino freeze-out 1 MeV Nuclei (d,He,Li) freeze-out 0.1 MeV

t~1 s Matter-radiation equilibrium 1 eV Latest scatterings 5·105 yr

Documents

Results from RHIC. Jens Sören Lange (Frankfurt University / GSI Darmstadt) XIII ISVHECRI, Pylos, Greece, 10.09.2004