Why RHIC won’t make

Long Island Disappear into a Black Hole

Why RHIC won’t make

Long Island Disappear into a Black Hole

James NagleJames NagleColumbia UniversityColumbia University

Why can’tRHIC make

Long Island Disappear into a Black Hole?

Why can’tRHIC make

Long Island Disappear into a Black Hole?

The New ColliderThe New Collider

• What physics are we trying to reveal at RHIC?What physics are we trying to reveal at RHIC?

• Will we destroy the earth in the process?Will we destroy the earth in the process?

• What signatures are we looking for?What signatures are we looking for?

• Where is the PHENIX experiment?Where is the PHENIX experiment?

DecDeconfinemententDecDeconfinementent

• Normally quarks are bound together (confined) in hadrons

• There are no observations of free individual quarks

• However, QCD predicts that at high density (5 to 10 ) and

high temperature (~ 150-200 MeV ~ 1012 oF), the quarks are no

longer confined, but rather are “asymptotically free” and form a plasma of quarks and gluons

u u

d

u u

d

u d

d

d

u

u

u

d

d

u

Phase Diagram of Phase Diagram of Nuclear MatterNuclear Matter

Phase Diagram of Phase Diagram of Nuclear MatterNuclear Matter

Phase Diagram of Nuclear Matter

Phase Diagram of Nuclear Matter

Net Baryon Density

Tem

pera

ture

RHIC (200 GeV/u)

SPS (20 GeV/u)

AGS (5 GeV/u)

EarlyUniverse

NeutronStars

Quark-Gluon Plasma

How does the reaction proceed?How does the reaction proceed?

Nuclei Collide at near the speed of lightNuclei Collide at near the speed of light

Temperatures get hot enough to create a plasmaTemperatures get hot enough to create a plasmaof quarks and gluons (phase transition)of quarks and gluons (phase transition)

System expands outward and cools,System expands outward and cools,thus going back through the phase transitionthus going back through the phase transition

Why is this interesting?Why is this interesting?

The Universe must have started outThe Universe must have started outas a quark-gluon plasma just after the as a quark-gluon plasma just after the Big Bang.Big Bang.

The core of neutron stars may beThe core of neutron stars may becomposed of very dense quark matter.composed of very dense quark matter.

Our theory of quarks (QCD) predictsOur theory of quarks (QCD) predictsa quark plasma, and this should bea quark plasma, and this should beexperimentally verified.experimentally verified.

Relativistic Heavy Ion ColliderRelativistic Heavy Ion Collider

Au + Au collisions at cms energy 40 TeV (200 GeV/u)• 1012 collisions per year

p + p collisions at 500 GeV• polarized beams

Everything in between

First Beam !First Beam !

At around 2 am on July 13th, 1999 the first beam made it around the ring. First measured via PHENIX beam-beam and scintillation counters.

12

List of Potential DisastersList of Potential Disasters

1. Black hole formation

2. Universe collapsing into new vacuum state

3. Strange Quark Matter eating the earth

(1) Black Holes(1) Black Holes

Can be dismissed with some basic General Relativity

• The Schwarzschild radius of a heavy ion collision:

• Radius of Au+Au collision compressed by a factor of 100:

metersc

GMRS49

2 102

metersR 1510

much less than Planck length !

Even if it could form, it would evaporate by Hawking Radiation in

10-83 seconds !M. Chiu for calculations

Where did the idea come from?Where did the idea come from?

JournalistsJournalists - when JFK Jr.’s flight - when JFK Jr.’s flight disappeared, reporters called disappeared, reporters called Brookhaven to ask if a black hole Brookhaven to ask if a black hole created at RHIC could have eaten the created at RHIC could have eaten the plane.plane.

Science FictionScience Fiction - in this book, - in this book, experiments including PHENIX and experiments including PHENIX and STAR study collisions which STAR study collisions which accidentally create baby universes.accidentally create baby universes.

(2) Vacuum Instability(2) Vacuum Instability

P. Hut’s proposal is it is possible that the ground state vacuum is not the vacuum we live in. We are simply trapped in a local minimum of the vacuum potential, deposited there in the early stages of the universe.

UU Present UniversePresent Universe

True Ground StateTrue Ground State

P. Hut, Nucl. Phys. A418, 301c (1984).P. Hut and M.J. Rees, Nature 302, 508 (1983).

Why heavy ion reactions? Answer - bubble nucleation only beyond some critical volume.

Cosmic Ray CollisionsCosmic Ray Collisions

4.3

0522

110

ATeV

AEfnumber A

Nature has been conducting RHIC-like collisions for a long time, and the universe is still here….

2.7)-2.5 (where EFlux

collisionsAu Au 1036 number

collisionsAu Au 1013 RHIC

And this is over 10 RHIC years !

compared to

Caveat: Relative AbundancesCaveat: Relative Abundances

Relative yield of Fe nuclei now measured up to 2 TeV/nucleon.

(well beyond RHIC energy)

However, the additional penalty of “ultra” heavy nuclei (Pb, Au, Pt) of ~ 10-5 is only measured at the lowest energies (GeV scale). W. Vernon Jones, Nucl. Phys. A418, 139c (1984).

W.R. Binns et al., Astro. J. 346, 997 (1989).

(3) Strange Quark Matter(3) Strange Quark Matter• SQM is a meta-stable or even stable multi-quark color singlet state

• roughly equal number of u, d, s quarks• States have a low charge to mass ratio (or even neutral)

• reduced Fermi energy, reduced Coulomb, no fission

• Ed Witten proposed that nuggets of SQM could have survived from the early universe and present a major source of Dark Matter.

• Stable and negatively charged SQM present a possible danger if it exists !

u du d s

Ene

rgy

Lev

el

Strange Quark Mass

Quark Matter Strange Quark Matter

Why Worry?Why Worry?

1. If small SQM (“strangelet”) is formed in RHIC collisions

2. If it has a long lifetime3. If it slows down and comes to rest in matter4. If it has negative charge, then it attracts a

positively charged nucleus and absorbs it5. If the negative state is more stable, the SQM

may lose positive charge and adjust its strangeness via electron capture or positron beta-decay

6. If it maintains negative charge, it will grow untilit falls to the center of the earth

7. Then it will then absorb the earth from the inside out, and due to the enormous release of energy, the planet would end in a “supernova-like” explosion

Strange NucleosynthesisStrange Nucleosynthesis

Experiment E864 at BNL-AGS

no SQM at 10-9 per collision

n

nn p

p u

u

u

u

u

dd

d d

ss s

s

Heavy Ion Collision - Formation of hypernuclei - Doorway to SQM

In this model, SQM production In this model, SQM production more likely at AGS rather than more likely at AGS rather than RHIC energies !RHIC energies !T.A. Armstrong et al., Phys. Rev. Lett. 79, 3612 (1997).

T.A. Armstrong et al., Phys. Rev. C, R1829 (1999).

Not Cheese, and not Strange Quark Matter

Not Cheese, and not Strange Quark Matter

Some cosmic ray collisions could have produced dangerous SQM, but how would we know….

1028 Fe + Fe collisions (AGS energy)

1018 Au + Au collisions (AGS energy)

1022 Fe + Fe collisions (RHIC energy)

1012 Au + Au collisions (RHIC energy)

Dangerous SQM can also be produced in CR-CR collisions and then fall into other objects thus producing “supernova-like” explosions.

Lunar Abundances

Element Lunar Highlands Lunar Lowlands EarthOxygen 446,000 417,000 466,000Silicon 210,000 212,000 277,000Aluminum 133,000 69,700 81,300Iron 48,700 132,000 50,000Calcium 106,800 78,800 36,300Sodium 3,100 2,900 28,300Potassium 800 1,100 25,900Magnesium 45,500 57,600 20,900Titanium 3,100 31,000 4,400Hydrogen 56 54 1,400Phosphorus 500 660 1,050Manganese 675 1,700 950Carbon 100 100 200Chlorine 17 26 130Chromium 850 2,600 100

Chemical Analysis in Weight parts per million

The abundance of Au is the lunar soil (regolith) is seven parts per billion.

(Au,Pt,Pb)/Fe ~ 10-5

Quite a large variation on the surface.

Most of these “ultra” heavy elements were deposited there

23

1. Black hole formation

2. Universe collapsing into new vacuum state

3. Strange Quark Matter eating the earth

List of Potential DisastersList of Potential Disasters

Review of Speculative ‘Disaster Scenarios’ at RHIC, W. Busza et al., hep-ph/9910333Will Relativistic Heavy Ion Colliders Destroy our Planet, A. Dar et al., hep-ph/9910471Growing S Drops, G.L. Shaw et al., Nature 337: 436 (1989)Technological Implications of Stable Strange Quark Matter, M.S. Desai et al., Nucl.Phys.Proc. Suppl.24B:207 (1991)

Signatures of Plasma FormationSignatures of Plasma Formation

A. Deconfinement • Suppression of quarkonia (J/, ’,) states

B. Thermal Radiation• Prompt , to e+e-, +-

C. Chiral Symmetry Restoration• Disappearance of state• Mass, width, B.R. modification of

D. Strangeness, Charm and Bottom Production• Nuclear effects, fast thermalization

E. Jet Quenching• High pt jets via leading particle

F. Equation of State• Hydrodynamic flow• Particle correlations, coalescence

J/ SuppressionJ/ Suppression

Perturbative Vacuum

cc

Color Screening

cc

Non-perturbative Vacuum

Perturbative Vacuum

cc

Vector meson J/bound state of a charm quark

and anti-charm quark

The pair feels an attractive force and canform the above bound state. However, in the middle of a quark-gluon plasma the attractive force is screened.

QCD ThermometerQCD Thermometer

Hadrons with radii greater than ~ D will be dissolved (suppressed)

Debye screening length D ~ 0.5 fm at a temperature T = 200 MeV

As the temperature is raised above the critical temperature, one should see the sequential suppression of the various “onium” states

Upcoming CERN Press ReleaseUpcoming CERN Press Release

“Strong evidence for the formation of a transient quark-gluon phase without color confinement is provided by the observed suppression of the charmonium states J/, c, and ’.”

Maurice Jacob and Ulrich Heinz

NA50 at the CERN-SPS

Discontinuity due to c melting

Drop due to J/ melting

Using Drell-Yan as control

Premature ConclusionsPremature Conclusions

“A clear onset of the anomaly is observed. It excludes models based on hadronic scenarios since only smooth behavior with monotonic derivatives can be inferred from such calculations” Phys. Lett. B 450, 456 (1999).

The second suppression is preliminary and contradicts the published results shown here in the above paper.

Initial State Parton ScatteringInitial State Parton Scattering

<pt2>N = <pt

2>pp + (N-1) pt

2

Prior collisions broaden the transverse momentum spectrum (“Cronin effect”)

S. Gavin et al., hep/9610432v2

Pt BroadeningPt Broadening

Deconfined plasma breaks up J/ formed at the core of the collision, which are the ones most likely to have high pt.

D.Kharzeev, M.Nardi, H.Satz, Phys. Lett. B405, 14 (1997).JLN, M. Bennett, Phys. Lett. B465, 21 (1999).

What should we think?What should we think?

Net Baryon Density

Tem

per

atu

reRHIC (200 GeV/u)

SPS (20 GeV/u)

AGS (5 GeV/u)

EarlyUniverse

NeutronStars

If the most central Pb-Pb collisions at CERN are starting to create a region of deconfined quarks and gluons, then RHIC collisions will be dominated by this plasma (large volume and long lifetime). Thus opening up a number of critical tools for studying the nature of this new form of matter.

However, I believe theCERN-SPS conclusionsare premature, and require more study.

RHIC’s higher energyalso opens up high ptprobes that are calculablein pQCD.

PHENIX Experiment at RHICPHENIX Experiment at RHIC

Two forward muon spectrometers

PHENIX - only RHIC experiment specifically designed to measure rare probes in the lepton and photon channels.

It can sample all Au + Au collisions up to 10 times RHIC’s design luminosity

Two central electron/photon/hadron spectrometers

Threshold EffectsThreshold Effects

1.0E-05

1.0E-04

1.0E-03

1.0E-02

1.0E-01

1.0E+00

1.0E+01

4 24 44 64 84 104 124 144 164 184 204 224 244

E(CM) in GeV

J/P

si r

ela

tiv

e c

ross

se

ctio

n

RHIC

SPS

J/

D-Y

RHIC is ideally situated for exploring charmonium as a probe of dense nuclear matter.

J/ remains a “rare” probe, but measurable with fine binning as a function of centrality, pt, and collision energy.

Charm and Bottom ProductionCharm and Bottom Production

D0 K- +

D0 K- e+ e

D0 K- +

B0 D- +

B0 D- e+ e

B0 D- +

D0D0 +- K+ K- D0D0 e+e- K+ K- ee

D0D0 +e- K+ K- e

Direct reconstruction of open charm is optimal.

One can also measure open charm and bottom contributions through single leptons and lepton pairs.

In order to understand J/ yields, we must understand charm production• Total production rates• Shadowing (nuclear effects)• Jet quenching in plasma

Direct Measure of Open CharmDirect Measure of Open Charm

Large combinatoric background in the hadronic channel.

D0 K- +

Silicon Detector to measure displaced vertex not included in PHENIX, but also looks difficult for any experiment due to high multiplicity.

Simple matching of all pairs is shown to work in PHENIX for p-p, p-A, and very peripheral A-A Study by Y. Akiba

Single LeptonsSingle Leptons

charm e-

beauty e-Drell-Yan e-

Dalitz and conversions e-

Electrons in PHENIX Muons in PHENIX

Study by Mickey Chiu, JLN Study by M. Brooks, J. Moss

Also, additional measurement of e- coincidence !

Critical addition of Upsilon Critical addition of Upsilon measurement !measurement !

Statistics for pt spectra !Statistics for pt spectra !

And excitation function !And excitation function !

Statistics chart:

Dilepton SpectraDilepton Spectra

Particle Probability

10% Central Au + Au

Statistics with 3000 hoursat 10 x design luminosity

(1 RHIC Year)

3.6 x 10-4 504 k 1.3 x 10-4 182 k

J/ 2.6 x 10-3 3.6 M’ 3.5 x 10-5 49 k

(1s) 7.6 x 10-6 10 k(2s+3s) 7.6 x 10-7 1 k

PHENIX - just about ready?PHENIX - just about ready?

PHENIX - just about ready!PHENIX - just about ready!

Exciting physics nowExciting physics now

We cannot calculate that these collisions will not destroyWe cannot calculate that these collisions will not destroythe universe, we only know this from the large number ofthe universe, we only know this from the large number ofcosmic ray collisions that have already occurred.cosmic ray collisions that have already occurred.

Thus, as experimentalists, the whole world of possibilitiesThus, as experimentalists, the whole world of possibilitiesfor discovery are before us (except destroying the universe).for discovery are before us (except destroying the universe).

RHIC Collider and PHENIX start the first RHIC Collider and PHENIX start the first run in March, 2000 !run in March, 2000 !