# Presentation: 935114

## Why RHIC won’t make Long Island Disappear into a Black Hole

**James Nagle**
**Columbia University**

## Why can’tRHIC make Long Island Disappear into a Black Hole?

## The New Collider

** ****What physics are we trying to reveal at RHIC?**
** ****Will we destroy the earth in the process?**
** ****What signatures are we looking for?**
** ****Where is the PHENIX experiment?**

## Deconfinement

-  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 ~ **10****12**** ****o****F**), the quarks are no longer confined, but rather are “asymptotically free” and  form a **plasma of quarks and gluons**

- d

- u

- u

- u

- d

- d

- u

## Phase Diagram of Nuclear Matter

## Phase Diagram of Nuclear Matter

**Phase Diagram of ****Nuclear Matter**

- Net Baryon Density

- Temperature

- RHIC (200 GeV/u)

- SPS (20 GeV/u)

- AGS (5 GeV/u)

- Early
- Universe

- Neutron
- Stars

- Quark-Gluon Plasma

## How does the reaction proceed?

**How does the reaction proceed?**

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

**Temperatures get hot enough to create a plasma**
**of quarks and gluons (phase transition)**

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

## Why is this interesting?

**The Universe must have started out**
**as a quark-gluon plasma just after the **
**Big Bang.**
**The core of neutron stars may be**
**composed of very dense quark matter.**
**Our theory of quarks (QCD) predicts**
**a quark plasma, and this should be**
**experimentally verified.**

## Relativistic 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 !

- 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.

## Slide 11

## List of Potential Disasters

- <footer>

**List of Potential Disasters**

**1.  Black hole formation**
**2.  Universe collapsing into **
**	****	****	****new vacuum state**
**3.  Strange Quark Matter **
**	****	****	****eating the earth**

## (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:

***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?

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

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

## (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.

**U**

- Present Universe

- True 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 Collisions

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

**And this is over 10 RHIC years !**

**compared to**

## Caveat:  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

-  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

- d

- u

- d

- s

- Energy Level

- 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 lifetime
- 3.  _If_ it slows down and comes to rest in matter
- 4.  _If_ it has negative charge, then it attracts a 		               	positively charged nucleus and absorbs it
- 5.  _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 until
- 	it 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 Nucleosynthesis

- Experiment E864 at BNL-AGS
** ****no SQM at 10****-9 ****per collision**

- 

- 

- n

- 

- n

- n

- p

- p

- 

**u**

**u**

**u**

**u**

**u**

**d**

**d**

**d**

**d**

**s**

**s**

**s**

**s**

- Heavy Ion Collision    -    Formation of hypernuclei   -  Doorway to SQM

**In this model, SQM production more likely at AGS rather than 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

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

**10****28**** Fe + Fe collisions (AGS energy)**
**10****18**** Au + Au collisions (AGS energy)**
**10****22**** Fe + Fe collisions (RHIC energy)**
**10****12**** 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

**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**

## List of Potential Disasters

- <footer>

**List of Potential Disasters**

- Review of Speculative ‘Disaster Scenarios’ at RHIC, W. Busza et al., hep-ph/9910333
- Will Relativistic Heavy Ion Colliders Destroy our Planet, A. Dar et al., hep-ph/9910471
- Growing 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 Formation

**Signatures 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/ Suppression

- Vector meson J/
- bound state of a charm quark 			and anti-charm quark

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

## QCD 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 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 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 Scattering

- <pt2>N = <pt2>pp + (N-1)  pt2

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

- S. Gavin et al., hep/9610432v2

## Pt 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?

**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 the**
**CERN-SPS conclusions**
**are premature, and **
**require more study.**
**RHIC’s higher energy**
**also opens up high pt**
**probes that are calculable**
**in pQCD.**

## PHENIX Experiment at RHIC

**PHENIX 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 Effects

**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 Production

**Charm and Bottom Production**

**D****0****      K****-****  ********+**

**D****0****      K****-****  e****+ ********e**

**D****0****      K****-****  ********+ **********

**B****0****      D****-****  ********+**

**B****0****      D****-****  e****+ ********e**

**B****0****      D****-****  ********+ **********

**D****0****D****0****      ********+********-****  K****+**** K****-**** ******************

**D****0****D****0****      e****+****e****-****  K****+**** K****-**** ********e********e**

**D****0****D****0****      ********+****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 Charm

**Direct Measure of Open Charm**

- Large combinatoric background in the hadronic channel.

**D****0****      ****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 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 !**

## Dilepton Spectra

**Critical addition of Upsilon measurement !**
**Statistics for pt spectra !**
**And excitation function !**

- Statistics chart:

**Dilepton Spectra**

## PHENIX - just about ready?

## PHENIX - just about ready!

## Exciting physics now

**We cannot calculate that these collisions will not destroy**
**the universe, we only know this from the large number of**
**cosmic ray collisions that have already occurred.**
**Thus, as experimentalists, the whole world of possibilities**
**for discovery are before us (except destroying the universe).**

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