Black Hole Factories:
How the LHC may usher in a new era of physics
A presentation by Jeremiah Graber
jsgraber@purdue.edu
Purdue University
10/05/07
I would like to thank Prof. Jones, Prof
Kruczenski, Zolton Gresce, Steven Giddins and
others
Black Hole Factories:
How the LHC may usher in a new era of physics
INTRODUCTION
QUESTIONS TO BE ASKED:
How would a black hole form?
• What conditions must be met?
• Black hole signatures
• Implications to physics
•
Black Hole Factories:
How the LHC may usher in a new era of physics
BLACK HOLE FORMATION
TERMINOLOGY:
• Schwarzschild Radius
• Event Horizon
• Plank Mass
• Hawking Radiation
• LHC
• Extra Dimensions
Black Hole Factories:
How the LHC may usher in a new era of physics
BLACK HOLE FORMATION
HOW ONE WOULD FORM:
• Collision with b < rs,
• b is impact parameter, rs is event horizon radius
• rs depends on mass
• Regardless of subsequent collisions, this forms an
Event Horizon
Black Hole Factories:
How the LHC may usher in a new era of physics
BLACK HOLE FORMATION
WHY THE LHC IS NEEDED:
• Overcoming coulomb repulsion
• High velocity, relativistic mass effect
Black Hole Factories:
How the LHC may usher in a new era of physics
HIERARCY PROBLEM
INTERACTION
COUPLING CONSTANT
Strong
1
Electromagnetic
1/137
Weak
1/106
Gravitational
1/1039
• Gravitational Constant is much smaller than others
• Many theories explain disparity
• Black hole theory depends on two
• Large extra dimensions
• Highly warped extra dimensions
• Why?
Black Hole Factories:
How the LHC may usher in a new era of physics
FORMATION CONDITIONS
WHY EXTRA DIMENSIONS?
• Black hole formation requires scattering energy ~ Plank Mass
• Plank mass is inversely proportional to coupling constant
• Appears to be 1019 GeV
• If “extra” dimensions exist, than Gravitational Coupling Constant might be
much larger
• Coupling constant only small in 4-space
• Rest spread out in other “y” dimensions
• Predicted Fundamental Plank Mass(M4) ~ Mw
• Predicts Plank Mass ~ 1 TeV
• Energy scale of LHC
Black Hole Factories:
How the LHC may usher in a new era of physics
FORMATION CONDITIONS
WHY LARGE OR WARPED?
What I promise to be the worst equation of the presentation,
metric of a warped geometry:
ds  e
2
2 A( y )
dx  g mn ( y )dy dy
2
4
m
n
Black Hole Factories:
How the LHC may usher in a new era of physics
FORMATION CONDITIONS
WHY LARGE OR WARPED?
ds  e
2
2 A( y )
dx  g mn ( y )dy dy
2
4
m
n
For ds2 to be large either:
• The area of the “extra” dimensions must be large
• The warp factor must be large
ds2 is directly proportional to the M4 Plank Mass
Black Hole Factories:
How the LHC may usher in a new era of physics
FORMATION CONDITIONS
WHY LARGE OR WARPED?
ds  e
2
2 A( y )
dx  g mn ( y )dy dy
2
4
m
n
• “A” is warp factor of space
• “m” is the “extra” dimensions. D – m = 4
Black Hole Factories:
How the LHC may usher in a new era of physics
FORMATION CONDITIONS
SUMMARY OF CONDITIONS:
• Collide Masses closer than rs
2Gm
• rs is dependant on mass
mr 
rs  2
• Relativistic Mass
c
• Plank Mass must be ~ 1 TeV
• Require D = 10
• Highly warped “extra” space (A > 3)
• Large volume of “extra” dimensions (fm6 for D = 10)
ds 2  e 2 A( y ) dx42  g mn ( y )dy m dy n
• LHC could produce 1 10 GeV black hole/ sec
m0
1  2
Black Hole Factories:
How the LHC may usher in a new era of physics
BLACK HOLE SIGNATURES
HOW DOES A BLACK HOLE RADIATE?
Consider an electron/positron
pair created near event horizon:
• Created due to zero point energy
• Normally nearly instantly annihilated
• One particle escapes, the other sucked into
black hole.
• To conserve energy, “sucked in” particle
must have negative energy
• Outside observer sees this as radiating
particles.
Black Hole Factories:
How the LHC may usher in a new era of physics
BLACK HOLE SIGNATURES
HOW MUCH DOES A BLACK HOLE RADIATE?
• Black holes radiate proportionally to their
temperature
• Average energy related to thermal energy
• Temperature is inversely proportional to mass
• Black holes only contain particles with Compton
wavelength < rs
• Large black holes can contain almost all
particles
• Smaller black holes must radiate many away
• Large black holes consume more than they
radiate
• Why small black holes collapse so quickly
Black Hole Factories:
How the LHC may usher in a new era of physics
BLACK HOLE SIGNATURES
Overview of Decay
• Balding Phase
• Settles into “hairless spinning” black hole
• 25% of energy lost
• Schwarzschild Phase
• Releases “Hawking Radiation”
• Looses 75% of energy
• Plank Size
• Unsure of what happens here
• Continues to radiate, thus disappears very quickly
Black Hole Factories:
How the LHC may usher in a new era of physics
BLACK HOLE SIGNATURES
BALDING PHASE
• “Hairless” when most information about the
original star is lost
• All that is left is Mass, Angular Momentum and
Charge.
• This happens to all black holes
• Very quick in micro-black holes
• Less than 8% of black hole’s lifetime
Black Hole Factories:
How the LHC may usher in a new era of physics
BLACK HOLE SIGNATURES
Schwarzschild Phase
• Phase with distinct, spectacular signatures
• Giddings model: majority of radiation released in
our 3-brane
• Large signature, 10 GeV of energy released
~ 1 picosecond
Black Hole Factories:
BLACK HOLE SIGNATURES
How the LHC may usher in a new era of physics
THEORETICAL SIGNATURES
Quarks and Gluons
72%
Spin 0
42%
Leptons
11%
Spin ½
40%
Massive Gauge Bosons
8%
Spin 1
16%
Nuetrinos and gravitrons
6%
Spin 2
2%
Higgs bosons
2%
Photons
1%
Black Hole Factories:
How the LHC may usher in a new era of physics
BLACK HOLE SIGNATURES
• 1 black hole/ sec creates undeniable signature
• No prediction of exact particles
• Possible it is random
• Roughly spherically symmetrical
• 80 – 95% of radiated energy visible
• Observe in atmosphere
Black Hole Factories:
How the LHC may usher in a new era of physics
CONCLUSIONS
WOULD PRODUCING BLACK HOLES BE DANGEROUS?
• Newspaper reports, Discovery Channel specials have sparked
protests about turning on the LHC
• The black hole would radiate away in 0.000000000001 seconds.
• Cosmic radiation strikes Earth with energy 5x of LHC
Black Hole Factories:
How the LHC may usher in a new era of physics
CONCLUSIONS
IMPLICATIONS OF LAB PRODUCED BLACK HOLES
• Evidence for “extra” dimensions
• Without “extra” dimensions collider requires 1016 TeV
• Predicts D ≥ 10 for ~ 1 TeV black holes
• Short distance physics would basically end
• Use high energy to probe short distances
• Is there a length shorter than the Plank length?
• Likely not answered
• rs is larger than Plank length