black holes and extra dimensions jonathan feng uc irvine penn state physics department colloquium 30...
Post on 19-Dec-2015
218 views
TRANSCRIPT
Black Holes and Extra Dimensions
Jonathan Feng
UC Irvine
Penn State Physics Department Colloquium
30 January 2003
30 January 2003 Penn State Colloquium Feng 2
The Standard Model
Carrier Force Group
photon
E&M U(1)
g gluon Strong SU(3)
Z
WWeak SU(2)
30 January 2003 Penn State Colloquium Feng 3
Tevatron
Precise Confirmation
30 January 2003 Penn State Colloquium Feng 4
Grand Unification
Unification “explains” SM charges
Requires c, massive neutrinos
30 January 2003 Penn State Colloquium Feng 5
Coupling Unification
• Forces are similar in strength
• Forces become more similar at high energies and short distances
• Unification almost exact with supersymmetry Dashed – Standard Model
Solid – Supersymmetry
Martin (1997)
30 January 2003 Penn State Colloquium Feng 6
What’s Missing
• The dog that didn’t bark – where’s gravity?
• Many deep problems, but one obvious one:
For protons, gravity is 10-36 times weaker.
• Equal for mstrong ~ 1018 GeV, where gravity becomes strong, far beyond expt. (~ TeV).
30 January 2003 Penn State Colloquium Feng 7
Kaluza-Klein Unification• Kaluza (1921) and Klein (1926)
considered D=5, with 1 dimension rolled into a circle:
D=5 gravity D=4 gravity + EM + scalar
gAB g + g5 + g55
• Kaluza: “virtually unsurpassed formal unity...which could not amount to the mere alluring play of a capricious accident.”
30 January 2003 Penn State Colloquium Feng 8
Extra Dimensions
• Suppose photons are confined to D=4, but gravity propagates in n extra dimensions of size L:
For r L, Fgrav ~ 1/r2
For r L, Fgrav ~ 1/r2+n
Garden Hose
30 January 2003 Penn State Colloquium Feng 9
…
gravity
EM
Str
engt
h
r1/mstrong
Gravity in Extra Dimensions
30 January 2003 Penn State Colloquium Feng 10
Strong Gravity at the Electroweak Scale
• Suppose mstrong is 1 TeV, the electroweak
unification scale
• The number of extra dims n then fixes L
• n=1 excluded by solar system, but n=2, 3,… are allowed by tests of Newtonian gravity
30 January 2003 Penn State Colloquium Feng 11
Tests of Newtonian GravitySt
reng
th o
f D
evia
tion
R
elat
ive
to N
ewto
nain
Gra
vity
Long, C
han, Price; H
oyle et al.
30 January 2003 Penn State Colloquium Feng 12
Kaluza-Klein States
• Extra dimensions of size L towers of Kaluza-Klein particles with masses ~1/L
• Large extra dims light states
• KK states may appear at colliders, in astrophysics (supernova cooling), …
f
f f ’
f ’graviton
_ _
30 January 2003 Penn State Colloquium Feng 13
Black Holes
• Solutions to Einstein’s equations
• Schwarzschild radius rs ~ MBH – requires large mass/energy in small volume
• Light and other particles do not escape; classically, BHs are stable
30 January 2003 Penn State Colloquium Feng 14
Black Hole Evaporation
• Quantum mechanically, black holes are not black – they emit Hawking radiation
• Temperature: TH ~ 1/MBH
Lifetime: ~ MBH3
• For MBH ~ Msun, TH ~ 0.01 K. Astrophysical BHs emit only photons, live ~ forever
• Form by accretion
30 January 2003 Penn State Colloquium Feng 15
• BH creation requires
ECOM > mstrong
• In 4D, mstrong ~ 1018 GeV,
far above accessible energies ~ TeV
• But with extra dimensions, mstrong ~ TeV is possible, can create micro black holes in elementary particle collisions!
BHs from Particle Collisions
30 January 2003 Penn State Colloquium Feng 16
Black Holes in the Laboratory
• What is the production rate?
• How will you know if you’ve created one?
S. Harris
30 January 2003 Penn State Colloquium Feng 17
Black Holes at Colliders• BH created when two
particles of high enough energy pass within rs . Cross section ~ rs
2
Penrose (1974)D’Eath, Payne (1992)
Eardley, Giddings (2001) ...
• Large Hadron Collider (2007): ECOM = 14 TeV
pp BH + X
• Find as many as 1 BH produced per second
Dimopoulos, Landsberg (2001)
30 January 2003 Penn State Colloquium Feng 18
Event Characteristics• For microscopic BHs,
~ 10-27 s, decays are essentially instantaneously
• TH ~ 100 GeV, so not just photons
j:l::,G = 75:15:2:8
• Multiplicity ~ 10
• Spherical events with leptons, many jets
De Roeck (2002)
30 January 2003 Penn State Colloquium Feng 19
Black Holes from Cosmic Rays
• Cosmic rays – the high energy frontier
• Observed events with 1019 eV ECOM ~ 100 TeV
• But meager fluxes! Can we harness this energy?
Kampert, Swordy (2001)
30 January 2003 Penn State Colloquium Feng 20
Use Cosmic Neutrinos• Cosmic rays create ultra-high
energy neutrinos:
BH gives inclined showers starting deep in the atmosphere
• Rate: as large as a few per minute somewhere on Earth
Feng, Shapere (2001)
30 January 2003 Penn State Colloquium Feng 21
Auger Observatory
30 January 2003 Penn State Colloquium Feng 22
Deep Inclined Showers
Coutu, Bertou, Billior (1999)
Capelle, Cronin, Parente, Zas (1998)Diaz, Shellard, Amaral (2001)
Anchordoqui, Feng, Goldberg, Shapere (2001)HiRes Collaboration (1994)
30 January 2003 Penn State Colloquium Feng 23
Cosmic Ray Black Holes
• Auger can detect ~100 black holes in 3 years
mst
rong
(T
eV)
Feng, Shapere (2001)
30 January 2003 Penn State Colloquium Feng 24
AMANDA/IceCube
• Neutrino telescopes may also detect BHs:
contained jets
through-going muons
• Similar rate: ~10 BH/year
Cosmic rays provide first chance to see black holes from extra dimensions
30 January 2003 Penn State Colloquium Feng 25
What You Could Do With A Black Hole If You Made One
• Discover extra dimensions
• Test Hawking evaporation, BH properties
• Explore last stages of BH evaporation, quantum gravity, information loss problem
• ……
30 January 2003 Penn State Colloquium Feng 26
Conclusions
• Gravity is either intrinsically weak or is strong but diluted by extra dimensions
• If gravity is strong at the TeV scale, we will find black holes in cosmic rays and colliders
30 January 2003 Penn State Colloquium Feng 27
Conclusions
• Gravity is either intrinsically weak or is strong but diluted by extra dimensions
• If gravity is strong, we will find black holes in cosmic rays and colliders
Anchordoqui, Feng, Goldberg, Shapere (2001)
mst
rong
(T
eV)
30 January 2003 Penn State Colloquium Feng 28
Gravity Is Weak
gravity
EM
Str
engt
h
r