Black Holes and Extra Dimensions Jonathan Feng UC

Black Holes and Extra Dimensions Jonathan Feng UC Irvine Penn State Physics Department Colloquium 30 January 2003 Penn State Colloquium

The Standard Model 30 January 2003 Carrier Force Group g photon E&M U(1) g gluon Strong SU(3) Z W Weak SU(2) Penn State Colloquium 2

Precise Confirmation Tevatron 30 January 2003 Penn State Colloquium 3

Grand Unification “explains” SM charges Requires nc, massive neutrinos 30 January 2003 Penn State Colloquium 4

Coupling Unification • Forces are similar in strength • Forces become more similar at high energies and short distances • Unification almost exact with supersymmetry 30 January 2003 Penn State Colloquium Martin (1997) Dashed – Standard Model Solid – Supersymmetry 5

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 Ge. V, where gravity becomes strong, far beyond expt. (~ Te. V). 30 January 2003 Penn State Colloquium 6

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 g. AB gmn + gm 5 + g 55 • Kaluza: “virtually unsurpassed formal unity. . . which could not amount to the mere alluring play of a capricious accident. ” 30 January 2003 Penn State Colloquium 7

Extra Dimensions • Suppose photons are confined to D=4, but gravity propagates in n extra dimensions of size L: For r >> L, Fgrav ~ 1/r 2 For r << L, Fgrav ~ 1/r 2+n Garden Hose 30 January 2003 Penn State Colloquium 8

Gravity in Extra Dimensions Strength EM … gravity 1/mstrong 30 January 2003 r Penn State Colloquium 9

Strong Gravity at the Electroweak Scale • Suppose mstrong is 1 Te. V, 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 10

Tests of Newtonian Gravity Strength of Deviation Relative to Newtonain Gravity Long, Chan, Price; Hoyle et al. 30 January 2003 Penn State Colloquium 11

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 graviton _ _ f 30 January 2003 f’ f’ Penn State Colloquium 12

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 13

Black Hole Evaporation • Quantum mechanically, black holes are not black – they emit Hawking radiation g g • Temperature: TH ~ 1/MBH Lifetime: t ~ MBH 3 • For MBH ~ Msun, TH ~ 0. 01 K. Astrophysical BHs emit only photons, live ~ forever • Form by accretion 30 January 2003 Penn State Colloquium 14

BHs from Particle Collisions • BH creation requires ECOM > mstrong • In 4 D, mstrong ~ 1018 Ge. V, far above accessible energies ~ Te. V • But with extra dimensions, mstrong ~ Te. V is possible, can create micro black holes in elementary particle collisions! 30 January 2003 Penn State Colloquium 15

Black Holes in the Laboratory • What is the production rate? • How will you know if you’ve created one? 30 January 2003 S. Harris Penn State Colloquium 16

Black Holes at Colliders • BH created when two particles of high enough energy pass within rs. Cross section ~ prs 2 Penrose (1974) D’Eath, Payne (1992) Eardley, Giddings (2001). . . • Large Hadron Collider (2007): ECOM = 14 Te. V pp BH + X Dimopoulos, Landsberg (2001) • Find as many as 1 BH produced per second 30 January 2003 Penn State Colloquium 17

Event Characteristics • For microscopic BHs, t ~ 10 -27 s, decays are essentially instantaneously • TH ~ 100 Ge. V, so not just photons: j: l: g: n, G = 75: 15: 2: 8 • Multiplicity ~ 10 • Spherical events with leptons, many jets 30 January 2003 De Roeck (2002) Penn State Colloquium 18

Black Holes from Cosmic Rays • Cosmic rays – the high energy frontier • Observed events with 1019 e. V ECOM ~ 100 Te. V • But meager fluxes! Can we harness this energy? Kampert, Swordy (2001) 30 January 2003 Penn State Colloquium 19

Use Cosmic Neutrinos • Cosmic rays create ultra-high energy neutrinos: § n 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 20

Auger Observatory 30 January 2003 Penn State Colloquium 21

Deep Inclined Showers Coutu, Bertou, Billior (1999) 30 January 2003 Capelle, Cronin, Parente, Zas (1998) Diaz, Shellard, Amaral (2001) Anchordoqui, Feng, Goldberg, Shapere (2001) Hi. Res Collaboration (1994) Penn State Colloquium 22

• Auger can detect ~100 black holes in 3 years mstrong (Te. V) Cosmic Ray Black Holes Feng, Shapere (2001) 30 January 2003 Penn State Colloquium 23

AMANDA/Ice. Cube • 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 24

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 25

Conclusions • Gravity is either intrinsically weak or is strong but diluted by extra dimensions • If gravity is strong at the Te. V scale, we will find black holes in cosmic rays and colliders 30 January 2003 Penn State Colloquium 26

• 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 mstrong (Te. V) Conclusions Anchordoqui, Feng, Goldberg, Shapere (2001) 30 January 2003 Penn State Colloquium 27

Gravity Is Weak Strength EM gravity r 30 January 2003 Penn State Colloquium 28