Black Holes and Extra Dimensions

Transcription

1 Black Holes and Extra Dimensions Jonathan Feng UC Irvine UC Riverside Physics Department Colloquium 24 October 2002

2 The Standard Model Carrier γ photon g gluon Z W Force E&M Strong Weak Group U(1) SU(3) SU(2) 24 October 2002 UC Riverside Physics Department Colloquium Feng 2

3 Precise Confirmation Tevatron 24 October 2002 UC Riverside Physics Department Colloquium Feng 3

4 Grand Unification Unification explains SM charges Requires ν c, massive neutrinos 24 October 2002 UC Riverside Physics Department Colloquium Feng 4

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) 24 October 2002 UC Riverside Physics Department Colloquium Feng 5

6 What s Missing The dog that didn t bark where s gravity? Many deep problems, but one obvious one: For protons, gravity is times weaker. Equal for m proton = m strong ~ GeV, where gravity becomes strong, far beyond expt. 24 October 2002 UC Riverside Physics Department Colloquium Feng 6

7 Gravity Is Weak EM Strength gravity r 24 October 2002 UC Riverside Physics Department Colloquium Feng 7

8 Kaluza-Klein Unification Kaluza (1921) and Klein (1926) considered D=5, with 1 dimension rolled into a circle: D=5 gravity Æ D=4 gravity + EM + scalar g AB Æ g µν + g µ5 + g 55 Kaluza: virtually unsurpassed formal unity...which could not amount to the mere alluring play of a capricious accident. 24 October 2002 UC Riverside Physics Department Colloquium Feng 8

9 Extra Dimensions Suppose photons are confined to D=4, but gravity propagates in n extra dimensions of size L: For r >> L, F grav ~ 1/r 2 For r << L, F grav ~ 1/r 2+n Garden Hose 24 October 2002 UC Riverside Physics Department Colloquium Feng 9

10 Gravity Becomes Stronger EM Strength gravity m strong r 24 October 2002 UC Riverside Physics Department Colloquium Feng 10

11 Strong Gravity at the Electroweak Scale Suppose m strong 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 24 October 2002 UC Riverside Physics Department Colloquium Feng 11

12 Tests of Newtonian Gravity Long, Chan, Price; Hoyle et al. Strength of Deviation Relative to Newtonain Gravity 24 October 2002 UC Riverside Physics Department Colloquium Feng 12

13 Kaluza-Klein States Extra dimensions of size L Æ towers of Kaluza-Klein particles with masses ~1/L Large extra dims Æ light states KK states may appear at colliders, in astrophysics, f graviton f _ f f 24 October 2002 UC Riverside Physics Department Colloquium Feng 13 _

14 Black Holes Solutions to Einstein s equations Schwarzschild radius r s ~ M BH requires large mass/energy in small volume Light and other particles do not escape; classically, BHs are stable 24 October 2002 UC Riverside Physics Department Colloquium Feng 14

15 Black Hole Evaporation Quantum mechanically, black holes are not black! They emit Hawking radiation Temperature T H ~ 1/M BH, lifetime τ ~ M BH3 : for M BH ~ M sun, T H ~ 0.01 K. Astrophysical BHs emit only photons, live ~ forever Form by accretion γ γ 24 October 2002 UC Riverside Physics Department Colloquium Feng 15

16 BHs from Particle Collisions BH creation requires E COM > m strong In 4D, m strong ~ GeV, far above accessible energies ~ TeV But with extra dimensions, m strong ~ TeV is possible, can create micro black holes in elementary particle collisions! 24 October 2002 UC Riverside Physics Department Colloquium Feng 16

17 Black Holes in the Laboratory What is the production rate? How will you know if you ve created one? S. Harris 24 October 2002 UC Riverside Physics Department Colloquium Feng 17

18 Black Holes at Colliders BH created when two particles of high enough energy pass within r s LHC: E COM = 14 TeV pp Æ BH + X Find as many as 1 BH produced per second Dimopoulos, Landsberg (2001) 24 October 2002 UC Riverside Physics Department Colloquium Feng 18

19 Event Characteristics For microscopic BHs, τ ~ s, decays are essentially instantaneously T H ~ 100 GeV, so not just photons: hadron:lepton = 5:1 Multiplicity ~ Spherical events with leptons, many jets De Roeck (2002) 24 October 2002 UC Riverside Physics Department Colloquium Feng 19

20 Black Holes from Cosmic Rays Cosmic rays the high energy frontier Observed events with ev Æ E COM ~ 100 TeV But meager fluxes! Can we harness this energy? Kampert, Swordy (2001) 24 October 2002 UC Riverside Physics Department Colloquium Feng 20

21 Use Cosmic Neutrinos Cosmic rays create ultrahigh energy neutrinos: ν Æ BH gives inclined showers starting deep in the atmosphere Feng, Shapere (2001) 24 October 2002 UC Riverside Physics Department Colloquium Feng 21

22 Deep Inclined Showers Coutu, Bertou, Billior (1999) 24 October 2002 UC Riverside Physics Department Colloquium Feng 22

23 Cosmic Ray Detection Auger Collaboration 24 October 2002 UC Riverside Physics Department Colloquium Feng 23

24 Auger Observatory 24 October 2002 UC Riverside Physics Department Colloquium Feng 24

25 Cosmic Ray Black Holes Auger begins 2004 can detect ~100 black holes in 3 years Provides first chance to see black holes from extra dimensions m strong (TeV) Feng, Shapere (2001) 24 October 2002 UC Riverside Physics Department Colloquium Feng 25

26 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 24 October 2002 UC Riverside Physics Department Colloquium Feng 26

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 m strong (TeV) Anchordoqui, Feng, Goldberg, Shapere (2001) 24 October 2002 UC Riverside Physics Department Colloquium Feng 27