1. 1 cosmology and particle physics (an overview) Joseph Lykken Fermilab and U. Chicago Joseph Lykken Fermilab and U. Chicago

2. 2 Starry Massages Thanks to Alvin, Leon & Co. for a great lecture series

3. 3 Quarks to the Cosmos how remarkable!

4. 4 tears of the antireductionists physics on the tiniest scales informs us about physics on the very largest scales, and vice-versa. physics is not an onion!

5. 5 you don’t need the Standard Model to predict the number of legs on a cockroach but do you need the Standard Model – and more - to understand the cosmos.

6. 6 the quarks to the cosmos connection exists because of two remarkable facts: gravity is weird gravity is weird the universe is weird the universe is weird

7. 7 gravity is weird effective field theory says that high energy physics is irrelevant for low energy physics – it can be replaced by matching conditions + operators suppressed by powers of (low momenta)/(big mass scales) by this argument, gravity should be irrelevant for large scale physics!

8. 8 gravity is weird but in fact gravity is a long-range force with no screening so on large scales it actually dominates.

9. 9 the universe is weird only because the universe is large, homogeneous, transparent, etc etc we can reconstruct its history!

10. 10 highlights from the previous Starry Messages

11. 11 Michael Turner

12. 12 Michael Turner

13. 13 dark matter and dark energy have nothing in common except darkness dark matter clusters like normal cold matter dark matter consists (probably) of massive weakly interacting particles. dark energy doesn’t cluster at all dark energy is vacuum energy (of something) or frustrated networks of topological defects, or something else weird.

14. 14 galaxies have dark matter halos

15. 15 Tim McKay

16. 16 Tim McKay

17. 17 Tim McKay

18. 18 Michael Turner

19. 19 Michael Turner

20. 20 John Carlstrom

21. 21 Andy Albrecht, DPF2002

22. 22 Michael Turner

23. 23 Rocky Kolb

24. 24 Rocky Kolb

25. 25 Rocky Kolb

26. 26 Rocky Kolb

27. 27 Rocky Kolb

28. 28

29. 29 Measured by DASI!

30. 30

31. 31 gravitational radiation Orbiting and merging massive objects emit gravitational radiation Two biggest experiments aiming to detect gravity waves: LISA (space-based, under development) LIGO (ground-based, running now) first-lock at Hanford Oct 2000 4 km

32. 32 Rocky Kolb

33. 33 it’s not just cosmology particle astrophysics and particle astronomy have direct connections to particle physics: weigh the neutrinos to < 0.2 – 0.6 eV using SDSS, weak lensing, etc -------- Nicole Bell’s talk use UHE cosmic ray neutrinos to probe CM energies > 1 TeV -------- John Learned’s talk use GLAST to detect gamma rays from neutralino annihilation -------- Steve Ritz’s talk

34. 34 the big picture

35. 35 What is the right way to describe the connection between cosmology/astrophysics and high energy physics?

36. 36 connection #1: There are many deep fundamental questions of cosmology whose elucidation will require extensive input from high energy physics Examples: what is the dark matter? what is the dark energy? how did inflation work? why no antimatter? how did the Big Bang happen?

37. 37 connection #2: There are many deep fundamental questions of particle physics whose elucidation will require extensive input from astrophysics Examples: are there new stable particles? are coupling constants constant? is there quantum gravity? what’s the physics of extra dimensions? is there grand unification?

38. 38 connections 1+2 imply: both fields need each other neither field can replace the other! we should simultaneously pursue an ambitious program of new experiments and observations in both fields This is a big challenge and a big opportunity!

39. 39 big challenges big opportunities big opportunities let’s look at some examples…

40. 40 energy frontier colliders Fermilab Tevatron Collider CERN Large Hadron Collider (2007) our job: explore the TeV energy scale, find the new physics big question: what is the origin of electroweak physics?

41. 41 supersymmetry at the TeV scale? does susy explain the Higgs? is the lightest susy particle stable for (basically) the same reason that the proton is stable? is susy a new source of CP violation? does susy imply grand unification?

42. 42 extra dimensions at colliders? look for graviton production! look for Kaluza-Klein copies of SM particles look for black hole production!

43. 43 TeV physics is exciting no matter what is your view of cosmology but the cosmology connection makes it even better

44. 44 dark matter CDM candidates that can be produced and identified at colliders: neutralinos neutralinos sneutrinos sneutrinos gravitinos gravitinos 4 th generation neutrinos 4 th generation neutrinos mirror partners mirror partners messenger particles messenger particles lightest Kaluza-Klein particles lightest Kaluza-Klein particles

45. 45 neutralino dark matter we are closing in fast on either discovery or exclusion!  collider searches (Tevatron, LHC)  direct searches with WIMP detectors (CDMS etc)  indirect searches (GLAST, AMS etc) there is a combined complementary attack using:

46. 46 already excluded CDMS, CRESST, GENIUS GLAST       J. Feng, K. Matchev, F. Wilczek LHC does the rest Tevatron reach Tevatron reach is better for nonminimal SUGRA models minimal SUGRA susy models

47. 47 how do we detect neutralino DM at colliders? look at missing energy signatures: QCD jets + missing energy like-sign dileptons + missing energy trileptons + missing energy leptons + photons + missing energy b quarks + missing energy etc.

48. 48 CDF 300 GeV gluino candidate from Run I: gluino pair strongly produced, decays to quarks + neutralinos

49. 49 how likely are we to discover neutralinos sooner rather than later? ask some theorists: susy needs lighter gluinos to avoid tuning (G. Kane, J. Lykken, B. Nelson, L-T Wang) look at models with nonuniversal gaugino masses e.g. models of Chattopadhyay Corsetti and Nath, which enforce b –  unification, and impose muon g-2 constraint:

50. 50 good news for the Tevatron

51. 51 good news for direct searches, too!

52. 52 sneutrino dark matter if sneutrinos are the LSP, they are dark matter but there are problems: LEP measurement of the invisible width of the Z boson implies M_sneutrino > 45 GeV but then expect low abundance due to rapid annihilation via s-channel Z and t-channel neutralino/chargino exchange.

53. 53 sneutrino dark matter L. Hall et al (1997): susy with lepton flavor violation can split the sneutrino mass eigenstates by ~> 5 GeV, enough to suppress the annihilation processes however, the same interaction seems to induce at least one neutrino mass ~> 5 MeV. this is now excluded completely by SuperK + SNO + beta decay. it appears that sneutrinos are ruled out as the dominant component of CDM

54. 54 gravitino dark matter large classes of susy models, i.e. gauge-mediated and other low-scale susy breaking schemes, produce light (keV) gravitinos that overclose the universe. loophole: Fujii and Yanagida have found a class of “direct” gauge mediation models where the decays of light messenger particles naturally dilutes the gravitino density to just the right amount! such models have distinctive collider signatures thus cosmology disfavors these models

55. 55 Kaluza-Klein dark matter H-S Cheng, J. Feng, and K. Matchev G. Servant and T. Tait If we live in the bulk of the extra dimensions, then Kaluza-Klein parity (i.e. KK momentum) is conserved. Could be a KK neutrino, bino, or photon So the lightest massive KK particle (LKP) is stable

56. 56 how heavy is the LKP? current data requires M LKP ~> 300 GeV LKP as CDM wants M LKP ~ 600 – 1200 GeV the LHC collider experiments will certainly see this!

57. 57 furthermore, we could have signals from direct searches, and even positrons for AMS H-C Cheng, J. Feng, K. Matchev G. Servant and T. Tait

58. 58

59. 59 the mystery of baryogenesis wherever you look you see matter and not antimatter. particle physics teaches us matter and antimatter are (mostly) the same. cosmology teaches us they exist in equal abundances in the early universe. what happened between then and now? baryogenesis! Mark Trodden, Cosmo02

60. 60 a perfect asymmetry remarkable region of concordance. possible for a single value of  ~10 -10. a major test of the Big Bang theory … … and our earliest direct cosmological data.

61. 61 how to get a baryon excess? Sakharov conditions: violate baryon number (B) or lepton number (L) violate CP depart from thermal equilibrium (because of the CPT theorem) There are LOTS of ways to do this!

62. 62 not the Standard Model the Standard Model even though in principle satisfies all 3 Sakharov criteria, (anomaly, CKM matrix, finite-temperature phase transition) cannot be sufficient to explain the baryon asymmetry! this is a clear indication, from observations of the universe, of physics beyond the standard model! Mark Trodden

63. 63 so what’s viable? electroweak baryogenesis models using supersymmetry, etc inflation driven GUT baryogenesis baryogenesis through preheating after inflation leptogenesis and many more … Mark Trodden

64. 64 particle expts and baryogenesis baryogenesis requires new sources of CP violation besides the CKM phase of the Standard Model (or, perhaps, CPT violation). B physics experiments look for new CP violation by e.g. over-constraining the unitarity triangle Susy models are a promising source for extra phases sorting out the neutrino sector may give clues to leptogenesis

65. 65 electroweak baryogenesis since colliders will thoroughly explore the electroweak scale, we ought to be able to reach definite conclusions about EW baryogenesis EW baryogenesis in susy appears very constrained, requiring a Higgs mass less than 120 GeV, and a stop lighter than the top quark M Carena et al

66. 66 such a light stop will be seen at the Tevatron

67. 67 The cosmic ray spectrum stretches over some 12 orders of magnitude in energy and some 30 orders of magnitude in differential flux: many Joules in one particle! cosmic rays David Gross: “cosmic rays are not astrophysics”

68. 68 Nicole Bell

69. 69 AGASA is an air shower ground array, HiRes is air fluorescence detectors

70. 70 a bright idea: calibrate HiRes! recommended for approval by the SLAC EPAC last month

71. 71 A test setup has already run in the SLAC FFTB

72. 72 exploits felicitous features of the SLAC FFTB

73. 73 NASA program director!

74. 74 Cross-calibrate!

75. 75

76. 76 the really big picture

77. 77 we are pretty confident of solving the mystery of dark matter during this decade, either by direct discovery or by process of elimination the mystery of dark energy, by contrast, ties into the deepest and most difficult questions of particle physics

78. 78 three mysteries  why is the cosmological constant so small?  what is the dark energy?  why –now- is the matter density and dark energy density about the same?

79. 79 why is the cosmological constant so small? regardless of what the dark energy actually is, the cosmological vacuum energy is no larger than (10 -3 eV) 4 whereas quantum field theory predicts that it is at least (100 GeV) 4 something is very very wrong here…

80. 80 why is the cosmological constant so small? we must be making a huge conceptual error in our thinking about how gravity is related to quantum degrees of freedom note that this is not just a Planck scale (10 19 GeV) quantum gravity problem – it involves physics at scales as large as 1/(10 -3 eV) ~ 1 mm! string theory to the rescue?

81. 81 string theory to the rescue? string theorists (not for lack of trying) have yet to demonstrate a possible string vacuum with broken supersymmetry but vanishing cosmological constant but the good news is that string theory has (at least) two profound and surprising properties that seem relevant to the cosmological constant…

82. 82 string theory to the rescue?  string theory is a holographic theory, i.e. the total number of quantum degrees of freedom in a small box is proportional to the area of the box, not the volume!  string theory predicts extra dimensions and branes. If we live on a brane, then the question is recast to: why is the brane so flat?

83. 83 what is the dark energy? the obvious answer is that it is a small positive cosmological constant, i.e. it is constant vacuum energy. it could also be “quintessence”, the slowly varying vacuum energy of a scalar field in an extremely flat potential it could also be something that is neither vacuum energy nor particles, e.g. a frustrated network of topological defects

84. 84 what is the dark energy? To test this, we should determine the equation of state of the dark energy: p = w(z)*  Where w(z) = 0 for matter w(z) = -1 for a cosmological constant w(z) = nontrivial function of redshift z for dynamical quintessence models

85. 85 Michael Turner

86. 86 measuring w(z) Constant w models SNAP simulated data

87. 87

88. 88 Sean Carroll why now? the evolving pie

89. 89 why now?  it is just a coincidence, like the fact that (TeV) 2 /M Planck ~ 10 -3 eV.  the quintessence vacuum energy is dynamically locked to the matter/radiation density  the quintessence vacuum energy oscillates

90. 90 the beginning of time an even bigger cosmological issue for particle physicists is what happened at the beginning of the Big Bang was there an early era of grand unification, preceded by an even earlier era of quantum gravity/string soup/spacetime foam? were space and time created dynamically?

91. 91 the beginning of time did the Big Bang really come from a singularity? if yes, do parameters of the Standard Model derive from initial conditions? can we show this? perhaps string theory smoothes out the singularity, allowing us to trace the history of the universe back before t=0!

92. 92 last words Want to know more? Contact our local experts: Fermilab Theoretical Astrophysics Dept. Center for Cosmological Physics at UC Our local SDSS, CDMS, Auger,… community