Cosmology/DM - I

1. Cosmology/DM - I Konstantin Matchev

2. Trying to answer the really big questions: What Do We Do? • Says who? How about DOE/NSF (he who pays the piper orders the tune…) 1. What is the Universe made of? ... 5. Can the laws of Physics be unified? … 126. What is the cause of the “terrible twos”?

3. The 9 Big Questions • Are there undiscovered principles of Nature: new symmetries, new physical laws? • How can we solve the mystery of dark energy? • Are there extra dimensions of space? • Do all forces become one? • Why are there so many kinds of particles? • What is dark matter? How can we make it in the lab? • What are neutrinos telling us? • How did the universe come to be? • What happened to the antimatter?

4. The need for new physics BSM Heavy elements 0.03%

5. Stable • Non-baryonic • Cold DARK MATTER Known DM properties DM: precise, unambiguous evidence for new particles (physics BSM)

6. BSM Theory Cookbook • Two approaches: • A: Take the SM and modify something. • B: Ask your advisor how to do A. • The Standard Model is a • Lorentz-invariant • gauge theory based on SU(3)xSU(2)xU(1) • of mostly fermions • but also one Higgs • in d=4 • As a rule, we expect new particles

7. Dark Matter Cookbook • Invent a model with new particles • Supersymmetry • Universal Extra Dimensions • Invent a symmetry which guarantees that at least one of them (the lightest) is stable • Fudge model parameters until the dark matter particle is neutral • Calculate the dark matter relic density • Use a computer program, e.g. MicrOMEGAs • Fudge model parameters until you get the correct relic abundance • If it works, don’t forget to write a paper

8. Outline of the lectures • All lecture materials are on the web: http://www.phys.ufl.edu/~matchev/PiTP2007 • Yesterday: became familiar with MicrOMEGAs • Implement the New Minimal Standard Model • Today: discuss several new physics models and their respective dark matter candidates • concentrate on WIMPs • Later today: discuss how collider and astro experiments can • determine DM properties • discriminate between alternative models • Homework exercises throughout today’s lectures (Davoudiasl, Kitano, Li, Murayama 2004)

9. Useful references • Jungman, Kamionkowski, Griest, hep-ph/9506380 • Bergstrom, hep-ph/0002126 • Bertone, Hooper, Silk, hep-ph/0404175 • Feng, hep-ph/0405215 • Baltz, Battaglia, Peskin, Wizansky, hep-ph/0602187 • Murayama, 0704.2276 [hep-ph] • Peskin, 0707.1536 [hep-ph]

10. DARK MATTER CANDIDATES • There are many candidates • Masses and interaction strengths span many, many orders of magnitude • But not all are equally motivated. Focus on: • WIMPs: natural thermal relics Dark Matter Scientific Assessment Group, U.S. DOE/NSF/NASA HEPAP/AAAC Subpanel (2007)

11. Thermal relic abundance - I • At early times, the DM particles and SM particles X are in thermal equilibrium • Freeze-out described by the Boltzmann equation • accounts for dilution due to Hubble expansion • describes depletion due to • describes resupply due to

12. Thermal relic abundance - II • is the total DM annihilation cross-section • Notice that we do not know the specific final states • The a-term is the one relevant for indirect detection (ongoing DM annihilations in the galactic halo) • Approximate analytic solution

13. HEPAP LHC/ILC Subpanel (2006) [band width from k = 0.5 – 2, S and P wave] What does WMAP tell us? • 3 unknowns: ; 1constraint • Thermal relics make up • all of the DM: 2. Thermal relics are WIMPs:

14. Supersymmetry • Extra dimension, but fermionic (q’s anticommute) • SUSY relates particles and superpartners • The SM particles and their superpartners have • Spins differing by ½ • Identical couplings • Introduce negative R-parity for superpartners • Forbids dangerous interactions allowing proton decay • Is it overrated? (do the HW in SUSY lecture1) • No tree-level contributions to precision EW data • Makes the lightest superpartner stable (dark matter!)

15. Neutralinos: {cc1, c2, c3, c4} DM CANDIDATES IN MSSM PS. Beyond the MSSM:

16. Neutralino spectrum • Lightest neutralino: • Mass eigenstates: • Consider the three limiting cases • Pure Bino: • Pure Wino: • Pure Higgsino:

17. Dark matter codes for SUSY • Public • Neutdriver (Jungman) • DarkSUSY (Gondolo, Edsjo, Ullio, Bergstrom, Baltz) • MicrOMEGAs (Belanger, Boudjema, Pukhov, Semenov) • Can also handle generic nonSUSY models • Includes all relevant processes • User-friendly, based on CalcHEP • Private • IsaRED (Baer, Balazs, Belyaev, Brhlik) • SSARD (Ellis, Falk, Olive) • Drees/Nojiri • Roszkowski • Arnowitt/Nath • Lahanas/Nanopoluos • Bottino/Fornengo • Use your favorite computer code to check and analyze the following examples

18. Bino dark matter • Possible channels • Bino annihilation is suppressed • No s-channel diagrams • 1/M suppression in t-channel • No gauge boson final states • Helicity suppression for fermion final states • neutralinos are Majorana fermions => S=0 • if s-wave, J=0 and helicity flip required on the fermion line (recall decay) • predominantly p-wave, but still suppression => • Binos give too much dark matter, unless other sparticles are light -> upper limits on SUSY masses?

19. Wino dark matter • Possible channels • Unsuppressed annihilation to W pairs • Cannot use threshold suppression light wino-like chargino • Result: wino relic density too small, unless the wino is rather heavy • HW: Assume all of the dark matter is pure winos. Use MicrOMEGAs to find the range of wino masses preferred by cosmology.

20. Higgsino dark matter • Possible channels • Unsuppressed annihilation to W and Z pairs • Cannot use threshold suppression light higgsino-like chargino • Result: higgsino relic density too small, unless the higgsino is rather heavy • HW: Assume all of the dark matter is pure higgsinos. Use MicrOMEGAs to find the range of their masses preferred by cosmology.

21. Mixed neutralino dark matter • Recap: • Pure Bino gives too much dark matter • Pure Wino gives too little dark matter • Pure Higgsino gives too little dark matter • How about mixed cases? • Mixed Wino-Higgsino DM: • Mixed Bino-Wino DM: • e.g. non-universal gaugino masses, rSUGRA • Mixed Wino-Higgsino DM: • E.g. focus point SUSY Birkedal-Hansen,Nelson 2001 Feng,KM,Wilczek 2000

22. The exceptional cases • Coannihilations: requires other particles to be degenerate with the LSP at the level of • Resonances (“funnels”): h, H/A or Z.

23. Focus point region Co-annihilation region Bulk region Minimal Supergravity (MSUGRA) • A simple and popular model: universal BC at MGUT WDMstringently constrains the model Too much dark matter Feng, Matchev, Wilczek (2000) Yellow: pre-WMAP Red: post-WMAP Cosmology highlights certain regions, detection strategies

24. MSSM soft SUSY breaking masses: RGE evolution • Gaugino universality: • LSP is not wino • EWSB condition: • is typically large

25. Sneutrino dark matter • Left-handed: direct detection rules it out as a dominant DM component • HW: prove it using MicrOMEGAs • Right-handed? Needs new interactions to thermalize and freeze out with the correct abundance • e.g. U(1)’ gauge interaction Falk,Olive,Srednicki 1994 Lee,KM,Nasri 2007

26. Universal Extra Dimensions Appelquist,Cheng,Dobrescu 2000 • Bosonic extra dimension with a new coordinate y • An infinite tower of Kaluza-Klein (KK) partners for all Standard Model particles • The SM particles and their KK partners have • Identical spins • Identical couplings • Automatic KK-parity for KK partners • Makes the lightest KK partner stable (dark matter!)

27. - - - = 2 2 2 2 2 E p p p m x y z - - - - = 2 2 2 2 2 2 E p p p p m x y z u p 2 = p u l p p 2 R 2 n n l = Þ = = p u p n 2 R R 2 n - - - = + = + 2 2 2 2 2 2 2 E p p p m p m x y z u 2 R Kaluza-Klein masses • In d=4 we have • With one extra dimension (u) we get • Recall particle-wave duality • Periodicity implies quantization of momentum • KK modes: particles with momentum in the ED:

28. UED Kaluza-Klein mass spectrum KK masses at tree-level KK masses at one-loop Cheng,KM,Schmaltz 2002 Cheng,KM,Schmaltz 2002 Several stable, charged KK particles Only the LKP is stable. The LKP is neutral (DM!)

29. KK dark matter • Direct detection • Lower bound on the rate • Relic density calculation • involved, many coannihilations Servant,Tait 2002 Burnell,Kribs 2005 Kong,KM 2005 Cheng,Feng,KM 2002

30. UED in D=6 • 2 extra dimensions • Gauge bosons have 2 extra polarizations • One is eaten as in D=5 • The other appears as a scalar in D=4 • The LKP is now the scalar KK hypercharge boson Dobrescu,Kong,Mahbubani 2007 Dobrescu,Hooper,Kong,Mahbubani 2007

31. mass • Spins differ by 1/2 same as SM same as SM • Higher levels no yes no SUSY or ED or something else?

32. earth, air, fire, water baryons, ns, dark matter, dark energy