Cosmology/DM - I Konstantin Matchev

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? Can the laws of Physics be unified? … 126. What is the cause of the “terrible twos”? Trying to answer the really big questions:

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?

Heavy elements 0.03% The need for new physics BSM

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

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

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

Outline of the lectures All lecture materials are on the web: 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)

Useful references Jungman, Kamionkowski, Griest, hep-ph/ Bergstrom, hep-ph/ Bertone, Hooper, Silk, hep-ph/ Feng, hep-ph/ Baltz, Battaglia, Peskin, Wizansky, hep-ph/ Murayama, [hep-ph] Peskin, [hep-ph]

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)

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

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

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

Supersymmetry Extra dimension, but fermionic (  ’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!)

Spin U(1)SU(2)Up-typeDown-type 2G graviton 3/2 1BW 0 1/2 0HdHd DM CANDIDATES IN MSSM Neutralinos:          Spin U(1) M 1 SU(2) M 2 Up-type  Down-type  m ̃ m 3/2 2G graviton 3/2G̃ gravitino 1BW 0 1/2B̃ Bino W̃ 0 Wino H̃ u Higgsino H̃ d Higgsino 0HuHu HdHd ̃ sneutrino PS. Beyond the MSSM:

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

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

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?

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.

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.

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

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

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

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

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

Universal Extra Dimensions 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!) Appelquist,Cheng,Dobrescu 2000

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: mpppE zyx  mppppE uzyx   2  u p R n R n p n R u    R n mpmpppE uzyx 

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

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

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

SUSY or ED or something else? mass Spinsdiffer by 1/2same as SM Higher levelsnoyesno

earth, air, fire, water baryons, s, dark matter, dark energy

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