DARK MATTER CANDIDATES Cody Carr, Minh Nguyen December 9 th, 2014.

Agenda Motivations (Cosmic & Atomic scales) Dark Matter categories The Dark Matter Zoo – Neutrinos – Neutralinos – Kaluza-Klein particles Summary

Galaxy Clusters For the disk: For the halo: Image courtersy:

CMB Anisotropy -Position (L) of First peak: Dark energy -Height of 2 nd peak: Baryonic DM -Relative height of all three peaks: DM

Gravitational Lensing -Alternative explanations of DM: Theory of GR is inaccurate -From gravitational lensing, this possibility is mostly ruled out Luminous matter is complete separate from DM (Clowe et. Al.)

Issues with the Standard Model Gauge Hierarchy problem – Solution: SUSY, – extra dimensions, etc. Strong CP problem – Solution: Axinos, etc. Neutrino mass problem New physics flavor problem Others problems

Dark Matter Candidate Categories Cold/Warm/Hot Dark matter: Energy of particle at “freeze out” WIMP: only interact with W, Z, not gluons, photons; m ~ 10 GeV – TeV. (neutralinos, KK particle, etc.) – WIMP miracle: if WIMP exists and stable, naturally produce a consistent relic density. superWIMP: more weakly interacting than WIMP, but easier to detect (sterile neutrinos, gravitino, etc.)

Dark Matter Zoo SM: neutrinos, sterile neutrinos, … SUSY: neutralinos, sneutrinos, gravitinos, axinos, … Universal Extra Dimension (UED): Kaluza-Klein particle B (1) Axions (CP problem) Others: Wimpzilla, little Higgs models, hidden DM sectors, Q-balls, scalar DM, crypton, brane-world dark matter, etc.

How to test a DM Candidate The ten-point test: 1.Does it match the relic density? 2.Is this cold? 3.Is it neutral? 4.It is consistent with BBN? 5.Does it leave stellar evolution unchanged? 6.Is it compatible with constraints on self-interactions? 7.Is it consistent with direct DM searches? 8.Is it compatible with gamma-ray constraints? 9.Is it compatible with other astrophysical bounds? 10.Can it be probed experimentally?

Neutrinos The relic density from Boltzmann equation: From WMAP, the dark matter relic density: From constraint of neutrinos mass:

From experiment, Higgs mass is 126 GeV. In SM, Higgs receive mass correction from fermion loops “Hierarchy problem”: Higgs bare mass = – 126 GeV The mother of all headaches If we introduce a new scalar field, then the correction to mass term is:

From experiment, Higgs mass is 126 GeV. In SM, Higgs receive mass correction from fermion loops “Hierarchy problem”: Higgs bare mass = – 126 GeV The mother of all headaches

(Minimal) Image courtesy:

How to create DM from MSSM Impose R parity: 1 for SM particle, -1 for supersymmetric particles R parity is conserved Lightest Supersymmetric Particle (LSP) can only annihilate with anti LSP, but not decay e.g: p is stable in SM, only annihilate R-parity is first motivated to explain proton life time

Neutralinos WIMP, Q = 0, C = 0 Sneutrinos ruled out by direct observation (cite) Gravitinos, axinos contain unfavorable features Only gauginos + higginos Interact with: photon, fermions, higgs bosons, gauge boson pairs.

Detection of neutralinos Hadron collider (e.g HEAT (94-95, 9 GeV surplus e+e-), Tevatron, LHC (‘15, 14 TeV), etc.) Gamma ray experiments (CDMS, EDELWEISS, etc.) Gamma rays/neutrinos from Galactic center. – (smoking gun signature)

Kaluza-Klein particles Extra dimensions to explain the cutoff energy UED: All SM fields can propagate in extra dimensions. Compared with: – Brane world scenario (SM fields restricted to 3D, only gravity propagate in the bulk) – Intermediate models (both gauge bosons and Higgs fields can propagate in the bulk) KK excited states: pyrgons (scale, ladder)

How to create DM from KK models Impose KK parity conservation. Lightest Kaluza-Klein Particle (KSP) do not decay, can only annihilate Candidate: KK mode of neutral gauge boson: B (1) and W 3 (1)

The status quo

Conclusion There are compelling evidences for DM From the WIMP miracle, it is fairly easy to make DM candidate There are many way to directly/indirectly probe dark matter DM serves as good testing ground for new theories in Particle physics

References Dark Matter Candidates from Particle Physics and Methods of Detection Particle Dark Matter: Evidence, Candidates and Constraints arXiv:hep-ph/ arXiv:hep-ph/ A direct empirical proof of the existence of dark matter arXiv:astro-ph/ v1 arXiv:astro-ph/ v1 Dark Matter Candidates: A Ten-Point Test arXiv: v2 arXiv: v2 A Supersymmetry Primer arXiv:hep-ph/ v6arXiv:hep-ph/ v6 Front page simulation: