Dark Forces, Dark Matter, and the GeV- Scale Discovery Frontier - PowerPoint PPT Presentation

Dark Forces, Dark Matter, and the GeV- Scale Discovery Frontier Philip Schuster Perimeter Institute New Light Weakly Coupled Particle Session CSS Conference July, 2013 1 Wednesday, 31 July, 13 1

Nice Source Summarizing Broad Physics Program: – Intensity Frontier Meeting at Argonne (April 2013) (see posted talks) Considerable documentation to help with discussions over the next three days 2 Wednesday, 31 July, 13 2

Outline • Theory of Dark Forces & Motivation – Fundamental Physics Motivation – Dark Matter Motivation – Precision Anomalies – Dark Matter Anomalies • What has been achieved recently • What will be achieved in next few years • Goals for next 10 years 3 Wednesday, 31 July, 13 3

Beyond the Standard Model We know there is dark matter ...but what is it? LHC and direct detection results challenge connection of dark matter to “weak-scale naturalness” 4 Wednesday, 31 July, 13 4

Copernican Particle Physics? p + , n, e – ? ... extension of Standard Model? ? ? ? (axion, superpartner, ...) Completely What do we actually know about the dark sector? new physics? 5 Wednesday, 31 July, 13 5

Beyond the Standard Model Dark Sector ? U (1) D × ... U (1) Y × SU (2) W × SU (3) s Look for interactions allowed symmetry! 6 Wednesday, 31 July, 13 6

Beyond the Standard Model Known matter interacts through three gauge forces (strong, weak, and electromagnetic) LHC looking for new matter interacting through the same forces ...but what about matter that is not charged under these forces? Gauge- & Lorentz-invariance restrict possible interactions with such matter to high dimension operators. New sub- GeV matter can be consistent. Wednesday, 31 July, 13 7

The “Portals” Searches can be organized around a small number of interactions allowed by Standard Model symmetries Higgs Portal exotic rare Higgs decays? � h | h | 2 | ⇥ | 2 � ν ( hL ) ⇥ Neutrino Portal not-so-sterile neutrinos? 2 � Y F Y 1 µ ν F 0 µ ν Vector Portal kinetic mixing? f a aF µ ν ˜ 1 F µ ν Axion Portal axion-like particles? Wednesday, 31 July, 13 8

The “Portals” Searches can be organized around a small number of interactions allowed by Standard Model symmetries Higgs Portal exotic rare Higgs decays? � h | h | 2 | ⇥ | 2 � ν ( hL ) ⇥ Neutrino Portal not-so-sterile neutrinos? Focus of this talk 1 2 � Y F Y µ ν F 0 µ ν Vector Portal f a aF µ ν ˜ 1 F µ ν Axion Portal axion-like particles? Wednesday, 31 July, 13 8

The Territory e + A ′ (A’ Electron/Muon Decays) A' Æ Standard Model e − 10 - 2 a m , 5 s KLOE a m , ± 2 s favored 10 - 3 BaBar APEX ê MAMI E774 Test Runs a e Unexplored e 10 - 4 E141 Orsay 10 - 5 U70 0.001 0.01 0.1 1 m A ' H GeV L 9 Wednesday, 31 July, 13 9

The Territory χ A ′ (A’ invisible “dark matter” Decays) χ Unexplored (Izaguirre, Krnjaic, PS, Toro) 10 Wednesday, 31 July, 13 10

GeV-Scale Discovery Frontier Tremendous opportunity to explore GeV-Scale dark matter and weakly coupled physics with novel small-scale experiments! What will we find? ? ? ? ? ? 11 Wednesday, 31 July, 13 11

Outline • Theory of Dark Forces & Motivation – Fundamental Physics Motivation – Dark Matter Motivation – Precision Anomalies – Dark Matter Anomalies • What has been achieved recently • What will be achieved in next few years • Goals for next 10 years 12 Wednesday, 31 July, 13 12

Sources and Sizes of Kinetic Mixing 1 2 � Y F Y µ ν F 0 µ ν • If absent from fundamental theory, can still be generated by perturbative (or non-perturbative) quantum effects – Simplest case: one heavy particle ψ with both EM charge & dark charge ψ γ A 0 e g D generates ✏ ∼ e g D 16 ⇡ 2 log m ψ M ∗ ∼ 10 − 2 − 10 − 4 13 Wednesday, 31 July, 13 13

Sources and Sizes of Kinetic Mixing 1 2 � Y F Y µ ν F 0 µ ν • If absent from fundamental theory, can still be generated by perturbative (or non-perturbative) quantum effects – In Grand Unified Theory, symmetry forbids tree- level & 1-loop mechanisms. GUT-breaking enters at 2 loops ψ γ A 0 X e g D generating ✏ ∼ 10 − 3 − 10 − 5 ( → if both U(1)’s are in unified groups) 10 − 7 14 Wednesday, 31 July, 13 14

Sources and Sizes of Mass Term • sub-MeV: non-perturbative physics (like Λ QCD ) • MeV-to-GeV is motivated by g-2 and dark matter anomalies • Possible origin: related to M Z by small parameter – e.g. supersymmetry+kinetic mixing ⇒ scalar coupling to SM Higgs, giving m A 0 ∼ √ ✏ M Z . 1GeV a motivated target of opportunity 15 Wednesday, 31 July, 13 15

“Top Down”-Motivated Region (A’ Electron/Muon Decays) A' Æ Standard Model 10 - 2 a m , 5 s KLOE a m , ± 2 s favored 10 - 3 BaBar APEX ê MAMI E774 Test Runs a e One loop mixing e 10 - 4 E141 Orsay Two loop mixing 10 - 5 U70 0.001 0.01 0.1 1 m A ' H GeV L 16 Wednesday, 31 July, 13 16

Projections vs. “top-down” A' Æ Standard Model 10 - 2 One-loop region well a m , 5 s covered below 500 KLOE a m , ± 2 s favored MeV 10 - 3 BaBar APEX ê MAMI E774 Test Runs a e One loop mixing Two-loop region e 10 - 4 explored by HPS E141 Two loop mixing Orsay 10 - 5 Mass reach should U70 be extended, and gap 0.001 0.01 0.1 1 m A ' H GeV L should be closed 17 Wednesday, 31 July, 13 17

Target of Opportunity? Precision Anomalies Muon g-2 U(1) D coupling modifies (g-2) μ , with correct sign. ε ~1-3 10 –3 can explain discrepancy with Standard Model [Pospelov ’08] [Hoeker ’10] Muonic hydrogen MeV-scale force carriers can explain the discrepancy between ( μ - ,p) Lamb shift [Pohl et al. 2010] and other measurements of proton charge radius. Requires couplings beyond kinetic mixing (lepton flavor-violating component) [Tucker-Smith & Yavin, 1011.4922] Wednesday, 31 July, 13 18

Projections vs. Muon G-2 A' Æ Standard Model 10 - 2 a m , 5 s KLOE a m , ± 2 s favored 10 - 3 BaBar APEX ê MAMI E774 Test Runs a e g-2 region for visible e A’ decays can be 10 - 4 E141 completely explored Orsay 10 - 5 U70 0.001 0.01 0.1 1 m A ' H GeV L 19 Wednesday, 31 July, 13 19

Target of Opportunity? Direct-Detection Anomalies Several light dark matter direct detection hints Dark matter interacting via dark photons is a viable explanation discussed at length in the literature CDMS collaboration, 1304.4279 Tracy Slatyer, IFW, April 2013 Argonne Meeting 20 Wednesday, 31 July, 13 20

Target of Opportunity? Direct-Detection Anomalies χ �� D ⇥ 2 m 2 p m 2 p A ′ χ ⌅ p χ ≈ 16 ⇤ m 4 A 0 ( m χ + m p ) 2 p χ ✓ � D ⇥ 2 ◆ 4 ◆ ✓ GeV ≈ 1 . 2 × 10 − 40 cm 2 10 − 12 m A 0 Direct detection equally sensitive to any DM component ✓ � D ⇥ 2 ◆ 4 ◆ ✓ GeV ∼ Ω DM So best fit is given by: 10 − 12 m A 0 Ω χ (ratio of densities) 21 Wednesday, 31 July, 13 21

Target of Opportunity? Direct-Detection Anomalies A' Æ Standard Model Region of interest 10 - 2 depends on a m , 5 s α D KLOE and “DM” partial d r e v o a f a m , ± 2 s 10 - 3 BaBar fraction Ω χ / Ω DM APEX ê MAMI E774 Test Runs a e α D = 10 − 2 α Ω χ / Ω DM = 10 − 4 e 10 - 4 E141 Ω χ / Ω DM = 10 − 4 α D = α Orsay 10 - 5 U70 Ω χ / Ω DM = 1 α D = α 0.001 0.01 0.1 1 m A ' H GeV L 22 Wednesday, 31 July, 13 22

Projections vs. Direct-Detection Will start to cover A' Æ Standard Model 10 - 2 large direct-detection a m , 5 s region, but will need KLOE a m , ± 2 s favored to do better 10 - 3 BaBar APEX ê MAMI E774 Test Runs a e α D = 10 − 2 α Ω χ / Ω DM = 10 − 4 e 10 - 4 E141 Ω χ / Ω DM = 10 − 4 α D = α Orsay 10 - 5 U70 Ω χ / Ω DM = 1 α D = α 0.001 0.01 0.1 1 m A ' H GeV L 23 Wednesday, 31 July, 13 23

Target of Opportunity? Cosmic Ray Anomalies Tracy Slatyer, IFW, April 2013 Argonne Meeting Increasing positron fraction may be due to DM annihilation/decay to A’s 24 Wednesday, 31 July, 13 24

Target of Opportunity? Cosmic Ray Anomalies Tracy Slatyer, IFW, April 2013 Argonne Meeting Fits to cosmic ray spectra prefer A‘ masses above the muon decay threshold (>210 MeV) 25 Wednesday, 31 July, 13 25

Target of Opportunity? Cosmic Ray Anomalies A' Æ Standard Model 10 - 2 a m , 5 s KLOE d r e v o a f a m , ± 2 s 10 - 3 BaBar APEX ê MAMI E774 Preferred by fits of Test Runs a e cosmic ray data to e 10 - 4 ~few TeV DM E141 annihilating to A’s Orsay 10 - 5 U70 0.001 0.01 0.1 1 m A ' H GeV L 26 Wednesday, 31 July, 13 26

Projections vs. DM Cosmic Ray A' Æ Standard Model 10 - 2 a m , 5 s KLOE a m , ± 2 s favored HPS and APEX will 10 - 3 BaBar APEX ê MAMI E774 Test Runs a e make progress, but will need to do better e 10 - 4 E141 Orsay Non-minimal dark 10 - 5 sector or modified U70 propagation consistent 0.001 0.01 0.1 1 with lighter A’ m A ' H GeV L 27 Wednesday, 31 July, 13 27

Projections (A’ invisible “dark matter” Decays) sub- 500 MeV WIMP search using MiniBooNE (see: arXiv:1211.2258 for proposal) 28 Wednesday, 31 July, 13 28

Projections (A’ invisible “dark matter” Decays) Potential searches using electron fixed-target (Izaguirre, Krnjaic, PS, Toro) 29 Wednesday, 31 July, 13 29