Old problems and New directions on axion DM

Transcription

1 Old problems and New directions on axion DM Frontiers of New Physics: Colliders and Bey nd ICTP, Trieste, 26 Jun 2014 Javier Redondo (LMU/MPP Munich)

2 The strong CP hint and axions - U(1)A is color anomalous, CP-violating phase is physical L SM q L m u e iδ m d e iδ u d... g R α s 8π G G θ QCD θ = θ QCD + δ Neutron EDM d n θ O(10 2 )[e fm] d exp n < [e fm] J µ A µ J µ 5 q g θ < 10 10!! - why is soooo small? is there any fundamental reason? massless q? P,CP symmetries? - (not in SM) - set tree level - loop problems - still ~ok Axion a - New axial U(1) c.a. symmetry - spontaneously broken (PGB!) - θ promoted to field θ a/f a - QCD potential θ 0 V eff (θ) θ

3 Axion mass and couplings (and model dependencies) - Peccei-Quinn symmetry, color anomalous, spontaneously broken at f a L = L SM + i QDQ (y Q L Q R Φ +h.c) λ Φ 4 + µ 2 Φ 2 Φ(x) =ρ(x)e i a(x) fa (KSVZ model) - At energies below f a L 1 2 ( a)2 + α s 8π G G a f a - At energies below Λ QCD, a η π 0 η... mixing axion mass m a m πf π f a 6meV 109 GeV f a axion couplings L a,i = N c N,a Nγ µ γ 5 N a f a + c aγ α 2π F µν F µν a f a +... nucleons... photons... mesons...

4 Parameter spaces: generic f a GeV Cold DM predictions Burst Duration HotDM CMB BBN SK SN1987A 1.0 PreInflationPQ? g ae Globular Clusters g aγ 0.5 PostInflationPQ? White Dwarfs g ae g ae Solar Neutrino flux g aγ 0.0 ADMX ADMXII IAXO CAST Telescope Beam Dump m a ev - Axions (if existing) are very light and very weakly interacting!

5 Axion cold dark matter: vacuum alignment - Axions: small mass, small interactions, thermal DM - non-thermal DM, Initial conditions time, 1/T Domains=horizon Cosmic strings Damped oscillations=cdm θ =0 strings SSB QCD D. Walls

6 Axion cold dark matter: vacuum alignment - Axions: small mass, small interactions, thermal DM - non-thermal DM, Initial conditions SSB SCENARIO-I realignment+cs+dws Domains=horizon Cosmic strings O(1) inhomogeneous DM θ =0 QCD-horizon scale miniclusters QCD D. Walls time, 1/T Damped oscillations=cdm strings

7 Axion cold dark matter: vacuum alignment - Axions: small mass, small interactions, thermal DM - non-thermal DM, Initial conditions time, 1/T Damped oscillations=cdm SSB INFLATION!! θ =0 QCD D. Walls strings

8 Axion cold dark matter: vacuum alignment - Axions: small mass, small interactions, thermal DM - non-thermal DM, Initial conditions SSB SCENARIO-II realignment only INFLATION!! θ =0 QCD D. Walls time, 1/T Damped oscillations=cdm strings

9 Rough relic abundance of axion Dark matter - Energy density redshifts as matter, from the onset of oscillations R1 3 ρ a (t) θ 2 IΛ 4 QCD R(t) R1 R 0 3 T0 T T 0 H1 m Pl T 0 ma m Pl 3 m 3/2 a - today... - doing it properly... (thermal axion mass) ρ a (t 0 ) θ 2 Im 3/2 a ρ a (t 0 ) θ 2 Im 7/6 a

10 Axion DM abundance fitting the observations 2.0 f a GeV Cold DM predictions 1.0 PreInflationPQ 0.5 SCENARIO-II Excluded (too much DM PostInflationPQ?? Burst Duration g ae HotDM CMB BBN SK SN1987A Globular Clusters g aγ White Dwarfs g ae 0.0 SCENARIO-I ADMX ADMXII g ae Solar Neutrino flux g aγ IAXO CAST Telescope Beam Dump m a ev

11 The isocurvature problem after BICEP2 - Axion fluctuates during inflation (entropy perturbations) SCENARIO-II P iso = dn a n a da2 a 2 I = H2 I π 2 a 2 I = H2 I π 2 f 2 aθ 2 I insisting on axion DM θ I = θ I (f a ) f a (H I ) Constraint, f a H I BICEP2 would exclude SC-II in the simplest models... EXCLUDED of course, there are plenty of ways out...

12 Laboratory

13 Experiments to detect axion DM - Dish antenna DM a photon to detect! B-field - Cavity experiments DM a amplify and detect B-field - Light propagation E x B - Oscillating EDM

14 DM around us ρ CDM 0.3 GeV cm 3 = m an a 1 2 m2 af 2 aθ 2 θ O(10 19 ) velocities in the galaxy phase space density v 300 km/s 10 3 c n a 4πp µev m a 4 occupation number is HUGE! still can treat it like a classical (NR) field Roughly... a(t) =a 0 cos(m a t) Fourier-transform a(x) ω m a (1 + v 2 /2+...) δω = m av 2 2 δω ω 10 6 ω m a

15 Axion - photon mixing in a magnetic field Raffelt, PRD 88 - In a magnetic field one photon polarization Q-mixes with the axion L I = g aγ B E a g aγ = c aγγ α 2πf a B-field Not axions, nor photons are propagation eigenstates! Axion-photon oscillations in a magnetic field, basis for - light shining through walls (LSW): DESY, GammeV,... - Helioscopes as CAST,SUMICO and IAXO... - Astrophysical anomalies? TeV transparency... and... - Haloscope DM detection

16 Axion - photon mixing in a magnetic field Raffelt, PRD 88 - Equations of motion for a plane wave (ω 2 k ) A a 0 g aγ B ω g aγ B ω m 2 a exp( i(ωt kz)). A a = 0 0. axion mixes with A-component PARALLEL to the external B-field - Dark matter solution v = k ω ; ω m a(1 + v 2 /2+...) A a It has a small E field! DM χa 1 exp( i(ωt kz)). χ a g aγb m a B 10 Tesla E a t A m a a 0 χ ρ CDM χ c γ 2

17 DM axions in a magnetic field ω m a k E a = ωχa 0 ω, k, a 0 B ext B a = k E a ω kχa 0

18 Photons from Transition radiation! Jaeckel and JR arxiv: E a = ωχa 0 ω, k, a 0 transmitted photon wave ω, ωn, E a 2 reflected photon wave ω, ωn, E a 2 B ext =0 B ext =0 sharp boundary

19 Photons from Transition radiation! Jaeckel and JR arxiv: B ext = B 2 B ext = B 1 index of refraction n 2 index of refraction n 1 χ 1 = gb 1 1 χ 2 = gb 2 1 m m a n 2 a n E a = ωχ 2 a 0 E a = ωχ 1 a 0 ω, k, a 0 transmitted photon wave reflected photon wave ω, ωn 2, (χ 1 χ 2 ) n 1 n 2 ωa 0 ω, ωn 1, (χ 2 χ 1 ) ωa 0 n 1 + n 2 n 1 + n 2 sharp boundary dω 1

20 Photons from Transition radiation! are perp! k kγ λ a 1/k λ γ 1/ω

21 Simplest experiment: Dish antenna Horns at al JCAP04(2013)016 P center E a 2 A dish χ 2 ρ CDM A dish B 5T c γ 2 2 A 1m 2 Watt spherical reflecting dish

22 Simplest experiment: Dish antenna Horns at al JCAP04(2013)016 ΝGHz A=10m2,T=5K,B=5T,t=1year, A=10m2,T=QL,B=10T,t=1year, ρ CDM 0.3GeV cm 3 cγ ADMX ADMX BFRT ADMXII ADMXHF CARRACK O(10^6) channels KSVZ DFSZ HS HKS PostInflationPQ DS PreInflationPQ m a ev broadband! :-) δω ω O(1) measure 1/octave of a decade with the same detector at the same time

23 Possible improvement Enhance the emissivity by multilayers of dielectric χ χ eff χ N Ν GHz back production and all reflexions... 4 layers tuned lambda/ ΧeffΧ 1 1 Increases sensitivity but losses bandwidth m a ev 10 2

24 Cavity searches (haloscopes) - Different understanding of the conventional HALOSCOPES

25 Cavity searches (haloscopes) Sikivie PRL 83 - Use two facing mirrors (simplistic resonant cavity in 1D) detector? E out te γ 1 re iωl (r 2 e i2ωl ) b 1 re iωl te γ b=0 round trip losses & phase transmission coefficient t 1 r 2 e i2ωl (optical resonator fed from both sides) 0 for ωl =2πn 0 for ωl = π +2πn

26 Cavity searches (haloscopes) Sikivie PRL Use two facing mirrors (simplistic resonant cavity in 1D) resonant ω γ L π +2πn detector transmission coefficient t negative interference? out amplitude amplitude radiated /t δω ω t2 ωl ω[1/πl] t

27 Cavity searches (haloscopes) Sikivie PRL Use two facing mirrors (simplistic resonant cavity in 1D) resonant ω γ L π +2πn detector? 10 transmission coefficient t out amplitude amplitude radiated /t δω ω t2 ωl resonant suppressed ω[1/πl]

28 Cavity searches (haloscopes) - Power Loss (cavity tuned!!); putting an pickup we can ideally extract the same P loss = 1 t 2 χ2 ρ CDM Area P out W m 2 B 10 T c γ Usual 3-D formula is P out = κ Q χ 2 ρ CDM (m a V ) G Q G = κ quality factor dv Emode B 2 B 2 V dv E mode 2 coupling

29 Comparison vs - broadband - quite insens. to mass L = π/m a - needs tune - very sens. to mass P dish P cavity A dishm 2 a Q cavity A dishm 2 a better at large mass - better at small mass

30 Conclusions - Axion DM - well motivated - underrepresented (getting better) - testable - key targets not covered - New experiment: dish antenna - a little short for axions - broadband/miniclusters! - good for ALPs, hidden photons! - boost with dielectric layers! - New understanding of the old experiments

31 Getting better - New IBS (Institute of Basic Science) Center for Axion and Precision Physics (CAPP) KAIST campus, Daejeon/Korea - + in US - Yale developing ADMX-HF - CASPER - Europe getting involved - CASPER, Budker@Mainz - DESY, CERN, Unizar - International AXion Observatory main goal: solar axions but also DM