MAD MAX Javier Redondo Universidad de Zaragoza (Spain) Max Planck Institute für Physik
Axions are necessarily dark matter - is it a dynamical field? (t, x) Energy generated by QCD! time 0 (t) = 0 cos(m a t) ~ One parameter theory (t, x) =a(t, x)/f a axion mass m a =6meV 109 GeV f a n n Coherent oscillations = Dark Matter Axions Measured today < 10 10 (strong CP problem)
Relic density as function of mass - Random IC (after a phase transition) - One Universal IC (inflation smoothens the axion field)
Theta evolution, Averaged SCENARIO I
DM dominated by string radiation
Axion dark matter - Axion DM scenarios Excluded (too much DM) ok sub Initial conditions set by : Phase transition (N=1) strings+unstable DW s
Axion dark matter - Axion DM scenarios tuned (anthropic?) ok tuned Excluded (too much DM) ok sub Excluded Initial conditions set by : Inflation smooth adm h 2 ' 2 I 80 µev m a 1.19 Phase transition (N=1) strings+unstable DW s
Detecting Axions adm =0.3 GeV cm 3 a = 1 2 (ȧ)2 + 1 2 m2 aa 2 = 1 2 m2 af 2 a 2 0 V 0 =3.6 10 19
Cavities Mirrors LC-circuit Spin precession Atomic transitions Optical
Excluded Axion experiments (target areas) SCENARIO I not DM ARIADNE 0 QCD > 10 14? QUAX? IAXO? test bench LC CAPP osc. EDM ADMX ADMX-HF Axion Dark Matter experiment (Seattle, Yale...) only one running
Axion experiments (target areas) SCENARIO I not DM ARIADNE QCD 0 > 10 14? IAXO? QUAX? MADMAX baby born Munich Axion Dark MAtter experience Excluded LC CAPP osc. EDM ADMX ADMX-HF only one running
Axion DM in a B-field L I = C a 2 a f a B E - In a static magnetic field, the oscillating axion field generates EM-fields L I = C a 2 (t) B ext E source B-field - Electric fields E a = C a B ext 2 0 cos(m a t) (amp independent of mass!) - Oscillating at a frequency! ' m a
Resonant cavity experiments - Haloscope (Sikivie 83) Amplify resonantly the EM field in a resonant cavity Output EM power P Q E a 2 (Vm a )Gapple on resonance res = m a 2 30 cm 0.6 cm - Noise P noise = T sys a / m 2 a 10 3 10-1 1 10 10 2 10 2 [GHz] RBF IAXO 10 3 10 2 - Signal (V / m 3 a ) P out / Vm a 1 m 2 a C a c 10 1 KSVZ DFSZ ADMX ADMX ADMX2 UF ADMX-HF CARRACK? 10 1 10-1 10-1 10-7 10-6 10-5 10-4 10-3 m a [ev] m a [µev]
- Do not give up volume -> Area pre MADMAX (dish antenna) D 1 m a spherical reflecting dish P E a 2 A
Radiation from a dielectric interface... E(t) = c 0B 2 cos(m a t) E(t) = c 0B 2 cos(m a t) Boundary conditions! Emitted EM-wave Emitted EM-wave E 1 = E 2
Radiation from a magnetised mirror : Power MIRROR Emitted EM-wave Power Area 2.2 10 27 Watt m 2 Ca 2 B 5T 2
Many dielectrics : MADMAX at MPP Munich Emitted EM-waves from each interface... + internal reflections... - Emission has large spatial coherence; adjusting plate separation -> coherence P boost factor Area 2.2 10 27 W B 2 m 2 C a 2 (!) 10T
One dielectric 0 2 = d - Frequency response Axion emission (boost factor) (n=2,3,4) 1.0 0.8 0.6 0.4 0.2 1.0 0.8 0.6 0.4 0.2 transmission coefficient 0 1 2 3 4 / 0 / 0 0 1 2 3 4
Close to nu0, many layers Emitted EM-waves from each interface... + internal reflections... boost factor (N=10,40,80; n=3,nu0=20 GHz) 140 120 100 80 60 40 N N 1 20 18 19 20 21 22 [GHz] Nice boost, excellent bandwidth!
Close to 2nu0, cavity effects When dielectrics are non-transparent, mild resonances appear that allow higher boosts mirror z zn n =1, n, n z=4.5, 4, 3.5, 3, 2.5 mm Maximum effect for z = 2,z d = 0 4 = 4n 6 5 zn=0.65 mm n=3 4 [...] 3 2 1 0 20 40 60 80 100 [GHz]
tuning JCAP 1701 (2017) Distances between layers allow tuning (transfer matrix formalism) Broadband vs narrowband central frequency
Potential reach A = 1 m^2 B-field = 10 T 80disk n=5
whys - why can it work? Large volume + (relatively) simple tuning long measurements broadband short measurements narrowband - What can go wrong? - 10T dipole-like Magnet, 1 m^2 aperture! - 1 m^2 dielectrics (tiling smaller pieces) - Tolerances (several micron distances) - difraction
Conclusions - Strong CP problem and dark matter motivate Axions - Most predictive model (N=1) mass~ 0.1 mev (fa ~ 10^11 GeV) - Many experimental efforts, solid player missing in that range - MW emission from interfaces is weak, make layered haloscope - Munich Axion Dark MAtter experiment