search for dark matter axions with madmax · 2019. 7. 19. · astro-physics helioscopes lsw a d m x...

Search for Dark Matter Axions with MADMAXDark Side of the Universe, Buenos Aires 15-19/07/19

Christian Strandhagen

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Dark Matter Candidates

FUZZYDark Matter

10-24 10-18

adapted from xkcd.com/2035

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FUZZYDark Matter

10-24 10-18


gravitinos

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FUZZYDark Matter

10-24 10-18


gravitinos

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FUZZYDark Matter

10-24 10-18


gravitinos

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The QCD AxionThe QCD Lagrangian contains a CP-violating term

→ violates T and P and thus CP→ induces electric dipole moment (EDM) of neutron

experimentally: →

Why is θ so small? → Strong CP problem

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The QCD AxionThe solution: make θ a dynamical parameter by introducing a scalar field by adding a new U(1)PQ symmetry (Peccei-Quinn)

U(1)PQ spontaneously broken at high energy scale fa

θ minimum is degenerate→ arbitrary value chosen

G. Raffelt

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potential gets tilted duringQCD phase transition (T < 1 GeV)

field starts oscillating→ axion acquires mass

G. Raffelt

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potential gets tilted duringQCD phase transition (T < 1 GeV)

field starts oscillating→ axion acquires mass

G. Raffelt

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QCD Axion Dark Matter

Axions created in early universe through initial misalignment are good candidate for cold dark matter

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astrophysical bounds

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too much dark matter* astrophysical bounds*depends on the actual cosmology

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too much dark matter* astrophysical bounds*depends on the actual cosmology

axion dark matter

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Axion Landscape

coup

ling

stre

ngth

(to

phot

ons)

gith

ub.c

om/c

ajoh

are/

Axio

nLim

its

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Axion Landscape

coup

ling

stre

ngth

(to

phot

ons)

QCD axion gith

ub.c

om/c

ajoh

are/

Axio

nLim

its

Axion-Like Particles ALPs

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Axion Landscape

coup

ling

stre

ngth

(to

phot

ons)

limits from

cosmology

gith

ub.c

om/c

ajoh

are/

Axio

nLim

its

QCD axion

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Axion Landscape

coup

ling

stre

ngth

(to

phot

ons)

limits from

cosmology

stellar evolution

astro-physics

gith

ub.c

om/c

ajoh

are/

Axio

nLim

its

QCD axion

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Axion Landscape

coup

ling

stre

ngth

(to

phot

ons)

limits from

cosmology

stellar evolution

astro-physics

helioscopes

LSW

gith

ub.c

om/c

ajoh

are/

Axio

nLim

its

QCD axion

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Axion Landscape

coup

ling

stre

ngth

(to

phot

ons)

limits from

cosmology

stellar evolution

astro-physics

helioscopes

LSW

AD

MX C

avit

y E

xp.

gith

ub.c

om/c

ajoh

are/

Axio

nLim

its

QCD axion

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Axion Landscape

coup

ling

stre

ngth

(to

phot

ons)

limits from

cosmology

stellar evolution

astro-physics

helioscopes

LSW

AD

MX

pro

ject

ed

gith

ub.c

om/c

ajoh

are/

Axio

nLim

its

QCD axion

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Axion Landscape

coup

ling

stre

ngth

(to

phot

ons)

limits from

cosmology

stellar evolution

astro-physics

helioscopes

LSW

AD

MX

pro

ject

ed

MA

DM

AX

p

roje

cte

d

gith

ub.c

om/c

ajoh

are/

Axio

nLim

its

QCD axion

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How to Detect Axions● axions are pseudo-scalar bosons (like pions)

and have a 2-photon-coupling:

● their de Broglie wavelength is large (O(m))→ we can treat them as classical wave→ axions appear as a source term in Maxwell’s equations

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How to Detect Axions

axion-induced electric field:

In an external B field Be the axion field a(t) sources an oscillating E field Ea

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Dielectric Haloscope

power emitted from single interface:

In an external B field Be the axion field a(t) sources an oscillating E field Ea

Ea is different in materials with different ε

At the surface, E|| must be continuous → emission of electromagnetic waves

Phys

. Rev

. D 8

8, 1

1500

2 (2

013)

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Dielectric Haloscope

power emitted from all interfaces:

● boost emitted power through– coherent emission from

multiple interfaces– resonance effects

● power boost factor

PRL

118,

091

801

(201

7)

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Dielectric Haloscope● |β|2 > 104 achievable with

80 disks and ε = 24

● non-uniform disk spacing of ~ λ/2 can achieve “broadband” response

● precision required for disk spacing < 10 µm

JCAP 061 (2017); arXiv:1612.07057

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Boost Factorfrequency is tuned by adjusting

disk spacings

area law: → broad-band scan for search → narrow-band to check signal candidates

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Proof of Principle SetupTest setup at MPP Munich

● up to 20 disks (Ø = 20 cm, ε ≈ 9)● reproducibility of positioning ~ µm

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● up to 20 disks (Ø = 20 cm, ε ≈ 9)● reproducibility of positioning ~ µm● compare reflectivity measurements

to model calculations

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● up to 20 disks (Ø = 20 cm, ε ≈ 9)● reproducibility of positioning ~ µm● compare reflectivity measurements

to model calculations● boost factor reproducible within

few MHz for 5 disks

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The MADMAX Collaboration

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MADMAXMAgnetized Disk and Mirror Axion EXperiment

EPJ C 79, 186 (2019) madmax.mpp.mpg.de

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MADMAX Timeline2017 – 2019

Design

EPJ

C 79

, 186

(201

9)

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Magnet

● design and construction of magnet drives time scale of project● peak field ~ 9 T, homogeneity < 20 %● dimensions of bore: length ~ 1 m, diameter ~ 1.5 m

block design with NbTi superconductor

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Magnet

● design and construction of magnet drives time scale of project● peak field ~ 9 T, homogeneity < 20 %● dimensions of bore: length ~ 1 m, diameter ~ 1.5 m

block design with NbTi superconductor

FoM = B2A = 100 T2 m2

has never been done before!

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Disks● requirements: high ε, low loss (tan δ)

→ candidate materials:– LaAlO3 (ε ≈ 24, tan δ ≈ few 10-5)– Sapphire (ε ≈ 9, tan δ ≈ 10-5)

● Ø = 1.25 m needed for 100 T2 m2

→ tiling necessary

● characterisation of dielectric properties @ 4K, f = 10-15 GHz ongoing

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Booster Simulation StudiesStudy achievable boost factor using different simulation methods to optimize design

● 3D effects (diffraction)● coupling to antenna

(beam shape)● dielectric loss● inaccuracies

(positioning, surface roughness, thickness)

● effects due to tiling● ...

→ ~30% loss (combined)

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- idealized 1D model- 3D model with diffraction- 3D power coupled to antenna

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→ small for tan δ < 10-4

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→ tilt < 0.1 mrad thickness ± 5 µm sourface roughness < 10 µm positioning < 10 µm

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→ tilt < 0.1 mrad thickness ± 5 µm sourface roughness < 10 µm positioning < 10 µm

More on the methods: arXiv:1906.02677

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Design2019 – 2022Prototype

first steps:● build an intermediate-scale

prototype of booster to test mechanics, receiver, …

● put it in an existing magnet● do some physics

EPJ

C 79

, 186

(201

9)

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Prototype Sensitivity - ALPs

MADMAXPrototype

Axion-like Particle Search:with less and smaller disks and lower B-field (~ 3T)→ don’t reach QCD axion sensitivitybutexplore new parameter space for ALPs

EPJ

C 79

, 186

(201

9)

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Sensitivity – Hidden Photons

MADMAXPrototype

Hidden photon searchhidden photon mixes with normal photon→ conversion doesn’t require magnetic field

EPJ

C 79

, 186

(201

9)

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Design2019 – 2022Prototype

2022 – 2025Construction

2025 – 2035Data taking

EPJ

C 79

, 186

(201

9)

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Experimental Siteplanned to be built at DESY in HERA Hall North→ use existing cryogenic infrastructure→ option to re-use H1 yoke to shield magnet

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Projected Sensitivity

MADMAX

EPJ

C (2

019)

79:

186

27

CAPP projection

search for dark matter axions with madmax · 2019. 7. 19. · astro-physics helioscopes lsw a d m x...

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