search for axion-like dark matter

Using cryogenic Penning trap LC detection circuits to search for axion-like dark matter

Jack Devlin (CERN, RIKEN)

17th International Conference on Topics in Astroparticle and Underground Physics (TAUP 2021) 31/08/2021

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Outline

1. An introduction to BASE and cryogenic Penning traps 2. Detecting axion-like particles (ALPs) at BASE

3. Future perspectives

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1. An introduction to BASE and cryogenic Penning traps 2. Detecting axion-like particles (ALPs) at BASE

3. Future perspectives

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Outline

C. Smorra et al., EPJ-Special Topics, The BASE Experiment, (2015)

The BASE collaboration

The entire CERN accelerator complex

The Meyrin site

The Antimatter Factory

3. CERN: Antiproton measurements

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10 Institutions, 3 Penning trap experiments:

1. Mainz: Proton measurements, laser cooling

2. Hannover/PTB: Laser cooling and quantum logic applied to protons

https://www.quantummetrology.de/equopt/research/quantum-logic- spectroscopy-of-anti-protons/

DOI: 10.21203/rs.3.rs-351267/v1

What does BASE-CERN normally do

A. Mooser et al., Nature 509, 596 (2014). S. Ulmer, et al., Nature524, 196 (2015) C. Smorra et al., Nature 550, 371 (2017) G. Schneider et al., Science 358, 1081 (2017)

BASE tests CPT symmetry by comparing the properties of protons and antiprotons

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Proton-to-antiproton g-factor

compared at 10

level with Larmor frequency measurements

Proton-to-antiproton charge to

mass ratio (q/m) compared at 10

level with cyclotron frequency

measurements

The BASE Penning trap

1.95 T B field from solenoid

Voltages applied to ring-shaped electrodes

Modified cyclotron 𝜈₊ = 28.9MHz

Magnetron 𝜈₋ = 6.5kHz

Axial

𝜈_𝑧 = 674kHz

Φ 0, 𝑧 𝐵_𝑒

Φ 𝜌, 𝑧 = 𝑉₀𝐶₂(𝑧² − 𝜌² 2 ) A Penning trap

Orbit is sum of three normal modes 𝜈_𝑧² + 𝜈₊² + 𝜈₋² = 𝜈_𝑐 = 𝑞

2𝜋𝑚𝐵_𝑒

Measure frequencies and get access to

charge-to-mass ratio and magnetic field

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The BASE frequency detectors

Measurement of ~1 fA image currents induced in trap electrodes

Resolving single antiproton spin flips requires high Q and low temperature LC resonant detectors

H. Nagahama et al., Rev. Sci. Instrum. 87, 113305 (2016).

I

V 𝐵_𝑒

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ℱ{𝑉(𝑡)}(dBV)

To room temp.

amps

Interesting ingredients for axion detection

Strong magnetic fields

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High-Q LC circuits

These can be used to detect axion-like dark matter!

Particle-detector interactions

Q=240,000

B_e I

1. An introduction to BASE and cryogenic Penning traps 2. Detecting axion-like particles (ALPs) at BASE

3. Future perspectives

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Outline

ALP-photon coupling

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ℒint = −𝑔_𝑎𝛾

4 𝑎𝐹_𝜇𝜈𝐹෨^𝜇𝜈 With ALP-photon coupling

Dark matter axion-like particles are (light) pseudoscalar bosons

J. A. Devlin et al., Phys. Rev. Lett. 126, 041301 (2021) and refs. therein C. P Salemi et al., Phys. Rev. Lett. 127, 081801 (2021)

Inside a conducting housing with 𝑑 ≪ 𝜆_𝑎, and where there is a strong field 𝐵_𝑒, the axions source a magnetic field

𝐵_𝑎 = 1

2𝑟𝑔_𝑎𝛾 𝐵_𝑒 𝜌_𝑎ℏ𝑐

𝑑

Pick up 𝐵 𝑎 with a

toroidal coil

Expected ALP signal

The resonator background The axion signal

𝐵_𝑎

𝑉rms = 𝑉𝑛2+ 𝑉_𝑎²

How to measure 𝑻 𝒛 ?

J. A. Devlin et al., Phys. Rev. Lett. 126, 041301 (2021).

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A “Boltzmann” thermometer

Trapped antiproton’s axial motion reaches thermal equilibrium with the detector-can use it as a “quantum” sensor B_e

1.

ℎ𝜐_𝑧

ℎ𝜐₋

axial

magnetron

2.

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Knowing strength of

inhomogeneity, can determine 𝑇_𝑧

3.

Magnetic inhomogneity alters trapping strength ∝ 𝜇

axial frequency shift∝ 𝜇 ∝ 𝑛₋

𝐵 = 𝐵₀ + 𝐵₂(𝑧²−𝜌²/2)

Limits

𝑔_𝑎𝛾 < 10⁻¹¹ GeV⁻¹

We use maximum likelihood estimation to estimate 𝑔_𝑎𝛾, and then decide if we have a discovery, or set limits

J. A. Devlin et al., Phys. Rev. Lett. 126, 041301 (2021); J. W. Foster et al. Phys. Rev. D 97 (2018).

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1. An introduction to BASE and cryogenic Penning traps 2. Detecting axion-like particles (ALPs) at BASE

3. Future perspectives

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Outline

Next step: frequency tuning

Cryogenic adjustable capacitance with compatible with high-Q already developed

Frederik Volksen

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Already could cover one

frequency octave

Dedicated axion detection insert

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Custom axion antenna insert for BASE magnet, purpose built to search for Axion- like particles.

At 3 detectors, each at a different frequency

3 different tunable capacitors

𝑒_𝑛

𝜅 = 2.4 nV/ Hz, 5 T, 1 year acquisition

High- frequency detector at 50-200 MHz, performance currently being evaluated

Device under construction at the moment

Thank you!

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Institutes:RIKEN, MPIK, CERN, University of Mainz, Tokyo University, GSI Darmstadt, University of Hannover, PTB Braunschweig

The BASE-CERN team