Shin-Shan Eiko Yu

Department of Physics & Center for High Energy and High Field Physics, National Central University

On behalf of the TASEH Collaboration

Taiwan Axion Search Experiment with Haloscope

Shin-Shan Eiko Yu 2

We Know Very Little about Dark Matter

Dark Energy 68.3%

Ordinary Matter 4.9%

Dark Matter 26.8%

• Evidence of dark matter well established from astrophysical observations

• CMB power spectrum, rotation curves, gravitational lensing

• No evidence so far from laboratory experiments

• Local DM density ~ 0.45 GeV/cm3Matter/Energy Today

1 GeV~1 TeV

Collider Reach22

Shin-Shan Eiko Yu

• Axion was proposed to solve the strong CP problem

• A pseudo-scalar particle (spin 0 with parity -1), low mass (10-12~10-2 eV)

• Could be produced with large quantity in the early universe

• Axion is a good dark matter candidate

• Stable, weakly interacting, and cold

• Axion could be detected via its two-photon coupling

3

Dark Matter and Axion

Static B field

RF photon

Laγγ = −gaγγφa E!"i B!"

Two free parameters: ma, gaγγ

For QCD axion models, these two parameters are related

Shin-Shan Eiko Yu 4

Current Status of Axion Searches

TASEH aims for ma~20 µeV with Δm=4 µeV

(fa = 5 GHz with 1 GHz span)

Shin-Shan Eiko Yu

• HAYSTAC

• ma=16.96-17.28 and 23.15-24 µeV

• Best limit at 1.38 x KSVZ model for 16.96-17.28 µeV

5

CAPP and HAYSTAC Results

• CAPP

• ma=6.62-6.82, 10.16-11.37, 13.0-13.9 µeV

• Best limit at 10.7126-10.7186 µeV

Shin-Shan Eiko Yu

• Academia Sinica: Prof. Yuan-Hann Chang, Hien Doan

• Ming Chi University of Technology/National Synchrotron Radiation Research Center: Prof. Wei-Yuan James Chiang, Yi-Chieh Chang

• National Central University: Prof. Yung-Fu Chen, Prof. Shin-Shan Eiko Yu, Hsin Chang, Ching-Fang Chen, Guan-Yu Chen, Wei-Cheng Hong, Chun-Chung Lu, Min-Wei OuYang, Ping-I Wu, Jing-Yang Zhang

• National Chung Hsing University: Prof. Watson Kuo, Wei-Chen Chien, Yu-Han Chang

6

Team Members

Shin-Shan YuYuan-Hann Chang Wei-Yuan ChiangYung-Fu Chen Watson Kuo

17 Members

Shin-Shan Eiko Yu

• A strong magnetic field (B) and a high-Q cavity (E) to convert axions to photons

• Large volume of cavity to enhance the conversion probability

• Low-temperature environment to reduce the background thermal photon

• Small signal power→ low-noise quantum-limited amplifier

• 5 GHz single photon = 0.2 K

7

Basic Experimental Setup

sensitivity on gaγγ ∝ BVQTsys

Shin-Shan Eiko Yu

• Initial runs with existing magnet (8 Tesla, 3-inch bore) from Prof. Yung-Fu Chen’s lab

• Plan to procure a commercial system (likely 9 Tesla with 15-cm bore), providing ~ 5x better sensitivity

8

Our Cryogenic System

mixing chamber plate

Shin-Shan Eiko Yu

• Pre-studies with HFSS

• Fabricated a single-frequency and a tunable cavity. Tested in the room temperature

• Initial measurement of Q was a factor of 3 lower, due to discontinuous/non-clean surface and mode crossing

• Reducing the height, polishing, silver plating, brazing, chemical cleaning + H firing, additional 9 cavities are produced for testing

• Investigating multi-cell cavities so to enhance effective volume

9

Current Status: Cavity

Periodic cavity

50 m

m

25 mm

Tunable-frequency cavity

Qtheory~8800-126004.750-5.876 GHz

46 m

m

46.48 mm

Single-frequency cavityQtheory~16309

V~0.078 L

V~0.048 L

Shin-Shan Eiko Yu

• For initial runs, the first-stage amplifier will be two high-electron-mobility transistors (HEMT) (Tsys~2 K, frequency span 4-8 GHz)

• Measurement of noise temperature done with initial setup

10

Current Status: Near-Term Readout

HEMT

Thermometer to measure Tp

Resister R0 Heater to control Tp

GTs = GTp +GTn

Shin-Shan Eiko Yu

• Development, fabrication, and test of Josephson Parametric Amplifier (JPA) (Tsys~0.2 K, frequency span 1.8 MHz) ongoing

• Collaborating with Prof. Chii-Dong Chen from Academia Sinica

• V1 (coplanar wave guide resonator) and V2 (LC tank resonator)

• Two V1 chips are in DRs and will be tested

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Current Status: Long-Term Readout

JPA v1

Packaging/Assembly�

SQUID�

JosephsonJunction�

Deviceoverview�

CouplingCapacitor�

Shin-Shan Eiko Yu

• Benchmark QCD axion model: KSVZ

• For ma=20 µeV, gaγγ=7.4×10-15 GeV-1

• Assuming 1 month of data taking and scan 1.1 GHz frequency range, Tsys=2 K, Q=10000, we may reach gaγγ=2.6×10-13 GeV-1 at 95% CL

12

Near-Term Reach of Sensitivity

TASEH

Shin-Shan Eiko Yu

• Benchmark QCD axion model: KSVZ

• For ma=20 µeV, gaγγ=7.4×10-15 GeV-1

• Assuming 1 month of data taking and scan 1.1 GHz frequency range, Tsys=2 K, Q=10000, we may reach gaγγ=2.6×10-13 GeV-1 at 95% CL

12

Near-Term Reach of Sensitivity

CA

CAPP

TASEH

Shin-Shan Eiko Yu

• We are looking for axion with a mass of ~20 µeV using a haloscope.

• We have formed a team with diversified expertise in particle physics, RF cavity, and low-temperature solid state physics.

• With future improvements, we may constrain the QCD gaγγ

• Use of JPAs as the first-stage amplifiers → Tsys = 0.2 K (x3)

• Upgrade of the cryogenic system and the magnet → 9 Tesla (x1.125)

• Explore cavity ideas to increase effective volume and Q → (x10)

13

Conclusion and Outlook

W-Meander by Prof. Chao-Lin Kuo arXiv: 2010.04337

Backup Slides

14

Shin-Shan Eiko Yu 15

Basic Formulas

Psig = gγ

2 α 2

π 2

!3c3ρaΛ4

⎛

⎝⎜⎞

⎠⎟× β

1+ βω c

1µ0

B02VCmnlQL

⎛

⎝⎜⎞

⎠⎟

Λ = 78 MeVρa = 0.45 GeV cm3

gaγγ =gγαπΛ2

⎛

⎝⎜

⎞

⎠⎟ ma

QL =Q0

1+ β

σ N = kBTsbt

16

Shin-Shan Eiko Yu

• Benchmark QCD axion model: KSVZ

• For ma=20 µeV, gaγγ=7.4×10-15 GeV-1

• Assuming 1 month of data taking and scan 1.1 GHz frequency range, Tsys=0.2 K, Q=50000, we may reach gaγγ=7.1×10-15 GeV-1 at 95% CL

17

Comparison with CAPP

QL

Shin-Shan Eiko Yu

• Benchmark QCD axion model: KSVZ

• For ma=20 µeV, gaγγ=7.4×10-15 GeV-1

• Assuming 1 month of data taking and scan 1.1 GHz frequency range, Tsys=0.2 K, Q=50000, we may reach gaγγ=7.1×10-15 GeV-1 at 95% CL

18

Comparison with CAPP

Shin-Shan Eiko Yu

• Benchmark QCD axion model: KSVZ

• For ma=20 µeV, gaγγ=7.4×10-15 GeV-1

• Assuming 1 month of data taking and scan 1.1 GHz frequency range, Tsys=0.2 K, Q=50000, we may reach gaγγ=7.1×10-15 GeV-1 at 95% CL

19

Comparison with HAYSTAC

4.1-4.178

2 JPAs

1.5 47000 (Q0)

HAYSTAC 2020

20 arXiv:1707.04591

Shin-Shan Eiko Yu

• Proposed to solve the strong CP problem —- Why is CP conserved in the strong interaction?

• the lack of neutron electric dipole moment: PRL 97, 131801 (2006)

• The Peccei-Quinn Solution

• Add a dynamic field, spontaneous broken and cancels any strong CP violation, resulting in a new pseudo-scalar particle, the Axion

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QCD Axion

dn < 2.9 ×10−26e cm (90% C.L.)

Original CP-violating term in the QCD

Lagrangian

φA : axion field,fA : axion decay constant

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Readout Chain

Shin-Shan Eiko Yu 23

JPA v1

JPA v1 (coplanar waveguide resonator)

Shin-Shan Eiko Yu 24

JPA v2

Lump Element JPA layout�

JPA v2 (LC tank resonator)

Shin-Shan Eiko Yu 25

Additional Cavities for Testing