Dark Matter Axion Searches Gray Rybka University of Washington - PowerPoint PPT Presentation

Dark Matter Axion Searches Gray Rybka University of Washington TAUP 2019, Toyama Rybka - TAUP 2019

Why Axions? The Strong CP Problem Lack of neutron electron dipole moment edm<3∙10 -26 e-cm Baker et al. indicates strong force is CP invariant PRL 97 2006 How can the weak force be CP violating but the strong force remains CP invariant? O(10 -10 ) cancellation required The Peccei-Quinn Solution Add a dynamic field, spontaneously broken, which cancels any strong CP violation -Peccei, Quinn This results in a new pseudoscalar particle, the Axion -Weinberg, Wilczek Rybka - TAUP 2019 2/49

The Axion The Axion has the same quantum numbers as, and mixes with, the π 0. This gives a fairly clear picture of how the axion couplings scale with axion mass. a g a gg In the QCD axion particular the axion-photon coupling has very little model dependence. Benchmark models: “KSVZ”: Ad hoc “hadronic” axion couplings. “DFSZ”: Grand unification. “DFSZ” is so compelling that a search needs sensitivity to DFSZ axions in order to be credible. Unfortunately, DFSZ couplings are almost x10 weaker than KSVZ. Rybka - TAUP 2019 3

Axions as Dark Matter As the Universe cools and the temperature falls below the Peccei-Quinn symmetry breaking scale, the axion field begins oscillating about the new minimum. Oscillation about the QCD minimum – Daniel Grin The classical simple assumption that Peccei-Quinn symmetry is broken after inflation yield a range of axions 1-100 ueV that could produce 100% dark matter. A pre-inflationary Peccei-Quinn symmetry breaking combined with anthropic or preferred energy scales can relax this mass constraint. Rybka - TAUP 2019 4

Axion Landscape The classic axion-like particle experiments are: Light Shining Through Walls : Laser photon-axion mixing E.g. old: OSQAR, ALPS future: ALPS-II Helioscopes : Axions from the sun E.g. old: CAST, Sumico future: IAXO Haloscopes : Axion dark matter E.g. old: ADMX, RBF future: ADMX G2 Source: PDG Rybka - TAUP 2019 5

A Wide World of Axion-Like Particles (ALPs) • The classic view of axion production in the early universe suggests QCD axions must be more than micro-eV to accommodate how much dark matter we see • However, recently, there has been a lot of exciting work that permits axions to be much lighter or more strongly coupled • Removing the strong-CP requirement • Anthropic arguments • Preferred energy scales • Ties to inflation • Ties to dark energy • Other new physics • This is a very active field Rybka - TAUP 2019 6

A Wide World of ALP Searches There has been an explosion of search techniques being explored • Black hole superradiance (using LIGO) ~10 -20 eV • Time varying nuclear EDM (e.g. CASPER) 10 -15 -10 -8 eV • Lumped circuit haloscopes (ABRACADABRA, DM Radio) 10 -8 – 10 -6 eV • Ring Resonators, Axion Radar, Atomic Interferometers etc. These are in too early development to have sensitivity to the QCD axion, Potential reach but the community is hopeful DOE Dark Matter BRN Report 2019 Rybka - TAUP 2019 7

The QCD Axion Dark Matter Sweet-Spot Analytic and Lattice predictions for the “classical” QCD (PQWW) axion mass making 100% dark matter when created post-inflation Cavity Frequency (GHz) 1 10 10 -9 Astrophysical bounds *String/Domain Wall 10 -10 contributions can push these Axion Coupling |g a γγ | (GeV -1 ) masses up/down, see T. Other axion experiments: 10 -11 Sekiguchi’s talk RBF, HAYSTAC, ORGAN, etc. 10 -12 10 -13 Ringwald (2018) ADMX Borsanyi (2016) 10 -14 (2018) Bonati (2016) Ballesteros (2016) *See also Klaer (2017) 10 -15 KSVZ Iwazaki arXiv:1810.07270 Berkowitz (2015) di Cortona (2016) For a 7 ueV mass prediction DFSZ 10 -16 Petreczky (2016) ADMX G2 Range 10 -17 1 10 100 Axion Mass µ eV Adapted from G.R, J. Phys. G Rybka - TAUP 2019 8 (2017)

Axion Haloscope for my Intro Physics Class Rybka - TAUP 2019 9

Axion Haloscope for my Intro Physics Class Axion Dark Electromagnetic Cavity Matter Resonance Axion-Photon Coupling Rybka - TAUP 2019 10

Axion Haloscope: How to search for Dark Matter Axions Dark Matter Axions will convert to photons in a magnetic field. The conversion rate is enhanced if the photon’s frequency corresponds to a cavity’s resonant frequency. Sikivie PRL 51:1415 (1983) Signal Proportional to Noise Proportional to Cavity Volume Cavity Blackbody Radiation Magnetic Field Amplifier Noise Cavity Q Rybka - TAUP 2019 11

Power in an Axion Haloscope Resonator Form Dark Matter Resonator Volume Factor Density Quality Power in Magnetic Model Frequency haloscope Field Coupling The better your signal to noise, the faster you can explore axion mass space Make These Large Make These Small Cavity Volume Cavity Blackbody Radiation Magnetic Field Amplifier Noise Cavity Q Rybka - TAUP 2019 12

The Axion Haloscope Amplify B- Field Digitize FFT This axion lineshape Power Spectrum has been exaggerated. A real signal would hide beneath the noise in Photon a single digitization. An axion detection Power Tuning Rod requires a very cold experiment and an ultra low noise Axion to photon receiver-chain. production � E • B Frequency Virtual Photon Unknown axion mass requires a tunable resonator B- Field C. Boutan Rybka - TAUP 2019 13

ADMX “G2” Dark Matter Search Goal: Find Dark Matter Axions Collaborating Institutions: UW, UFL, LLNL FNAL, UCB, PNNL LANL, NRAO, WU, UWA, Sheffield The ADMX collaboration gratefully acknowledges support from the US Dept. of Energy, High Energy Physics DE-SC0011665 & DE-SC0010280 & DE-AC52-07NA27344 Also support from LLNL and PNNL LDRD programs and R&D support the Heising-Simons institute ADMX collaboration meeting, UW, December 2018 Rybka - TAUP 2019 14

ADMX Design Key technologies: -millikelvin cryogenics -ultralow noise quantum amplifiers 15 Rybka - TAUP 2019 15

Scanning Technique The cavity is scanned in few kHz steps with 100 seconds integration ime over the frequency range. The power spectra are filtered for expected axion lineshapes Multiple spectra are combined to reach our sensitivity. Candidate excesses are rescanned. Transient candidates or candidates that do not follow cavity lineshape (RFI) can be Rybka - TAUP 2019 16 vetoed.

ADMX Cryogenics Temperature for example weeks, 2017 vs 2018 We had a significantly lower temperature, and better noise in 2018. Expect even better in 2019 Rybka - TAUP 2019 17

Scan Speed and Noise Temperature Scan speed is proportional to (noise temperature) -2 The limiting factor in our noise temperature is amplifier noise Transistor Amplifiers: 2K SQUID, JPA Quantum Amplifiers: 50 mK Rybka - TAUP 2019 18

Quantum Amplifiers ADMX Tunable MSA Sean O’Kelley, Clarke Group, UC Berkeley ADMX JPA • Enabling Technology! Yanjie Qiu, • Superconducting Interference Device Siddiqi Group, UC Berkeley (SQUID) amplifiers • Josephson Parametric Amplifiers (JPA) Rybka - TAUP 2019 19

Synthetic Axion Signal Injection Axion-shaped RF signal are periodically injected into the cavity, blind to the analysis. Most signals are unblinded at the time of rescan to verify our detection efficiency. Some (like this one) are not unblinded until the decision to ramp the magnet down. Note much more data is required in a rescan than during the initial scan. Rybka - TAUP 2019 20

Preliminary Sensitivity from 2018 Run Dark: Maxwell-Boltzmann Lineshape, Light: N-Body Lineshape We estimate sensitivity to DFSZ dark matter axions between 2.8 and 3.3 ueV This is four times as much mass range with much more even DFSZ coverage. 3 Gaps from mode crossings in cavity. Paper in preparation! Rybka - TAUP 2019 21

Moving to Higher Frequencies Previous experiments Rybka - TAUP 2019 22

Why are higher frequencies more challenging? • Smaller resonator volume decreases signal • Resonator Q worse at high frequencies • Standard quantum limit increases noise How will future Axion Experiments counter these? • More sophisticated, large volume resonators • Sub-quantum limited amplifiers • Bigger magnets • Field tolerant high-Q resonators Rybka - TAUP 2019 23

ADMX G2 – Multicavity Systems Maintain detection volume at higher frequencies Multicavity system 1-2 GHz Prototype fabricated, tested Rybka - TAUP 2019 24

Higher Frequency Proof-of-Principles 10 -10 10 -10 2017 Operations Axion Coupling g A γ (GeV -1 ) -Small-volume ‘sidecar’ demonstrator 10 -11 10 -11 A -Demonstration of higher-frequency technology -Piezoelectric Tuning 10 -12 10 -12 -Higher-order modes 10 -13 10 -13 -Traditional Quantum Amplifiers 17.35 17.35 17.4 17.4 17.45 17.45 17.5 17.5 17.55 17.55 17.6 17.6 Axion Mass m A ( µ eV) -New ALP Exclusion Limits at 17, 22, and 30 ueV -Boutan et al. Phys. Rev. Lett. 121, 261302 B C 2018 Determinations - Found that the 2017 piezo design worked better 20 20 21 21 22 22 23 23 24 24 25 25 29.65 29.65 29.7 29.7 29.75 29.75 29.8 29.8 Axion Mass m A ( µ eV) Axion Mass m A ( µ eV) 2019 Explorations 10 5 10 5 g A γ / g A γ DFSZ 10 4 10 4 10 3 10 3 - Wideband Quantum Amplifiers A B C 10 2 10 2 10 1 10 1 ADMX - Feedback systems 10 0 10 0 5 5 10 10 15 15 20 20 25 25 30 30 35 35 - Sensitivity to new frequency ranges Axion Mass m A ( µ eV) Rybka - TAUP 2019 25