How to detect dark matter? Part 2 MARIANNA MARIANNA MARIANNA - PowerPoint PPT Presentation

How to detect dark matter? Part 2 MARIANNA MARIANNA MARIANNA MARIANNA SAFRONOV SAFRONOV SAFRONOV SAFRONOV A A A A June 2019, Ameland Netherlands Summer school Search for new physics with low-energy precision tests

How to detect ultralight dark matter? 22 eV 10 12 eV 10 10 10 - 10 eV 10 - eV 10 eV 10 eV eV µ eV µ eV eV eV eV eV GeV eV GeV eV GeV eV GeV -22 - - 22 22 - - -12 12 12 µ µ Ultralight dark matter has to be bosonic – Fermi velocity for DM with mass >10 eV is higher than our Galaxy escape velocity. Bosonic dark matter (DM) with mass m φ < 1eV λ − 3 λ Dark matter density in our Galaxy > where is the dB dB de Broglie wavelength of the particle. Then, the dark matter exhibits coherence and behaves like a classical field.

Effects of ultralight DM on standard model particles Such DM classical field can:  Cause precession of nuclear and electron spins  Drive currents in electromagnetic systems  Induce equivalence principle-violating accelerations of matter  Modulate the values of the fundamental constants of nature, inducing changes in atomic transition frequencies and local gravitational field. 2   ≈ v − 6   10 Signal is line at frequency = DM mass and width 10 -6   c

Interactions of bosonic ultralight dark matter DM: SM: are M. S. Safronova, D. Budker, D. DeMille, Derek F. Jackson-Kimball, A. Derevianko, and Charles W. Clark, Rev. Mod. Phys. 90, 025008 (2018).

Current experimental efforts in searches for bosonic ultralight dark matter Spin 0 S HAYSTAC 0 PS 1 V 1 AV M. S. Safronova, D. Budker, D. DeMille, Derek F. Jackson-Kimball, A. Derevianko, and Charles W. Clark, Rev. Mod. Phys. 90, 025008 (2018).

Slide from: Karl van Bibber, S = 0 The Axion GPMFC workshop pseudoscalar θ (think) T T CP

The Primakoff Effect P. Sikivie, Phys. Rev. Lett. 51 (1983) 1415 Magnet γ a γ∗ ≡ B ∴ Primakoff Effect Classical EM field Sea of virtual photons the Slide from: Karl van Bibber, GPMFC workshop

The microwave cavity axion search -Your car radio on steroids For e.g., m a = 10 µ eV : ρ a ~ 10 14 cm –3 FFT λ DeB ~ 100 m Preamplifier Magnet Cavity Local Oscillator γ a Power ∆ f / f ~ 10 –6 γ ∗ × Frequency f = m a c 2 / h Slide from: Karl van Bibber, GPMFC workshop

Slide from: Karl van Bibber, GPMFC workshop How to go higher & lower in frequency (mass) Size & geometry of the cavity determines the frequency of the microwave cavity experiment Natural scale is cavities of diameter 50 – 5 cm ~ 0.5 GHz – 5 GHz, or 2 – 20 µ eV mass To go lower in frequency, a lumped-parameter LC circuit allows one to decouple the dimension of the cavity from the frequency LC, DM Radio To go higher in frequency, an open (Fabry-Perot) resonator is much more natural than cavities ORPHEUS, MADMAX

Slide from Peter Graham

Slide from Peter Graham

DARK MATTER SEARCHES WITH ATOMIC CLOCKS

How do fundamental constants vary? Slow drifts Stochastic Transient Dark energy? variations Oscillations Topological dark matter Dilaton dark matter or axion-like particles A. Derevianko, Conf. Ser. 723 (2016) 012043

Ultralight dark matter Dark matter coupling to the Standard Model photons gluons Dark matter quarks electrons Measure: couplings d i vs. DM mass A. Arvanitaki et al., PRD 91, 015015 (2015)

Ultralight dark matter searches with clocks Comparing frequencies of hyperfine to optical clocks Dark matter Comparing frequencies of optical to optical clocks   2 α 2 q   Enhancement = + − = K E E q 1 0 2 E  α  factor 0 0

Measuring ratios of optical clock frequencies for dark matter detection Need: • Best short-term stability σ σ 1 at ∆τ ∆τ σ σ ∆τ ∆τ • Long total measurement time to improve sensitivity But: only until you reach the DM coherence time • Lowest systematic uncertainty • Largest possible enhancement factor combination (K 2 -K 1 )

Ultralight dark matter DM virial velocities ~ 300 km/s Dark matter parameters One oscillation per second One oscillation per 11 days

Clock measurement protocols for the dark matter detection Single clock ratio measurement: averaging over time τ 1 Make N such measurements, preferably regularly spaced τ int ∆τ Detection signal: A peak with monochromatic frequency in the discrete Fourier transform of this time series. A. Arvanitaki et al., PRD 91, 015015 (2015)

Clock measurement protocols for the dark matter detection Single clock ratio measurement: averaging over time τ 1 Make N such measurements, preferably regularly spaced Al least one dark matter oscillation during this time τ int ∆τ No more than one dark matter oscillation during this time or use extra pulse sequence Detection signal: A peak with monochromatic frequency in the discrete Fourier transform of this time series. A. Arvanitaki et al., PRD 91, 015015 (2015)

Experimental results Dy: K. Van Tilburg, N. Leefer, L. Bougas, and D. Budker, Phys. Rev. Lett. 115, 011802 (2015). Rb/Cs: A. Hees, J. Guéna, M. Abgrall, S.Bize,and P. Wolf, Phys. Rev. Lett. 117, 061301 (2016)

From PRL 120, 141101 (2018)

? From PRL 120, 141101 (2018)

Projected clock limits A. Arvanitaki et al., PRD 91, 015015 (2015)

Sr optical clock vs. silicon cavity project limits

Transient variations Dark matter clumps: point-like monopoles, one-dimensional strings or two-dimensional sheets (domain walls). If they are large (size of the Earth) and frequent enough they may be detected by measuring changes in the synchronicity of a global network of atomic clocks, such as the Global Positioning System. GPM.DM collaboration: Roberts at el., Nature Communications 8, 1195 (2017)

Global sensor network. The participating Sr and Yb optical lattice atomic clocks reside at NIST, Boulder, CO, USA, at LNE-SYRTE, Paris, France, at KL FAMO, Torun, Poland, and at NICT, Tokyo, Japan Wcisło et al., Sci. Adv. 4: eaau4869 (2018)

Wcisło et al., Sci. Adv. 4 (2018) Constraints on the coupling of dark matter to electromagnetism. The energy scale Λ which inversely parametrizes the strength of the DM-SM coupling as a function of the wall width d.

How to improve laboratory searches for the variation of fundamental constants & dark matter? 1. Improve uncertainties of current clocks – [????] more orders. 2. Improve stabilities of the clock ratio measurements (particularly with trapped ion clocks). Clock sensitivity to all types of the searches for the variation of fundamental constants, including dark matter searches require as large enhancement factors K to maximize the signal. 3. Build new clocks based on different systems a. Highly-charged ions b. Nuclear clock c. New Yb two-transition clock scheme d. Molecular clocks

The Future Advances in Atomic Clocks Ion chains Large ion crystals 3D optical lattice clocks Measurements beyond the quantum limit Entangled clocks Orders of magnitude improvements with current clocks Image credits: NIST, Innsbruck group, MIT Vuletic group, Ye JILA group

The Future: New Atomic Clocks Science 347, 1233 (2015) Clocks with ultracold highly charged ions Nuclear clock First demonstration of quantum logic spectroscopy at PTB, Germany

Nuclear clock Only 7.8eV energy of a nuclear transition (laser-accessible) ! Existence of this isomer 229m Th state was confirmed: Wense et al., Nature 533, 4751 (2016) Laser spectroscopic characterization of the 229m Th nuclear clock isomer 229m Th (measured isomer nuclear radius and quadrupole Nuclear transition moment): Thielking et al ., Nature 556, 321(2018) 160(10) nm Science 347, 1233 (2015) Lifetime ~ 5000s Nuclear charge radii of 229 Th from isotope and isomer shifts: Safronova et al ., Phys. Rev. 229 Th Lett. 121, 213001 (2018).

Th nuclear clock 229m Th Large (MeV) Coulomb energy difference Nuclear transition 160(10) nm compensated by MeV difference in the Lifetime ~ 5000s nuclear binding energy? 229 Th Then, possible 4-5 orders of magnitude enhancement to m q the variation of α and but orders of magnitude Λ QCD uncertainty in the enhancement factors. Provides access to couplings of Standard Model particles to dark matter via other terms besides the d e (E&M). It is crucial to establish actual enhancement!

M. G. Kozlov, M. S. Safronova, J. R. Crespo López-Urrutia, P. O. Schmidt, Rev. Mod. Phys. 90, 45005 (2018).

A recent explosion of new proposals for dark matter searches at all masses! Great potential for AMO dark matter searches. Many new developments coming in the next 10 years! NEW IDEAS?