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Encounters with the Axion Encounters with the Axion Pierre Sikivie (U of Florida) University of Miami e-Colloquium October 7, 2020 Supported by US Department of Energy grant DE-SC 00101296 Helen Quinn Roberto Peccei Chiral symmetry breaking in the two flavor quark model (u,d) 4 Nambu-Goldstone bosons S. Weinberg The Problem In Quantum Chromodynamics (QCD) has a Adler-Bell-Jackiw anomaly, and is therefore explicitly broken. Quantum tunneling events, called instantons, produce axial charge for each flavor ‘t Hooft, 1976 θθ = − ..... arg (mutmmd ... ) The Strong CP Problem θθ = − arg (mut mmd ... ) = θ − arg det (YYud ) is expected to be of order one The absence of P and CP violation in the strong interactions requires from upper limit −10 θ ≤ 10 on the neutron electric dipole moment A level pooltable on an inclined floor g UPQ (1) • is a symmetry of the classical action • is spontaneously broken • has a color anomaly Peccei and Quinn, 1977 If a U PQ (1) symmetry is assumed, relaxes to zero, and a light neutral pseudoscalar particle is predicted: the axion. Weinberg, Wilczek 1978 Steven Weinberg Frank Wilczek A self adjusting pooltable g 1 ton Searching for the pooltable oscillation quantum g 1 ton f f a γ γ a gγ = 0.97 in KSVZ model 0.36 in DFSZ model Axions are constrained by • beam dump experiments • rare particle decays • radiative corrections • the evolution of stars J.E. Kim M. Shifman A. Vainshtein V.I. Zakharov M. Dine W. Fischler M. Srednicki A. Zhitnitsky Axion constraints 105 1010 1015 fa (GeV) −5 −10 ma(eV) 1 10 10 laboratory searches stellar evolution A self adjusting pooltable g 1 ton Effective potential V(T, Φ ) V Re Φ Im Φ Tf > a fTa > > 1 GeV 1GeV > T axion strings axion domain walls Axion production by vacuum realignment V V a a T ≥ 1 GeV T ≤ 1 GeV initial misalignment angle J. Preskill, M. Wise & F. Wilczek, L. Abbott & PS, M. Dine & W. Fischler, 1983 Axion constraints 105 1010 1015 fa (GeV) −5 −10 ma(eV) 1 10 10 laboratory cosmology searches stellar evolution Axion Electrodynamics Axion Electrodynamics In background electric and magnetic fields the axion field is a source of electromagnetic radiation γ X Axions convert to photons in a magnetic field and vice-versa γ X BUT We may search for axions produced in the Sun or present on Earth as dark matter • Axion helioscope 1.3 keV • Axion haloscope Axion dark matter is detectable PS '83 a γ X A/D FFT UF Axion Project David Tanner Neil Sulllivan + Chris Hagmann (PhD student) Rochester-Brookhaven-Fermilab Collaboration Adrian Melissinos et al. Yannis Semertzidis (CAPP, Korea) Chris Hagmann and the UF axion detector A new magnet for the cavity experiment Karl van Bibber 8T magnet from Michael Turner Wang NMR, Inc ADMX SQUIDs from Leslie Rosenberg and J. Clarke’s group Gray Rybka at U. Wash. ADMX meeting at Fermilab HAYSTAC at Yale Cavity haloscopes under construction • at INFN laboratory in Legnaro QUAX • at University of Western Australia ORGAN • at CERN RADES • at INFN laboratory in Frascati KLASH Cavity haloscopes under construction • at INFN laboratory in Legnaro QUAX • at University of Western Australia ORGAN • at CERN RADES Constraints on dark matter axions from cavity haloscopes We may search for axions produced in the Sun or present on Earth as dark matter • Axion helioscope 1.3 keV • Axion haloscope Tokyo Helioscope - Sumico Makoto Minowa et al. CERN Axion Solar Telescope Konstantin Zioutas et al. International AXion Observatory Igor Irastorza et al. Axio-Electric and Primakoff Effects e.g. Dimopoulos, Starkman & Lynn, 1986 Frank Avignone constraints from SOLAX, COSME, DAMA, CDMS, EDELWEISS, XMASS, CUORE, CDEX, Xenon, LUX, PandaX Many approaches to axion detection Dielectric haloscopes MADMAX Nuclear Magnetic Resonance CASPEr Axion to magnon conversion QUAX LC circuit ABRACADABRA, SLIC, DMradio Axion echo Shining light through walls (SLW) ... ALPs, OSQAR Long range forces ARIADNE Axel Lindner Stellar evolution constraints white dwarf cooling SLW in astrophysical magnetic fields Marco Roncadelli Axions relate to • particle physics • nuclear physics • astrophysics • cosmology • solid state physics (topological insulators) • atomic physics • statistical mechanics (Bose-Einstein condensation) • ... Axion production by vacuum realignment V V a a T ≥ 1 GeV T ≤ 1 GeV initial misalignment angle Axions produced by vacuum realignment are cold dark matter Cold axion properties • number density • velocity dispersion if decoupled • phase space density Bose-Einstein Condensation if identical bosonic particles are highly condensed in phase space and their total number is conserved and they thermalize then most of them go to the lowest energy available state why do they do that? by yielding their energy to the non-condensed particles, the total entropy is increased. preBEC BEC Axion field dynamics O. Erken, From self-interactions PS, H. Tam & Q. Yang 2012 From gravitational self-interactions Thermalization occurs due to gravitational interactions PS + Q. Yang, PRL 103 (2009) 111301 with lm= ( δ v)-1 q Gm2 q2 at time t1 −1 Γg ()/t H () t ∝ tat () ∝ at() Tidal torque theory neighboring protogalaxy Stromberg 1934; Hoyle 1947; Peebles 1969, 1971 Tidal torque theory with ordinary CDM neighboring protogalaxy the velocity field remains irrotational Tidal torque theory with axion BEC net overall rotation is obtained because, in the lowest energy state, all axions fall with the same angular momentum Galactic halos live in phase space ordinary fluid d(r;t) v(r;t) dark matter (collisionless) fluid f (r,v;t) DM forms caustics in the non-linear regime . x x DM particles in phase space x x ρ ρ x x A shell of . particles, part of . a continuous flow. The shell has net oreall rotation. As the shell falls in and out of the galaxy, it turns itself inside out. Sphere turning inside out simulations by Arvind Natarajan in case of net overall rotation The caustic ring cross-section D-4 an elliptic umbilic catastrophe Tidal torque theory with ordinary CDM neighboring protogalaxy the velocity field remains irrotational For collisionless particles If initially, then for ever after. in case of irrotational flow On the basis of the self-similar infall model (Filmore and Goldreich, Bertschinger) with angular momentum (Tkachev, Wang + PS), the caustic rings were predicted to be in the galactic plane with radii (n =1,2,3...) 40kpc vrot jmax an = n 220km/s 0.18 jmax ≅ 0.18 was expected for the Milky Way halo from the effect of angular momentum on the inner rotation curve. Galactic rotation curves r galactic mass GM () r v()2 r = r rotation speed Effect of a caustic ring of dark matter upon the galactic rotation curve Rotation curve of Andromeda Galaxy from L. Chemin, C. Carignan & T. Foster, arXiv: 0909.3846 10.3 15.4 29.2 kpc 10 arcmin = 2.2 kpc Inner Galactic rotation curve Inner Galactic rotation curve from Massachusetts-Stony Brook North Galactic Pane CO Survey (Clemens, 1985) IRAS 12 µm (l , b) = (80oo , 0 ) 10oo× 10 IRAS 12 µm (l , b) = (80oo , 0 ) 10oo× 10 IRAS 25 µm (l , b) = (80oo , 0 ) 10oo× 10 GAIA sky map (2016) S. Chakrabarty, Y. Han, A. Gonzalez & PS, 2007.10509 Conclusions • Axions solve the strong CP problem • A population of cold axions is naturally produced in the early universe which may be the dark matter today • Axion dark matter is detectable.
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