Small Scale experiments for fundamental physics

Transcription

1 Small Scale experiments for fundamental physics ICTP Summer School on Particle Physics, June Part 4 A. Geraci, University of Nevada, Reno

2 Syllabus Introduction New (scalar) forces Gravitational Waves and Ultralight Dark Matter New (spin-dependent) forces (relation to axions, EDMS, Cosmic DM experiments)

3 Outline for Lectures Lecture 3 New (spin-dependent) forces Background Torsion balance tests Magnetometry New techniques: (ARIADNE) Relation to axions, EDM experiments, Cosmic DM experiments

4 Axions Light pseudoscalar particles in many theories Beyond Standard model Peccei-Quinn Axion (QCD) solves strong CP problem θ <10 10 QCD Dark matter candidate Experiments: e.g. ADMX, CAST, LC circuit, Casper Also mediates spin-dependent forces between matter objects at short range (down to 30 µm) Can be sourced locally R. D. Peccei and H. R. Quinn, Phys. Rev. Lett. 38, 1440 (1977); S. Weinberg, Phys. Rev. Lett. 40, 223 (1978); F. Wilczek, Phys. Rev. Lett. 40, 279 (1978). J. E. Moody and F. Wilczek, Phys. Rev. D 30, 130 (1984).

5 Axion-exchange between nucleons Scalar coupling θ QCD Pseudoscalar coupling Axion acts a force mediator between nucleons N N ( g N s ) 2 g N s g N P ( g N p ) 2 Monopole-monopole Monopole-dipole dipole-dipole

6 Spin-dependent forces Monopole-Dipole axion exchange ˆ) ˆ ( ) ( / 2 2 r e r r m g g r U a r a f N p N s + = σ λ π λ m f σ r B eff µ Fictitious magnetic field

7 Spin-dependent forces- torsion balance Lab-fixed, Solar source CP violation test With polarized electrons Axion-like particle (ALP) search: B. R. Heckel, E. G. Adelberger, C. E. Cramer, T. S. Cook, S. Schlamminger, and U. Schmidt Phys. Rev. D 78, (2008) S. A. Hoedl, F. Fleischer, E. G. Adelberger, and B. R. Heckel Phys. Rev. Lett. 106, (2011).

8 Noble gas alkali-metal co-magnetometer B Rb Rb Polarize Rb Interactions with electrons 3 He Polarize 3 with He cause 3 He Rb laser by tilt spin-exchange Magnetic field tilt cancels 3 He He Best operating frequency 3 He resonance Search for spin-dependent forces Neutron non-magnetic spin-spin force Spin-mass CP-odd force polarized 3 He spins, direction reversed every 3 sec by NMR Sensitivity (1σ) = 18 phz = GeV Smallest frequency shift ever measured G. Vasilakis, J. M. Brown, T. W. Kornack, MVR, Phys. Rev. Lett. 103, (2009) Slide from : Michael Romalis 2 gsg U ( r) = 8π m Astrophysical gravitational limits (G. Raffelt) e 2 r a r λ Current experiment expected sensitivity f p r / λa ( ˆ σ rˆ) Existing experiments

9 The Axion Resonant InterAction Detection Experiment (ARIADNE) A. Arvanitaki and AG., Phys. Rev. Lett. 113, (2014). Mark Cunningham (UNR) Mindy Harkness (UNR) Jordan Dargert (UNR) Chloe Lohmeyer (UNR) Asimina Arvanitaki (Perimeter) Aharon Kapitulnik (Stanford) Eli Levenson-Falk (Stanford) Sam Mumford (Stanford) Josh Long (IU) Chen-Yu Liu (IU) Mike Snow (IU) Erick Smith (IU) Justin Shortino (IU) Mofan Zhang (IU) Andrew Rusch (IU) Yannis Semertzidis (CAPP) Yun Shin (CAPP) Yong-Ho Lee (KRISS)

10 QCD Axion parameter space DM Radio LC Circuit ABRACADABRA ARIADNE QUAX Orpheus MADMAX Adapted from

11 Axion Parameter space CASPEr DM Radio LC Circuit ABRA- CADABRA ARIADNE Adapted from Graham, arxiv:

12 Axion and ALP searches Source Coupling Dark Matter (Cosmic) axions Solar axions Photons ADMX, ADMX-HF DM Radio, ABRA- CADABRA, LC Circuit, MADMAX CAST IAXO Nucleons CASPEr-Electric CASPEr-Wind Lab-produced axions Light-shining-thruwalls (ALPS, ALPS-II) ARIADNE

13 Axion-exchange between nucleons Scalar coupling θ QCD Pseudoscalar coupling Axion acts a force mediator between nucleons N N ( g N s ) 2 g N s g N P ( g N p ) 2 Monopole-monopole Monopole-dipole dipole-dipole

14 Spin-dependent forces Monopole-Dipole axion exchange ˆ) ˆ ( ) ( / 2 2 r e r r m g g r U a r a f N p N s + = σ λ π λ m f σ r B eff µ Different than ordinary B field Does not couple to angular momentum Unaffected by magnetic shielding Fictitious magnetic field

15 Using NMR for detection m f r σ Spin ½ 3 He Nucleus B eff U = µ B ext Bloch Equations dm dt = γm B 2 B ω = µ N ext Spin precesses at nuclear spin Larmor frequency Axion B eff modifies measured Larmor frequency ω = γb

16 Constraints on spin dependent forces G. Raffelt, Phys. Rev. D 86, (2012). Magnetometry experiments G. Vasilakis, et. al, Phys. Rev. Lett. 103, (2009). K. Tullney,et. al. Phys. Rev. Lett. 111, (2013) P.-H. Chu,et. al., Phys. Rev. D 87, (R) (2013). M. Bulatowicz,et. al., Phys. Rev. Lett. 111, (2013). nedm bound θ QCD <10 10 Standard Model lower bound 16 θ >10 QCD

17 ARIADNE: uses resonant enhancement Spin ½ 3 He Nucleus Oscillate the mass at Larmor frequency B ext B eff = B cos( ωt) B eff U = µ B ext Bloch Equations dm dt = γm B 2 B ω = µ N ext Time varying Axion B eff drives spin precession produces transverse magnetization Amplitude is resonantly enhanced by Q factor ~ ωt 2. Can be detected with a SQUID

18 Concept for ARIADNE Unpolarized (tungsten) segmented cylinder sources B eff Applied Bias field B ext 2 B ω = µ N ext Laser Polarized 3 He gas senses B eff (Indiana U) squid pickup loop Y.-H. Lee (KRISS) Limit: Transverse spin projection noise Superconducting shielding (Stanford) A. Arvanitaki and A. Geraci, Phys. Rev. Lett. 113, (2014).

19 Hyperpolarized 3 He Ordinary magnetic fields cannot be used to reach near unity polarization exp[ µ N B / k B T ] Optical pumping techniques Indiana U. MEOP apparatus Metastability exchange optical pumping M Batz, P-J Nacher and G Tastevin, Journal of Physics: Conference Series 294 (2011) Rev. Sci. Instrum. 76, (2005)

20 Experimental parameters Rotational stage 3 sample chambers source mass 4 mm 11 segments 100 Hz nuclear spin precession frequency 2 x / cc 3 He density 10 mm x 3 mm x 150 µm volume Separation 200 µm Tungsten source mass (high nucleon density)

21 Sensitivity θ QCD >10 16 θ QCD <10 10 A. Arvanitaki and AG., Phys. Rev. Lett. 113, (2014).

22 Complementarity with nedm experiments Improved nedm measurement reduces thickness of this axion band, Disovery turns it into a line. Still need to measure the mass! θ QCD >10 16 θ QCD <10 10

23 Experimental challenges Magnetic gradients Nonlinearities Barnett Effect Trapped magnetic flux Vibration isolation Magnetic noise from thermal currents Design/Simulation Work: Magnetic gradient reduction strategy Experimental testing in progress: Vibration tests, Shielding factor f test thin-film SC

24 Superconducting Magnetic Shielding Essential to avoid Johnson noise Meissner Effect No magnetic flux across superconducting boundary Method of Images Make image currents mirrored across the superconducting boundary T > T Dipole with image 24 c T < T c

25 The Problem of Unwanted Images mm ARIADNE uses magnetized spheroid Constant interior field 3He 3He 3He BB BB iiii = const. BB iiii mm ii Magnetic shielding introduces image spheroid Interior field varies mm mm 3He BB iiii const. BB iiii mm ii variations in nuclear Larmor frequency! 3He 3He BB But want to drive entire sample on resonance 25

26 Flattening Solution 1 coil simple configuration Expected field from spheroid ~1 μt I on the A range Spheroid 1 coil (circular) Symmetry 26

27 Gradient Cancellation No cancellation Gradient cancellation 98 times flatter I = 1.6 A s Frac = 0.17% Sample area enabling T 2 of ~100 s 27

28 Tuning Solution D Coils Tune field with Helmholtz coils Helmholtz field only flat near the center Geometry restrictions prevent the spheroid from being centered in traditional Helmholtz coils D coils look like Helmholtz coils when their images are included I Spheroid D coils Inner straight-line currents cancel Outer currents do not One D coil and image (bird s eye view) 28

29 Rotary stage vibration and tilt Rotary test chamber Build an interferometer to measure the change in distance (d). We can find theta (Ө) from: Ө= cos -1 ((L-d)/L) Interferometers We can solve for the wobble distance (X) by: X= Lsin(Ө)

30 Fiber-coupled laser interferometers Laser Source 90:10 fiber coupler Reference Photodiode Signal Photodiode Fiber Tip Reflector PZT Fringe visibility ~0.13 Sensitivity ~160 nm/v Shot noise limit ~20 pm/hz 1/2

31 Speed stability test - direct drive stage Optical encoder Current feedback control VelCmd (THETA) (deg/msec) Stage speed stability error unloaded, in air VelCmd (THETA) (deg/msec) VelFbk (THETA) (deg/msec) VelErr (THETA) (deg/msec) VelErr (THETA) (deg/msec) Time (sec) Rotation speed control 8.3 Hz ~ 1 part in RMS ~ 1 part in 3000 Allows utilization of T2 > 100s Phase Amplitude E-3 1E-4 1E-5 1E-6 1E-7 1E-8 1E-9 1E-10 1E Frequency Frequency

32 SQUID Magnetometers 1 cm Y.H. Lee, KRISS 1000 Field noise (ft rms / Hz) Frequency (Hz) 4.5 ft rms / Hz Measured inside a magnetically shielded room (without Nb tube)

33 Preliminary test of superconductive shielding L-He dewar Y.H. Lee, KRISS, Yun Shin (CAPP) Eli Levenson-Falk (Stanford) Nb tube: 23 mm ID 1 mm thick Length 200 mm Field coil Applied field: μt pp range (at 8 Hz) SQUID magnetometer: Near the center of Nb tube Shielding factor: (0.5-3) x10 9 for transverse field Goal: 10 8 with thin film Nb SC shield tests planned Apr 2017

34 Summary for ARIADNE ARIADNE New resonant NMR method Gap in experimental QCD axion searches 0.1 mev < m a < 10 mev Complementary to cavity-type (e.g. ADMX) experiments No need to scan mass, indep. of local DM density Complementary to nedm experiments Next tests shielding (Stanford/Korea), vibration (UNR), 3 He system (Indiana)

35 Dipole-Dipole axion forces Spin-polarized source mass May be competitive with astrophysical bounds Magnetic shielding requirements more stringent Nuclear spin Electron spin

36 N. Cresini et.al., Arxiv: QUAX-gpgs

37 N. Cresini et.al., Arxiv: New limits from QUAX gsgp (May 2017) Torsion pendulum Magnetometry

38 Lots of opportunities to probe low energy fundamental physics! Short distance gravity tests Equivalence principle tests EDMs Axions Ultralight DM (scalars, axions, ALPS) Gravitational waves several others

39 The Length Scales in the Universe Hubble Neutrinos Dark Energy Standard Model LHC Planck Scale in meters 80% of the energy scale left to explore

40 The Length Scales in the Universe Hubble Neutrinos Dark Energy Standard Model LHC Planck Scale in meters There are more things in heaven and earth, Horatio, Than are dreamt of in your philosophy. - Hamlet 80% of the energy scale left to explore From M. Arvanitaki