Helium-Xenon-Comagnetometry: Searches for new Physics with Spin Clocks
Ulrich Schmidt
He-Xe-Comagnetometry: Search for new Physics with Spin ClocksCollidingColliding Pizza Pizza Seminar Seminar 26.06.2017 26.6.2017 Helium‐Xenon‐Comagnetometry: Searches for new Physics with Spin Clocks
Introduction: ¾ For what are spin clocks good for ? ¾ Search for new Physics with Spin Clocks: the classical example: EDMs He-Xe- ¾ Setup and operating conditions Comagnetomtry ¾ Search for axion like spin-dependent : short-range interactions ¾ Search for an 129Xe EDM Conclusion:
Outlook: ¾ HeXeniA
He-Xe-Comagnetometry: Search for new Physics with Spin Clocks Colliding Pizza Seminar 26.06.2017 2 Introduction: Features of 3He/129Xe spin-clocks Atomic clock Spin clock Oscillator + Frequency divider + Counter
133Cs F=4 Micro-Wave f = 9.192… GHz F=3
δ = int < 3/ μHzhVf
State detection accuracy (absolute scale): + δf ≈ 3 µHz frequency feedback corresponding energy shift δΕ ≈ 1.5·10-29 GeV
Spin clock : G reference transition at f ≈ 10 Hz accuracy to trace B with δf/f ≈ 10-13 tiny frequency shifts accuracy (absolute scale): ≈ 6 orders of δf ≈ 1 pHz → δΕ ≈ 4·10-36 GeV magnitude higher
He-Xe-Comagnetometry: Search for new Physics with Spin Clocks Colliding Pizza Seminar 26.06.2017 Measurement sensitivity: 129Xe electric dipole moment
E E hh ( υυν) 4 ⋅⋅=Δ−Δ⋅=Δ⋅ dE Bo ↑↑ ↑↓ Xe 4⋅×= 10−15 eVs 1pHz ΔE ΔE ΔE o ↑↑ ↑↓ V 4110×⋅330 ×⋅ 110ecm− cm The Cramer-Rao Lower Bound (CRLB) sets the lower limit on the variance
Correction for 2 12 * σ ≥ T -relaxation f 2 2 3 × TC 2 )( 2 π )2( ()BW ⋅⋅⋅ TfSNR σ
⎡Fourier 11⎤ 1 σ ∝∝×⎢⎥ ∝ f ⎢⎥width T 13 ⎢⎥⎣ ⎦ [# data points∝ T]22T
σφ ∝ 1/ T
2 example: SNR = 10000:1 , f BW = 1 Hz , T= 1 day ⇒ σ f ≈ pHz
He-Xe-Comagnetometry: Search for new Physics with Spin Clocks Colliding Pizza Seminar 26.06.2017 4 Free induction decay Polarized nuclear spins generate a macroscopic magnetic moment which precesses around a static B-field B0 Example: Nuclear Magnetic Resonance
t - * Magnetometer envelope∝ e T2 G ωLL==2πν γ B
(G. D. Cates, et al., Phys. Rev. A 37, 2877) (ms ) 111 * += 2 TTT 2,1 field 24 2 2 GGG 2 G 2 41 R γ ⎛ ⎞ 4 ⎜ ,1 z ,1 y 2∇+∇+∇≈ x,1 ⎟ ∇⋅⋅∝ BpRBBB T2, field 175D ⎝ ⎠
He-Xe-Comagnetometry: Search for new Physics with Spin Clocks Colliding Pizza Seminar 26.06.2017 5 Nuclear spin properties: “First order” nuclear structure: Both nuclei have one unpaired neutron, which accounts for the nuclear spin. All other nucleons are paired with 1 antiparallel spins → J = 2
μnN= −1.913μ μ =−2.1276μ 3He N μ =−0.7779μ 129 Xe N
3He polarization Optical pumping of metastable 3He*-atoms ( MEOP )
3He and 129Xe polarization Spin exchange with optically pumped Rb-vapour ( SEOP )
He-Xe-Comagnetometry: Search for new Physics with Spin Clocks Colliding Pizza Seminar 26.06.2017 6 3He free spin-precession signal
SQUID parameters: d pHe= 1-3 mbar P = 10-50% R =2.9 cm; d = 6cm R → ΔB = 10-30 pT
3 ⎛ R ⎞ Signal: pTB ][220][ Pmbarp ⋅⋅⋅≈Δ ⎜ ⎟ ⎝ d ⎠
12 8 system noise 4 inside BMSR-2
[pT] 0 ~ 2 fT/√Hz
SQUID -4 B
-8
-12 0246810
time [h]
He-Xe-Comagnetometry: Search for new Physics with Spin Clocks Colliding Pizza Seminar 26.06.2017 7 Test of CRLB via Allan Standard Deviation (ASD) τ N −1 ()()− ()τυτυ2 1 ∑ i+1 i ()τσ= i=1 υ 2 N −1 ii+1
Limit: 60s 1 only for T < 60s 3/2 σ T υ reaches CRLB Non-gaussian noise: magnetic field drifts intrinsic noise …
2
He-Xe-Comagnetometry: Search for new Physics with Spin Clocks Colliding Pizza Seminar 26.06.2017 8 MEOP Polarizer Mainz: 3He
He Xe
N2 SEOP Polarizer PTB: 129Xe
He-Xe-Comagnetometry: Search for new Physics with Spin Clocks Colliding Pizza Seminar 26.06.2017 9 BMSR 2, PTB Berlin
LTc- SQUID
The 7-layered magnetically shielded room (residual field < 2 nT)
3He (4.5 mbar )
6 cm
B0 ≈ 0.4 μT 129Xe-EDM (Helmholtz-coils) G Teilchenkolloquium 14.05.2013 B ,, zyx ≈∇ /20 cmpT He-Xe-Comagnetometry: Search for new Physics with Spin Clocks Colliding Pizza Seminar 26.06.2017 10 3He / 129Xe clock comparison to get rid of magnetic field drifts
406.68 drift ~ 1pT/h
B [nT] 406.67
δν ∼ 10-5 Hz/h 406.66
0 5 10 15 20 t [h]
B0
129 Xe (4,7 Hz) 3He (13 Hz)
129Xe-EDM γ γ ωω HeHe ω =Φ⋅−Φ=ΔΦ const=⋅−=Δ 0 . Teilchenkolloquium 14.05.2013He, HeL Xe , XeL γ γXe Xe
He-Xe-Comagnetometry: Search for new Physics with Spin Clocks Colliding Pizza Seminar 26.06.2017 11 BtSHeHeHeHeXeXeXeXelinconst( )=⋅ c cos(ωωωω t ) +⋅ s sin( t ) +⋅ c cos( t ) +⋅ s sin( t ) +⋅+ c t c
10000 T
f 0 Fitting subset ê -10000 subset left: -20000 χ2/dof = 1.03 -30000
Amplitude -40000 -50000 -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 f
do 70000 ê
time s 2 c 60000 r 100 50000 T f 50 ê ê 40000 0 30000 -50 20000 10000 residuals -100 0
-150 number of subsets pe 0.0 0.5 1.0 1.5 2.0 2.5 3.0 129Xe-EDM-1.5 - 1.0 - 0.5 0.0 0.5 1.0 1.5 c 2 dof Teilchenkolloquium 14.05.2013time s
He-Xe-Comagnetometry: Search for new Physics with Spin Clocks Colliding Pizza Seminar 26.06.2017ê 12 ê Subtraction of deterministic phase shifts
3 6 Φ=He 212Hz1day6.510π ⋅ ⋅ = ⋅ 2 ΔΦ 1 rad ΔΦ = ΦHe −γγ He/ Xe Φ Xe ê 0
phase -1
-2
-3 0 20 000 40 000 60 000 80 000 time s 0.00 ΔΦ =ca +lin ⋅ t -0.02 ê rad ê -0.04 alin: earth rotation and -0.06 chemical shift -0.08 phaseresiduals -0.10 129Xe-EDM Teilchenkolloquium0 20 000 14.05.201340000 60000 80000 time s He-Xe-Comagnetometry: Search for new Physics with Spin Clocks Colliding Pizza Seminar 26.06.2017 13 ê Subtraction of deterministic phase shifts
0.00 T f 8000 -0.02 ê rad ê -0.04 6000 litude
-0.06 p 4000 -0.08 phaseresiduals -0.10 2000 Xenon Am 0 20 000 40000 60000 80000 time s 0 20000 40 000 60000 80000 time s ê 0.004 ΔΦ =ca + ⋅ t rad lin ê ê 0.002 ** −−tT//2,He tT2,Xe 0.000 +⋅aeHe + aeXe ⋅
-0.002 ** −−tT/(22,He ) tT/(22,Xe ) phaseresiduals +⋅be + be ⋅ -0.004 He Xe 0 20000 40000 60 000 80000 + time s Φ (t)spin-coupling a: generalized Ramsey-Bloch-Siegert-Shift ∝ Magnetisation ê b: Bloch-Siegert-Shift ∝Magnetisation2 of other spin species
He-Xe-Comagnetometry: Search for new Physics with Spin Clocks Colliding Pizza Seminar 26.06.2017 14 ASD of frequency residuals
He-Xe-Comagnetometry: Search for new Physics with Spin Clocks Colliding Pizza Seminar 26.06.2017 The detection of the free precession of co-located 3He/129Xe sample spins can be used as ultra-sensitive probe for non-magnetic spin interactions of type: G G V − magnnon . = a ⋅σ
¾ Search for a Lorentz violating sidereal modulation of the Larmor frequency ~ G rV /)( = b ˆ ⋅= σε/ = ¾ Search for spin-dependent short-range interactions Axion like particles G /)( = = σ ⋅ ncrV ˆ / =
¾ Search for EDM of Xenon G G rV = d/)( n σ ⋅−= E / =
¾ … γ He Observable: ωω,HeL ω ,XeL ≠⋅−=Δ 0 γ Xe
He-Xe-Comagnetometry: Search for new Physics with Spin Clocks Colliding Pizza Seminar 26.06.2017 16 Search for axion like particles with 3He ‐ 129Xe spin clocks
Institut für Physik, Universität Mainz: C. Gemmel, W. Heil, H.Hofsetz, S. Karpuk, Y. Sobolev, K. Tullney
Physikalisch-Technische-Bundesanstalt, Berlin: M. Burghoff, W. Kilian, S. Knappe-Grüneberg, W. Müller, A. Schnabel, F. Seifert, L. Trahms
Physikalisches Institut, Ruprecht-Karls-Universität Heidelberg: F. Allmendinger, U. Schmidt
He-Xe-Comagnetometry: Search for new Physics with Spin Clocks Colliding Pizza Seminar 26.06.2017 17 Search for a new pseudoscalar boson (Axion-like particle) Gerardus 't Hooft,: QCD has a non-trivial vacuum structure that in principle permits CP-violation
−16 −26 from neutron EDM we get: dn θ 10310 ⋅⋅<⋅≈ cme Original proposal for Axion ( R. Peccei, H.Quinn PRL 38(1977),1440) as possible solution to the „Strong CP Problem“ that cancels the CP violating term in the QCD Lagrangian
Modern interest: Dark Matter candidate. All couplings to matter are weak
Axions, if they exist, it will be very light and will mediate a macroscopic CP violating force
⋅ fm ⎛1012 GeV ⎞ m ≈ ππ 6μeV ⋅≈ ⎜ ⎟ energy scale P.Q.-symmetry a ⎜ ⎟ fa : is spontaneously broken fa ⎝ fa ⎠
He-Xe-Comagnetometry: Search for new Physics with Spin Clocks Colliding Pizza Seminar 26.06.2017 18 If axions are dark matter, they are a relic of the early universe. A particular scenario coupled with the requirement that the axion mass density not severely over close the universe results in a lower bound to the axion mass.
Current Axion Search Experiments
¾ Solar Axion Telescope – „CAST“ CAST ¾ Dark Matter Axion Search – „ADMX“
¾ Vacuum Optical Properties –“PVLAS“ etc.
¾ Photon Disappearance Experiments
¾ New Force Search – Torsion Pendulums, etc.
He-Xe-Comagnetometry: Search for new Physics with Spin Clocks Colliding Pizza Seminar 26.06.2017 19 19 Short range interaction of the axion
Yukawa-type potential with monopole-dipole coupling: G⎛ 11 ⎞ )( nrV ˆ σκ⎜ +⋅= ⎟e−r / λ (Moody and Wilczek PRD 30 130 (1984)) ⎝ λ rr 2 ⎠ 2 = gg = ⎛ −6 eV10 m << −2 eV10 ⎞ ps ⎜ a ⎟ :with κ = , λ = ⎜ −5 −1 ⎟ ⎝ m10 λ << m10 ⎠ 8π mn acm
polarized matter G unpolarized matter N G n N N nˆ σn N n gs gp axion Faxion G nˆ N N σn Faxion
He-Xe-Comagnetometry: Search for new Physics with Spin Clocks Colliding Pizza Seminar 26.06.2017 20 How to measure? G B ω HeL, = γ He ⋅ tBt )()( unpolarized ωClose = ω HeL, tt )()( + Δω 3He matter
(Pb-glass, BGO) (with: Δ=ωπδν 2 ⋅ =V / =)
Position: Close
3He ωFar = ω HeL, tt )()(
Position: Far
Δ⇒ ω = ωClose −ωFar Requirement: ωL,He ()tconst= .
He-Xe-Comagnetometry: Search for new Physics with Spin Clocks Colliding Pizza Seminar 26.06.2017 21 Dewar housing
the LTc-SQUIDs
Pb-glass (2009 run) BGO crystal (2010 run)
3He/129Xe cell
129Xe-EDM Teilchenkolloquium 14.05.2013
He-Xe-Comagnetometry: Search for new Physics with Spin Clocks Colliding Pizza Seminar 26.06.2017 2222 Results
B LR0
September 2010: 6 runs (each ~9 hours) gap = 2.2 mm Mass sample: BGO crystal with density ρ=7.13 g/cm³
=> ΔνSR = (-2.9 ± 6.9 ± 0.4) nHz (95% C.L.)
2 G G = gg PS ⎛ G ⎞⎛ 11r ⎞ −r /λ Analysis: VSP )r( = ⎜ ⋅σ ⎟⎜ + ⎟⋅e 8π ⎝ ⎠⎝ λ rrrm 2 ⎠
Average potential
Δ(δν) the sensitivity level of gSgP can be determined by: 129Xe-EDMg g < 4 (2 π ) 2 m δ ( Δν ) / (NV ħ
He-Xe-Comagnetometry: Search for new Physics with Spin Clocks Colliding Pizza Seminar 26.06.2017 23 Exclusion Plot for new spin-dependent forces (axion like particles )
direct search: Phys.Rev.Let. 111, 100801 (2013) 1: S. Baeßler et al. Phys. Rev. D, 75, 075006 (2007). 2:T. Jenke et al. Phys. Rev. Let. 112 151105 (2014) 3: A.P. Serebrov et al. JETP Letters, 91, 6 (2010). 4: A.K.Petukhov et al. Phys. Rev. Lett., 105, 170401 (2010). 5: A.N. Youdin et al. Phys. Rev. Lett., 77, 2170 (1996). 6: arXiv:submit/0534993 Excluded region [hep-ex] 18 Aug 2012C. 7: P.-H. Chu et al. Phys. Rev. D, 87, 011105(R) (2013).
9: He/Xe for Δx ≈ 0mm
He-Xe-Comagnetometry: Search for new Physics with Spin Clocks Colliding Pizza Seminar 26.06.2017 24 Exclusion Plot for new spin-dependent forces (axion like particles )
arXiv:1205.1776v2 [hep-ph] 29 Jul 2012: Georg Raffelt 3 (3): A.P. Serebrov et al. limits from combining stellar energy-loss arguments with JETP Letters, 91, 6 (2010). results from Newton’s inverse square law tests 1 (4): A.K.Petukhov et al. Phys. Rev. Lett., 105, 170401 (2010). 2 (5): A.N. Youdin et al. Phys. Rev. Lett., 77, 2170 (1996).
He-Xe limit not in the original plot of Raffelt
Excluded region
He-Xe-Comagnetometry: Search for new Physics with Spin Clocks Colliding Pizza Seminar 26.06.2017 25 Courtesy of B. Santra
He-Xe-Comagnetometry: Search for new Physics with Spin Clocks Colliding Pizza Seminar 26.06.2017 26 Our world is composed of matter
... and not antimatter
3 nγ ≈ 400/cm (CMB)
≈ 3 nb 0.2 protons/m − nn η = b b ×≈ 106 −10 nγ SM prediction based on observed flavor-changing CP-violation (CKM-matrix) − nn η = b b ≈10−18 nγ
He-Xe-Comagnetometry: Search for new Physics with Spin Clocks Colliding Pizza Seminar 26.06.2017 Motivation for EDM searches Unsolved puzzle : Why is there much more matter than antimatter in the universe ? "Sakharov conditions" are: Baryon number violation, CP-symmetry violation and out of thermal equilibrium.
CP violation within the Standard Model is to small to generate observed baryon asymmetry ⇒ search for CP violation bigger than predicted by the Standard Model. ⇒ Good candidates: EDM of electron, neutron and nuclei
If no EDM is found => strong constrains for Models beyond the SM or method to rule Model out
He-Xe-Comagnetometry: Search for new Physics with Spin Clocks Colliding Pizza Seminar 26.06.2017 28 Search for a particle EDM
-26 ● dn<3×10 ● -29 • de<8.7×10 Science 343,269 2014 ● -30 dHg<7.4×10 arXiv:1601.04339v2, 2016
-32 dn(SM) ≈10
He-Xe-Comagnetometry: Search for new Physics with Spin Clocks Colliding Pizza Seminar 26.06.2017 Nuclear Atomic Molecular ΔE ≈10-23eV Hg ΔE ≈10-27eV Tl ΔE ≈10-20eV ThO ΔE ≈10-17eV
observable EDM
atomic EDM
nuclear EDM
hadron EDM
particle EDM
He-Xe-Comagnetometry: Search for new Physics with Spin Clocks Colliding Pizza Seminar 26.06.2017 30 Atomic EDM‘s
eff = ext + int = ε ⋅ EEEE ext = 0
++
E Eint ext K dEDM
G G EDM atom ⋅−=Δ EdE ext -- G G EDM ε ⋅⋅−= Ed ext = 0
¾ L.I.Schiff (PR 132 2194,1963): System of non-relativistic charged point particles that interact electrostatically can not have an EDM
He-Xe-Comagnetometry: Search for new Physics with Spin Clocks Colliding Pizza Seminar 26.06.2017 31 Atomic and Molecular EDMs Schiff’s screening theorem: For a non relativistic system made up of point like charged particles which interact electrostatically and an arbitrary external field, the shielding is complete For the measurement of an EDM search for exceptions: - Heavy paramagnetic atoms and molecules
the relativistic effect of the electromagnetic interaction YbF Eeff = 14.5 GV/cm between electrons and the nucleus enhances effectively ThO Eeff = 84 GV/cm the external field. - Heavy diamagnetic Atoms (closed electron (sub-)shell) finite size effect: Schiff’s screening is not perfect, but suppresses EDM-coupling by 1 to 3 orders of magnitude 3 2 − de ≠ 0 → datom ≠ 0 ~ Z α de − P,T-odd eN interaction 2 Tensor-Pseudotensor ~Z GFCT 3 Scalar- Pseudoscalar ~Z GFCS − Nuclear EDM – finite size Schiff moment induced by P,T-odd N-N interaction ~10-25 η [ecm]
He-Xe-Comagnetometry: Search for new Physics with Spin Clocks Colliding Pizza Seminar 26.06.2017 32 Parameter 199Hg Best alternate limit -27 -29 de / (e ⋅cm) 3.0×10 ThO:8.6×10 -26 -26 dn/ /(e ⋅cm) 1.6×10 n: 2.9×10 -25 -23 dp/(e ⋅cm) 2.0×10 TlF: 5.4×10 -11 -10 θQCD 8.5×10 n: 2.4×10
-8 -7 CS 1.3×10 Tl:2.4×10 -10 -7 CT 1.5×10 TlF:4.5×10 -7 -4 CPS 1.2×10 TiF: 3×10 η 8.0×10-5 Xe: 5×10-2
Reduced Limit on the Permanent Electric Dipole Moment of 199Hg 199 −30 d ()Hg≤⋅ 7.4 10 e ⋅ cm B. Graner, Y. Chen, E. G. Lindahl, and B. R. Heckel arXiv:1601.04339v2 [physics.atom-ph] 20 Jan 2016
199 −−2 20 −−22 23 −25 ddCCC()Hg=+×+×+×+×⋅ 10eTSP (2.0 10 5.9 10 6 10S 3.9 10η )e cm
129 −−3 21 −23 −23 −26 ddCCC( Xe)=+×+×+×+×⋅ 10eTSP (5.2 10 5.6 10 1.2 10S 6.7 10η )e cm d ()129 Xe≤⋅ 3.3 10−27 e ⋅ cm 6× less sensitive to CP violating interactions
He-Xe-Comagnetometry: Search for new Physics with Spin Clocks Colliding Pizza Seminar 26.06.2017 33 Magnetically shielded room (MSR) at Jülich Research Center
Inside dimensions: 3×2.5×2.4 m3
Shielding factor:
≈ 300 @ 1Hz
He-Xe-Comagnetometry: Search for new Physics with Spin Clocks Colliding Pizza Seminar 26.06.2017 34 He-Xe-Comagnetometry: Search for new Physics with Spin Clocks Colliding Pizza Seminar 26.06.2017 Sketch of experimental setup
typically: 4 mbar He l He 8 mbar Xe dewar 40 mbar SF6
gas preparation low Tc-SQUID area outside MSR gradiometer(s)
-5 kV • • +5 kV
129 → Xe pneumatic valve
3→ He SF6 B0(cos-coil) Bv(solenoid)
gas transfer line Turbo pump Btrans He-Xe-Comagnetometry: Search for new Physics with Spin Clocks Colliding Pizza Seminar 26.06.2017 36 Scheme inner setup of the 129Xe-EDM experiment
(1) Conductive Plastic housing (2) Glass cell with silicon lids (3) High voltage electrodes with cabling
(4) Filled with SF6 (5) Cryostat made of carbon fiber, inside special low temperature SQUID Gradiometers
He-Xe-Comagnetometry: Search for new Physics with Spin Clocks Colliding Pizza Seminar 26.06.2017 37 Mounting of the Cosin-coil and the µ-metal cylinder at Mainz
He-Xe-Comagnetometry: Search for new Physics with Spin Clocks Colliding Pizza Seminar 26.06.2017 38 Fiber glass cryostat inside are 3 SQUID gradiometers
He-Xe-Comagnetometry: Search for new Physics with Spin Clocks Colliding Pizza Seminar 26.06.2017 39 Hyperpolarized gases
M. Repetto
Ch. Mrozik
Xe-Polarizer ( 129Xe: 91%) 3He-Polarizer He-Xe-Comagnetometry: Search for new Physics with Spin Clocks Colliding Pizza Seminar 26.06.2017 40 He-Xe-Comagnetometry: Search for new Physics with Spin Clocks Colliding Pizza Seminar 26.06.2017 41 Status of the 129Xe EDM
Best limit of EDM 129Xe: (0.7 ± 2.8)⋅10-27 e⋅cm by M. A. Rosenberry and T. E. Chupp (2001)
- Apparatus is setup and running - 3 weeks of data taking July 2016 - Best run same statistical limit as Rosenberry and Chupp within 6 hours - discovery a „new“ systematic effect: „magnetization“ field of polarized nuclear spins in a cylindrical cell causes additional frequency/phase-shifts - remodeling of the apparatus for use of a spherical cell - 2 weeks of data taking July 2017 - Goal: EDM 129Xe < 1.0⋅10-27 e⋅cm - Data evaluation finished autumn 2017 He-Xe-Comagnetometry: Search for new Physics with Spin Clocks Colliding Pizza Seminar 26.06.2017 42 Institut für Physik, Universität Mainz: W. Heil, M. Repetto, P. Blümeler, M. Doll, S. Karpuk, Y. Sobolev, St. Zimmer
Physikalisches Institut, Ruprecht‐Karls‐Universität Heidelberg: F. Allmendinger, U. Schmidt
KVI‐Groningen Olivier Grasdijk K. Jungmann, L.Willmann
Forschungszentrum Jülich H.‐J. Krause, A. Offenhäusser
He-Xe-Comagnetometry: Search for new Physics with Spin Clocks Colliding Pizza Seminar 26.06.2017 Conclusion
He-Xe-comagnetometry: spin clocks are a very powerful method to search for very tiny spin dependent effects
Best limits for new physics obtained with He-Xe spin clocks:
Short range pseudoscalar spin coupling: direct search for ALPs improved by more than 4 order of magnitude over half of the range of the axion window
Not discussed: best limit for Lorenz violating coupling of the nucleon spin to a relic background field; preferred direction
Xe-EDM is on the way for best limit
Still new ideas to use HeXe spin clocks ->
He-Xe-Comagnetometry: Search for new Physics with Spin Clocks Colliding Pizza Seminar 26.06.2017 44 Outlook He-Xe Spin Clocks Peter W. Graham and Surjeet Rajendran Cosmic Axion Spin Precession DOI: 10.1103/PhysRevD.88.035023 (2013) Experiment (CASPEr) Interaction of nuclei with back ground axion (like) dark matter field leads to:
oscillating EDM Axion wind; in resonance with gradient of Larmor precession axion field → transversal magnetization → transversal magnetization
He-Xe-Comagnetometry: Search for new Physics with Spin Clocks Colliding Pizza Seminar 26.06.2017 45 Outlook He-Xe Spin Clocks New Project HeXeniA (He Xe nuclei interact with axions) (embedded within the “exploring dark matter” proposal for a cluster of excellence)
5Hz Larmor frequency is in resonance with axion/ALP mass of 2⋅10-14 eV
⎛⋅102.1 19 GeV ⎞ m 105 −13eV ⋅⋅≈ ⎜ ⎟ ALP ⎜ f ⎟ ⎝ ALP ⎠
energy scale of f ALP spontaneously broken symmetry
He-Xe-Comagnetometry: Search for new Physics with Spin Clocks Colliding Pizza Seminar 26.06.2017 46 He-Xe-Comagnetometry: Search for new Physics with Spin Clocks Colliding Pizza Seminar 26.06.2017 47 He-Xe-Comagnetometry: Search for new Physics with Spin Clocks Colliding Pizza Seminar 26.06.2017 48 He-Xe-Comagnetometry: Search for new Physics with Spin Clocks Colliding Pizza Seminar 26.06.2017 49 (¤8¤¨!
He-Xe-Comagnetometry: Search for new Physics with Spin Clocks Colliding Pizza Seminar 26.06.2017 50