Search for CP violation using laser-cooled atoms レーザー冷却原子によるCP対称性破れの探索 Frontier Research Institute for Interdisciplinary Sciences (FRIS), Tohoku University Hirokazu Kawamura Outline • Laser-cooling techniques • CP-violation and EDM • Electron EDM and Atomic EDM • Cs EDM experiment • Fr EDM project at Tohoku E B RCNP workshop “CP violation in elementary particles and composite systems” Nov. 10, 2014, RCNP, Osaka University Hirokazu Kawamura, Search for CP-violation using laser-cooled atoms Laser-cooling and trapping for neutral atoms Interactions between laser and neutral atoms Laser beams Potentials atoms Cooling and/or trapping Very longer interaction time Traditional atomic beam experiments Thermal beam ~ high velocity Short interaction time Hirokazu Kawamura, Search for CP-violation using laser-cooled atoms 2 b-decay experiments using laser-cooled atoms Angular correlations in nuclear b decay J nucleus pe A-correlation pν neutrino D-correlation P-odd T-odd (P-even) e.g. TRINAT at TRIUMF (J.A.Behr) electron Neutrino is reconstructed from electron and recoil nucleus. Trapping techniques are good to measure recoil momentum! Hirokazu Kawamura, Search for CP-violation using laser-cooled atoms 3 T-violation = CP-violation under CPT theorem Electric dipole moments Nuclear b decay positron spin Nuclear spin CP T ≠ EDM antinucleus electron ≠ P ≠C Hirokazu Kawamura, Search for CP-violation using laser-cooled atoms P ≠ 4 Historical electron EDM limits 1E-20 -20 10 e-EDM limit (ecm) 1E-22 10-22 10-24 1E-24 Cs Cs fountain Cs Cs Hg Xe Cs TlF Cs 10-26 1E-26 10 1E-28 -28 10 1E-30 1960 The Schiff shielding theorem is violated by relativistic effects. GdFeGar TlF Tl YbF Tl Tl Hg Atomic systems provide such a powerful probe of the electron EDM. YbF ● with atomic or molecular beam ■ with atomic cell ◆ with solid ThO The ACME Collaboration Science 343 (2014) 269 -30 1970 1980 1990 Year 2000 Hirokazu Kawamura, Search for CP-violation using laser-cooled atoms 2010 5 Hierarchy of CP-odd sources & observable EDMs R is the enhancement factor cN accounts for permanent nuclear EDMs and T-violating e-N interactions Hirokazu Kawamura, Search for CP-violation using laser-cooled atoms 6 Electron EDM from Atomic EDM arXiv:1301.1681v2, arXiv:1308.6283v2 Hg 0.5 ThO ~ CS/10-7 Hg Alkali atoms -0.5 YbF Tl -0.6 de/(10-26 ecm) 0.6 Hirokazu Kawamura, Search for CP-violation using laser-cooled atoms 7 Modern electron EDM experiments eEDM groups Commins, Tl beam Hinds, YbF beam ACME, ThO beam Cornell, trapped HfF+ Weiss, trapped Cs v (m/s) 420 590 200 26 0.02 Eapp (MV/m) 12 1 0.01 10-4 15 |R| 585 1.45x106 109 1010 120.5 Eeff (GV/m) 7.2 1450 10000 1000 1.8 t (s) 3x10-3 6.4x10-4 1.5x10-3 0.1 3 t･Eeff 0.022 0.93 15 100 5.4 dN/dt (s-1) 109 6x104 105 <100 2x108 3x10-28 2.4x10-30 de limit (ecm) 1.6x10-27 Ref. 1.05x10-27 8.7x10-29 (measured) (measured) (measured in (plan) 2013) (plan) PRL88(200 2)071805 Nature473 (2011)493 J.Phys.B43(2 010)074007 KunyanZhu (2013)PhD Hirokazu Kawamura, Search for CP-violation using laser-cooled atoms J.Mol.Spectro. 270(2011)1 8 Cesium EDM projects Atomic beam PRL21(1968)1645 Cell PRL63(1989)965 3D optical lattice PRA63(2001)033401 Fountain PRA75(2007) 063416 -24 |de| < ~ 10 ecm -26 |de| < ~ 10 ecm proposal |de| < 10-22ecm ~ spokesperson affiliation David Weiss Penn State Univ. Dan Heinzen Univ. of Texas Kazuhito Honda Shizuoka Univ. Harvey Gould LBNL (Berkeley) method 133Cs 133Cs in 1D optical lattice in far off resonance trap 133Cs Laser-cooling and trapping techniques in 3D optical lattice 133Cs fountain Hirokazu Kawamura, Search for CP-violation using laser-cooled atoms 9 Cs EDM experiment (Weiss, PennState) Cold atoms in optical lattices have a long coherence time and motional field effects are greatly suppressed. trapped Cs in 1D optical lattice (1064nm) B -E E 20cm Transparent electrodes (ITO) Precision measurements and active stabilization of E and B fields. Common mode noise rejection with 2 simultaneous interferometers leads to be insensitive to B field fluctuations. Ultimate check of systematic errors using alternating measurements with 2 alkali species, Cs and Rb. Hirokazu Kawamura, Search for CP-violation using laser-cooled atoms 10 Ultimate projected sensitivity Energy levels of 133Cs F=3 in a ~150kV/cm E field (no B field) -2 400Hz -3 mF=0 +1 -1 +2 +3 (plan for 133Cs) Zoom in mF=±3 plan for 87Rb +3 -3 R = 26 N = 8x109 atoms (density limited) mF = 1, gF = -1/2 Comparable to 133Cs ThO exp.: 8.7x10-29 ecm (measured in 2013) Hirokazu Kawamura, Search for CP-violation using laser-cooled atoms 11 Experimental equipment Optical lattices Glass cell (10μK) Polarization-gradient cooling beams Cs oven (100oC) Hirokazu Kawamura, Search for CP-violation using laser-cooled atoms 12 Francium EDM project Hirokazu Kawamura, Search for CP-violation using laser-cooled atoms Francium Heaviest alkali metal = Francium : ⇒simple electronic structure and large nucleus ⇒Enhancement factor: Z=87 R~103 de d Fr R~ Fr d atom de No stable isotopes: radioactive atom Several isotopes with long half-life ⇒210Fr =3.2 min, 211Fr =3.1 min, 212Fr =20. min. Enhancement factor |R| Enhancement of electron EDM Laser cooling and trapping techniques: localize atoms ⇒ Improve both statistical and systematic effects Hirokazu Kawamura, Search for CP-violation using laser-cooled atoms Blundell, Griffith, and Sapirstein (2012) 1000 Fr Mukherjee, Sahoo, Nataraj, and Das (-2011) 800 Tl 600 400 Cs 200 Rb 0 0 20 40 60 Atomic number 80 14 Fr EDM project at CYRIC, Tohoku Univ. Beam swinger Fr production by oxygen beam and gold target 18O5+ Deflector Triplet-Q1 Ion beam transportation by electrostatic lenses Wien filter Beam purification by velocity filter Au target (Thermal ionizer) Triplet-Q2 Rb ion Triplet-Q3 Hirokazu Kawamura, Search for CP-violation using laser-cooled atoms Cyclotron & Radioisotope Center (CYRIC) Cyclotron Target room 210Fr K=110MeV AVF cyclotron 10GHz ECR IS 100MeV Fr production 18O + 197Au 215-xFr + xn Stancari et al., NIMA557(2006)390 Hirokazu Kawamura, Search for CP-violation using laser-cooled atoms 16 Laser-cooled francium factory (current) Laser room Cyclotron Beam swinger Target room 18O5+ Ext. room Cyclotron Wall MOT Au target Neutralization Hirokazu Kawamura, Search for CP-violation using laser-cooled atoms 17 Fr ion production 210,211Fr (6.54MeV) Fr+ Einzel lens 208,209Fr 209,210Rn Extraction electrode 207At 205At 212Fr 206Po 18O5+ (6.64MeV) 211Po Oven Fr count rate [a.u.] 197Au 6 4 target (f10) ~1000oC Target temperature dependence Fr+ 18O5+ solid liquid 2 18O5+: 0 850 ~200enA 1000 950 900 Gold temperature [oC] Au Gold melting point = 1064oC. Hirokazu Kawamura, Search for CP-violation using laser-cooled atoms 18 Purify the ion beam using Wien filter Neutralizer E x B field only Fr ions Exp. conditions - Coil current = 11.7A (B field ~400G) - E field 2080V/m for A=210 23Na 39K 85Rb 197Au FC current (pA) 100 200 Mass/Charge 210Fr 16 FC current (nA) 100 10 10 1 0.1 10-1 0.01 0.001 10-3 0.0001 0 Courtesy of Tamii (RCNP) 300 6 12 4 8 2 4 0 Hirokazu Kawamura, Search for CP-violation using laser-cooled atoms 0 100 200 300 Mass/Charge 400 19 SSD count (cps) Background (~10nA) + Fr ions (~10fA) Neutralization & Magneto-optical trap Laser beam Rb trap image anti-Helmholtz coils Vacuum glass cell Trap CCD camera Rb signals SSD Ion beam Neutralizer target (yttrium) FC Ion beam detector Hirokazu Kawamura, Search for CP-violation using laser-cooled atoms 17sec 20 Approaches to increase trapped atoms with Rb Fluorescence (a.u.) Neutralizer temperature dependence Non-stick coating (OTS) glass cell Longer trapping life 120 80 40sec 40 0 Optimized at ~1000oC 6.0 7.5 9.0 10.5 Neutralizer heating current (A) 60 Prefer lower energy 40 20 0 1 2 3 Light-induced atomic desorption Fluorescence (a.u.) Fluorescence (a.u.) Implantation energy dependence High power light 4 Rb ion beam energy (keV) Hirokazu Kawamura, Search for CP-violation using laser-cooled atoms UV LED power (mW) 21 Laser light sources for Fr trap Intensity 210Fr Energy Level F’=15/2 F’=13/2 7P3/2 F’=11/2 F’=9/2 with repumping light 0th (trap) Repump 718.13 nm Trap 718.216 nm F=13/2 7S1/2 F=11/2 10th sideband Reference frequency 127I2 P(78)1-9 718.222nm Signal (V) 210Fr ~3GHz Dube & Trinczek, Opt.Soc.Am.B21(2004)1113 Simsarian et al., PRL76(1996)3522 2 Error signal 1 0 -1 -2 Frequency reference for the trapping light is obtained. Frequency (GHz) 0 20 40 60 80 Frequency (MHz) The frequency 22 and Hirokazu Kawamura, Search for CP-violation using laser-cooled atoms difference between the trapping repumping light are fixed by using the error signal. Electric field application Rb trap with ITO electrodes 𝛼exp /ℎ = 0.14 ± 0.008 Hz/ V cm 2 𝛼ref /ℎ = 0.122306 16 Hz/ V cm 2 K. E. Miller, D. Krause, Jr., and L. R. Hunter, Phys. Rev. A 49,5128, (1994) ITO coated glass plate 𝐹 2𝐹 𝐹 𝐹 =4 =3 =2 =1 Trap (D2) 5 2 P3 hyperfine structure 5 2 P1 2 𝐹=3 𝐹=2 5 2 S1 2 𝐹=3 𝐹=2 Repump (D1) 85Rb ℰ Transition frequency shifts Hirokazu Kawamura, Search forfield. CP-violation using laser-cooled atoms in a dc electric Preliminary 23 Optical magnetometer B Magnetic field: quantization axis n Shift of the spin precession frequency due to the EDM: nEDM = n+ - n- < 1 mHz <=> Magnetic field fluctuation < 10 fT => Rb atomic magnetometer based on the Nonlinear Magneto-Optical Rotation (NMOR) effect D. Budker et al.,PRA 62. : Magnetic sensitivity: ~ 0.1 fT / Hz E B -E n 043403.(2000). Linear polarized lights k Rb atom B NMOR spectrum with FM light B 150 nT NMOR ① Production of Rb spin alignment by the linearly polarized lights. (Rb atoms have the linear dichroism.) ②Alignment precession around B. (The axis of the dichroism rotates around B. ) ③Rotation of the polarization plane of the light through the interaction with the alignment . With frequency modulated light (nmod = 5 kHz) - Center : 550 nT - Width : 150 nT <= Wall relaxation of the cell which confines Rb atoms Residual field of the magnetic shield which the cell is placed inside. Cell production, Demagnetization of the shield Hirokazu Kawamura, Search for CP-violation using laser-cooled atoms Fr-EDM collaboration (2014) Cyclotron and Radioisotope Center (CYRIC), Tohoku University S. Ando, T. Aoki, H. Arikawa, K. Harada, T. Hayamizu, T. Inoue*, T. Ishikawa, M. Itoh, K. Kato, H. Kawamura*, K. Sakamoto, A. Uchiyama, and Y. Sakemi *Frontier Research Institute for Interdisciplinary Sciences (FRIS), Tohoku University The University of Tokyo Tokyo Inst. Tech Tokyo Metropolitan University Tokyo Univ. Agri. Tech. T. Aoki K. Asahi T. Furukawa Osaka University Japan Atomic Energy Agency Kyoto University Indian Tech. Roorkee K. Hatanaka K. Imai T. Murakami H. S. Nataraj Tokyo Inst. Tech. Tohoku University Osaka University Okayama University T. Sato Y. Shimizu H. P. Yoshida A. Yoshimi Kyushu University Foreign students T. Wakasa J. Mathis (ENSICAEN), L. Koehler (TU Darmstadt) Hirokazu Kawamura, Search for CP-violation using laser-cooled atoms FRIS A. Hatakeyama 25 Toward the clarification of CP violation EDM violates T symmetry = CP violation under CPT theorem Electron EDM requires atomic EDMs and T-violating e-N interactions Many species not only paramagnetic and also diamagnetic Other approaches such as b-decay experiments Electron EDM experiments are dominated by polar molecules and laser-cooled alkali atoms Cesium EDM experiment is active Heaviest alkali atom, Francium EDM project Hirokazu Kawamura, Search for CP-violation using laser-cooled atoms 26 Hirokazu Kawamura, Search for CP-violation using laser-cooled atoms D-correlation in b decay emiT Collaboration, PRL107(2011)102301 19Ne J. Ng and S. Tulin, Phys. Rev. D 85 (2012) 033001 experiment, PRL38(1977)464 & PRL52(1984)337 Model independent Leptoquark models (with light right-handed neutrinos) For mLQ > 300 GeV, the neutron EDM Hirokazu Kawamura, Search for CP-violation bound using laser-cooled implies 𝐷𝑡atoms 𝜅 < 3 × 10−5 . Energy level shifts of 133Cs (484MHz) Hirokazu Kawamura, Search for CP-violation using laser-cooled atoms Courtesy of Yong-Sup Ihn
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