Moments dipolaires électriques: Cas de physique Bilan des mesures à PSI - Guillaume Pignol, Conseil scientifique LPSC, 25 novembre 2016 - INDICO LPSC
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Moments dipolaires électriques: Cas de physique Bilan des mesures à PSI Guillaume Pignol, Conseil scientifique LPSC, 25 novembre 2016 1
L’origine de l’asymétrie matière − = ≈ 6 × 10−10 est inconnue Conditions de Sakharov (1967) pour la baryogénèse 5 % baryons • Univers hors équilibre • Nombre baryonique non conservé 69 % • Violation de la symétrie CP Energie 26% Matière noire noire 2
Dipôles Electriques et symétrie T > PLAY > ↑↓ ≈ ↑↑ ≈ 2 2 ↑↓ − ↑↑ = ℏ < REWIND < Un EDM non nul viole la symétrie T Et donc viole CP 3
Dipôles Electriques et symétrie CP EDMs: couplage fermion-photon ℒ = − 5 -partie imaginaire du diagramme- 2 effectivement généré par des corrections radiatives. → = < 300 × 10−28 cm (Grenoble, 2006) < 2000 × 10−28 cm (Seattle, 2016) < 0.9 × 10−28 cm (Harvard, 2014) EDMs: sonde indirecte de physique à distance 10−26 cm LHC: sonde directe à distance 10−17 cm 4
EDMs dans le modèle standard La contribution CKM à l’EDM des fermions est nulle à 2 boucles (pour l’électron elle est aussi nulle à 3 boucles). Prédiction: ≈ ≈ 10−33 cm Bruit de fond Kobayashi-Maskawa négligeable La contribution QCD du terme thêta 8 génère potentiellement un gros EDM pour le neutron et le proton = − ≈ × 10−16 cm → < 10−10 « Strong CP problem » 5
EDMs en supersymétrie au TeV Le MSSM contient ~40 paramètres imaginaires violant CP. Ellis, Ferrara, Nanopoulos, PLB 114 (1982). Del Aguila et al.,PLB 126 (1983). EDM induit par les termes de masse molle EDM induit par la matrice de des squarks et des gluinos masse des neutralinos 2 1 TeV ≈ 2 ≈ × 10−25 cm 4 « SUSY CP problem » 6
EDMs en supersymétrie au PeV Scénario split SUSY, matrice de masse anarchique de saveur Altmannshofer, Harnik, Zupan, JHEP 1311 (2013) Voir aussi McKeen, Pospelov, Ritz, PRD 87 (2013) 7
Baryogénèse électrofaible en SUSY Baryogénèse « Wino driven » pratiquement exclue Baryogénèse « Bino driven » pratiquement exclue Li, Profumo, Ramsey-Musolf, PLB 673 (2009) 8
EDMs et les couplages du Higgs Barr, Zee, PRL 65 (1990) Chen, Dawson, Zhang JHEP (2015) EDMs sensibles au couplage du Higgs violant CP. 9
Baryogénèse électrofaible, modèle 2HDM Shu, Zhang, PRL 111 (2013) ℎ1 = 125 GeV, ℎ2 = 400 GeV 10
Résumé • EDMs sensible à la nouvelle physique à l’échelle électrofaible et au-delà. • Test décisif de la baryogénèse SUSY • Complémentarité avec le LHC pour sonder les couplages du Higgs • Complémentarité EDMs neutron/proton et électron 11
Panorama des mesures EDM Mesure à PSI 12
Panorama mondial 13
Projets en compétition, EDM hadroniques Horizon 2025 → < 10−27 cm avec les UCNs Futur: < 10−28 cm sur anneaux de stockage 14
Appareil actuel High voltage, E = ± 132 kV 12 cm 4 layers mu-metal shield photomultiplier Mercury lamp SWITCH UCN source 5T polarizer (SC magnet) Spin flipper Iron analyser 15
Compensation des fluctuations de B Uncorrected neutron frequency - + - + - +- + - +- + n = 2 Mercury-corrected neutron frequency Hg Hg = 2 ncorr ∝ Hg 16
Ongoing data production at PSI 2013: 2867 cycles (tests) 2014: 2139 cycles (tests) 2015: 36 sequences produced, 20317 cycles 2016: 47 sequences produced, 22630 cycles 17
Sensibilité statistique ℏ sensibilité statistique: = 2 PSI, routine 11 16000 180 0.8 1.1 Tableau présenté au CS LPSC novembre 2013 18
Production de données en cours à PSI 19
Analyse statistique these Y. Kermaidic corr corr − 1 /ppm − 1 /ppm / Hg / Hg 20
Production scientifique 2012-2016 12 articles reliés à EDM, dont 7 résultats importants 1. Electric-dipole-moment searches: Reexamination of frequency shifts for particles in trap. Pignol&Roccia, PRA 85 (2012) 2. A measurement of the neutron to 199Hg magnetic moment ratio. PLB 739 (2014) 3. Constraining interactions mediated by axion-like particles with ultracold neutrons. PLB 745 (2015) 4. Measurement of a false electric dipole moment signal from 199Hg atoms exposed to an inhomogeneous magnetic field. EPJD 69 (2015) 5. Observation of gravitationally induced vertical striation of polarized ultracold neutrons by spin-echo spectroscopy. PRL 115 (2015) 6. Gravitational depolarization of ultracold neutrons: Comparison with data. PRD 92 (2015) 7. A revised experimental upper limit on the electric dipole moment of the neutron. PRD 92 (2015) -> ré-analyse des données ILL basée sur 1,2,6. 21
Production scientifique à venir en 2017 Recherche d’une oscillation de l’EDM: Contrainte compétitive sur la matière noire Axion Mesure améliorée du nEDM: • Convergence des analyses Est/Ouest • finalisation des systématiques (stage+these Laura Ferraris) • Unblinding 22
Exposés suivants: • n2EDM au LPSC • EDM sur anneaux de stockage 23
Conclusions: EDMs au LPSC EDM du neutron: IN2P3 / LPSC en position très visible dans la collaboration nEDM@PSI EDM sur anneaux de stockage: Positionnement stratégique pour le futur dans le contexte européen « physics beyond colliders » Complémentarité: • Moyen terme (nEDM) – long terme (pEDM) • Même cas de physique. Organisation d’une école thématique internationale aux Houches en 2019 ou 2020 (financement ERC) • Effets systématiques similaires: dynamique du spin
Projets en compétition 2017 2018 2019 2020 2021 2022 2023 2024 n2EDM n2EDM PSI nEDM construction & commissionning data production Large Scale Commissionning and SNS Integration data taking TRIUMF Phase I Phase II 25
Projet nEDM -> n2EDM à PSI n2EDM n2EDM n2EDM data nEDM construction commissioning production 2017 2018 2019 2020 2021 2022 2023 26
Baryons and antibaryons in the Universe 1015 GeV AMS (Alpha Magnetic Spectrometer) Inflation ends? onboard the International Space Station 100 GeV Electroweak transition 1 MeV 1 eV Decoupling of CMB 1 meV Today Not a single anti-helium detected in cosmic rays (yet) 27
Cosmic Microwave Background 1015 GeV Inflation ends? 100 GeV Electroweak transition 1 MeV [Planck (2014)] 1 eV Decoupling of CMB 1 meV Today CMB = 6.05 ± 0.07 × 10−10 28
Big Bang Nucleosynthesis 1015 GeV Inflation ends? 100 GeV Electroweak transition 1 MeV 1 eV Decoupling of CMB 1 meV Today [Deuterium abundance from Lyα, Cooke et al (2014)] BBN = 6.0 ± 0.1 × 10−10 29
Electroweak phase transition 1015 GeV Standard Model: Inflation ends? 2d order 100 GeV Phase transition Electroweak transition 1 MeV 1 eV Decoupling of CMB Beyond Standard Model: 1 meV Today 1st order Phase transition? 30
Electroweak baryogenesis? Sakharov conditions at electroweak phase transition 1 Departure from thermal equilibrium requires BSM scalar sector to get a strong first order transition. May or may not be accessible at the LHC 2 Violation of B conservation SM sphaleron transitions in the symmetric phase 3 CP violation requires BSM physics, accessible by the next generation of EDM experiments 31
Outline 1 Matter antimatter asymmetry 2 CP violation, electric dipole moments 3 The nEDM experiment 4 Systematics 32
CP violation in weak interactions • Tiny (∼ 10−3 ) CP asymmetry discovered by Cronin and Fitch (1964) looking at 0 → + − ← → • Explained by the Kobayashi-Maskawa mechanism (1973) Flavour ′ Mass eigenstates ′ = eigenstates ′ Complex CKM matrix • Confirmed with “B factories” in 2000’s with many observables, e.g. Γ 0 → + − ≠ Γ 0 → − + ← → Asymmetry ≈ 30 % ! 33
Sensitivity to CP violation Beyond Standard Model • Present limit: < 3 × 10−26 cm • Standard model (KM) prediction: ≈ 10−31 cm • Possible contribution from new physics: 2 sin ℏ ≈ 16 2 2 2 1 TeV ≈ × sin × 10−25 cm multi-TeV BSM sensitivity Testing electroweak baryogenesis 34
Outline 1 Matter antimatter asymmetry 2 CP violation, electric dipole moments 3 The nEDM experiment 4 Systematics 35
First EDM experiment with a neutron beam Smith, Purcell and Ramsey, Phys. Rev. 108, 120 (1957) D: counter A’: spin analyzer C’ :Second RF pulse π /2 spin-flip Free precession in E and B fields ... C: Apply RF pulse π/2 spin-flip... A: spin polarizer 36
First EDM experiment with a neutron beam Smith, Purcell and Ramsey, Phys. Rev. 108, 120 (1957) Vary the RF frequency and measure the resonance curve. Do it for parallel and antiparallel E and B fields. Result: = −0.1 ± 2.4 × 10−20 cm ℏ ≈ 2000 m s , Statistical sensitivity: = ≈2m 2 ≈ 1 ms Main systematic effect: the relativistic motional field = × / 2 37
Getting slower, getting better… 38
Neutron optics, cold and ultracold neutrons Thermal neutrons Cold neutrons E < = 25 meV have large wavelength Cold neutrons > 0.2 nm They behave like waves, affected by the Fermi potential of matter Ultracold neutrons (order of 100 neV) Neutrons with energy < 100 neV, are reflected by material walls they can be stored in material bottles. 39
Institut Laue Langevin in Grenoble Vercors European synchrotron ILL high flux reactor 58 MW Most intense neutron source in the world 1015 n / cm2 / s 40
PF2 instrument (Physique Fondamentale 2) at ILL Filling UCN bottles ∼ 20 UCN cm3 Since 1985 41
The Sussex/RAL/ILL apparatus Apparatus installed at PF2 (1986-2009) Best limit: < 3 × 10−26 cm obtained with 1998 − 2002 data [Baker et al, PRL (2006) ; Pendlebury et al, PRD (2015)] 42
UCN source at the Paul Scherrer Institute pulsed UCN source One kick per 5 min online since 2011 600 MeV, 2.2 mA 43
Finally a worldwide comparison of UCN sources Diter Ries (PhD) stainless steel bottle 44
The nEDM collaboration 13 laboratories 7 countries 48 members 10 PhD students 45
Moving the apparatus to PSI in 2009 46
199Hg Magnetometer Continuous optical pumping in a polarization chamber, polarized gas injected in the precession chamber Modulated absorption of polarized light in the precession chamber 47
Next phase: n2EDM. 2 chambers in a colossal magnetic shield
Broader context 5 nEDM projects worldwide Other EDMs: • Electron (atomic and molecular physics) • 199Hg (atomic physics) • Francium (radioactive atomic physics) • Proton (storage ring) 49
Outline 1 Matter antimatter asymmetry 2 CP violation, electric dipole moments 3 The nEDM experiment 4 Systematics 50
Motional field is back! Magnetic transverse field Motional (transverse) field ⊥ = − ( + ) = × / 2 2 = Frequency shift correlated with electric field for fast Hg particles! 2 2 • Special case (uniform gradient) Hg = 32 2 [Pendlebury et al, PRA 70 (2004)] ∞ 2 • General Refield theory = Im − 0 ∗ ( ) 4 0 2 Hg = ⋅ ⊥ 2 2 [G. Pignol and S. Roccia, PRA 85 (2012)] 51
Direct verification at PSI [Afachet al, EPJD 69 (2015)] Part of Yoann Kermaidic’s PhD thesis 52
The gravitational shift... UCN gas Mercury gas = = 1±ℎ +⋯ Hg Hg 0 Same precession chamber Direct measurement Using an array of Cesium magnetometers 53
Using the gravitational shift Strategy: the “crossing point analysis” EDM B down True EDM = B up Hg Hg Further n n complications = = = 1 + Grav + T + Earth + ⋯ Hg Hg Hg Hg ℎ 2 ↑ ↓ Grav = ± T = Earth 0 2 02 Gravitational shift Transverse fields Earth rotation 54
Effect of Earth rotation 55
Effect of Earth rotation 56
Accuracy cross-check [2 ppm] [0.2 ppm] S. Afach et al., Phys. Lett. B 739, 128 (2014) 57
Conclusion Data production at PSI Perspective: n2EDM @ PSI = 1.2 × 10−26 cm assembly starts end-2017 accumulated ( nov 2016) Remove the blinding in 2017 Sensitivity increase minimum 10 Dismount summer 2017 In maximum 10 years Baryogenesis @EW transition -> Yes or no? 58
MERCI On recherche des nouveaux collaborateurs pour n2EDM On embauche des postdocs ! 59
Light shift • No scalar light shift (expected) • No vector light shift 60
Transverse field systematics UCNs: 2 it takes ~ 3 Larmor rotations T = to cross the chamber. 2 02 Adiabatic regime: 2 n ∝ = 0 + 2 0 Mercury: Atoms cross the cell ~ 60 times during a Larmor rotation Non-adiabatic regime: Hg ∝ = 0 Field mapping (not that easy…) to measure 2 61
Conclusion Data production at PSI End 2016: = 1.2 × 10−26 cm stop data production accumulated improve (slightly) the ILL result. ( nov 2016) 2017: reveal the blinding. End 2017: install n2EDM shield. We think we 202X: improved understand our accuracy by a factor 10. systematic effects pretty well. Baryogenesis at EW transition? yes or no. 62
Tester la baryogénèse électrofaible Find ft baryogenesis -> 6037 Find ft baryogenesis and ft “electric dipole moment” -> 911 Find ft “electric dipole moment” -> 5578 Find ft LHCb -> 9318 63
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