S. Roccia, on behalf of the nEDM collaboration at PSI Search for the nEDM at the Paul Scherrer Institute
Outlines — 2 — EDM, ALP, mirror neutrons Co-magnetometer era Co-magnetometer + magnetometer era OILL n2EDM ILL 1979-2009 PSI 2020-???? OILL RAL/Sussex/ILL collab. PSI 2009-2017 dn<3.10 -26 e.cm (2006)
The nEDM landscape — 3 — A nonzero particle EDM violates T, P and, SM predictions (strong sector) assuming CPT conservation, also CP . -19 10 Neutron EDM Upper Limit [ e cm] -20 10 ORNL, Harvard MIT, BNL Strong CP problem -21 10 LNPI -22 10 Sussex, RAL, ILL QCD < 10 -10 10 orders of magnitude -23 10 -24 10 -25 10 -26 10 Supersymmetry predictions Beyond SM + cosmology -27 10 -28 10 Phase in the CKM matrix SM predictions (weak sector) -31 Standardmodel calculations 10 -32 10 1950 1960 1970 1980 1990 2000 2010 2020 Year of Publication
The nEDM search — 4 — B 0 T B E B h E e d > > > d n > m m E Neutrons reflected for all incidence D angles: UCNs M See poster by N. HILD
The nEDM search — 5 — The Ramsey’s method of separated oscillating fields Spin-Up Neutron Counts 24000 22000 20000 18000 x x x 16000 x 14000 12000 10000 Resonant freq. x = working points 29.7 29.8 29.9 30.0 30.1 Applied Frequency (Hz)
The nEDM search — 6 —
The nEDM search — 7 — First limitation ….. Magnetic field fluctuations Mercury co-magnetometer (1998) Cesium magnetometer array (2009)
The nEDM search — 8 — Excellent stability • (dynamic SFC & 4 layer magnetic shield) Stability (AD) @400s: ~<400fT • Stabilisation of the ambient field ~ 100 nT Stabilisation of the inner field ~ 100 pT Afach et al., J. Appl. Phys. 116 , 084510 (2014)
The nEDM search — 9 — 3.5 days The Hg co-magnetometer 1.6pT 1 0 0 p T
The nEDM search — 10 — Monitoring of the vertical gradient Homogenisation of the magnetic field
A nEDM apparatus — 11 — A non perfect Co-magnetometer • Gravitational shift G PSI 2012 In the precession chamber B0 up B0 down Mercury UCNs g
Some results — 12 — S. Afach et al., PLB 739 , 128 (2014)
The nEDM apparatus — 13 — Geometrical phase shift Hg comagnetometer Pendlebury et al, PRA 70 032102 (2004) Motional (transverse) field Magnetic transverse field Frequency shift correlated with electric field False EDM for Mercury (fast regime of GPE) At 1 st order in gradients See Poster by L. FERRARIS-BOUCHEZ S. Afach et al, EPJD 69 , 225 (2015)
A nEDM apparatus — 14 — The analysis strategy (RAL/Sussex/ILL like) and associated systematic errors Geometrical phase shift: frequency shift for particles in traps (large for the Hg atoms) EDM B down B up In the case of an inhomogeneous B-field Indirect systematic effect due to local At 1 st order in gradients dipoles Pignol et al, PRA 85 042105 (2012)
Some results — 15 — Gravitational enhanced depolarization and associated frequency shift P. G. Harris et al., Phys. Rev. D 89, 016011, (2014) Gravitational depolarization of ultracold neutrons: Comparison with data, Phys Rev D 92,5 (2015)
— 16 — Some results See poster by Spin-echo spectroscopy G. ZSIGMOND g z Physical review letters 115 (16), 162502 (2015)
Some results — 17 — Physical Review D 92 (9), 092003 (2015)
nEDM sensitivity — 18 — nEDM@ILL nEDM@PSI n2EDM@PSI 2006 2016 2020 Statistical sensitivity Chamber 1 1 2 Diameter (cm) 47 47 100 Neutron/cycle 14 000 15 000 400 000 E(kV/cm) 8.3 11 (15) 15 T(s) 130 180 180 α 0.45 (0.6) 0.75 (0.80) 0.8 Pushing the limit of the technique Sens/day(e.cm) 30*10 -26 11*10 -26 1.4*10 -26 at room temperature Sens (500 days) 1.3*10 -26 5.0*10 -27 6.4*10 -28 World record for sensitivity
2016 + 2015: data taking — 19 — 2015: 112 days 2016: 139 days ● 2016 : 1.5 % of available pulses missed
2016 + 2015: data taking — 20 — On-going analysis (preliminary) - Blinded data - 2 analysis teams (East/West) Demonstrated sensitivity after analysis (2015-2016) * PRELIMINARY & BLINDED * but systematic effects
EDM by product — 21 — C. Abel et al. (RAL-Sussex-ILL collab. + PSI collab + King’s College London) Physical Review X 7, 041034 (2017) PSI data: high sensitivity Still blinded ILL data: long data taking Another result to come (2017 data taking) : see poster by P. MOHANMURTHY
n2EDM — 22 — EDM, ALP, mirror neutrons Co-magnetometer era Co-magnetometer + magnetometer era OILL n2EDM ILL 1979-2009 PSI 2020-???? OILL RAL/Sussex/ILL collab. PSI 2009-2017 dn<3.10 -26 e.cm (2006)
n2EDM — 23 — EDM, ALP, mirror neutrons Co-magnetometer era Co-magnetometer + r e b magnetometer era m a h c e l b u a o r D e OILL n2EDM ILL 1979-2009 PSI 2020-???? L OILL L I & I P N P RAL/Sussex/ILL collab. PSI 2009-2017 dn<3.10 -26 e.cm (2006)
nEDM sensitivity: looking backward and going forward — 24 — See poster by D. VICENTE PAIS nEDM@ILL nEDM@PSI n2EDM@PSI 2006 2016 2020 Chamber 1 1 2 Diameter (cm) 47 47 80 Neutron/cycle 14 000 15 000 121 000 E(kV/cm) 8.3 11 (15) 15 T(s) 130 180 180 α 0.45 (0.6) 0.75 (0.80) 0.8 Sens/day(e.cm) 30*10 -26 11*10 -26 2.6*10 -26 Sens (500 days) 1.3*10 -26 5.0*10 -27 1.2*10 -27 See poster by 1.5*10 -27 G. ZSIGMOND
R&D towards n2EDM — 25 — Hg co-magnetometer nEDM sensitivity: 50-70 fT (35 fT) n2EDM requirements: 26 fT Demonstrated sensitivity: 8 fT Used for nEDM data taking in 2017 But also new current source Using a potassium magnetometer → see poster by P. Koss
2017&2018: Hard work in the UCN hall — 26 — See poster by P. Flaux June 2018 installation of the shielded room See n2EDM poster by B. LAUSS
Merci ! — 27 —
Summary — 28 — ● n2EDM R&D efforts merged into one concept design ● Highly based on demonstrated techniques ● Shielded room expected in 2018 ● nEDM operated with high efficiency and world-record sensitivity ● Systematic effect studies reanalysis of 2006 data ● More data in 2017 for by products Thanks Merci
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