Поиск ЭДМ нейтрона кристалл-дифракционным методом Воронин Владимир ПИЯФ, Гатчина Секция ЯФ ОФН РАН, ИТЭФ March 20161

Neutron EDM Non zero EDM means the P and T violation P P – spatial inversion С С – particle – antiparticle inversion Т Т – time inversion CPT theorem (Lüders (1954); Pauli(1955)) (Our world is СРТ invariant) Non zero nEDM means СР violation 21 March 20162

History of nEDM experiment Standard model d n ~( ) e cm New physics to explain the baryon asymmetry (experiment - n b /n  ~ SM - n b /n  ~ ) d n ~( ) e cm Neutron scattering in-flight magnetic resonance UCN magnetic resonance 21 March 20163

Idea nEDM experiment 2(E·D) -E +EDD Interaction time with Е Sensitivity to nEDM Neutron size R n ~ cm, d n /R n ~ 3  Corresponding size from Earth is ~ 2 μm Current accuracy to d n 21 March 20164

Sensitivity to neutron EDM E~ grad V e ~(0.1-1)GV/cm UCN method Crystal-diffraction method E ~ 10 kV/cm τ ~ 1000s (time of life) Е τ ~ 10 7 (V·s)/cm Е τ Now Е τ ≈ 10 6 (V·s)/cm τ a ~ 0.01 c (absorption) 10 7 (V·s)/cm ЕτЕτЕτЕτ Electron bonding energy ~ a few eV Å 21 March 20165

+ - Neutron optic of NCS crystal M. Forte, J. Phys. G: Nucl. Phys. (1983) V. G. Baryshevskii and S. V. Cherepitsa, Phys. Stat. Sol. B128 (1985) V. V. Fedorov, Proc. of XXVI Winter LNPI School, vol. 1, Leningrad (1991) 65. Wave function g d L V || v  k k+g Electric field Deviation from Bragg condition Electric field depends on a deviation from Bragg condition E E (Neutron energy) 21 March 20166

 /2 Idea of the experiment For  /2 reflection E || v n and H s ~[E x v n ]≈0+E-E 21 March 20167

Electric field quartz (110) plane L c =14 cm Bragg angle ≈ · 10 8 V/cm Theory + 0.8·10 8 V/cm Variation of the  T on  1K E ≈  10 8 V/cm 21 March 20168

Test experiment PNPI V.V. Fedorov, E.G. Lapin, I.A. Kusnetsov, S.Yu. Semenikhin, V.V. VoroninILL M. Jentschel, E. Lelievre-Berna, V. Nesvizhevsky, A. Petoukhov, T. Soldner, F.Tasset 21 March 20169

Layout of the experiment. 6 m 21 March

nEDM measurement d n =(2.4  6.5) e cm P 0 =0.82 K BG = 0.85 K r =0.7 E= (0.7±0.1) 10 8 V/cm 21 March

Improvement the sensitivity for current geometry of experiment Test setup Full scale setup K imp Crystal size, cm14x2x250x10x Beam size, cm  27 S=5.7 6x12 S= Beam collimation, sr (4/700 )2 = 3.2 · (12/450) 2 =7.1 · Reducing the background Absorption in quartz K s = d n, e cm per day March

Crystal quartz test Now we have quartz crystal with summary size 100x100x500 mm 3 with  d/d~ March Доклад Семенихина С.Ю.

21 March D analysis of neutron polarization Magnetic field || surface of the superconductor. H L ≈0H L ≠0 P Current accuracy of spin orientation is ~10 -2 rad ~10 -2 rad for routine experiment ~10 -3 rad ~10 -3 rad can be reached for special cases F. Tasset, P.J. Brown, E. Lelie`vre-Berna, T. Roberts, S. Pujol, J. Allibon, E. Bourgeat-Lami, Physica B, (1999)

21 March CRYOPAD-D under construction 60cm Size - 60cm 10x10 cm 2 Beam aperture –10x10 cm Nutator fields homogeneity –

CrystalSymmetry group hkld, (Å)E g, 10 8 V/cm  a, ms E g  a, (kV  s/cm)  -quartz (SiO 2 ) 32(D 6 3 ) Bi 12 SiO 20 I Bi 12 GeO 20 I PbOP c a BeO6mm Parameters of some NCS crystals !!! We should looking for new NCS crystal !!! 21 March

Storage variant t=0 0<t<2t a t=2t a 3 He cell Detector HfHf HiHi Perfect crystal reflection T=T 0 T=T 0  T Up to 1000 reflections (  s ~1 s) M.R. Jaekel, C.J. Carlile, E.Jericha, D.E. Schwab and H. Rauch, SPIE Vol EUV, X-Ray, and Neutron Opticas and Sources, 353 (2000) 21 March

Some numerical estimation Bragg width – Responsible time – Crystal acceleration – (fast piezoelectric element?) 21 March

Sensitivity estimation E g, 10 8 V/cm , ms Count rateKgKg  d, e  cm per day  -quartz (110) in-flight (L=50cm) 10 4 n/s (ILL PF1) (2-3) Bi 12 SiO 20 (444) storage (L=15 cm) 10 3 n/s (ESS - SP) 10 (2-3) March

Conclusion  d ~(2-3)· e·cm per 100 day of measurement Full-scale setup with quartz crystal could have a sensitivity  d ~(2-3)· e·cm per 100 day of measurement Storage modification of crystal-diffraction nEDM experiment could reach a sensitivity  d ~(2-3)· e·cm  d ~(2-3)· e·cm for the short pulse ESS and BSO crystal 21 March

21 March Summary of the systematic Residual magnetic field Value Time stability 3D analysis of polarization The crystals alignment The ΔT 0 control ~ K ~0.01 arc degree Flat windows of CRYOPAD P odd rotation is d n ~ e cm