Charged Partices Eectric Dipoe Moment Searches in Storage Rings Paoo Lenisa Università di Ferrara and INFN - Itay MESON 2016 Krakow, Poand, June 4 th 2016
Eectric Dipoes Definition p =q s Charge separation creates an eectric dipoe Orders of magnitude H 2 O moecue: permanent EDM (degenerate GS of different Parity) P. Lenisa Atomic physics Hadron physics Charges e e r 1 -r 2 1 Å = 10-8 cm 1 fm = 10-13 cm naive expectation 10-8 e cm 10-13 e cm observed water moecue 2 10-8 e cm Search for EDM in Storage Rings neutron < 3 10-26 e cm EDM = 3 10-26 e cm separation between u and d quarks < 5 10-26 cm 2
EDM of fundamenta partices Moecues have arge EDM because of degenerated ground states with different parity Eementary partices (incuding hadrons) have a definite partiy and cannot have EDM Uness P and T reversa are vioated µ: magnetic dipoe moment d: eectric dipoe moment P. Lenisa Permanent EDMs vioate P and T Assuming CPT to hod, CP is vioated aso 3
Matter-Antimatter asymmetry Equa emounts of matter and antimatter at the Big Bang. Universe dominated by matter. η= nb nb nγ Observed SM prediction 6x10-10 10-18 1967: 3 Sacharov conditions for baryogenesis Baryon number vioation C and CP vioation Therma non-equiibrium New sources of CP vioation beyond SM to expain this discrepancy They coud manifest in EDM of eementary partices P. Lenisa Carina Nebua (Largest-seen star-birth regions in the gaaxy) 4
EDM: hystory and imits History of neutron EDM EDM imits P. Lenisa Search for EDM in Storage Rings 5
Why charged partices EDMs? No direct measurements for charged partices exist; Partiay higher sensitivity (compared to neutrons): Longer ife-time; More stored protons/deuterons; Compementary to neutron EDM: d d =d p +d n -> access to θ QCD EDM of one partice aone not sufficient to identify CP-vioating source P. Lenisa Search for EDM in Storage Rings 6
EDM of charged partices: use of storage rings PROCEDURE Pace partices in a storage ring Aign spin aong momentum ( freeze horizonta spin precession) Search for time deveopment of vertica poarization d s /dt = d E P. Lenisa Search for EDM in Storage Rings 7
Requirements POLARIMETER The sensitivity to poarization must by arge (0.5). The efficiency of using the beam must be high (> 1%). Systematic errors must be managed (< 10 6 ). LARGE ELECTRIC FIELDS (E=10 MV/m). N.P.M. Brantjes et a. NIMA 664, 49 (2012) POLARIZED BEAM Poarization must ast a ong time (> 1000 s). Poarization must remain parae to veocity. SYSTEMATIC ERROR PLAN P. Lenisa Search for EDM in Storage Rings 8
Systematics One major source: Radia B r fied mimics EDM effect Exampe: d = 10-29 e cm with E = 10 MV/m If µb r de r this corresponds to a magnetic fied: (Earth magnetic fied = 5 10-5 T) Soution Use two beam running cockwise and countercockwise. Separation of two beams sensitive to B BPM with reative resoution < 10 nm required use of SQUID magnetomers (ft/ Hz)? Study @ FZJ P. Lenisa Search for EDM in Storage Rings 9
Spin precession in a storage ring: Thomas-BMT Equation Ω: anguar precession frequency d: eectric dipoe moment γ: Lorentz factor G: anomaus magnetic moment P. Lenisa Search for EDM in Storage Rings 10
Spin precession in a storage ring: Thomas-BMT Equation Ω: anguar precession frequency d: eectric dipoe moment γ: Lorentz factor G: anomaus magnetic moment Dedicated ring: pure eectric fied, freeze horizonta spin motion: =0 ony possibe if G>0 (proton) P. Lenisa Search for EDM in Storage Rings 11
Spin precession in a storage ring: Thomas-BMT Equation Ω: anguar precession frequency d: eectric dipoe moment γ: Lorentz factor G: anomaus magnetic moment Dedicated ring: pure eectric fied, freeze horizonta spin motion: =0 ony possibe if G>0 (proton) combined E/B ring (e.g. deuteron): =0 P. Lenisa Search for EDM in Storage Rings 12
Spin precession in a storage ring: Thomas-BMT Equation Ω: anguar precession frequency d: eectric dipoe moment γ: Lorentz factor G: anomaus magnetic moment COSY: pure magnetic ring, access to EDM d via motiona eectric fied vxb RF - E and B fieds to suppress GB contribution P. Lenisa Search for EDM in Storage Rings 13
Spin precession in a storage ring: Thomas-BMT Equation Ω: anguar precession frequency d: eectric dipoe moment γ: Lorentz factor G: anomaus magnetic moment COSY: pure magnetic ring, access to EDM d via motiona eectric fied vxb RF - E and B fieds to suppress GB contribution negecting EDM term: spin-tune = γg P. Lenisa Search for EDM in Storage Rings 14
Summary of different options Advantage Disadvantage 1. Pure magnetic ring Existing (COSY upgrade) Lower sensitivity 2. Pure eectric ring No B fied Ony p 3. Combined ring Works for p, d, 3 He Both E and B required P. Lenisa Search for EDM in Storage Rings 15
COoer SYnchrotron (FZ-Jüich, GERMANY) COSY provides poarized protons and deuterons with p = 0.3 3.7 GeV/c Idea starting point for charged partices EDM search Search for EDM in Storage Rings 16
COoer SYnchrotron (FZ-Jüich, GERMANY) Momentum: <3.7 GeV/c Circumference: 183 m Poarized proton and deuteron Beam poarimeter (EDDA detector ) Instrumentation avaiabe for manipuation of poarization (RF soenoid) 17
Experimenta tests at COSY Inject and acceerate poarized deuterons to 1 GeV/c P. Lenisa Search for EDM in Storage Rings 18
Experimenta tests at COSY Inject and acceerate poarized deuterons to 1 GeV/c Fip spin in the horizonta pane with hep of soenoid P. Lenisa Search for EDM in Storage Rings 19
Experimenta tests at COSY Inject and acceerate poarized deuterons to 1 GeV/c Fip spin in the horizonta pane with hep of soenoid Extract sowy (100 s) beam on target Measure asymmetry and determine spin precession P. Lenisa Search for EDM in Storage Rings 20
EDDA beam poarimeter ASYMMETRIES ε V = L R L + R p V A y beam eooo VERTICAL poarization Anayzing power ε H = U D U + D p H A x HORIZONTAL poarization Anayzing power Beam moves toward thick target continuous extraction 21 Eastic scattering (arge cross section for d-c)
Spin-precession measurement P. Lenisa Search for EDM in Storage Rings 22
Resuts: spin coherence time Short Spin coherence time: Unbunched beam: Δp/p=10-5 ->Δγ/γ=2x10-6, T rev =10-6 s Decoherence after < 1s Bunching eiminates 1 st order effect in Δp/p: SCT τ = 20 s Long Spin coherence time: Betatron osciations cause variation of orbit ength Correction wit sextupoes SCT τ = 400 s P. Lenisa Search for EDM in Storage Rings 23
Spin-tune Spin tune ν s = γg = nb. of spin rotations/nb. of partice revoutions Deuterons: p d = 1 GeV/c (γ=1.13), G = - 0.14256177 (72) -> ν s = γg - 0.161 P. Lenisa Search for EDM in Storage Rings 24
Resuts: Spin-tune measurement Precision: 10-10 in one cyce of 100 s (ange precision: 2πx10-10 = 0.6 nrad) It can be used as a too to investigate systematic errors Feedback system to keep poarization aigned with momentum in a dedicated ring or at with respect to RF Wien fiter (-> next sides) P. Lenisa Search for EDM in Storage Rings 25
Appication: Spin feedback system Simuation of an EDM experiment using µ: Poarization rotation in horizonta pane (t = 85 s) RF soenoid (ow ampitude) switched on (t = 115 s) COSY-RF controed in steps of 3.7 mhz (f rev =750603 Hz) to keep spin phase at RF-soenoid constant Poarization sowy rotates back to vertica direction P. Lenisa Search for EDM in Storage Rings 26
The goa: first direct measuerement of deuteron EDM with RF-technique Pure magnetic ring (existing machines) Probem: precession caused by magnetic moment:. - 50 % of time ongitudina poarization to momentum - 50 % of time is anti- E* in partice rest frame tits spin (due to EDM) up and down No net EDM effect Search for EDM in Storage Rings 27
The goa: first direct measuerement of deuteron EDM with RF-technique Pure magnetic ring (existing machines) Probem: Soution; precession use of resonant caused magic by magnetic Wien-fiter moment:. in ring (E+vxB=0) - 50 % of time ongitudina poarization to momentum - E*=0 50 % of time partice is anti- trajectory not affected B* 0 magnetic moment is infuenced E* in partice rest frame tits spin (due to EDM) up and down net EDM effect can be observed! No net EDM effect Search for EDM in Storage Rings 28
Operation of magic RF Wien fiter Osciating radia E and B fieds. beam energy Td=50 MeV Search for EDM in Storage Rings 29
RF-Wien fiter E R = - γ x B y Magic RF Wien Fiter no Lorentz force Avoids coherent betatron osciations of. First direct measurement at COSY. Prototype commissioning in 2015 New RF stripine Wien fiter to be instaed at COSY beginning of 2017. 30
Simuations and Projections EDM signa is buid-up of vertica poarization Radia magnetic fied mimic same buid-up Eg: misaignments of quadrupoes cause unwanted B r Run simuations to understand systematics effects Genera probem: track 10 9 partices for 10 9 turns! Simuation by M. Rosentha Orbit RMS Δy RMS is a measure of misaignments Random misaignments from 1 µm to 1 mm η = 10-5 corresponds to EDM of 5 x 10-20 e cm P. Lenisa Search for EDM in Storage Rings 31
Summary and Outook EDMs high sensitive probes of CP vioation. Storage ring and poarization technoogy pave the way to charged partice EDM. First promising resuts at COSY: Spin coherence time: few hundred seconds. Spin tune measurement: 10-10 in 100 s. Spin feedback system: aows to contro spin. Simuations: to understand systematics. Goa: first direct measurement of deuteron EDM in 2018-19 Technica design report for a dedicated machine. 2016 ERC AdG EDM search in Storage rings Consortium: FZJ (prof. H. Stroeher) RWTH Aachen (prof. J. Praetz) University of Ferrara (prof. P. Lenisa) P. Lenisa Search for EDM in Storage Rings 32
P. Lenisa Search for EDM in Storage Rings 33
Eectrostatic eectron ring First ever DIRECT measurement of eectron EDM. Compact Magic energy for eectron: 14.5 MeV (γ=29.4) E = 2-6 MeV/m 2πR = 50-20 m Technica chaenge, modest investment. 15 (± 5) M 20 FTE Mandatory step for arger machines (proton and deuteron 2πR > 250 m). Open issue: poarimetry. (from R. Taman) P. Lenisa Search for EDM in Storage Rings 34