POLARIMETRY FOR A STORAGE-RING ELECTRIC-DIPOLE-MOMENT MEASUREMENT 8 - - PowerPoint PPT Presentation

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POLARIMETRY FOR A STORAGE-RING ELECTRIC-DIPOLE-MOMENT MEASUREMENT 8 - - PowerPoint PPT Presentation

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POLARIMETRY FOR A STORAGE-RING ELECTRIC-DIPOLE-MOMENT MEASUREMENT 8 JUNE 2018 MARIA UREK FOR THE JEDI COLLABORATION MOTIVATION Barion Asymmetry Problem Barion Asymmetry Observation Standard Cosmological Model x ( N N

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POLARIMETRY FOR A STORAGE-RING ELECTRIC-DIPOLE-MOMENT MEASUREMENT

8 JUNE 2018 MARIA UREK FOR THE JEDI COLLABORATION Ż

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8 June 2018 Maria Żurek – Polarimetry for EDM

MOTIVATION

Barion Asymmetry Observation Standard Cosmological Model

( N

B

– N

B

) / N

γ

6

x

1

  • 1

~ 1

  • 1

8

Barion Asymmetry Problem

Page 2

Matter Antimatter

Preconditions needed to explain it (Sakharov):

  • C

and C P violation

  • Baryon number violation
  • Thermal non-equilibrium in the early Universe

C P violation in Standard Model

  • Electroweak sector (CKM matrix well established)
  • Strong interactions ( -term, strong-

θ C P puzzle) Predictions orders of magnitude too small to explain the asymmetry! New sources of C P violation can be seen in EDM of particles

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8 June 2018 Maria Żurek – Polarimetry for EDM

ELECTRIC DIPOLE MOMENT

Page 3

d μ

S

The observable quantity - Energy:

  • of electric dipole in electric field
  • of magnetic dipole in magnetic field

H violates T and P

  • symmetry if d≠0

T violation C P violation (C P T conserved)

External fields Pseudo vectors

C P

  • symmetry violation
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8 June 2018 Maria Żurek – Polarimetry for EDM

Current limits

ELECTRIC DIPOLE MOMENT

Upper limits

Page 4

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8 June 2018 Maria Żurek – Polarimetry for EDM

PRINCIPLE OF EDM MEASUREMENT

Charged Particles in a Storage Ring

Page 5

General idea: Observation of EDM interaction with electric field “Frozen spin” - Spin parallel to momentum Simplified case – pure E field: η 0: spin rotation out of horizontal plane ≠ Build-up of vertical polarization η ∝ spin rotation angle EDM ~ 10-29 e·cm effect of the order of deg/hour μ Extremely small effects!

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8 June 2018 Maria Żurek – Polarimetry for EDM

HOW TO MEASURE BEAM POLARIZATION?

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Scattering from Carbon target

2π detector - “beam” view Up/Down asymmetry ∝ horizontal component of polarization Px Right/Left asymmetry ∝ vertical component of polarization Py EDM signal appears here Needed to maintain “frozen spin” condition Typically A

y

~ . 6

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8 June 2018 Maria Żurek – Polarimetry for EDM

POLARIMETRY FOR AN EDM EXPERIMENT

Challenge: measurement of tiny polarization build-up

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For proton EDM ~ 10-29 e·cm and ~ 1year of measurement Minimization of asymmetry error:

➔ Maximization of FoM

Long term reproducibility:

➔ Continuous measurement for a long time

EDM signal

Polarimetry requirements

Systematics count! Figure of Merit Efficiency High Ay

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8 June 2018 Maria Żurek – Polarimetry for EDM

ACTIVITY AT COSY

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Jülich Electric Dipole moment Investigations (JEDI) http://collaborations.fz-juelich.de/ikp/jedi/

Polarimetry-group activity:

  • Development of dedicated polarimeter

based on LYSO crystals

  • Database experiment with WASA

detector Motivation:

  • Optimal configuration of the polarimeter

R&D with towards first proof-of-principle EDM experiment for deuterons and protons Goal: Ay, Ayy, d /d σ Ω for

  • dC elastic scattering
  • main background reactions (deuteron breakup)
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8 June 2018 Maria Żurek – Polarimetry for EDM

DEUTERON DATABASE EXPERIMENT WITH WASA

Detector Setup

Page 9

Beamtime in November 2016 (2 weeks) Deuteron energies: 170, 200, 235, 270, 300, 340, 380 MeV Nominal beam polarization: (Py,Pyy) = (0,0), (-⅔,0), (⅔,0), (½, -½), (-1, 1) Targets: C and CH2 Setup: Modified WASA Forward Detector

Range Hodoscopes Plastic scintillators Proportional Chambers Window Counters Plastic scintillators Trigger Hodoscope Plastic scintillator Target position

  • Full coverage

φ

  • range 4° - 17°

θ 17

  • 17
  • 4
  • 4
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8 June 2018 Maria Żurek – Polarimetry for EDM

DATABASE EXPERIMENT WITH WASA

Analyzing power for elastic dC scattering

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8 June 2018 Maria Żurek – Polarimetry for EDM

DATABASE EXPERIMENT WITH WASA

Analyzing power for elastic dC scattering

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Preliminary

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8 June 2018 Maria Żurek – Polarimetry for EDM

DATABASE EXPERIMENT WITH WASA

Elastic dC cross-section:

  • Luminosity calculated using deuteron-proton

elastic scattering registered with CH2 target

  • Discrepancy in available world data even 40%
  • Statistical errors shown
  • Additional systematic errors ~ 7%

Page 12

Cross section for Ed

kin = 270 MeV

Ermish et al. PRC 71, 064004 Sekiguchi et al. PRC 65, 034003 Hatanaka et al.

Private communication

Sakamoto et al. PLB 367, 60

PLB 549, 307

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8 June 2018 Maria Żurek – Polarimetry for EDM

DATABASE EXPERIMENT WITH WASA

Page 13

Figure of Merit for Ed

kin = 270 MeV

FoM = d /d A σ φ

y 2

FoM = d /d σ Ω Ay

2

Artificial enhancement by sin term θ Optimal working conditions for : 5-9 θ

  • PLB 549, 307
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8 June 2018 Maria Żurek – Polarimetry for EDM

DATABASE EXPERIMENT WITH WASA

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Figure of Merit for Ed

kin = 200 MeV

FoM = d /d A σ φ

y 2

FoM = d /d σ Ω Ay

2

Artificial enhancement by sin term θ Optimal working conditions for : 12-16 θ

  • PRC 70, 034318
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8 June 2018 Maria Żurek – Polarimetry for EDM

WASA AS A POLARIMETER

Elliptical tight cut Band cut All triggers Pure deuteron elastic Single deuteron in FRH3 Single track in FRH3

d

FRH3 FRH2 FRH1

Possible energy acceptance:

  • 1. Track reaching stopping layer
  • Pure elastic deuteron
  • Single deuteron
  • Single track
  • 2. Single track in one layer before
  • 3. Single track in two layers before etc.

p d

Page 15

Trigger cut

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8 June 2018 Maria Żurek – Polarimetry for EDM

WASA AS A POLARIMETER

FoM = NAy

2 – detector acceptance included

  • Flat for 3-14o for single track in stopping layer

(red line).

  • Removing protons enhances FoM for higher

angles because of larger Ay (magenta line).

Figure of Merit for Ed

kin = 200 MeV

Page 16

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8 June 2018 Maria Żurek – Polarimetry for EDM

WASA AS A POLARIMETER

FoM = NAy

2 – detector acceptance included

  • Optimal for single track in stopping layer

(red line).

  • Distribution is peaking.
  • Removing protons doesn't enhance FoM but

enhances Ay (magenta line).

Figure of Merit for Ed

kin = 235 MeV

Page 17

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8 June 2018 Maria Żurek – Polarimetry for EDM

WASA AS A POLARIMETER

FoM = NAy

2 – detector acceptance included

  • Optimal single track in one before stopping

layer (red line).

  • Peak narrower then for 235 MeV.
  • Removing protons doesn't enhance FoM but

enhances Ay (magenta line and blue line).

Figure of Merit for Ed

kin = 270 MeV

Page 18

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8 June 2018 Maria Żurek – Polarimetry for EDM

WASA AS A POLARIMETER

FoM = NAy

2 – detector acceptance included

  • Optimal for single track in stopping layer

(red line).

  • Peak is narrower then for 270 MeV.
  • Removing protons doesn't enhance FoM but

enhances Ay (magenta line and blue line).

Figure of Merit for Ed

kin = 300 MeV

Page 19

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8 June 2018 Maria Żurek – Polarimetry for EDM

SUMMARY

  • EDMs of elementary particles key for understanding

sources of CP violation

➔ explanation of matter – antimatter imbalance

  • Extremely ambitious measurement for charged particles
  • Preparations for proof-of-principle experiment at COSY in

progress for deuterons

  • Polarimetry development to face the challenge of measurement
  • f tiny polarization build-up
  • Database measurement shows right direction to go

Page 20

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8 June 2018 Maria Żurek – Polarimetry for EDM

THANK YOU!

http://collaborations.fz-juelich.de/ikp/jedi/ mariakzurek@gmail.com @mariakzurek

Page 21

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8 June 2018 Maria Żurek – Polarimetry for EDM

BACKUP

Page 22

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8 June 2018 Page 23 Maria Żurek – Polarimetry for EDM

Disentangle the fundamental source(s) of EDMs

Experiment Where is the EDM? How do we understand it? Dream

Electric Dipole Moment of proton and deuteron

MOTIVATION

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8 June 2018 Maria Żurek – Polarimetry for EDM

Thomas-BMT equation:

In storage rings (magnetic field – vertical, electric field - radial)

Magnetic moment causes fast spin precession in horizontal plane

SPIN IN MAGNETIC AND ELECTRIC FIELD

Page 24

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8 June 2018 Page 25 Maria Żurek – Polarimetry for EDM

High precision storage ring alignment, stability, field homogeneity High intensity beams N = 4 x 1010 per fill Polarized hadron beams P = 0.8 Large electric fields E = 10 MV/m Long spin coherence time τ = 1000 s Polarimetry analyzing power A = 0.6, acc. f = 0.005

Even in Pure Electric Ring – lots of sources of syst. uncertainties → Very small radial B field can mimic an EDM effect μBr ~ dEr Challenge: systematic uncertainties on the same level!

EXPERIMENTAL REQUIREMENTS

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8 June 2018 Maria Żurek – Polarimetry for EDM

EDMs of charged hadrons: p, d R&D with deuterons p = 1 GeV/c G = -0.14256177(72) νs

  • 0.161

≈ f 120 kHz ≈

R&D AT COSY

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8 June 2018 Page 27 Maria Żurek – Polarimetry for EDM

Measurement of fast precessing polarization

  • Phys. Rev. ST Accel. Beams 17, 052803 (2014)

Precise determination of spin tune

  • Phys. Rev. Lett. 115, 094801 (2015)

Spin coherence time

  • Phys. Rev. Lett. 117, 054801 (2016)

Phase lock of spin precession

  • Phys. Rev. Lett. 119, 014801 (2017)

Dedicated polarimetry & Database for future polarimetry Beam instrumentation Wien filter commissioning

R&D AT COSY

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8 June 2018 Page 28 Maria Żurek – Polarimetry for EDM

E* field tilts spin due to EDM 50% of time up 50% of time down

WIEN FILTER METHOD

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8 June 2018 Page 29 Maria Żurek – Polarimetry for EDM

  • Wien Filter: introduces B and E

field oscillating with radio frequency

  • Lorentz force vanishes: no effect
  • n EDM rotation
  • Effect: Adds extra horizontal

precession

Wien Filter has to be always in phase with the horizontal spin precession! Feedback system developed and tested: Phys. Rev. Lett., 119, 014801 (2017) Resonant frequency controlled, precession of spin phase locked

WIEN FILTER METHOD

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8 June 2018 Page 30 Maria Żurek – Polarimetry for EDM

WIEN FILTER COMMISSIONING

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8 June 2018 Page 31 Maria Żurek – Polarimetry for EDM

Preliminary Preliminary

Spin build-up as a function of phase ~ sinΔφ → Feedback system works properly!

Controlled via WF frequency

WIEN FILTER COMMISSIONING – 90O MODE

SPIN ROTATIONS WITH PHASE LOCK

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8 June 2018 Page 32 Maria Żurek – Polarimetry for EDM

We see vertical polarization buildup - EDM-like signal Two systematic contributions:

  • 1. Residual, radial magnetic field from WF
  • effect equivalent to WF rotation
  • 2. Field imperfections in COSY
  • transverse contribution: equivalent to WF rotation
  • longitudinal contribution: equivalent to additional static solenoid field

The measurement shows the stability of COSY conditions within 24 hours

Preliminary

WIEN FILTER COMMISSIONING – 0O MODE

SPIN ROTATIONS WITH PHASE LOCK

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8 June 2018 Page 33 Maria Żurek – Polarimetry for EDM

POLARIMETRY

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8 June 2018 Page 34 Maria Żurek – Polarimetry for EDM

POLARIMETRY

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8 June 2018 Page 35 Maria Żurek – Polarimetry for EDM

POLARIMETRY

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8 June 2018 Page 36 Maria Żurek – Polarimetry for EDM

Monitoring phase of asymmetry with fixed spin tune

P R L 1 1 5 , 9 4 8 1 ( 2 1 5 )

SPIN TUNE MEASUREMENT

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8 June 2018 Page 37 Maria Żurek – Polarimetry for EDM

At the beginning all spin vectors aligned After some time spin vectors all out of phase

Polarization vanishes → measurement time limited

SPIN COHERENCE TIME

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8 June 2018 Page 38 Maria Żurek – Polarimetry for EDM

SPIN COHERENCE TIME

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8 June 2018 Page 39 Maria Żurek – Polarimetry for EDM

Goal: Maintain resonance frequency and phase between spin precession and Wien filter

  • keep precession frequency stable
  • match frequency and phase to Wien filter

P R L , 1 1 9 , 1 4 8 1 ( 2 1 7 )

Test at COSY: control spin tune via COSY rf: control phase to external frequency by accelerating/decelerating spin precession

CONTROLLING SPIN DIRECTION

Feedback system