# Presentation: 184424

## Yannis K. Semertzidis
Brookhaven National Lab

- _Brookhaven National Lab_

- HEP Seminar
- BNL, 20 November 2008

_**Deuteron & proton EDM Experiment:**_Storage ring EDM experiment with 10-29 ecm sensitivity using the “Frozen Spin Method”

- Utilizing the strong E-field present in the rest frame of a relativistic particle in a storage ring.
- Its physics reach is beyond the LHC scale and complementary to it.

## Physics at the Frontier, pursuing two approaches:

- Energy Frontier

- Precision Frontier

- which are complementary and   inter-connected.  The next SM   will emerge with input from both approaches.

## Physics of EDM

- _Physics of EDM_

-    The Deuteron EDM at 10-29e∙cm has a reach of  ~300TeV or, if new physics exists at the LHC scale,10-5 rad CP-violating phase.

**It can help resolve the missing mass (anti-matter) mystery of our universe.**

## Spin is the only vector defining a direction of a “fundamental” particle with spin

## A Permanent EDM Violates both T & P Symmetries:

- EDM physics without spins is not important
- (batteries are allowed!)

## CP-Violation is one of three conditions to enable a universe containing initially equal amounts of matter and antimatter to evolve into a matter-dominated universe, which we see today....

- _Andrei Sakharov 1967:_
- CP-Violation is one of three conditions to enable a universe containing initially equal amounts of matter and antimatter to evolve into a matter-dominated universe, which we see today....

## CP-violation was discovered at BNL in 1964

## CP-violation is established

- The SM CP-violation is not enough to explain the apparent Baryon Asymmetry of our Universe by ~10 orders of magnitude.
- A new, much stronger CP-violation source is needed to explain the observed BAU.

## EDM Searches are Excellent Probes of Physics Beyond the SM:

- _EDM Searches are Excellent Probes of Physics Beyond the SM:_

-    Most models beyond the SM predict values within the sensitivity of current or planned experiments:
- SUSY
- Multi-Higgs
- Left-Right Symmetric ...
- The SM contribution is negligible...

## Short History of EDM

- 1950’s neutron EDM experiment started to search for parity violation (before the discovery of P-violation)
- After P-violation was discovered it was realized EDMs require both P,T-violation
- 1960’s EDM searches in atomic systems
- 1970’s Indirect Storage Ring EDM method from the CERN muon g-2 exp.
- 1980’s Theory studies on systems (molecules) w/ large enhancement factors
- 1990’s First exp. attempts w/ molecules. Dedicated Storage Ring EDM method developed
- 2000’s Proposal for sensitive dEDM exp. developed.

## Important Stages in an EDM Experiment

_**Important Stages in an EDM Experiment**_

- _Polarize:_state preparation, intensity of beams
- _Interact with an E-field:_the higher the better
- _Analyze:_high efficiency analyzer
- Scientific Interpretation of Result!  Easier for the simpler systems

## Measuring an EDM of Neutral Particles

*H ****= -(****d**** E******+ ****μ**** B******) ******● ******I/****I*

***m******I *****= 1/2**

***m******I *****= -1/2**

**ω****1**

## EDM methods

- Neutrons: _U_ltra _C_old _N_eutrons, apply large E-field and a small B-field. Probe frequency shift with E-field flip
- Atomic & Molecular Systems: Probe 1st order Stark effect
- Storage Ring EDM for charged particles: Utilize large E-field in rest frame-Spin precesses out of plane (Probe angular distribution changes)

## EDM method Advances

- Neutrons: advances in stray B-field effect reduction; higher UCN intensities
- Atomic & Molecular Systems: high effective    E-field
- Storage Ring EDM for D, P: High intensity polarized sources well developed; High electric fields made available; spin precession techniques in SR well understood

## EDM method Weaknesses

- Neutrons: Intensity; High sensitivity to stray      B-fields; Motional B-fields and geometrical phases
- Atomic & Molecular Systems: Low intensity of desired states; in some systems: physics interpretation
- Storage Ring EDM: some systematic errors different from g-2 experiment, geometrical phases...

## Neutron EDM Timeline

_**Neutron EDM Timeline**_

**2005**

**Exp begin**
**data taking**

**Exp goal**

**2007**

**PSI**

**~10****-27****e********cm**

**2008**

## The Storage Ring EDM experiment

## The Electric Dipole Moment precesses in an Electric field

_**The Electric Dipole Moment precesses in an Electric field**_

## Electric Dipole Moments in Magnetic Storage Rings

_**Electric Dipole Moments in Magnetic Storage Rings**_

- e.g. 1 T corresponds to 300 MV/m for
- relativistic particles

## Storage ring EDM: The deuteron case (proton is similar)

- High intensity sources (~1011/fill)
- High vector polarization (~80%)
- High analyzing power for ~1 GeV/c (250MeV)
- Long spin coherence time possible (>103s)
- Large effective E*-field

## Freezing Spin Precession: it depends on the a=(g-2)/2 value

- Making the dipole B-field = 0, the spin precession is zero at (magic) momentum (0.7 GeV/c for protons)

- Magic momentum: Proton, sens.: 3x10-29 ecm

## Effect of Radial Electric Field

- Yannis Semertzidis, BNL

_**Effect of Radial Electric Field**_

- Low energy particle
- ...just right
- High energy particle

- Spin vector

- Momentum vector

## Effect of Radial Electric Field

_**Effect of Radial Electric Field**_

- ...just right

- Spin vector

- ,P=0.7GeV/c
- for protons

## E-field strength

- The field emission with and without high pressure water rinsing (HPR).

- Recent developments in achieving high E-field strengths makes this option appealing

## E-field strength

## Deuteron: Momentum 1 GeV/c, B=0.5 T, E=120KV/cm

- Using a combination of dipole B-fields and radial E-fields to freeze the spin.  The required E-field is

- Combined E&B-fields:

- Deuteron, sensitivity: 10-29 ecm

## Large a=(g-2)/2 vs. small a value

- Use a radial *E**r*-field to cancel the g-2 precession
- but use the VxB internal E*-field to precess spin.
-  For 1 GeV/c deuteron momentum, V/c=0.5, B=0.5T and E* = 75MV/m; the effect is enhanced by ~*E**r**/(**a****2**)*

## deuteron EDM search at BNL

**deuteron EDM search at BNL**

**EDM storage ring**

**A longitudinally polarized deuteron beam is stored in the EDM ring for ~10****3****s.**

**The strong effective E*-field~V×B will precess the **
**deuteron spin out of plane if it possesses a non-zero EDM**

**Modest e-cooling**
**required**

## Slide 31

## The three spin components at the polarimeter location for different g-2 cancelation factors:

- Sz

- Sx

- Sy

- NO EDM

## The three spin components at the polarimeter location for different g-2 cancelation factors:

- Sz

- Sx

- Sy

- NO EDM

## The three spin components at the polarimeter location for different g-2 cancelation factors:

- Sz

- Sx

- Sy

- WITH EDM

## The three spin components at the polarimeter location for different g-2 cancelation factors:

- Sz

- Sx

- WITH EDM

## dEDM polarimeter principle: probing the deuteron spin components as a function of storage time

- D

- L

- U

- R

- “extraction” target – residual gas

- “defining aperture”
- polarimeter target 12C

- detector
- system

- carries EDM signal
- small
- increases slowly with time

- carries in-plane precession signal

- _dEDM polarimeter principle: probing the deuteron spin components as a function of storage time_

- beam

## Cross section and analyzing power

## Deuteron Statistical Error (250MeV):

- _Deuteron Statistical Error (250MeV):_

***p    *: 103s    Polarization Lifetime (Coherence Time)
*A   *: 0.3    The left/right asymmetry observed by the polarimeter
*P   *: 0.8    The beam polarization
*N**c*: 41011d/cycle The total number of stored particles per cycle
*T**Tot*: 107s   Total running time per year
*f*     : 0.01    Useful event rate fraction
*E**R*  : 12 MV/m Radial electric field

## Storage

_**S**__**torage**_
_**R**__**ing**_
_**E**__**DM**_
_**C**__**ollaboration**_

**www.bnl.gov/edm**

## Possible dEDM Timeline

**08**

**07**

**09**

**10**

**11**

**12**

**13**

**14**

**15**

**16**

**17**

- Spring 2008, Proposal to the BNL PAC
- 2008-2012 R&D phase; ring design
- Fall 2011, Finish systematic error studies:                                    a) spin/beam dynamics related systematic errors.                         b) Polarimeter systematic errors studies with polarized 	deuteron beams
- c) Finalize E-field strength to use
- d) Establish Spin Coherence Time
- Start of 2012, finish dEDM detailed ring design
- Fall 2012, start ring construction
- Fall 2014, dEDM engineering run starts
- Fall 2015, dEDM physics run starts

## Main issues

- Polarimeter systematic errors to 1ppm (early to late times-not absolute!)
- Average vertical electric field very strict (CW and CCW injections need to repeat to ~10-6m)
- E-field strength: 120kV/cm
- Average E-field alignment: 10-7 rad; stability.
- B-field and E-field combined. Geometrical phases: local spin cancellation ~10-4. Stability?; Sensitive Fabry-Perot resonator to be developed
- Spin Coherence Time: ~103s

## Main polarimeter systematic errors

## Off axis/angle systematic error

- _Off axis/angle systematic error_

- Pickup electrodes monitor the beam axis direction to better than 10μrad.
- The polarimeter detector will be designed to have ~500μm/event pointing accuracy, or better than 10μm on the average position early to late.

- Our measurements at KVI

- Prediction

- The required position stability: ~100μm
- The required beam axis stability: ~100μrad

## Tests at COSY ring at Juelich/Germany

- Goals: Construct prototype dEDM _polarimeter_.  Install
- in COSY ring for commissioning, calibration, and testing for sensitivity to EDM polarization signal and systematic errors.

- Current location
- behind present EDDA
- detector.

## From the June 2008 run at COSY

- Yannis Semertzidis, BNL

## From the September 2008 run at COSY

- Vector asymmetry

- V+

- V−

- T+

- T−

- Unp

- Resonance crossing
- (full spin flip)

- Unpolarized state has
- some vector polarization
- (note flip).

## General Plan

- The usual asymmertry

- changes in first order due to errors.

- The cross ratio

- cancels first-order errors.

- But this will have second-order errors.  To cancel these, we need to know
- how they depend on the error, which is measured using something with a
- first-order dependence.  Using the same quantities in an independent way:

- can be such a parameter.

## φ

- X displacement of beam at target  (cm)

- Ideally,

- εCR

- The φ term depends
- simply on the
- error at the target
- (polarization tends
- to drop out).

- Then, the cross-ratio
- deviations from flat
- are parametrized as
- a function of φ.

## Polarimeter work by fall 2009

- We expect to get enough data at COSY for an early to late stability in asymmetry of ~50ppm (statistics limited).

## Clock Wise (CW) and Counter Clock Wise (CCW) injections

- CW and CCW injections to cancel all T-reversal preserving effects.  EDM is T-violating and behaves differently.
- Issue:  Stability of E-fields as a function of time

## Clock Wise (CW) and Counter Clock Wise (CCW) injections

_**Clock Wise (CW) and Counter Clock Wise (CCW) injections**_

- Solution:  Use the 2-in-1 magnet design for simultaneous CW and CCW storage.

- Rameesh Gupta et al.

## Electric field work by fall 2009

- We expect to show 15MV/m (150kV/cm) for 2cm plate separation on prototypes (no B-field present).
- By spring 2010 we expect to show average plate alignment to 10-7 rad.

## Correction of Spin Frequency Perturbation

**Conclusion: **
** ****The proposed spin coherence time (****SCT****) is possible, in principle, with the help of sextupoles**

## The dEDM ring lattice

- 8.4m

- 8.4m

- 9m

- 0.8m

- Straight section (s.s.)

- Bend section (BE), Quadrupoles and sextupoles
- in between BE sections

- 0.864 m

- 16 free spaces (80cm) in the s.s. per ring
- 4 places in s.s. reserved for the kicker
- 1 free space for the RF cavity (normal)
- 1 free space for the AC-solenoid
- 2 polarimeters

- Horizontal beam radius (95%): 6mm

- Ring circumference: 85m

## Simulation tools : UAL (courtesy of N. Malitsky ) + SPINK (courtesy of A.U. Luccio )
Multiparticles with Gaussian distribution
All Initial spin vectors points to the longitudinal direction
Distribution categories: 
Horizontal distribution with
Vertical distribution with
Momentum spread 
Definition of Sx, Sy, Sz, S
<Sx> : radial component of polarization
<Sy> : vertical component of polarization
<Sz> : longitudinal component of polarization
S       : 
1 million turns ~ 1.5 second

**Multiparticles with Gaussian distribution**
**All Initial spin vectors points to the longitudinal direction**
**Distribution categories: **
**Horizontal distribution with**
**Vertical distribution with**
**Momentum spread **
**Definition of Sx, Sy, Sz, S**
**<Sx> : radial component of polarization**
**<Sy> : vertical component of polarization**
**<Sz> : longitudinal component of polarization**
**S       : **
**1 million turns ~ 1.5 second**

**Simulation Conditions**

## Searching for optimum sextupoles (I)

**Searching for optimum sextupoles (I)**

## Searching for optimum sextupoles (II)

**Searching for optimum sextupoles (II)**

## Searching for optimum sextupoles (III)

**Two sets of sextupoles are next to focusing and defocusing quads. Both horizontal and vertical motion are included.  **

## Searching for optimum sextupoles (IV)

**Besides two sets of sextupoles next to focusing and defocusing quads, a third set of sextupole component is introduced in the BE section . Both horizontal and vertical motion are included.  **

## Searching for optimum sextupoles (V)

**Three sets of sextupoles are located next to focusing, defocusing quads and in the BE section . Particles with horizontal, vertical motion and momentum spread are included.  **

## SCT work by fall 2009

- We expect to have (with simulation) ~50s of SCT.

## Proton vs. deuteron comparison

| Particle | E-field needed | Dipole B-field needed (combined E&B fields) | Flipping field for CW, CCW injections | Sensitive Fabry-Perot resonator needed |
| --- | --- | --- | --- | --- |
| Proton | Yes | NO | NO | NO |
| Deuteron | YES
 | YES
(Space restrictions; e- trapping) | B: YES
E: No
 | YES
 |

## Proton vs. deuteron comparison

| Particle | Local g-2 phase cancellation | SCT | Polarimeter  |
| --- | --- | --- | --- |
| Proton | It will be better than10-7 by E-field design | No horizontal pitch effect | Simpler; A sweet spot at 0.7GeV/c  |
| Deuteron | 10-4; requires high stability | Vertical & horizontal pitch effects | Tensor polarization; break-up protons
 |

## Proton vs. deuteron comparison

| Particle | Ring circumference | Sensitivity | Running |
| --- | --- | --- | --- |
| Proton | ~200m | 3x10-29 e-cm /year | Simpler (no dipole B-field associated costs) |
| Deuteron | ~85m | 10-29 e-cm /year
 | B-field stability after flip; B-field running cost |

## Proton EDM on our way to deuteron?

- Preparation for proton EDM could be ready in three years and ~$2M for R&D
- Preparation for deuteron EDM could be ready in four to five years and ~$4-5M for R&D

## Physics strength comparison

| System | Current limit [ecm] | Future goal | Neutron equivalent |
| --- | --- | --- | --- |
| Neutron | <1.6×10-26 | ~10-28 | 10-28 |
| 199Hg atom
 | <2×10-28
 | ~2×10-29 | 10-25-10-26
 |
| 129Xe atom | <6×10-27 | ~10-30-10-33
 | 10-26-10-29
 |
| Deuteron nucleus |  | ~10-29 | 3×10-29- 5×10-31
 |

## If nEDM is discovered at 10-28 ecm level?

- _If nEDM is discovered at 10__-28 __e____cm level?_

**The deuteron EDM is complementary to **
**neutron and in fact has better sensitivity.**

## Physics Motivation of dEDM

- _Physics Motivation of dEDM_

-    The Deuteron EDM at 10-29e∙cm has a reach of  ~300TeV or, if new physics exists at the LHC scale, 10-5 rad CP-violating phase.  Both are much beyond the design sensitivity of LHC.

**Sensitivity to SUSY-type new Physics:**

**Sensitivity to new contact interaction: 3000 TeV**

## Deuteron, Proton EDM 

- _Deuteron, Proton EDM _

- High sensitivity to non-SM CP-violation
- Negligible SM background
- Physics beyond the SM (e.g. SUSY) expect  CP-violation within reach
- Complementary and better than nEDM
- Proton and deuteron EDM a good goal
- If observed it will provide a new, large source of CP-violation that could explain the Baryon Asymmetry of our Universe (BAU)