Sm Sminaire inaire de des do doctorants ctorants 16 Avril 2015 - - PowerPoint PPT Presentation

199 99Hg

g co-magn magnet etometr

• metry

y stu tudy dy in in th the nE e nEDM DM ex exper periment iment at at th the P e Pau aul l Sc Scher errer er In Insti titu tute e (Swit itzerlan zerland) d)

Yoann nn Kerm ermaïd ïdic ic

Sém Séminaire inaire de des do doctorants ctorants

16 Avril 2015

MOTIVATION

2

Sci cient entific ific mot

• tiv

ivati ations

• ns
• The neutron states are only defined relatively to its spin 𝝉
• Any spin 𝝉 couples to:

to 𝐶 via 𝝂 ← magnetic moment to 𝐹 via 𝒆 ← electric dipole moment

• Τ | ⟩

𝜈 = −| ⟩ 𝜈 Τ | ⟩ 𝑒 = +| ⟩ 𝑒

• If 𝒆𝐨 is not zero, T (CP) symmetry is violated
• 3

Experimental upper bound: 𝒆𝐨 𝒇𝒚𝒒 < 𝟒. 𝟐𝟏𝟑𝟕 𝒇. 𝐝𝐧

• 1. SM predicts 𝒆𝐨 ∼ 𝟐𝟏𝟒𝟑 𝒇. 𝐝𝐧

weak weak CPV (𝜀CKM @ 2 loops)

[Khriplovitch, 1981]

• 2. Additional CPV sources from BSM models constrained by 𝑒
• 3. How sensitive to new physics we are to 1 loop process?

𝑒 ≈ 10𝑓.cm × sin(𝝌𝑫𝑸) × 1 𝑈𝑓𝑊 𝑁

• Sci

cient entific ific mot

• tiv

ivati ations

• ns

[Ral al-Su Sussex ssex-ILL, ILL, 2006] 006]

4

[Pospelov & Ritz, 2005]

Internationa ernational l co context ext

• PS

PSI nEDM collaboration at the Paul Scherrer Institute (Switzerland)

8 countries (Switzerland, Germany, France, UK, Poland, Belgium, USA, Russia) 48 members / 11 PhD students

• SNS

SNS nEDM collaboration Oak Ridge (USA)

• PNPI

PI-ILL ILL nEDM experiment Grenoble (France)

• TRI

RIUMF MF nEDM collaboration Vancouver (Canada)

• LA

LANL nEDM collaboration Los Alamos (USA)

• And others…

5

The nEDM experiment

6

• Hamiltonian of the problem:

𝐼 = −𝜈 ⃗ 𝜏 𝐶 − 𝑒 ⃗ 𝜏 𝐹

• Energy level splitting:

Th The e measu asurement ement pri rinciple nciple

𝚬𝑭𝐂 = 𝟕. 𝟐𝟏𝟐𝟓 eV

𝑪 = 𝟐 𝛎𝐔

𝚬𝑭𝐅 < 𝟒. 𝟐𝟏𝟑𝟑 eV

𝐅 = 𝟐𝟏 ⁄ 𝐥𝐖 𝐝𝐧

GS 2𝜈𝐶 2𝑒𝐹 2𝑒𝐹

7

Th The e measu asurement ement pri rinciple nciple

• Hamiltonian of the problem:

𝐼 = − ⃗ 𝜈 𝐶 − ⃗ 𝑒 𝐹

• Measure a neutron spin precession frequency shift proportional to an

applied electric field!

• ↑↑
• = −𝜈𝐶↑ − 𝑒𝐹↑

↑↓

• = −𝜈𝐶↑ + 𝑒𝐹↓

𝒆 =

𝒊 (𝝃↑↑𝝃↑↓) 𝟓𝑭

True rue only y if 𝑪↑ = 𝑪↑!

8

Expe xperim riment ental al setup up

B0

0 ≈ 1 T

E E ≈ ¡10 ¡kV/cm ~2 m

9

~50 cm ~2 m

NB: Upgraded RAL-Sussex spectrometer

Expe xperim riment ental al setup up

1. 1. Production duction of Ultr tra a Cold ld Neutr utron

• ns

s (UCN) N) in the new PSI UCN source ce 𝑭𝐕𝐃𝐎 ∼ 𝟐𝟏𝟏 𝐨𝐟𝐖 2.

• 2. UCN are spin

in-polari polarize zed d ↑ wit ith a 5T 5T magnetic etic field ld 3.

• 3. Fi

Fill l the prec eces essio sion chamber mber 4.

• 4. Stor

tore e UCN for 20 200 0 s with th (E, B) paral allel lel

• r antip

iparallel arallel

1. 1. Ap Apply

𝝆 𝟑 pul

pulse (2 (2s) 2. 2. Spin freely precess s (2 (200s) 3. 3. Ap Apply

𝝆 𝟑 pul

pulse e (2s 2s)

5.

• 5. Measu

sure e neutron counts nts with th spin in Up & D Down

• wn

10 10

B0

0 ≈ 1 T

E E ≈ ¡10 ¡kV/cm

[Ramsey, 1956]

Fit to to the e centra ntral Rams msey y fring nge e (201 013 3 data) ta)

N spin ↓ N spin ↑

Th The e Ramsey msey meth ethod

• d

𝝆 𝟑 pulse

se = oscil cillating lating magnet netic ic field ld

→ 𝐶 𝑢 = 𝐶 cos 𝜕 𝑢 ⃗ 𝑦 + sin 𝜕 𝑢 ⃗ 𝑧 𝑸(↑→↓) ∝ cos 𝑔

− 𝒈𝐌

Δ𝜉 𝑸(↑→↓) maximiz imized ed if 𝒈𝐒𝐆 = 𝒈𝐌 =

𝜹𝐨 𝟑𝝆 𝑪𝟏

Larmor mor frequen quency cy

11 11

Neutron frequency (run 7650) E↑ No E-field E↓

Expe xperim riment ental al ch chall llenges enges

Reminder: Earth magnetic field ≈ 50 50 T = = 5 50.106

6 pT

pT 3 days

12 12

ORDER RDER OF MAGNITUDE DE OF MAGNET NETIC IC FIELD LD FLUCT UCTUATION IONS: S:

• E+

+ to

to E-: : ∆𝑪 ~ 𝟖 pT 𝝉𝒆𝒐 ~ 𝟑. 𝟐𝟏𝟑𝟒 𝒇.cm

(1970)

• Cyc

ycle le: ∆𝑪 ~ 𝟏. 𝟔 pT 𝝉𝒆𝒐 ~ 𝟐. 𝟐𝟏𝟑𝟓 𝒇.cm

(1980)

• nEDM:

M: ∆𝑪 ~ 𝟔 fT 𝝉𝒆𝒐 ~ 𝟐. 𝟐𝟏𝟑𝟕 𝒇.cm How w can we we achieve ieve a 5 5 fT magnetic etic field ld sensitiv itivity ity?

199Hg co-magnetometry

13 13

Fu Functioni ctioning ng pri rinciple nciple

Need to correct for magnetic field drift every cycle with a 100 fT precision

19 199Hg

Hg atomi tomic c magnet etomet etry = Same sampled led vo volu lume durin ring g the same integrat tegrated ed ti time as as UCN

13 133Cs

Cs ato tomic mic magnet etomet

• metry

= Spatia tial l magnet etic ic field ld distributi tribution

• n

14 14

[Ral-Sussex-ILL, 1997] [Bison, 2006]

Fu Functioni ctioning ng pri rinciple nciple

• 199Hg atoms are spin polarized by
• ptical pumping

(40s)

• Apply a

𝝆 𝟑 puls

lse

(2s)

• Free precession in (x, y) plane

(200s)

z x y B0

𝐽 𝑢 = 𝐵𝑓

𝝊 sin 𝝏𝐌𝒖 + 𝝌

Oscillating phase @ Larmor frequency 𝑔

= 𝛿 𝐶 ≈ 8 Hz

Relaxation time constant due to wall collision ≈ 100 s

I(t) T (s)

15 15

Corr

• rrecti

ection

• n of ma

magnetic netic fie ield ld drif rift

x 7 𝝉𝒈𝐨 𝒈𝐨 = 𝟐 𝟑𝝆 𝑼𝐪 𝜷 𝑶𝐕𝐃𝐎 ≈ 𝟏. 𝟔 𝐪𝐪𝐧 𝝉𝒈𝐈𝐡 𝒈𝐈𝐡 = 𝟒 𝟑 𝟐 𝐓𝐎𝐒 𝑼𝐪 𝑶𝐠𝐣𝐮 𝟐 + 𝒇𝟑

⁄ 𝑼𝐪 𝝊 ≈ 𝟏. 𝟏𝟖 𝐪𝐪𝐧

• The co-magnetometry allows to be only

statist atistica ically lly limit ited ed by UCN → ¡ ¡ ¡ ¡𝝉𝒆/𝐝𝐳𝐝𝐦𝐟 = 𝟐. 𝟐𝟏𝟑𝟓 𝒇. 𝐝𝐧

• Need to repeat X cycles to reach the

𝟐𝟏𝟑𝟕 𝒇. 𝐝𝐧 level, with 𝑌 → ∞ !! (Actually ~ 10 000 = months hs)

16 16

Curr urrent ent stati atistica stical l sensitivity nsitivity

𝒆𝐨 < 𝟐𝟑. 𝟒 × 𝟐𝟏𝟑𝟕 𝒇. 𝐝𝐧 (2 months full time)

• nEDM data analysis software

→ ¡ ¡ ¡ ¡EDM EDMA

• Expected sensitivity in 2-3 years

→ ¡ ¡ ¡ ¡𝝉𝒆 = 𝟐 − 𝟑. 𝟐𝟏𝟑𝟕 𝒇. 𝐝𝐧

• Control of systematics?

17 17

Curr urrent ent co contr trol

• l of s

f syst stematics ematics

Moti tional al 19

199Hg

g false se EDM ← corr rrec ection tion of this is effect ct 𝟓𝟏 ± 𝟓𝟏

18 18

Mot

• tional

ional 19

199Hg

Hg in induced uced fa fals lse e EDM DM

• Reminder:
• The motional 199Hg induced false EDM arises from transverse magnetic field :
• Different 199Hg frequency shift source arise: 𝜀𝜕 = 𝜀𝜕 + 𝜀𝜕 + 𝜀𝜕 + ⋯
• 𝐶 𝑢

≈ 𝜖𝐶 𝜖𝑨 𝑠 𝑢

• 𝐶× 𝑢 ≈ 𝐹

𝑑 𝑤(𝑢)

𝑒 = ℏ (𝜕↑↑ − 𝜕↑↓) 4𝐹

Vertica cal magnetic c field field gr gradie dient Position n in the trans nsverse plane Spee Speed d in in the e trans nsverse plane Longitud udinal nal electri ric field

𝜀𝜕 ∝

• 𝐶 𝑢 +

𝐶× 𝑢 + ⋯

• 19

19

𝐶 ⃗ 𝑨 𝐶 ⃗ 𝑠 𝑪

Mot

• tional

ional 19

199Hg

Hg in induced uced fa fals lse e EDM DM

• Reminder:
• Different 199Hg frequency shift source arise: 𝜀𝜕 = 𝜀𝜕 + 𝜀𝜕 + 𝜀𝜕 + ⋯
• Hypothesis: Unifo

form rm vertical magnetic field gradients in a cylind lindric rical al cell

• Theoretical expression:

𝜀𝜕 = ±

• 𝐹
• which leads to:

𝒆𝐈𝐡

𝐠𝐛𝐦𝐭𝐟 = ± ℏ𝜹𝟑𝑬𝟑 𝟒𝟑 𝒅𝟑 𝝐𝑪𝒜 𝝐𝒜

𝑒 = ℏ (𝜕↑↑ − 𝜕↑↓) 4𝐹

20 20

[Pignol, 2012] [Pendelbury, 2006]

Mot

• tional

ional 19

199Hg

Hg in induced uced fa fals lse e EDM DM

Data B0 down Data B0 up Best fit to the data: 𝑒

(𝑕) = 𝑏 . 𝑕

Theoretical slope Result: sult: 𝒃𝐟𝐲𝐪 = 𝟐. 𝟐𝟑𝟑 𝟒𝟔 × 𝟐𝟏𝟑𝟖 𝒇. 𝐝𝐧/

𝐪𝐔 𝐝𝐧

𝒃𝐮𝐢 = 𝟐. 𝟐𝟓𝟗 × 𝟐𝟏𝟑𝟖 𝒇. 𝐝𝐧/

𝐪𝐔 𝐝𝐧

Available: arxiv:1410.8259 “Measurement of a false electric dipole moment signal from

19 199Hg atoms exposed to an inhomogeneous magnetic field”

21 21

Larmor frequency definition: The gyromagnetic ratio of the two species reads: Interpretation as a new measurement of whether 𝛿 or 𝛿 at the ppm level Results in agreement with previous measurement Available: Physics Letters B 739, 128-132 (2014)

Ne Neut utron

• n to
• 19

199Hg

Hg mag agnetic netic moment

• ment ra

ratio io

𝑺 = 𝒈𝐨 𝒈𝐈𝐡 = 𝜹𝐨 𝜹𝐈𝐡 𝟐 + 𝜺𝐟𝐛𝐬𝐮𝐢 + 𝜺𝐡𝐬𝐛𝐰 + ⋯ 𝒈𝐌 = 𝜹 𝟑𝝆 𝑪𝟏 𝜹𝐨 𝜹𝐈𝐡 = 𝟒. 𝟗𝟓𝟑𝟓𝟔𝟖𝟓 𝟒𝟏 [𝟏. 𝟖𝟗 𝐪𝐪𝐧]

22 22

Toward n2EDM

23 23

n2E 2EDM DM project

• ject
• 2 precession chambers
• Optimized geometry to increase NUCN
• Keep 199Hg co-magnetometry
• Sensitivity: 𝝉𝒆 = 𝟔. 𝟐𝟏𝟑𝟖 𝒇. 𝐝𝐧

24 24

R& R&D Data ta tak aking ing

No Now 20 2017-20 2020 20 2025 2025

10 10-25

25

10 10-26

26

5.1 .10-27

7 (e.c

.cm) m)

19 199Hg

Hg test st bench nch @ @ LPS LPSC

• Goal is to study properties of 199Hg co-magnetometer
• Increase number of UCN/cycle = increase in co-mag. sensitivity!
• Sensitivity depends on:

Input polarization

• > Signal to Noise Ratio

→ Sur urfac face stat ate depen penden dent Depolarization time

• > Coherence time of the signal
• Contribution of LPSC technical groups & ILL glass ware

𝝉𝒈𝐈𝐡 𝒈𝐈𝐡 ∝ 𝟐 𝐓𝐎𝐒 𝑼𝐪 𝑶𝐠𝐣𝐮 𝟐 + 𝒇𝟑

⁄ 𝑼𝐪 𝝊

25 25

26 26

19 199Hg

Hg test st bench nch @ @ LPS LPSC

Perspect spectiv ives es

• Fi

Finalize lize th the 19

199Hg

g test t bench ch constructio struction

• Take

e physics sics data ta with th the 19

199Hg

g tes test t bench ch end of spring ing

• Parti

ticip cipat ate e to to the n2E 2EDM M 19

199Hg

g co-mag.

• ag. Design

ign

• Maintain

ntain online ine data a quali lity ty softw twar are

• Conti

ntinue ue deve veloping loping my offline line data ta analysi lysis s softwar tware: e: EDMA MA

• Improve
• ve pyAMI

AMI datab abase ase integrat tegration ion in the collab llaboration

• ration
• Get the best

st upper er limit it on 𝒆𝐨 ?? ??

27 27

Thank you for your attention