Tanya Zelevinsky & CeNTREX Collaboration...Tanya Zelevinsky & CeNTREX Collaboration Columbia...
Transcript of Tanya Zelevinsky & CeNTREX Collaboration...Tanya Zelevinsky & CeNTREX Collaboration Columbia...
Proton EDM search with cold molecules
Tanya Zelevinsky &
CeNTREX Collaboration
Columbia University, New York
CeNTREX = Cold molecule Nuclear Time Reversal EXperiment
Fundamental symmetries with
quantum science techniquesSearch for T-reversal symmetry violating forces
Tabletop scale experiments
Exceed the energy reach of LHC
10,000,000,001 10,000,000,000
Matter Antimatter
Could explain 10-10 asymmetry,
measured from photon-baryon ratio
Searching for new T-violating interactions
Equal amounts of
matter and antimatter
NAIVE EXPECTATION: OBSERVED
:Mostly photons; little matter;
almost no antimatter
photons
matter
antimatter
• T-violation required to explain the baryon asymmetry
• T-violation in Standard Model is too small by orders of magnitude
• Need new T-violating forces associated with new particles of ~TeV mass
• Standard Model extensions
A. Sakharov, JETPL 5, 27 (1967)
Charge asymmetry violates T, P
Size of charge asymmetry depends on mass of new particles:
Larger effect for lighter virtual particles, or simpler processes
+ +
- -
T + +
- -≠
+ +
- -
m
EDM
Searching for new T-violating interactions
J. Feng, ARNPS 63, 351 (2013)
0.3 1 3 10 30
Superpartner mass (TeV)
𝑢 , ෩𝑑 , 𝑒
LHC
Atom,
molecule,
neutron
EDMs
Natural scale
for supersymmetry
Projected
EDMs
Sensitivity to particles that mediate T-violating forces
TeV
Energy
nuclear
atomic
Fundamental CP phases
EDMs of diamagnetic atoms
(Hg, Ra)and molecules (TlF)
Nucleon EDMs (n, p)
EDMs of paramagneticatoms and molecules
(Cs, Fr, Tl, YbF, ThO, HfF+),solid state
e EDMθQCD,
quark EDMs,CEDMs
Leptonic
Leptonic and hadronic EDMs
Hadronic
Quantum mechanics (Schiff theorem) & simple reasoning →
𝐸 = 0on pointlike, nonrelativistic charged particle
within neutral atom or molecule
Loopholes lead to observable atomic & molecular EDMs:
• Electron relativistic motion → eEDM de
• Nucleus finite size → Schiff moment S nEDM or pEDM
Molecules are ~105× more polarizable than atoms
Origin of EDMs in atoms and molecules
Search for a nuclear charge asymmetrySchiff moment in 205Tl nucleus, shows up in TlF molecules
Torque from intramolecular E-field →
precession of nuclear spin
Tl
F
Ԧ𝑑𝑆𝑀
Ԧℰ𝑙𝑎𝑏 ∼ 104 V/cmԦℰ𝑖𝑛𝑡
F nuclear spin:
• Low Z → small EDM
• Co-magnetometer to
suppress systematics
Search for a nuclear charge asymmetrySchiff moment in 205Tl nucleus, shows up in TlF molecules
𝛿𝑑𝑆𝑀~ℏ
ℰ𝑒𝑓𝑓𝜏 𝑁Measurement sensitivity
Ԧℰ𝑖𝑛𝑡 = 0
Ԧ𝑑𝑆𝑀 ⋅ Ԧℰ𝑖𝑛𝑡 = 𝑑𝑆𝑀ℰ𝑒𝑓𝑓 ≠ 0
Intramolecular field at nucleus:
Tl
F
Ԧ𝑑𝑆𝑀
Cryogenic molecular beam
Laser detection
& cooling
t ~ 20 ms
ሶ𝑁 > 107/ s
100% molecules
detected
ℰ𝑒𝑓𝑓 ∼ 30 kV/cm
finite
nuclear size
<10-30 ecm
Search for a nuclear charge asymmetrySchiff moment in 205Tl nucleus, shows up in TlF molecules
𝛿𝑑𝑆𝑀~ℏ
ℰ𝑒𝑓𝑓𝜏 𝑁Measurement sensitivity
Ԧℰ𝑖𝑛𝑡 = 0
Ԧ𝑑𝑆𝑀 ⋅ Ԧℰ𝑖𝑛𝑡 = 𝑑𝑆𝑀ℰ𝑒𝑓𝑓 ≠ 0
Intramolecular field at nucleus:
D. Cho et al., PRA 44, 2783 (1991)D. Wilkening et al., PRA 29, 425 (1984)E. Hinds and P. Sandars, PRA 21, 480 (1980)
Tl
F
Ԧ𝑑𝑆𝑀
Cryogenic molecular beam
Laser detection
& cooling
t ~ 20 ms
ሶ𝑁 > 107/ s
100% molecules
detected
New
methods
ℰ𝑒𝑓𝑓 ∼ 30 kV/cm
finite
nuclear size
• Tl is sensitive to Schiff moment (∝ 𝐴2/3 𝑍2)
• Polarization ~0.5 at E ~30 kV/cm: ~104 relative to 199Hg
• Quasi-cycling optical transition
• Can use electronic ground state
• 19F nuclear spin: small EDM, internal co-magnetometer
• High yield from cryogenic buffer-gas beam source
• Spectroscopy and sensitivity well-known from past work
Advantages of TlF molecules
CeNTREX sensitivity to hadronic EDM
Generation I
Projected 30× sensitivity improvement in qQCD
and proton EDM
compared to 199Hg
parametrizes the
allowed CP violation
B. Graner et al., PRL 116, 161601 (2016)
~ 0.2 mHz @ T ~ 300 hours integration time
Generation II
Additional 10-100 improvement from laser cooling
J. M. Pendlebury et al., PRD 92, 092003 (2015)
Experiment design
Experiment design
• Ablated TlF entrained in 16 K neon
• ~1011 molecules / s / quantum state, pulsed
• ~200 m/s
Cryogenic beam source
The cold cell is kept at 16 K;
neon buffer gas flows through the cell
A focused laser pulse ablates a
solid TlF target,
introducing hot TlF molecules
Hot TlF are cooled by neon.
~10% of TlF molecules leave the cell,
forming the molecular beam
Experiment design
• Collect population in J = 0, F = 0
• Laser + mwaves
• E = B = 0
𝑋1Σ+
𝐵3Π+
13 GHz
27 GHz
40 GHz
271 nm
J = 1
J = 2
J = 1
J = 0
J = 3
Rotational cooling
At ~5 K, most molecules are in J = 0 ~ 5
Experiment design
• Move population to J = 2 for optimal downstream focusing
• J = 2 preparation: mwaves, E = 100 V/cm, B = 0
• Electrostatic lens: 30 kV/cm, B = 0
𝑋1Σ+
13 GHz
27 GHzJ = 2
J = 1
J = 0
Electrostatic molecule lens
Move molecules to J = 2, for a large restoring force
𝑋1Σ+
13 GHz
27 GHzJ = 2
J = 1
J = 0
Electrostatic molecule lens
Move molecules to J = 2, for a large restoring force
quadrupole potential
Quadratic Stark shift for J = 2
𝑋1Σ+
13 GHz
27 GHzJ = 2
J = 1
J = 0
Electrostatic molecule lens
Move molecules to J = 2, for a large restoring force
quadrupole potential
30
enhancement
Experiment design
• Move population to J = 1 science state
• mwaves
• E = 1 kV/cm, B = 20 G
Experiment design
• 3 m long spin-precession region
• 30 kV/cm electrodes for uniform E-field
• RF & static B-field coils, B 0
• Magnetic shielding
• >3 long, 30 cm diameter
vacuum glass tube
• Metal endcaps for sealing and
electrical connections
• Magnetic shielding: Metglas,
high-permeability
amorphous metal alloy
• Machined glass electrodes
with graphite coating for low
magnetic noise, 30 kV/cm
Interaction region
𝑋1Σ+
27 GHzJ = 2
J = 1
• >3 long, 30 cm diameter
vacuum glass tube
• Metal endcaps for sealing and
electrical connections
• Magnetic shielding: Metglas,
high-permeability
amorphous metal alloy
• Machined glass electrodes
with graphite coating for low
magnetic noise, 30 kV/cm
Interaction region
3 m long E-field plates,
separated by 2 cm
Experiment design
• Map nuclear-spin precession states onto J = 1, 2
• mwaves
• E = 1 kV/cm, B = 20 G
Experiment design
• Lasers + mwaves detect both spin states
• Cycling fluorescence detected, 100 UV photons / molecule
• E = B = 0
Optical cycling in molecules
E. Norrgard et al., PRA 95, 062506 (2017)
Scattering ~100 photons in TlF:
fluorescence detection & laser cooling
l = 272 nm
L. Hunter et al., PRA 85, 012511 (2012)
Optical cycling in molecules
T. Wright, B.S. Thesis, Amherst College (2018)
Scattering ~100 photons in TlF:
fluorescence detection & laser cooling
3 excited states
12 ground states
3 bright states
9 dark states
22 kHz
176 kHz
15 kHz
Optical cycling in molecules
T. Wright, B.S. Thesis, Amherst College (2018)
Scattering ~100 photons in TlF:
fluorescence detection & laser cooling
Polarization dark states:
remix via
polarization modulation
Optical cycling in molecules
T. Wright, B.S. Thesis, Amherst College (2018)
Scattering ~100 photons in TlF:
fluorescence detection & laser cooling
Hyperfine dark states:
remix via
microwaves to J = 0
@ 13 GHz
Optical cycling in molecules
T. Wright, B.S. Thesis, Amherst College (2018)
Scattering ~100 photons in TlF:
fluorescence detection & laser cooling
Polarization-modulation + microwave
dark-state remixing
molecular
beam
optical
passes
Only ~40 photons/molecule
Scattering rate:
1/10 of Gmax = G Ne / (Ne+Ng)
OK for efficient detection &
rotational cooling
• Laser sidebands spaced by g = 1.6 MHz cover Doppler width
• Multipass arrangement, uniform laser intensity
• Optical polarization switching @ 1 MHz
• Dark-state-mixing mwave polarization switching @ 1 MHz
43 photons
Optical cycling in TlF
L. Hunter (Amherst Colege)
(calibration)
Cryogenic beam source Rotational cooling Electrostatic quadrupole lens
3x tunable UV laser systems Stable frequency reference
CeNTREX under construction
pulse tube
refrigerators
UV laser
directed
through the
beam source
turbopump
optical
detection
flange for
molecular
beam output
Cryogenic molecular beam source
Chamber with
buffer-gas cell
and shields
cell assembly
4K shield
40K
shield
vacuum
chamber
Cryogenic molecular beam source
ablation
light enters
molecules
exit
laser port
Rotational cooling
J = 1 2
27 GHz
mwave horns
J = 2 3
40 GHz
mwave horns
J = 0 1
13 GHz
mwave horn
System 199Hg n 205TlF
Latest result 2016 2006(2015) Projected, 2021 Improvement
Sens. to QCD
q param.
𝜕𝜈/𝜕𝜃
0.1 Hz 300 Hz 105 Hz
Sens. to
quark
chromo-EDM
𝜕𝜈/𝜕 ሚ𝑑𝑞
11016 Hz/[e·cm] 21018 Hz/[e·cm] 21020 Hz/[e·cm]
Sens. to p/n
EDM 𝜕𝜈/𝜕𝑑𝑝/𝑛11015 Hz/[e·cm] 21018 Hz/[e·cm] 61018 Hz/[e·cm]
Limit on 𝜃 < 110-10 < 210-10 < 210-12 30
Limit on ሚ𝑑𝑞(cm)
ሚ𝑑𝑢 − ሚ𝑑𝑑< 1.510-27
0.5 ሚ𝑑𝑢 + ሚ𝑑𝑑< 310-26
ሚ𝑑𝑢 + ሚ𝑑𝑑< 110-27
1.5*-30
Limit on
𝑑𝑛(e·cm)<610-26 <310-26 Not competitive
Limit on
𝑑𝑝(e·cm)<910-25 Not competitive <310-26 30
*sensitive to a linear combination of parameters nearly orthogonal to comparison
Projected sensitivity comparisons
Principal Investigators
David DeMille
(Yale)
David Kawall
(UMass)
Tanya Zelevinsky
(Columbia)
Postdoc
J. Olivier Grasdijk
(Yale)PhD students
Konrad
Wenz
(Columbia)
Oskari
Timgren
(Yale)
Jakob
Kastelic
(Yale)
Tristan
Winick
(UMass)
Trevor
Wright
(Yale)
Mick
Aitken
(Columbia)
Steve Lamoreaux
(Yale)
CeNTREX teamFunding:
NSF,
Templeton,
Heising-Simons