Clocks to weigh Beyond Standard Model Physics: Muon g

Clocks to weigh Beyond Standard Model Physics:
Muon g-2 and the Neutrino Mass Scale
Martin Fertl
Nuclear Particle Astrophysics Seminar
Outline
• Introduction: The standard model in one picture • The new muon g-­‐2 experiment at FNAL • Project 8: A frequency based neutrino mass measurement • Summary
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Yale 3/3/2016
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The Standard Model of Particle Physics in one
picture
2008
2012
2004
2015
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2002
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Why Beyond Standard Model Physics ?
Plenty of experimental evidence that the Standard Model is not complete!
Some of the questions which are not answered by the SM: • Baryon asymmetry of the Universe! Why are we here? • Dark Matter: What is it? • Dark Energy: What is it? • How do neutrinos obtain mass? Mass hierarchy of fermions! • How heavy are neutrinos at all? • Gravity is completely absent in this picture!
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Three frontiers of particle physics
Complementary approaches are needed to find the crack(s) in the SM! Beyond Standard Model Physics
Highest energy and cosmology Highest intensity / exposure
Direct production Lepton flavor violation of BSM particles @LHC • μ→ e, μ→ eɣ, μ→ eee, … • 0νββ,… Astroparticle physics CMB, galaxies, BAO, … New particles/interactions • WIMPs, axions,…
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Highest precision Detection experiments Yale 3/3/2016
•
•
•
•
•
μ and e g-­‐2 exp. ν mass scale ν oscillation experiments electric dipole moments decay correlations
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Highest precision measurements …
… often follow A. Schawlow’s advice: “Never measure anything but frequency” Hydrogen 1S-­‐2S σ = 4.2·∙10-­‐15 Electron g-­‐factor σ = 2.8·∙10-­‐13 Electron mass in u σ = 2.9·∙10-­‐11 Hänsch et al., 2011
Gabrielse et al., 2008
Sturm et al., 2014
Frequency (ratio) measurements also for:
Neutrino masses New approach!
Muon g-­‐2
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The cyclotron frequency in a nutshell
Cyclotron motion: • Only charged particles • In non relativistic limit a ratio of precisely measured constants fc,0 =
1 eB
2⇡ me
• Energy dependent (Lorentz factor) fc =
fc,0
=
Limits the cyclotron as accelerator
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eB
2⇡ me + Ekin /c2
Measurement of kinetic energy!
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Anomalous magnetic moments
Relation between magnetic moment and spin of a charged lepton:
µ
~ e,µ,⌧
e
= ge,µ,⌧
~se,µ,⌧
2me,µ,⌧
From the Dirac equation (1928): Dirac
ge,µ,⌧
=2
Proc. R. Soc. London A 1928 117
Kusch and Foley (1947): Phys. Rev., 72, 1256, 1947 geexp = 2.002 29(8)
Anomalous magnetic moment: Schwinger (1947/48): Phys. Rev., 73, 416, 1948
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g = g Dirac (1 + ae,µ,⌧ )
a1e loop QED
↵
=
2⇡
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99.6% of a! 8
The muon anomalous magnetic moment
All interactions in the quantum loops add to a µ
:
aµ = aµ (QED) + aµ (had) + aµ (weak) + aµ (BSM)
Uncertainty of SM prediction dominated by hadronic vacuum polarization!
e.g.
[66] DHMZ: M. Davier et al., Eur. Phys. J. C 71, 1515 (2011), [67] HLMNT: K. Hagiwara et al., J. Phys. G 38, 085003 (2011)
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The recent BESIII results agree well with KLOE data! 9
Sensitivity to Beyond Standard Model Physics
For the electron:
(ge ) = 2.8 ⇥ 10
13
!
(ae ) = 0.24 ⇥ 10
9
So why bother measuring (a
µ ) 
140
⇥
10
9 at all? New interactions will have new contributions
2
gBSM
(lepton mass)
al (BSM) /
16⇡ 2 (new particle mass)2
✓
mµ
me
◆2
⇡
✓
105
0.5
◆2
⇡ 42000
ae (BSM) = 0.24 ppb !
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aµ (BSM) = 10 000 ppb
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aSM
µ
⇡ 750 ppb
aµ
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Experimental approach to aμ at FNAL
Clock comparison of muon spin precession and cyclotron frequency
s
p
s
p
g=2
g>2
Measure the anomalous spin precession frequency:
✓
◆
Qe
g 2 Qe
!a = !s !c ⌘ a µ
B=
B
m
2
m
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The 𝜋± and μ± decay: a self analyzing
polarimeter
Source of polarized muons νμ
π+
Analysis of μ+ spin in laboratory μ+
Analysis of μ+ spin at rest Lorentz boost: Time dilatation allows for extended observation time!
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The last muon g-2 experiment: BNL E821
Characteristic numbers: • Dipole field B = 1.45 T • Ring diameter: 14m • µ storage region: 9 cm ⌀ • 24 calorimeter stations • 2 straw tracker stations • 𝜔c = 6.7 MHz ⟶ 149 ns… • 𝜔a = 228 kHz ⟶ 4.37 μs
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A decay positron histogram of BNL E821
3.6·109 decay electrons, BNL E821 collab., 2001 data set, Ee > 1.8 GeV
0 to 100 μs 100 to 200 μs 200 to 300 μs 300 to 400 μs 400 to 500 μs 500 to 600 μs 600 to 700 μs M. Fertl
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Current status of the muon g-2
aE821
µ,exp
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=
gµ
2
2
= 11 659 208.9(54)stat (33)sys (63)total ⇥ 10
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G.W. Bennett et al., Physical Review D 73, 072003 (2006)
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Anomalous spin precession frequency
!
~a =
"
Qe
~
aµ B
m
✓
aµ
◆ ~ ~#
1
⇥E
2
1
c
Suppress the motional magnetic field CERNIII, BNL E821, FNAL E989 • Hot muon beam • Vertical, electrical focusing • Magic muons with ɣ=29.3
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~ =0
for ~ · B
Small corrections for 6= magic
and ~ · B
~ 6=
0 (pitch correction) Qe
!
~ a = + aµ
m
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✓
+1
◆⇣
⌘
~·B
~ ~
≅0
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The FNAL E989 error budget
Complete error budget for FNAL E989 given in Full Technical Design Report M. Fertl
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Higher precision: more observed muons
• Unique accelerator chain at FNAL: accumulate 21x BNL E821 statistics • Linac and Booster: 1x 4.0·∙1012 p+/pulse • Re-­‐bunching p+ in recycler ring: 4x 1.0·∙1012 p+/pulse to avoid pile-­‐up • 8 GeV, 120 ns pulse length • 10ms pulse separation
Courtesy: M. Convery
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2013: Shipping the superconducting magnet
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2014/2015: The storage ring assembly in MC1
New MC1 building: more stable foundation, temperature stability ±1°C
Ring assembly time lapse video removed
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The precision magnetic field
and nuclear magnetic resonance measurements
70 ppb uncertainty of mag. field folded with muon distribution in storage region Superconducting coils
90 mm diameter muon storage region, 14 m ring diameter Excitation of free induction decay and pick-­‐up
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Magnetic field survey during the experiment
Between muon operation • 17 pNMR probes • Vacuum compatible trolley • Cycles the ring once a day • Multipole decomposition M. Fertl
During muon operation • 376 pNMR probes in vacuum chamber walls • Interpolate the magnetic field in time • Temperature dependence of pet. jelly! Yale 3/3/2016
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Design of improved pNMR probes
Addressed the problems of the E821 pNMR probe design after careful study
100.00 mm
Serial inductor coil
Base piece with double crimp connection
B
Outer crimp ring
8.00 mm
End cap with threaded hole
Petroleum jelly volume
Inner conductor of capacitor
Parallel inductor coil
Double shielded cable
Inner crimp ring
PTFE tuning piece with slot
• Exc. el. connection • Non corrosive pet. jelly instead of water in all probes • No Stress tuning • Factor 1.75 higher LC circuit quality factor
Coordinated the production of the parts for the new probes. M. Fertl
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The pNMR assembly chain an Q&A
Ronaldo UW undergraduate
Cole, UW undergraduate
• Highly reliable probes • Built 430 pNMR probes • All shipped to FNAL for installation • 28 in use for shimming right now
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Rachel, UW graduate student
measured at UMass, Amherst
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Ramping up and shimming the magnet
Sept 22, 2015: First full field since 2001
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Magnet design allows nearly decoupled adjustment of magnetic field multipoles • adjusting air gaps (dipole) • adjusting wedge shims (quadrupole) • adjust edge shims (sextupole)
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28 pNMR probes on the shimming cart
Shimming cart pulled by stepper motor
as of Jan 2016: 400 ppm
25 pNMR probes in circular matrix 3 pNMR probes at fixed probe locations
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Yale 3/3/2016
Courtesy: Matthias Smith UW graduate student
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The new muon g-2 experiment at FNAL
collaboration
8 countries 30 institutions 150 people overall 100 physicists
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Neutrino mass limits from laboratory nuclear
beta decay experiments
T2 beta decay kinematics model independent 2
m (⌫e ) =
X
i
2
|Ue,i | m2i
0νββ decay searches • model-­‐dependent T1/2 |M|2|mββ|2 • effective Majorana mass: ∝
m
=
X
Uei2 mi
i
• Probes Majorana nature of neutrino • current status: m < 0.2 0.4eV
< 20 50 meV
• potential reach: m
• possible in 35 natural isotopes M. Fertl
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Beta decay electron spectrum
Effective neutrino mass imprinted on the decay electron spectrum
X
dN
G2F m5e cos2 ✓C
2
2
=
|M
|
F
(Z,
E
)
p
E
|U
|
Pk (Emax Ee
nuc
e
e
e
ei
dEe
2⇡ 3 ~7
i,k
q
2
⇥ (Emax Ee Vk )
m2⌫i · ⇥ (Emax Ee Vk m⌫i )
Fractional decay rates for T2 10 eV: 2·∙10-­‐10 1 eV: 2·∙10-­‐13
Vk )
• Incoherent sum over all possible decay channels • Initial and final state population distribution • Current limit:
m⌫¯e , < 2.05 eV (95% CL)
Kraus et al. Eur. Phys. J. C 40, 447, 2005
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Electrostatic spectrometer with magnetic
adiabatic conversion (MAC-E) technique
70 m long, 10 m diameter vacuum tank • Window less gaseous tritium source (1010 Bq) • Molecular T2 • Anticipated mass sensitivity: < 200 meV (90% CL) • Resolution scales like the area of the analyzing plane
New technique needed for independent confirmation or to scale beyond MAC-­‐E sensitivity
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Cyclotron radiation emission spectroscopy
Novel approach: J. Formaggio and B. Monreal, Phys. Rev D 80:051301 (2009) • Cyclotron radiation from single electrons • Source transparent to microwave radiation • No electron transport from source to detector • Highly precise frequency measurement
fc =
fc,0
=
1
eB
1 eB
⇡
2⇡ me + Ekin /c2
2⇡ me
1
Ekin
+
me c 2
✓
◆2
Ekin
+ ...
me c2
| {z }
!
8
4
⇥ 10 for
forEkin
Ekin
=100
eV
0.13%
=18.6
keV
P (17.8 keV, 90 , 1 T) = 1 fW
P (30.2 keV, 90 , 1 T) = 1.7 fW
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Small but readily detectable with state of the art detectors
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A simulated single electron signal
What are the characteristic features of a detected signal?
In time frequency domain: • Sudden onset of microwave power • Slowly rising frequency • Sudden stop when e lost from trap M. Fertl
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Frequency and energy resolution of CRES
Energy vs. frequency resolution in 1T field:
Ekin
=
Ekin
✓
me c2
1+
Ekin
◆
Magnetic mirror trap
⌫c
⌫c
⇡ 28 for e-­‐ at tritium endpoint
Ekin ⇡ 0.2 eV !
⌫c ⇡ 28 GHz !
⌫c
⇡ 4 ⇥ 10
⌫c
7
⌫c ⇡ 11 kHz
Frequency resolution vs. observation time:
⌫c ⇥ tobs
1
! tobs
2⇡
tobs cos ✓ ⇡ 20 m
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For typical P8 settings up to:
14 µs
for a 1a8.8 electron for
17.8keV keVelectron
and 89° pitch angle
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sin ✓min =
r
Bmin
! 85
Bmax
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The apparatus: the outside
50 K cold head
Low noise cryogenic amplifiers
Ben Laroque, UCSB graduate student
Isolation vacuum system
83Rb/83mKr gas system
Super conducting magnet, 52 mm bore
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The apparatus: the inside
WR42 waveguide
83mKr supply lines
Electron spin resonance modulation coil
Upper bathtub trap coil
Upper Kapton window
Gas volume
Harmonic trap coil
Lower Kapton window
Lower bathtub trap coil
WR42 waveguide tickler port
WR42 waveguide short
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The microwave detector
• Cryogenic preamplifiers (50K physical temp.) • Double stage frequency mixing (24.2 GHz, 0.6 GHz to 1.2 GHz)
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The first light in the detector
energy changing gas collisions
sudden onset of power
linearly rising frequency
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A cyclotron radiation emission spectrum
of 83mKr conversion electrons
15 eV FWHM
50 eV
Asner et al., Physical Review Letters, 114, 162501 (2015) M. Fertl
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Press coverage
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Axial motion: side band generation
Magnetic bottle introduces a degeneracy between kinetic energy and pitch angle! eB
fc =
m + Ekin /c2
✓
cot2 ✓
1+
2
◆
Axial electron motion ⟶ Modulation of cyclotron frequency ⟶ Side band generation
VERY PRELIMINARY!
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The near future of Project 8
Demonstrate CRES with continuous beta spectrum of T2:
Build a tritium compatible waveguide cell with larger active volume
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Demonstrate critical technology developments for scale up • Magnetic field volume: MRI magnet • Improved magnetic field control
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Improving the ESR measurement setup
ESR measurement used for relative magnetic field comparison, based on DPPH 80 MHz
Source: http://web.nmsu.edu/ snsm/classes/chem435/Lab7/
Jared Kofron, PhD Thesis, UW, 2015
DPPH
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New coax cable ESR measurement setup
DPPH BDPA 0.4Vrms on field modulation, variable microwave power
Megan, UW undergraduate
• Replace dielectric in waveguide cable with glue/BDPA radical mixture • Close outer conductor • Install in a small electro magnet (mod. coils)
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The Project 8 collaboration
D. M. Asner, J. L. Fernandes, E.C. Finn, A. M.Jones, J. R. Tedeschi, B. A. VanDevender Pacific Northwest National Laboratory, Richland, WA P. J. Doe, A. Asthari, M. Fertl, J.N. Kofron, E.L McBride, M. L. Miller, R. G. H. Robertson, L. J. Rosenberg, G. Rybka, M. G. Sternberg, M. Wachtendonk, N.L. Woods University of Washington, Seattle, WA J.A. Formaggio, D. Furse, P. Mohanmurthy, N. S. Oblath, D. Rysewyk Massachusetts Institute of Technology, Cambridge, MA L. de Viveiros, B. H. Laroque, M. Leber, B. Monreal University of California, Santa Barbara, CA R. Bradley National Radio Astronomy Observatory, Green Bank, WV Th. Thümmler Karlsruher Institut fuer Technologie, Karlsruhe, Germany S. Böser Universität Mainz, Mainz, Germany
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Summary and Outlook
A new muon g-­‐2 experiment is rapidly coming online at FNAL! • Redesigned, built, and delivered 430 pNMR probes to measure the spatial distribution and the time stability of the magnetic field • First muons expected in the experiment early FY17 Project 8 has demonstrated cyclotron radiation emission spectroscopy • Successfully built the prototype experiment • Developing the next stage of the experiment with molecular tritium Thank you!
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