NEUTRINO MASS STUART FREEDMAN MEMORIAL SYMPOSIUM BERKELEY, JAN 11, 2014 Hamish Robertson, University of Washington a long wait for a little weight
Feb 23, 2016
NEUTRINO MASS
STUART FREEDMAN MEMORIAL SYMPOSIUMBERKELEY, JAN 11, 2014
Hamish Robertson, University of Washington
a long wait for a little weight
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Neutrinos oscillate, have mass
Super-KamiokandeKamLAND
SNO
Particle Physics Cosmology
What is the neutrino mass scale?
NEUTRINO MASS FROM BETA SPECTRA
neutrino massesmixing
With flavor mixing:
from oscillations mass scale
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5
MASS LIMITS FROM TRITIUM
6Hamish Robertson, Stuart Freedman, Tom Bowles, Carol Bowles, Karl-Erik Bergkvist. Erice 1980. (from Tom)
7Tom Bowles, Carol Bowles, Stuart Freedman, Hamish Robertson, Erice 1980. (from Tom)
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Magnetic spectrometers showed no kink. But they had shape correction factors.
"Contrary to intuition, a nullresult is not inherently more reliable than a positive one.”
J.J. Simpson
Grabowski spectrometer
CURRENT STATUS:
Mainz: solid T2, MAC-E filter C. Kraus et al., Eur. Phys. J. C40, 447 (2005)
Troitsk: gaseous T2, MAC-E filter V. Aseev et al., PRD 84 (2011) 112003
Together:…mv < 1.8 eV (95% CL)
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MASS AND MIXING PARAMETERS
m212 7.54+0.21
-0.21 x 10-5 eV2
m322| 2.42+0.12
-0.11 x 10-3 eV2
mi > 0.055 eV (90% CL) < 5.4 eV (95% CL)*
12 34.1+0.9-0.9 deg
23 39.2+1.8-1.8 deg
13 9.1+0.6-0.7 deg
sin213 0.025+.003-.003
Marginalized 1-D 1- uncertainties. *C. Kraus et al., Eur. Phys. J. C40, 447 (2005); V. Aseev et al. PRD 84 (2011) 112003.Other refs, see Fogli et al. 1205.5254 10
Oscillation Kinematic
TLK
KATRINAt Karlsruhe Institute of Technologyunique facility for closed T2 cycle:Tritium Laboratory Karlsruhe
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A direct, model-independent, kinematic method, based on β decay of tritium.
~ 75 m long with 40 s.c. solenoids
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~0.4 eV
First measurement, UIE = 700V, electron gun source.July 12, 2013.
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Measuring something and getting it wrong?
A WINDOW TO WORK INMolecular excitations
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Energy loss
KATRIN’S UNCERTAINTY BUDGET
StatisticalFinal-state spectrum
T- ions in T2 gasUnfolding energy loss
Column densityBackground slope
HV variationPotential variation in source
B-field variation in sourceElastic scattering in T2 gas
σ(mv2) 0 0.01 eV2
σ(mv2)total= 0.025 eV2
15mv< 0.2 eV (90 % CL)
WHAT IS THE BRANCHING RATIO FOR T2 → 3HeT+?
Source Experiment TheorySnell Wexle
rTH 0.932
± 0.019
0.895 ±
0.011
---
T2 --- 0.945 ±
0.006
0.36
Need a test of the final-state theory for KATRIN and Project 8
Tritium Recoil-Ion Mass Spectrometer (TRIMS)
MASS RANGE ACCESSIBLE
PresentLab Limit1.8 eV
starting2016
KATRIN
18K. Abazajian, CF5 Summary
e
μ
τ c
s
ud
t
b
νh
νmνlmeV
eV
keV
MeV
GeV
TeVLEPTONS QUARKS
??
MASS RANGE ACCESSIBLE
PresentLab Limit1.8 eV
starting2016
KATRIN
THE LAST ORDER OF MAGNITUDE
If the mass is below 0.2 eV, how can we measure it? KATRIN may be the largest such experiment possible.
Size of experiment now:Diameter 10 m.
Rovibrational states of THe+, HHe+ molecule
Source T2 column density near max
Next diameter: 300 m!
σ(mv)2 ~ 0.38 eV2
(B. Monreal and J. Formaggio, PRD 80:051301, 2009)
Radiated power ~ 1 fW
CYCLOTRON RADIATION FROM TRITIUM BETA DECAY
Working on the UW prototype25.5-GHz waveguide cell
SIGNAL IS A RISING “CHIRP” IN FREQUENCY
PROJECT 8: A PHASED APPROACH
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PROJECT 8 SENSITIVITY
NEUTRINO MASS LIMITS FROM BETA DECAY
2013 2014 2015 2016 2017 2018 2019
Analysis 2
Planck:
Construction Running
KATRIN:
Phase IProof concept Prototype
Project 8:
NEUTRINO MASS: SOME MILESTONES
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28Stuart Freedman, Steve Elliott, Hamish Robertson. Spanish coast 1992. Photo by John Wilkerson.
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CAPTURE OF RELIC NEUTRINOS
PTOLEMY project
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CAPTURE OF RELIC NEUTRINOS
PTOLEMY project
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PTOLEMY Experimental Layout
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Tritium Source Disk(Surface Deposition)
High Field Solenoid
Long High Uniformity Solenoid (~2T)
AcceleratingPotential
MAC-E filter(De-accelerating
Potential)
AcceleratingPotential
RF Tracking(38-46 GHz)
Time-of-Flight(De-accelerating
Potential)
CryogenicCalorimeter
(~0.1eV)
Low FieldRegion
e-
E0-18.4keV
0-1keV(~150eV)
E0
E0+30kV
~50-150eVbelow
Endpoint
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PTOLEMY SUMMARY
100 g of tritium (1 MCi) on 12-m diameter disk.Relic capture rate ~ 10/year without local clustering.Also presumably able to measure mass, active and sterile.Transition-edge sensor array to provide basic 0.1-eV resolution.Tagging with RF cyclotron radiation a la Project 8.Necessary to understand quantum effects of binding of T2 on surface.
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INPUTS1. Present laboratory limit 1.8 eV (90% CL) from
Mainz and Troitsk experiments on tritium2. KATRIN experiment under construction. 3. Project 8 in proof-of-concept phase.4. Cosmological inputs driven by Planck, SPT, ACT,
Sloan …
Planck XVI
WP = WMAP Polarization dataAL = weak lensing parameterτ = optical depth at recombination
“…Planck lensing likelihood favourslarger Σm than the temperature power spectrum.”
FIRST PLANCK ANALYSIS (MARCH 2013)
(B. Monreal and J. Formaggio, PRD 80:051301, 2009)
CYCLOTRON RADIATION FROM TRITIUM BETA DECAY
25.5-GHz waveguide cell
NEUTRINOLESS DOUBLE BETA DECAY
1 sigmaW. Rodejohann, 1206.2560
Depends on mv but not a `direct’ measurement
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ELECTRON CAPTURE HOLMIUM EXPT (ECHO)
187
J.F. Wilkerson
39J.F. Wilkerson
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ELECTRON CAPTURE HOLMIUM EXPT (ECHO)
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NEUTRINO MASS PHYSICS IMPACT
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SUMMARYDirect mass measurements are largely model independent:
• Majorana or Dirac• No nuclear matrix elements• No complex phases• No cosmological degrees of freedom
One experiment in construction (KATRIN); 2015 start.Three experiments in R&D (Project 8, ECHo, PTOLEMY)