Measuring the Mass Scale of

ν

J. A. Formaggio Massachusetts Institute of Technology Oscillations

The Sudbury Neutrino Observatory MINOS Body of Evidence

Super-Kamiokande MINOS KamLAND SNO

The phenomena of neutrino oscillations is now firmly Super-Kamiokande established.

KamLAND Neutrino Oscillations

The Sudbury Neutrino Observatory MINOS sin2 (✓ )=0.0241 0.0025 13 ± Body of Evidence Reactor & Long Baseline

2 sin (✓12Super-Kamiokande)=0.307 0.016 2 ± 5 2 MINOS m =(7.54 0.26) 10 eV 12 ± ⇥ KamLAND SNO Solar

2 sin (✓23)=0.386 0.022 2 ± 3 2 The phenomena of m =(2.43 0.09) 10 eV 23 ± ⇥ neutrino oscillations is now firmly Super-Kamiokande established. Atmospheric

Camilieri, Lisi, WilkersonKamLAND Ann. Rev. 57 (2008). Fogli et al, arXiv:1205.5254 (hep-ph) More Questions

What We Don’t Know

(1) What is the absolute scale of neutrinos?

(2) What is the mass hierarchy?

(3) What is the nature of neutrino mass? More Questions

What We Don’t Know

(1) What is the absolute scale of neutrinos?

(2) What is the mass hierarchy?

(3) What is the nature of neutrino mass? More Questions

What We Don’t Know

(1) What is the absolute scale of neutrinos?

(2) What is the mass hierarchy?

(3) What is the nature of neutrino mass? Normal? Inverted? More Questions

What We Don’t Know

(1) What is the absolute scale of neutrinos?

(2) What is the mass hierarchy?

(3) What is the nature of neutrino mass?

Dirac Majorana? Just cold dark matter matter dark cold Just Neutrino Masses Newfrom Frontiers Cosmology

• Cosmology looks at the sum of neutrino masses ➙

(gravitational effect) withmass neutrino matter dark Cold

n i m,i = = critical critical Large Scale Structure The Strategy Galaxy Surveys (a naive view) WMAP Temperature Map

Weak lensing

CMB, Polarization

Surveys (galaxy, weak)

Lyman α

Max Tegmark, 2005 CMB Polarization Lyman α Current Limits

• Limits for neutrino masses depend in part on:

Which data is used, and... • Komatsu et al 2010 • ...what assumptions are made.

Set w = -1 w ≠ -1

WMAP 7 only ∑ mν < 1.3 eV ∑ mν < 1.4 eV

WMAP7 + BAO ∑ mν < 0.58 eV ∑ mν < 1.3 eV + H0

WMAP7 + BAO ∑ mν < 0.7 eV ∑ mν < 0.9 eV + SN Current Limits

• Limits for neutrino masses depend in part on:

Which data is used, and... • Komatsu et al 2010 • ...what assumptions are made. WMAP Alone

WMAP + H0 + BAO Set w = -1 w ≠ -1

Gonzales- Garcia WMAP 7 only ∑ mν < 1.3 eV ∑ mν < 1.4 eV

arXiv: WMAP7 + BAO 1006.3795 ∑ mν < 0.58 eV ∑ mν < 1.3 eV + H0 v2

WMAP7 + BAO (and many ∑ mν < 0.7 eV ∑ mν < 0.9 eV + SN others) Current Limits

• Limits for neutrino masses depend in part on:

Which data is used, and... • Komatsu et al 2010 • ...what assumptions are made. WMAP Alone

WMAP + H0 + BAO Set w = -1 w ≠ -1

Gonzales- Garcia WMAP 7 only ∑ mν < 1.3 eV ∑ mν < 1.4 eV

arXiv: WMAP7 + BAO 1006.3795 ∑ mν < 0.58 eV ∑ mν < 1.3 eV + H0 v2

WMAP7 + BAO (and many ∑ mν < 0.7 eV ∑ mν < 0.9 eV + SN others) • Planck alone can push PLANCK neutrino limits down 1 eV.

• Host of new experiments coming to the forefront can push even lower.

PLANCK

WMAP PLANCK Systematic Effects Nonlinearities Moving • As precision demands Forward... moves to 1%, non-linear effects, degeneracies, baryons, etc. all begin to play a role.

• Numerical simulations and Moving to the semi-analytical techniques normal hierarchy used to address. Y. Y. Y. Wong, 2010 scale now requires 1% precision on the power spectrum. Degeneracies Baryon Effects S. Hannestad Phys. Rev. Lett 95 221301

P ⌦ 12 ⌫ 1% P ' ⌦m ' Equation of stateof (w) Equation

Rudd, Zentner & Kravtsov, 2007 Direct Probes

If massive, the neutrino takes away some energy...

...from the (which we detect)

3 3 + - H ➟ He + e + νe

Beta decay allows a kinematic determination of the neutrino mass

No dependence on cosmological models or matrix elements Direct Probes

If massive, the neutrino takes away some energy...

...from the electron (which we detect)

3 3 + - H ➟ He + e + νe

Beta decay allows a kinematic determination of the neutrino mass

No dependence on cosmological models or matrix elements B field

T 2 gas

Frequency Measurement KATRIN Electromagnetic Spectroscopy

KATRIN is currently the prominent experiment for beta decay measurements.

New techniques being explored in the future: MARE & ECHO Calorimetry MARE and Project 8 Spectroscopic: MAC-E Filter MAC-E Filter Technique

KATRIN

Inhomogeneous magnetic guiding field.

Retarding potential acts as high-pass filter

3 3 + H He + e +¯ High energy resolution (ΔE/E = Bmin/Bmax = 0.93 eV) e The KATRIN Experiment Electron Beta Decay Spectrum

Tritium Beta Decay

3 3 - Detector H → He e νe 1 e-/s

Pre & Main spectrometers 103 e-/s

Tritium retention system 1010 e-/s

Windowless Gaseous Tritium Source 19 5 x 10 T 2/s The Windowless Gaseous Tritium Source ((WGTS))

• Gaseous tritium source provides source of beta-decay .

• Use of injection + differential pumping to T2 Specifications provide well-controlled gas column density. • Tritium activity: 1.7 x 1011 Bq

• Tritium throughput: 40 g T2/day • In-situ monitoring of purity of gas via • Temp. stability + 0.03 mK @ 30K 11 laser Raman spectroscopy. • Electron flux: 10 β/s • Column Density: 5 x 1017 cm-2

Detector

Transport Tritium Source & Pumping Main Spectrometer Demonstrator

Recent milestone: Demonstrator achieves 30 + 0.03 K neon stability Order of magnitude improvement

Solenoid testing Beam alignment (< 0.5 mm)

Detector

Transport Tritium Source & Pumping Main Spectrometer WGTS Magnet Testing at CEA Saclay

Recent milestone:

Main solenoids pass stress tests. The Main Spectrometer

Inner wire electrodes installed for rejection of low energy particles produced from cosmic rays.

Combination of precision high voltage and low magnetic field with correction air coils.

Inherent resolution of ΔE = 0.93 eV.

Detector

Transport Tritium Source & Pumping Main Spectrometer Air coil testing Vessel entrance Recent milestones: Air coils fully installed. Inner wire electrodes installed. Vessel sealed and undergoing vacuum tests.

Detector

Transport Tritium Source & Pumping Main Spectrometer The Main Spectrometer

Recent milestone:

Final pump port closed and sealed as of May 2012

Real World Simulation

Excellent progress in the simulation of the experiment on this scale. The Detector

Final electron detection occurs on a segmented silicon detector (148 pixels for spatial resolution).

Two high-field magnets provide final focusing of tritium decay electrons onto detector.

Multiple background reduction techniques (veto, material selection, etc.) employed.

Detector

Transport Tritium Source & Pumping Main Spectrometer Detector Installation

Recent milestones:

Detector installed at KIT

Undergoing final commissioning in conjunction with main spectrometer.

Detector

Transport Tritium Source & Pumping Main Spectrometer Spectrometer and air coils

Detector Projected Sensitivity KATRIN Sensitivity 2 Δmβ,stat = 0.018 Assumes 3 yr eV2 running

Major systematics

2 include source purity, Δmβ = 0.017 ,sys HV stability, source eV2 stability and T2 final states

Neutrino Mass Goals

Discovery: 350 meV (at 5σ )

Sensitivity: 200 meV (at 90% C.L.)

Commence Tritium Running in 2015 Can we push further? • KATRIN will achieve 200 meV scale. Can direct measurements push lower to the normal hierarchy scale? 10 meters across • Any future experiment needs to be able to (a) have a better scaling law -11 for increased target mass and (b) 10 mbar vacuum improve its energy resolution.

KATRIN Sensitivity MARE & ECHO • Uses 187Re as its beta source (one of the lowest endpoints, 2.3 keV)

Bolometric: • Advantages: • No backscattering • No atomic or molecular final state effects.

MARE • Disadvantages: • Extremely long half- life. • Pileup backgrounds.

Cryogenic setup 187 187 Re Os + e + ¯ in Milan e MARE & ECHO • New Technology: • Use of magnetic micro calorimeters. Minimize Bolometric: rise time and energy resolution. • MKID devices (1-10 GHz) resonating super- conductors. • Reduces pileup, increases pixelation and energy resolution 183 163 MARE Ho + e Dy +⌫ ! ⇤ e

• New Isotopes: • Also exploring 183Ho electron capture

187 187 Re Os + e + ¯e R&D to lead to eV sensitivity Project 8 “Never measure anything but frequency.” Source ≠ Detector

I. I. Rabi A. L. Schawlow

• Use cyclotron Simulation run frequency to extract (10!50 events) eB electron6 energy. !()= = K + me 5 Non-destructiverare high-energy many overlapping • low-energy electrons measurement4 electrons of electronPower (arb. units) energy.

3 E = 17572 eV Theta = 1.565 2 B field signal 1 T2 gas

0 Frequency 25.6 25.8 26 26.2 26.4 26.6 26.8 27 27.2 Frequency (GHz) 3 3 + H He + e +¯ e B. Monreal and J. Formaggio, Phys. Rev D80:051301 Cyclotron Frequency ! eB The Concept !()= 0 = K + me

Radiative Power Emitted • Coherent radiation emitted can be collected and used to measure the energy of the 2 2 2 electron in a non-destructive manner. 1 2e !0 Ptot( ,)= k k 4⇡✏ 3c 1 2 0

B. Monreal and J. Formaggio Phys. Rev. D80:051301 (2009). • Uniform B field

• Low pressure T2 gas. B field

• Antenna array for T2 gas cyclotron radiation detection. The Tritium Spectrum

• Look at a simulated tritium spectrum watched by a synthetic array (evenly spaced antennas over 10 meter uniform field).

• Low energy electrons dominate at higher frequencies.

• Rare, high energy electrons give a clean signature near endpoint. The Tritium Spectrum

• Look at a simulated tritium spectrum watched by a synthetic array (evenly spaced antennas over 10 meter uniform field).

• Low energy electrons dominate at higher frequencies.

• Rare, high energy electrons give a clean signature near endpoint. Project 8 Collaboration

J. Formaggio, D. Furse, N. Oblath Massachusetts Institute of Technology

R. Bradley T. Thuemmler R. Patterson National Radio Astronomy Observatory Karlsruhe Institute of Technology California Institute of Technology

Shepard Doelman, Alan Rogers M. Bahr, B. LaRoque, M. Leber, B. Monreal Haystack Observatories University of California, Santa Barbara

J. Kofron, L. McBride, R.G.H. Robertson, Leslie Rosenberg, Gray Rybka University of Washington, Center for Experimental Nuclear Physics and Astrophysics

D.M. Asner, J. Fernandes, A.M. Jones, J.F. Kelly, B.A. VanDevender Pacific Northwest National Lab Prototype Status

Monolithic assembly inserted into 2-in diameter vertical bore of 1T s.c. magnet.

Source gas flows directly through waveguide fiducial volume. Dual waveguide Cyclotron power transported in prototype both directions to low-noise 30 GHz amplifiers loaned by NRAO.

Signal mixed down to lower frequency (250 MHz bandwidth) and fully digitized. ESR Run on Digitizer Run 16, 12/10/2011 140000 B=0.875103 T B=0.86914 T (background) Magnetic Trapping 135000 Difference x5 + offset

130000

125000

120000 ESR Measurement

115000

110000 Power (unnormalized, linear)

105000

100000

95000 10 20 30 40 50 60 70 80 90 Frequency (MHz)

Magnetic bottle Trapping coil Trapping field 1 T field (27 GHz)

Use 0.93 Tesla field, where signal occurs at ~26 GHz with quadrupole trapping coil. Implies path length ~km. Trapping will be needed System monitors field in-situ using DPPH ESR monitoring. Δf −6 ΔE = 1eV ⇒ = 2 × 10 ⇒ tmin = 30 µs ΔB f Overall stability of prototype ~ 1×10−5 B Environmental Interference Upcoming Plans (now eliminated) Tickler

Did first test run in Sep 2011, a more intense run set for later this fall.

Dual System with greater waveguide monitoring of vacuum, prototype temperature, and calibration of fields.

In future, also exploring tuned RF cavities, at weaker split-ring resonator fields and larger volumes for 4 f0 = 2.07 GHz, Q ~10 tritium running. Moving Beyond the • One needs to either switch to (extremely pure) atomic tritium or other isotope with equivalent Inverted Scale yield.

• High intensity sources of tritium might be • Most effective tritium source achieved so far achievable using similar techniques as employed involves the use of gaseous molecular tritium. in H/D production.

• Main challenge is achieving the purity and • Method will eventually hit a resolution “wall” transport of atomic tritium. Requires heavy which is dictated by the roto-vibrational states R&D. of T2. This places a resolution limit of 0.36 eV.

Spectrum of rot-vib-excitations in electronic ground state (57%) Jerziorski B et al., 1985 Phys. Rev. A 32 2573 Final States 1.7 eV 2σ ≈ .7 eV

       Electronic excitation of 3HeT+ (43%) The next generation of beta decay experiments will provide greater sensitivity to the neutrino mass scale.

KATRIN is the current next- generation experiment designed to reach this level of sensitivity. Future experiments, such as Project 8, MARE and ECHO are also being ν developed using calorimetric and frequency techniques. ν Thank you for your attention Upcoming WMAP PLANCK Data

PLANCK

• Planck alone can push neutrino limits down 1 eV.

• Host of new experiments coming to the forefront. Upcoming WMAP PLANCK Data

PLANCK Probe Current Mission Reach • Planck alone can push neutrino limits CMB 1.3 eV CMBPol 0.6 eV down 1 eV.

CMB Lensing None CMBPol 0.05 eV • Host of new experiments Galaxy 0.6 eV LSST 0.1 eV coming to the Distribution forefront.

21 cm None SKA 0.05 eV Upcoming WMAP PLANCK Data

PLANCK Probe Current Mission Reach • Planck alone can push neutrino limits CMB 1.3 eV CMBPol 0.6 eV down 1 eV.

CMB Lensing None CMBPol 0.05 eV • Host of new experiments Galaxy 0.6 eV LSST 0.1 eV coming to the Distribution forefront.

21 cm None SKA 0.05 eV High Voltage Monitoring

KATRIN sensitivity goal requires 60 mV precision at 18.6 kV.

System monitored with high precision HV divider (10-6 stability).

In-situ monitoring of 83mKr line using refurbished Mainz spectrometer.

Recent milestones: Monitor spectrometer installed. HV stabilization ~x3 better than specification.

Detector

Transport Tritium Source & Pumping Main Spectrometer Main Spectrometer

E = 18.4-18.6 keV ΔE =0.93 eV 24 m long, 10 m wide vacuum region. Precision MAC-E filter.

spectrometerpre-

Pre-Spectrometer main spectrometer E = 18.3 keV ΔE =80 eV Filters most low energy electrons from beta spectrum detector Next Steps

Continue prototype tests: • Continue study of resonant cavities for enhanced • detection. • Next 83mKr run scheduled in 2 weeks. Begin “scalable design” for few eV precision mass • measurement. • Provide measurement of Kr line width. • Proposal for large experiment, for 2014. • Insert small amount of tritium as test

~ 40 µCi of T2 (KATRIN is ~ 3 Ci)