Neutrino Physics @Berkeley

Alan PoonGroup Leader, Neutrino Astrophysics Group

http://neutrino.lbl.gov

Neutrinos

Professor Proton

• Following the ATLAS (LHC) talk…Gino the Neutrino

is the weakly interacting neutrino.

Answer key at http://neutrino.lbl.gov/crossword

The Berkeley Neutrino Puzzle

Look for green bold-faced hints in this talk!

Neutrino Physics @Berkeley• In the past decade, LBNL’s Nuclear Science and Physics Divisions played

leadership roles in KamLAND and Sudbury Neutrino Observatory (SNO), which demonstrated non-zero neutrino mass and neutrino oscillations.

• In the past few years, the Daya Bay reactor neutrino experiment measured the unknown mixing angle 𝜃13. [more later]

Neutrino Physics @Berkeley• In the past decade, LBNL’s Nuclear Science and Physics Divisions played

leadership roles in KamLAND and Sudbury Neutrino Observatory (SNO), which demonstrated non-zero neutrino mass and neutrino oscillations.

• In the past few years, the Daya Bay reactor neutrino experiment measured the unknown mixing angle 𝜃13. [more later]

SNO KamLANDDaya Bay

• In the past decade, LBNL’s Nuclear Science and Physics Divisions played leadership roles in KamLAND and Sudbury Neutrino Observatory (SNO), which demonstrated non-zero neutrino mass and neutrino oscillations.

• In the past few years, the Daya Bay reactor neutrino experiment measured the unknown mixing angle 𝜃13. [more later]

Neutrino Physics @Berkeley

SNO KamLANDDaya Bay

• In the past decade, LBNL’s Nuclear Science and Physics Divisions played leadership roles in KamLAND and Sudbury Neutrino Observatory (SNO), which demonstrated non-zero neutrino mass and neutrino oscillations.

• In the past few years, the Daya Bay reactor neutrino experiment measured the unknown mixing angle 𝜃13.

• In 2015: – 1 Nobel Prize (SNO) – 3 Breakthrough Prizes (Daya Bay, KamLAND, SNO)

Neutrino Physics @Berkeley• In the coming decade, we will try to answer the following

fundamental questions concerning the neutrinos: – lepton number violation – CP violation in the neutrino sector – neutrino mass hierarchy – absolutely mass scale of the neutrinos – Dirac and/or Majorana nature of the neutrinos

Graphics from Symmetry Magazine

Reactor θ13 ~ 9°

Solar θ12 ~ 34°

Atmospheric θ23 ~ 45°

• A weak eigenstate is a linear combination of mass eigenstates :

where U = Pontecorvo-Maki-Nakagawa-Sakata (PMNS) matrix.

Neutrino mixing

U =

⎛

⎝

Ue1 Ue2 Ue3

Uµ1 Uµ2 Uµ3

Uτ1 Uτ2 Uτ3

⎞

⎠

=

⎛

⎝

1 0 0

0 cos θ23 sin θ23

0 − sin θ23 cos θ23

⎞

⎠

×

⎛

⎝

cos θ12 sin θ12 0

− sin θ12 cos θ12 0

0 0 1

⎞

⎠

×

⎛

⎝

cos θ13 0 e−iδCP sin θ13

0 1 0

−eiδCP sin θ13 0 cos θ13

⎞

⎠

|��� |�i�

|��� =3�

i=1

U�i|�i�

You can measure the mixing angles with different sources

Neutrino mixing

The discovery of neutrino oscillation (hence neutrino mass) provides the first direct evidence of

physics beyond the Standard Model of Particle Physics.

If is on the Big Bang Theory, it must be important

Neutrino mass questions

Cosmology:

β decays:

ββ decays:

Oscillations:

m�� =3⇥

i=1

��U2eimi

��

m� =

⌅⇤⇤⇥3�

i=1

|Uei|2 m2i

�m2ij = m2

j �m2i

�m =

3�

i=1

mi = m1 + m2 + m3

Measuring the “mass”[mi]

Determining the hierarchy

Normal m

ass

msmallest

12

3

Inverted

mass

msmallest

12

3

Neutrino mass questions

Cosmology:

β decays:

ββ decays:

Oscillations:

m�� =3⇥

i=1

��U2eimi

��

m� =

⌅⇤⇤⇥3�

i=1

|Uei|2 m2i

�m2ij = m2

j �m2i

�m =

3�

i=1

mi = m1 + m2 + m3

LBNL and UCB programs cover all these measurements

Measuring the “mass”[mi]

Determining the hierarchy

Normal m

ass

msmallest

12

3

Inverted

mass

msmallest

12

3

Neutrino Oscillation Experiments

• Daya Bay [Kam-Biu Luk]

• DUNE [Kam-Biu Luk] • THEIA [Gabriel Orebi Gann]

• IceCube [Spencer Klein]

Daya Bay

• Ongoing reactor antineutrino experiment focusing on• Precise measurement of mixing angle θ23

and mass splitting |Δm232|• Precise measurement of absolute flux and energy spectrum of reactor antineutrinos• Search for a light sterile neutrino• Search for new neutrino phenomena• Search for supernova neutrinos

• Continue collecting data until 2020.

Neutrino oscillations - future

Deep Underground Neutrino Experiment (DUNE)

• A long-baseline neutrino experiment designed for studying• CP violation in neutrino oscillation• Neutrino mass-hierarchy problem• Precise measurement of mixing angle θ23 and mass splitting Δm232• Nucleon decay• Supernova neutrinos

• Berkeley involves in• ProtoDUNE – beam-test of full-scale liquid-argon TPC at CERN• Design and detector R&D of near detector • Simulation and physics analysis using NERSC supercomputers

THEIA• Large WbLS detector (50-100 kton)

• Fast, high-efficiency photon detection with high coverage

• Deep underground (e.g. Homestake)

• Isotope loading (Gd, Te, Li...)

• Flexible! Target, loading, configuration

➡ Broad physics program!

➡ long baseline, NLDBD, solar, geonu, nucleon decay, supernova, DSNB….

Concept paper - arXiv:1409.5864

R. Bonventre, J. Caravaca, F. Descamps, B. Land, G. D. Orebi Gann, J. Wallig

Hit

Tim

e Re

sidua

ls (n

s)

0

0.2

0.4

0.6

0.8

1

1.2

1.4

Hit

Tim

e Re

sidua

ls (n

s)

0

0.2

0.4

0.6

0.8

1

1.2

1.4

Local R&D: CHESSCHErenkov Scintillation Separation experiment

• Ring-imaging of cosmic muons

• Demonstrate separation in charge & time

• Successful separation in LAB, LAB/PPO and WbLS!

➡ Directional info in a low-threshold detector Unprecedented level of in-situ background rejection

Neutrinoless Double Beta Decay Experiments

• CUORE (130Te) [Brian Fujikawa, Yury Kolomensky]

• MAJORANA (76Ge) [Alan Poon] • SNO+ (130Te) [Gabriel Orebi Gann]

Beta Decay Experiment

• KATRIN (3H) [Alan Poon]

Neutrinoless double-beta decay is a big deal

Lepton number violation and Neutrinoless Double Beta Decays

Lepton number violationSM allowed process

T1/2 ~1018-21 y T1/2 >1026 y

CUORE @ Berkeley

Cuoricino CUORECUORE-02003–2008 2013–2015 2016–202211 kg 130Te 11 kg 130Te 206 kg 130Te

• Located at LNGS (Gran Sasso) • TeO2 crystal serves as both source of radioactive

decay and detector for resultant electrons • Bolometer:

• Electrons deposit energy in crystal • Energy converted into heat • Temperature of crystal read out using thermistor thermometers

CUORE @ Berkeley• Detector assembly (complete)

• Taking commissioning data

• Data processing and monitoring (CUORE-0 and CUORE)

• Neutrinoless double-beta decay analysis (CUORE-0 and CUORE)

• Hardware R+D for future experiments

Superconducting transition edge sensors (TES) for detecting heat pulse and Cherenkov light

Dilution refrigerator on campus18

MAJORANA DEMONSTRATOR• Physics:

•To search for LNV via 76Ge 0νββ decay •To search for light WIMPs (<10 GeV/c2)

• Status: – Production data taking in progress

• LBNL contributions: – Development and procurement of 76Ge detectors – Design and fabrication of low-noise signal processing

electronics; detector construction & commissioning – Simulation and analysis

• Future: – R&D for a ton-scale experiment starting

SNO+

• Load LAB with 0.5% natTe — NDBD search

• Ultra-low background (solar ν dominates)

• Large target mass, easy to scale

• Sensitivity to bottom of IH in phase II!

• Broad program of other physics! Solar, supernova, geoneutrino, nucleon decay

• Water data taking ongoing right now! LS data — autumn 2017.

R. Bonventre, J. Caravaca, F. Descamps, C. Kefelian, B. Land, G. D. Orebi Gann, J. Wallig

• Analysis (DBD, solar, backgrounds)

• DAQ leaders - HV control, alarm GUI, channel monitoring

• Constructing optical calibration source

• Responsible for calibration of PMT array & electronics

• 780 ton scintillator (LAB)

• 9500 PMTs

Neutrino mass

⇡+ ! µ+ + ⌫µ

Knowing the neutrino mass is important!

β decay: KATRIN

• 3H beta decay • Sensitivity: mβ<0.2 eV (90% CL) • Commissioning in progress. • 3H Data taking will begin next year • LBNL involves in analysis activities

β decay: KATRIN

• 3H beta decay • Sensitivity: mβ<0.2 eV (90% CL) • Commissioning in progress. • 3H Data taking will begin next year • LBNL involves in analysis activities

β decay: KATRIN

• 3H beta decay • Sensitivity: mβ<0.2 eV (90% CL) • Commissioning in progress. • 3H Data taking will begin next year • LBNL involves in analysis activities

The most energetic accelerators in the universeThe UCB/LBNL IceCube Group

● Cosmic-rays have been observed with energies up to 3*1020 eV (50 joules!) ● Despite 100 years of effort, we have not found the accelerators that produce

these particles ● Charged cosmic-rays bend in transit ● IceCube is a 1 km3 neutrino detector at the South Pole. ● 5,160 buried optical sensors detect Cherenkov light from the charged particles

produced in high-energy (>100 GeV) neutrino interactions in the polar icecap. ● We have observed cosmic neutrinos with energies up to ~5 PeV (5*1015 eV) ● These neutrinos should (eventually) pinpoint these accelerators ● The flux is near the predicted upper limits, so sources should be easy to find. ● We have eliminated or disfavored most of the popular theories for the origins of

these neutrinos: gamma-ray bursts, active galactic nuclei (galaxies containing supermassive black holes…), or supernovae.

● … a real science mystery… you can help solve it! ● IceCube also studies many other physics topics: dark matter, cosmic-ray

anisotropies, magnetic monopoles, other exotica…

IceCube @ LBNL● A friendly group with 1 senior staff, 1 postdoc, 1-2 grad students and (usually) 1

undergrad ● LBNL played key roles in IceCube hardware ● Active in astrophysical neutrinos and cosmic-ray physics

● Measurement of the astrophysical neutrino flavor (νe:νµ:ντ) ratio* ● Measurement of the atmospheric νe energy spectrum ● First observation of neutrino absorption in the Earth and measurement of the neutrino-

nucleon cross-section* ● Future interests include

● Characterization of TeV-PeV energy neutrino events (ν:ν ratio, etc.) via inelasticity measurements* and a more detailed energy spectra of the cosmic neutrino signal

● Precision measurement of the neutrino-nucleon cross-section ● Searches for leptoquarks, extra-dimensions or other exotica that would affect the cross-section

● Unusual classes of cosmic-ray events ● Gen2 – a proposed ~ 10 km3 upgrade to IceCube to study cosmic neutrinos in detail, ● ARIANNA, a proposed 100 km3 experiment to search for radio pulses emitted when ultra-

high energy neutrinos interact in the Antarctic Ross Ice Shelf. ● If you are interested in finding out more, please contact me:

● Spencer Klein, at (510) 486-5470, or srklein@lbl.gov • = Dissertation of current/past • UCB student

Neutrino programs @ Berkeley

ICECUBE

The ‘light’ (neutrino) side wants you!

And the ‘dark’ (matter) side wants you too! …next up

Backup

Double Beta Decay (ββ)

odd-odd

even-even╳

• Even-even nucleus (Z,A) whose pairing forces make it more bound than neighbor (Z+1,A), but less so than (Z+2,A).