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The Ghostly Neutrino Steve Boyd, University of Warwick
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Page 1: The Ghostly Neutrino Steve Boyd, University of Warwick.

The Ghostly Neutrino

Steve Boyd, University of Warwick

Page 2: The Ghostly Neutrino Steve Boyd, University of Warwick.

“If we are to understand “why weare here” and the basic propertiesof the universe we live in, we mustunderstand the neutrino.”

American Physical Society Report - 2004

Page 3: The Ghostly Neutrino Steve Boyd, University of Warwick.

A little bit of history

What are they?

Where do they come from?

Why study them?

A recent surprise

The T2K Project

Page 4: The Ghostly Neutrino Steve Boyd, University of Warwick.

CRISIS

Page 5: The Ghostly Neutrino Steve Boyd, University of Warwick.

Energy(Ra) ≠ Energy(Ac)+Energy(e)

Page 6: The Ghostly Neutrino Steve Boyd, University of Warwick.

“At the present stage of atomictheory we have no argumentsfor upholding the concept ofenergy balance in the case ofb-ray disintegrations.”

Neils Bohr

Page 7: The Ghostly Neutrino Steve Boyd, University of Warwick.

Wolfgang Pauli

“Desperate remedy.....”“I do not dare publish this idea....”“I admit my way out may look improbable....”“Weigh it and pass sentence....”

“You tell them. I'm off to a party”

Page 8: The Ghostly Neutrino Steve Boyd, University of Warwick.

Energy(Ra) ≠ Energy(Ac)+Energy(e)

Page 9: The Ghostly Neutrino Steve Boyd, University of Warwick.

Energy(Ra) Energy(Ac)+Energy(e)+ Energy(Neutrino)

Page 10: The Ghostly Neutrino Steve Boyd, University of Warwick.

What are neutrinos?

Page 11: The Ghostly Neutrino Steve Boyd, University of Warwick.

Electron, e

Tiny mass ( 1 )

-

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Electron Neutrino, ne

0

Very tiny mass(<0.0000001)

Electron, e

Tiny mass ( 1 )

-

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x 500

Page 17: The Ghostly Neutrino Steve Boyd, University of Warwick.

Very tiny mass(<0.0000001)

e

ne

e

ne

Electron Neutrino, ne

0

Very tiny mass(<0.0000001)

Electron, e

Tiny mass ( 1 )

-

Page 18: The Ghostly Neutrino Steve Boyd, University of Warwick.

In experiments neutrinos are NEVER seen.

We can only detect them through the byproducts of their interactions with matter.

Type of the charged particle detected used to infer the type of incoming neutrino.

e e

Page 19: The Ghostly Neutrino Steve Boyd, University of Warwick.

Electron Neutrino, ne

Electron, e

mass ( 1 ) -Muon Neutrino, nm

Muon, m

mass ( 200 ) -TauNeutrino, nt

Tau, t

mass ( 3500 ) -3 Lepton Types

Page 20: The Ghostly Neutrino Steve Boyd, University of Warwick.

m

ne

t

ne

Page 21: The Ghostly Neutrino Steve Boyd, University of Warwick.

Electron Antineutrino, ne

Positron, e+

mass ( 1 ) +

3 Antiparticles

Muon Antineutrino, nm

Muon, m+

mass ( 200 ) +Tau Antineutrino, nm

Tau, t+

mass ( 3500 ) +

Page 22: The Ghostly Neutrino Steve Boyd, University of Warwick.

Where do they come from?

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Everywhere

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From the Big Bang

Artist's conception

Page 26: The Ghostly Neutrino Steve Boyd, University of Warwick.

From the Big Bang

Artist's conception

One cubic foot of space contains about 10,000,000 neutrinos leftover from the Big Bang.

Page 27: The Ghostly Neutrino Steve Boyd, University of Warwick.

From Astrophysical Objects

Supernovae created the heavy elements (us) and neutrinos appear to be important to the explosion dynamics.

Page 28: The Ghostly Neutrino Steve Boyd, University of Warwick.

From the Sun

≈ 70 million per cm2 per second at the Earth

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From Cosmic Rays.

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Geoneutrinos

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From Us.

Page 33: The Ghostly Neutrino Steve Boyd, University of Warwick.

So why don't we notice?

n are almost ghosts. They interact extremely weakly with matter.

To a neutrino a planet is mostly empty space.

Page 34: The Ghostly Neutrino Steve Boyd, University of Warwick.

"The chances of a neutrino actually hitting something as it travels through all this howling emptiness are roughly comparable to that of dropping a ball bearing at random from a cruising 747 and hitting, say, an egg sandwich."

Douglas Adams

Page 35: The Ghostly Neutrino Steve Boyd, University of Warwick.

500,000,000,000,000 solar n just went through you

Page 36: The Ghostly Neutrino Steve Boyd, University of Warwick.

enpn

enpn

enpn

enpn

enpn

enpn

enpn

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Why do we study them?

Page 38: The Ghostly Neutrino Steve Boyd, University of Warwick.

Probes of environments that we otherwise cannot see

Probes of objects too far away for anythingelse

Cosmological and astrophysical implications

Matter/Antimatter imbalance

Page 39: The Ghostly Neutrino Steve Boyd, University of Warwick.

Probes of environments that we otherwise cannot see

Probes of objects too far away for anythingelse

Cosmological and astrophysical implications

Matter/Antimatter imbalance

NEUTRINO

ASTROPHYSICS

Page 40: The Ghostly Neutrino Steve Boyd, University of Warwick.
Page 41: The Ghostly Neutrino Steve Boyd, University of Warwick.

Probes of environments that we otherwise cannot see

Probes of objects too far away for anythingelse

Cosmological and astrophysical implications

Matter/Antimatter imbalance

Page 42: The Ghostly Neutrino Steve Boyd, University of Warwick.

Universal Structure

m eV m eV

m eV m eV

Page 43: The Ghostly Neutrino Steve Boyd, University of Warwick.

Probes of environments that we otherwise cannot see

Probes of objects too far away for anythingelse

Cosmological and astrophysical implications

Matter/Antimatter imbalance

Page 44: The Ghostly Neutrino Steve Boyd, University of Warwick.

Why is there more matter than antimatter?

=

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Why is there more matter than antimatter?

Page 46: The Ghostly Neutrino Steve Boyd, University of Warwick.

Sub-Atomic Talk Show Disasters

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CP ViolationQ. Is there a difference betweenthe physics of matter and antimatter?

A.Yes there is.

We study this herewith an experimentcalled BaBar

“B0 / B0 mixing”

Page 48: The Ghostly Neutrino Steve Boyd, University of Warwick.

Q. Is there a difference betweenthe physics of matter and antimatter?

A.Yes there is.

We've never seen it in neutrinos, though.

Matter-Antimatter Asymmetry

n

n

nn

nn

n

n n

n

nn

“Leptogenesis”

Page 49: The Ghostly Neutrino Steve Boyd, University of Warwick.

How to study this?

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Neutrino OscillationsTHE discovery in neutrinos of the last 20 years

l

nl

l

nl

A typical neutrino experiment

Page 51: The Ghostly Neutrino Steve Boyd, University of Warwick.

The Sun is Broken!!!

Ray Davis – Early 1970s

Page 52: The Ghostly Neutrino Steve Boyd, University of Warwick.

An atom a day

e Cl37 e- Ar37

1 Ar atom every two days

Only

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Less than expected

Expected

Measured

Num

ber

n o

bse

rved

Page 54: The Ghostly Neutrino Steve Boyd, University of Warwick.

Neutrino OscillationsTHE discovery in neutrinos of the last 20 years

e

ne

m

nm

Neutrinos were changing flavour betweensun and detector!

Page 55: The Ghostly Neutrino Steve Boyd, University of Warwick.

Distance Travelled

Pro

b.

It is

ne

0

1

e

ne

m

nm

Page 56: The Ghostly Neutrino Steve Boyd, University of Warwick.

Eh?

Q. How can a ne spontaneously turn into a nm?

Page 57: The Ghostly Neutrino Steve Boyd, University of Warwick.

Eh?

Q. How can a ne spontaneously turn into a nm?A. The ne isn't a particle. It's three!

ne ≡ “that thing which was always produced/detected with an electron”

e

ne

Page 58: The Ghostly Neutrino Steve Boyd, University of Warwick.

Quantum Stuff

e

ne

en1

en2

en3

=or

or

60%

30%

10%

Page 59: The Ghostly Neutrino Steve Boyd, University of Warwick.

e

ne

m

nm

Original n1,n2,n3

mixture

Different n1,n2,n3

mixture

n1,n2,n3

travelsat differentspeeds

This can only happen if n1,n2,n3 have different massesOnly gives us differences in masses

Long journey

Page 60: The Ghostly Neutrino Steve Boyd, University of Warwick.

Why so important?The Standard Model of Particle Physicshas no explanation for a non-zero, but tiny, neutrino mass – so we are in “unknown physics” territory.

Neutrino masses link to GUT theories.

Has cosmological implications (mass balance,structure)

Posc e≠ Posc e

Page 61: The Ghostly Neutrino Steve Boyd, University of Warwick.

The T2K Experiment

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University of Warwick

University of Sheffield

Imperial College, University of London

Oxford University

University of Liverpool

University of Lancaster

Queen Mary College, University of London

Rutherford-Appleton Laboratories

Page 63: The Ghostly Neutrino Steve Boyd, University of Warwick.

295 km

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295 km

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JPARC Facility

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JPARC Facility

TARGET nm

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295 km

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Super-Kamiokande

nm

ne

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Super-Kamiokande

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Water Cerenkov

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Electron-like : has a fuzzy ring

Muon-like : has a sharp edged ring andparticle stopped in detector.

Page 76: The Ghostly Neutrino Steve Boyd, University of Warwick.

Open Questions

How much do n1,n2 and n3 weigh?

Why are they so much lighter than all the other massive particles?

Are neutrinos the same as antineutrinos?

Are neutrinos the reason we are here at all?

Page 77: The Ghostly Neutrino Steve Boyd, University of Warwick.

‘‘...these kind of findings have implications that are not limited to the laboratory. They affect the whole of society — not only our economy, but our very view of life, our understanding of our relations with others, and our place in time.’’

Bill Clinton

Page 78: The Ghostly Neutrino Steve Boyd, University of Warwick.
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P e=sin2 2sin21.27 m2 LE

L

sin2(2q)

Dm2 = m12-m2

2

Page 80: The Ghostly Neutrino Steve Boyd, University of Warwick.

Why do blue sky research?5% of jobs in UK are in physics-based sectorsGross added value from physics sectors was

estimated to be 70 billion pounds in 2005Synergy between PP projects and industry – industry

acquires added skills base for other applicationsTraining - 50% of PP PhDs go into other sectors

Radioisotope productionSensors for medical applicationsHigh level computing for biological modellingSpin off tools for other science (e.g. DIAMOND)Nuclear fusion researchMuon tomography in border securityAirport scannersRock ImagingCancer treatment using next gen cyclotrons