Neutrino

The of Physics The Higgs make up stuff

Force

Charged

Neutrinos

3 generations of matter particles Properties Electrically neutral

Very very small mass (but non-zero)

They are the most common particle in the universe

The Big Bang Accelerators and Reactors 20 The Sun 10 ν/s 11 2 300 /cm3 10 /cm /s

Neutrino Sources

Cosmic Rays Radioactive decay Astrophysics 2 (Supernovae) 1 ν/cm /s in the earth 106 ν/cm2/s Neutrino Properties Electrically neutral

Very very small mass (but non-zero)

They are the most common particle in the universe

They only interact through the

To a neutrino a planet is just a wisp of fog

Roughly 100 trillion go through you every second

You can never detect the - just what they do when they interact in our detectors. # Neutrino Detections =

Probability of a neutrino to interact 

Flux of neutrinos ×

Number of target

Detectors need to be big...

...very big

...very big

Neutrinos : Particles In Disguise

Neutrinos are relaxed about identity. They can change type as they propagate from point to point.

They can only do this if they have mass. e  Long journey   e 

e 

e  distance 

1

e ν  μ s i t I

. b ν e o r P

0 Distance Travelled T2K : A neutrino flavour oscillation experiment

    295 km  e

Why study them?

Neutrinos are cool...

Why study them?

Why study them?

Why is the universe dominated by matter and not anti-matter?

The way neutrinos (and anti-neutrinos) change flavour could help answer this question.

Summary

Neutrinos are cool!

"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-Mostly Harmless

The chances of this happening is about 1 part in 1014

Matter

light

Anti-Matter 2 E = mc Matter

light

Anti-Matter

The reverse reaction should also happen with the same probability Equal amounts of matter and

1 of matter to 0.0000000001 atoms of antimatter It's Quantum.....

3 |ν >= U |ν > where U is a unitary matrix α ∑i=1 αi i i

i( Ek t − pk x) 2 |νk (t,x )>=e |νk (0,0)> → P(ν α(0,0)→ν β (t,x ))=|< νβ(t,x )|να (0,0)>|

2 * * i E E t p p x |< t,x | 0,0 >| U U U U e (( j − k) −( j− k) ) νβ( ) να ( ) =∑k ∑ j α k α j β k β j

E E t p p x p2 m2 p2 m2 x p p x= ( j − i ) −( j− i) =(√ j + j −√ i + i ) −( j − i)

2 2 2 1 m j 1 mi Δ mij ( p j (1+ )−pi (1+ ))≈ 2 p j 2 pi 4E

2 cosθ sin θ 2 2 Δ m12 L U = P(ν α (0,0)→ν β(t,x ))=sin (2θ) sin ( ) (−sin θ cosθ) 4E