The invisible world

The elementary particles

Study Nature’s phenomena…

Look for the hidden laws behind these phenomena…

Experiment beyond our senses…Experiment beyond our senses…

• Length (meters) 10-15 m = size of atom’s nucleus 1 m = you 4.10+16 m = distance that separate us from the star Alpha Centauri (4 light-years)

• Time (seconds) 10-23 s = lifetime of particle Z0 1 s = you 10+17 s = sun’s lifetime

• Energies (Joules) 10-19 J = energy of a photon emitted by a lamp 10-7 J = landing of a mosquito 10+9 J = your meals during the day 10+16 J = atomic bomb of 1 Megaton 10+26 J = light energy from the sun…every second!

Scale factors

Lets enter the invisible world

10 meters

A rose tree

0.1 meter = 10 cm

A fly on a rose tree leaf

Lets enter the invisible world

10-3 meter = 1 mm

The eye of a fly

Lets enter the invisible world

Detectors of the invisible

The optical microscope

Onions cells

10 micron

10-5 meter = 10 microns

A hair on the eye of a fly

Lets enter the invisible world

The electronic microscope

First electronic microscope : E. Ruska and M. Knoll , 1932 (Nobel prize 1986)

Optical microscope Electronic microscopeLight beam Electrons beamOptical lenses Electromagnetic lensesresolution 0.5 micrometer resolution 0.0002 micrometer

= h / p = longueur d’onde

h = constante de Planck

p = impulsion de la particule = mv

0.1 micron

Chloroplast within a plant cell

Detectors of the invisible

10-7 meter = 0.1 micron

The base of the hair and cells that make the eye of the fly

Lets enter the invisible world

A few examples of scalesThe small…

You need the same number of cells to make a human being as stars to make a galaxy (100 billions)

10-8 meter ~ 100 Angströms

A DNA strand within the nucleus of a cell

Lets enter the invisible world

In 1990. the scanning tunneling microscope allowed researchers working at IBM to write the first letters in history written using nanotechnologies by placing 35 xenon atoms on a nickel surface.

First scanning tunneling microscope: G. Binnig et H. Rohrer in 1981 (IBM, Zürich), Nobel prize 1986

Scanning tunneling microscope (STM)

Voir aussi: http://www.cndp.fr/themadoc/micro3/rep_mcp.htm

Detectors of the invisible

10-10 meter = 1 Angström

A carbon atom. It is one of the element that makes a molecule found in DNA

Gold atoms deposited on a layer of carbon

Lets enter the invisible world

You need as many atoms to make an orange as oranges to fill the Earth

A few examples of scalesThe very small…

10-14 meter = 10 fermis

The nucleus of a carbon atom (drawing)

Lets enter the invisible world

You need as many atom’s nucleus to fill an atom as oranges to cover France entirely…15 times!

A few examples of scalesThe very very small…

Experiment ALEPH, at CERN

Detectors of the invisible

10-15 meter = 1 fermi

A proton in the nucleus (drawing)

A proton contains 3 quarks

Lets enter the invisible world

Lets enter the invisible world

At the end of the invisible world

Nuclear physics and particle physics

Elementary particles known in 2006

Forces

Strong interaction

gluon

quark

quark10-14 m

Forces

Electromagnetic interaction

photon

electronquark

Billions of km

Forces

Weak interaction

W+

neutrinoquark

10-14 m

n → p + e- + e

W+ W- Z0

Unification of the interactions

1 GeV = 1.6 1010 Joules

102 105 1010 1015 GeV

Weak interaction + electromagnetic interaction = electroweak interaction

(1967-1973) Glashow, Salam, Weinberg

Need Higgs

Unification of the 3 interactions: electromagnetic, weak and strong

Forces

Gravitation interaction

graviton

electronquark

Billions of km

Lets summarize:Matter and forces…

http://www.diffusion.ens.fr/vip/tableG00.html

…and the anti-matter

1928 : P. Dirac predicts the existence of anti-matter

Collision between a electron and an anti-electron 1993: the LEP at CERN

Anti-electron trace in a C. Anderson bubble chamber

1932: C. Anderson discovers the anti-electron

…anti-matter (2)

A B

A B CPT(A) CPT(B)

C(A) C(B)

Three fundamental transformations:

P: parity inversion

C: matter anti-matter

T: time reversal

CP(A) CP(B)

http://ppd.fnal.gov/experiments/e871/public/phys_slides.html

…anti-matter (3)

P

C CPEscher

…anti-matter (4)

≠

?

Right Left

Right

Left

Right

Left

• Symmetry violated: P parity

• Are there any other symmetries violated? Symmetry C matter ↔ anti-matter ?

…anti-matter (5)

Today in our universe

This ratio was though to be in the past

10105

photons

matière

photons

eantimatièrmatière

n

n

n

nnR

91036 R

• Diffuse cosmic background

• First nucleosynthesis models

• Number of stars

At the beginning, for 1 billion anti-matter particles,

there must have been 1 billion and 3 matter particles

Cosmic microwave background has been measured

One condition:

CP violation

…anti-matter (6)

The search for cosmic anti-matter

To observe anti-matter in space, we « only » need sending a magnet

matter Anti-matter

Cosmic ray

The experiment AMS (Alpha Magnetic Spectrometer) was conceived to observe anti-matter in space

we can count cosmic rays and classify them by types

…Anti-matter (7)

AMS 02

Space constraints

• Mass < 7 t

• 3 m x 3 m

• Power consumption < 2 kW

• Resistance :

• Temperature -50° / +50°

• Vacuum

• Vibrations

A simple magnet is not enough, we also need a particle physics detector

ATLAS for the LHC

• More than 7000 t

• 44 m x 20 m

• Power consumption > MW

• Immobilised 100m under ground

…anti-matter (8)

The detectors need to be very precise. We need to be able to reject:

1 proton in 104 positons1 Helium in 103 positons1 électron in 102 positons1 proton in 106 photons

Particle identification in AMS

Lets quickly go through history

Experiments that changed everything

E. Rutherford, H. Geiger et E. Marsdensent Helium particles (alpha particles) on gold leaf/sheet.

…

Surprise: the gold leaf/sheet looks like butter containing very small particles. Rutherford will interpret these as Gold atom’s nuclei

The mystery of beta disintegration

W. Pauli suggests a new particle: the neutrino

e

e

Experiments that changed everything

The first neutrino detector.

Built in 1956 by C. Cowan et F. Reines,near Savannah River’s nuclear reactor, USA

water+cadmium

1 neutrino out 1020 interacts with the detector !Reactor: 1020 neutrinos/sDetector at 12m3 neutrinos detected every hour

Experiments that changed everything

SLAC: discovery of quarksElectrons-protons collisions

SLAC and Brookhaven: discovery of quark « charme »electrons-positrons collisions

Fermilab: discovery of quark « bottom »protons-protons collisions

CERN: discovery of bosons W and Zprotons-antiprotons collisions

CERN: only three family of particleselectrons-positrons collisions

Fermilab: discovery of quark « top »proton-antiproton collisions

1968

1974

1977

1983

1993

1995

Experiments that changed everything

Giant detectors for tiny particles…

ALEPH detector studied high energy collisions

SuperKamiokande track the sun’s neutrinos

Today’s experiments

The theory that changed everything…quantum mechanics

E. Fermidescribed weak

interaction

W. Paulipredicted the

existence of the neutrino

P. Diracpredicted the existence

of anti-matter

L. De Brogliepredicted wave-particle

duality

Some of the players

Particle and wave wave function:

E = H

Orbitale 2s Orbitale 2p Orbitale 3d z

Distribution of the probability of finding an electron in an atom

Quantum mechanicsa new way to see the invisible

http://hypo.ge.ch/physic/simulations/orbitales/orbitales.html

« Old » way to look at electrons in an atom

Thomas Young’s experiment with photons

The mystery of quantum mechanics

Thomas Young’s experiment with electrons

The mystery of quantum mechanics

Small particles… awsome consequences

Thermonuclear bomb

Small particles… great consequences

Proton therapy

Seeking to understand what matter is made out of…Trying to see the invisible…

…has led to a better understanding of the human body, our Sun inner workings, the development of new materials (semi-conductors) or new light sources (such as lasers)