The invisible world The elementary particles

Study Nature’s phenomena… Look for the hidden laws behind these phenomena…

Experiment beyond our senses…

Length (meters) m = size of atom’s nucleus 1 m = you m = distance that separate us from the star Alpha Centauri (4 light-years) Time (seconds) s = lifetime of particle Z 0 1 s = you s = sun’s lifetime Energies (Joules) J = energy of a photon emitted by a lamp J = landing of a mosquito J = your meals during the day J = atomic bomb of 1 Megaton 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 microscopeElectronic microscope Light beam Electrons beam Optical lensesElectromagnetic lenses resolution 0.5 micrometer resolution micrometer l= h / p l = 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 scales The 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 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: Detectors of the invisible

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 scales The very small…

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 scales The very very small…

Experiment ALEPH, at CERN Detectors of the invisible

meter = 1 fermi A proton in the nucleus (drawing) A proton contains 3 quarks 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 m

Forces Electromagnetic interaction photon electron quark Billions of km

Forces Weak interaction W+W+ neutrino quark m n → p + e - + e W + W - Z 0

Unification of the interactions 1 GeV = Joules GeV Weak interaction + electromagnetic interaction = electroweak interaction ( ) Glashow, Salam, Weinberg Need Higgs Unification of the 3 interactions: electromagnetic, weak and strong

Forces Gravitation interaction graviton electron quark Billions of km

Lets summarize: Matter and forces…

…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 BCPT(A) CPT(B) C(A) C(B) Three fundamental transformations: P: parity inversion C: matter  anti-matter T: time reversal CP(A) CP(B)

…anti-matter (3) P C CP Escher

…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 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 10 4 positons 1 Helium in 10 3 positons 1 électron in 10 2 positons 1 proton in 10 6 photons Particle identification in AMS

Lets quickly go through history

Experiments that changed everything E. Rutherford, H. Geiger et E. Marsden sent 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 nene 00ne00ne 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 interacts with the detector ! Reactor: neutrinos/s Detector at 12m 3 neutrinos detected every hour Experiments that changed everything

SLAC: discovery of quarks Electrons-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 Z protons-antiprotons collisions CERN: only three family of particles electrons-positrons collisions Fermilab: discovery of quark « top » proton-antiproton collisions 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. Fermi described weak interaction W. Pauli predicted the existence of the neutrino P. Dirac predicted the existence of anti-matter L. De Broglie predicted wave-particle duality Some of the players

Particle and wave  wave function: y E y = H y Orbitale 2sOrbitale 2pOrbitale 3d z Distribution of the probability of finding an electron in an atom Quantum mechanics a new way to see the invisible « 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)