Transcript Lets enter the invisible world

The invisible world
The elementary particles
Study Nature’s phenomena…
Look for the hidden laws
behind these phenomena…
Experiment beyond our senses…
Scale factors
• 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!
Lets enter the invisible world
10 meters
A rose tree
Lets enter the invisible world
0.1 meter = 10 cm
A fly on a
rose tree leaf
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10-3 meter = 1 mm
The eye of
a fly
Detectors of the invisible
The optical
microscope
Onions cells
10 micron
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10-5 meter = 10 microns
A hair on
the eye of a
fly
Detectors of the invisible
First electronic microscope : E. Ruska and M. Knoll , 1932 (Nobel prize 1986)
The electronic
microscope
= h / p
 = longueur d’onde
h = constante de Planck
p = impulsion de la particule = mv
Chloroplast within a plant cell
0.1 micron
Optical microscope
Electronic microscope
Light beam
Optical lenses
resolution 0.5 micrometer
Electrons beam
Electromagnetic lenses
resolution 0.0002 micrometer
Lets enter the invisible world
10-7 meter = 0.1 micron
The base of
the hair and
cells that
make the
eye of the
fly
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)
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10-8 meter ~ 100 Angströms
A DNA strand
within the
nucleus of a cell
Detectors of the invisible
First scanning tunneling microscope: G. Binnig et H. Rohrer in 1981 (IBM, Zürich), Nobel prize
1986
Scanning tunneling
microscope (STM)
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.
Voir aussi: http://www.cndp.fr/themadoc/micro3/rep_mcp.htm
Lets enter the invisible world
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
A few examples of scales
The very small…
You need as many atoms to make an orange
as oranges to fill the Earth
Lets enter the invisible world
10-14 meter = 10 fermis
The nucleus
of a carbon
atom
(drawing)
A few examples of scales
The very very small…
You need as many atom’s nucleus to fill an atom as
oranges to cover France entirely…15 times!
Detectors of the invisible
Experiment ALEPH, at CERN
Lets enter the invisible world
10-15 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
10-14 m
quark
Forces
Electromagnetic
interaction
photon
electron
Billions of km
quark
Forces
Weak interaction
W+
neutrino
10-14 m
quark
n → p + e- + n e
W+ W- Z0
Unification of the interactions
Unification of the 3 interactions:
electromagnetic, weak and strong
Weak interaction + electromagnetic interaction
= electroweak interaction
(1967-1973) Glashow, Salam, Weinberg
Need Higgs
102
105
1010
1 GeV = 1.6 1010 Joules
1015
GeV
Forces
Gravitation
interaction
graviton
electron
quark
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 antimatter
Anti-electron trace in a
C. Anderson bubble
chamber
1932: C. Anderson discovers the anti-electron
Collision between a electron and an anti-electron
1993: the LEP at CERN
…anti-matter (2)
A
A
B
B
C(A)
C(B)
CPT(A)
CPT(B)
CP(A)
CP(B)
Three fundamental transformations:
P: parity inversion
C: matter  anti-matter
T: time reversal
http://ppd.fnal.gov/experiments/e871/public/phys_slides.html
…anti-matter (3)
P
C
Escher
CP
…anti-matter (4)
• Symmetry violated: P parity
Right
≠
Left
• Are there any other symmetries violated? Symmetry C matter ↔ anti-matter ?
Left
Right
?
Left
Right
…anti-matter (5)
Cosmic microwave
background has been
measured
Today in our universe
nmatière  nantimatière nmatière
R

 5  1010
n photons
n photons
• Diffuse cosmic background
• First nucleosynthesis models
• Number of stars
This ratio was though to be in the past
  6  R  3  109
At the beginning, for 1 billion anti-matter particles,
One condition:
there must have been 1 billion and 3 matter particles
CP violation
…anti-matter (6)
The search for cosmic anti-matter
To observe anti-matter in space, we « only » need sending a magnet
Cosmic ray
matter
Anti-matter
we can count cosmic rays and
classify them by types
The experiment AMS (Alpha Magnetic Spectrometer) was conceived to observe
anti-matter in space
…Anti-matter (7)
A simple magnet is not enough, we also need a particle physics detector
ATLAS for the LHC
AMS 02
•
More than 7000 t
Space constraints
•
44 m x 20 m
•
Mass < 7 t
•
Power consumption > MW
•
3mx3m
•
Immobilised 100m under ground
•
Power consumption < 2 kW
•
Resistance :
•
Temperature -50° / +50°
•
Vacuum
•
Vibrations
…anti-matter (8)
Particle identification in AMS
The detectors need to be very precise. We
need to be able to reject:
1 proton in 104 positons
1 Helium in 103 positons
1 électron in 102 positons
1 proton in 106 photons
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
Experiments that changed everything
The mystery of beta disintegration
ne
0
W. Pauli suggests a new
particle: the neutrino
0ne
Experiments that changed everything
1 neutrino out 1020 interacts with the detector !
Reactor: 1020 neutrinos/s
Detector at 12m
3 neutrinos detected every hour
The first neutrino detector.
Built in 1956 by C. Cowan et F. Reines,
near Savannah River’s nuclear reactor, USA
water+cadmium
Experiments that changed everything
1968 SLAC: discovery of quarks
Electrons-protons collisions
1974 SLAC and Brookhaven: discovery of quark « charme »
electrons-positrons collisions
1977 Fermilab: discovery of quark « bottom »
protons-protons collisions
1983 CERN: discovery of bosons W and Z
protons-antiprotons collisions
CERN: only three family of particles
1993 electrons-positrons collisions
Fermilab: discovery of quark « top »
1995 proton-antiproton collisions
Today’s experiments
Giant detectors for
tiny particles…
SuperKamiokande track the sun’s neutrinos
ALEPH detector studied high energy collisions
The theory that changed everything…
quantum mechanics
Some of the players
E. Fermi
W. Pauli
L. De Broglie
P. Dirac
described weak
interaction
predicted the
existence of the
neutrino
predicted wave-particle
duality
predicted the existence
of anti-matter
Quantum mechanics
a new way to see the invisible
Particle and wave  wave function: y
Ey = Hy
Distribution of the probability of finding an electron in an atom
Orbitale 2s
Orbitale 2p
Orbitale 3d z
http://hypo.ge.ch/physic/simulations/orbitales/orbitales.html
« Old » way to look at
electrons in an atom
The mystery of quantum mechanics
Thomas Young’s experiment with photons
The mystery of quantum mechanics
Thomas Young’s experiment with electrons
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 (semiconductors) or new light sources (such as lasers)