Transcript Introducing Particle Physics

Introducing
Particle Physics
Journey into the
heart of matter
University of Birmingham
Master class,23rd April 2008
Ravjeet Kour
Topics
Fundamental particle
Leptons & quarks
Properties
Antiparticles
Forces in nature
Carrier of the forces
Properties
University of Birmingham
Master class,23rd April 2008
Ravjeet Kour
So what is particle physics?
 Everything in the
universe is made of
Particle of matter:
called fundamental
Particles
 Particle Physics : Study
these Particle
 Work out how they
interact to make the
Universe look and
behave the way it does
University of Birmingham
Master class,23rd April 2008
Ravjeet Kour
Fundamental elements
What is fundamental
University of Birmingham
Master class,23rd April 2008
Ravjeet Kour
Standard model
6 quarks, 6 leptons
Every particle is associated with the antiparticle
University of Birmingham
Master class,23rd April 2008
Ravjeet Kour
Anti particles
University of Birmingham
Master class,23rd April 2008
Ravjeet Kour
University of Birmingham
Master class,23rd April 2008
Ravjeet Kour
University of Birmingham
Master class,23rd April 2008
Ravjeet Kour
University of Birmingham
Master class,23rd April 2008
Ravjeet Kour
University of Birmingham
Master class,23rd April 2008
Ravjeet Kour
 Quarks have fractional
charge
(P = uud = 2/3+2/3-1/3=1)
 Each quark has its anti
particle
 Carry another type of
charge: colour charge
University of Birmingham
Master class,23rd April 2008
Ravjeet Kour
University of Birmingham
Master class,23rd April 2008
Ravjeet Kour
colour charge
o Quarks & gluons are colour charge
particles
3 colour
charges
o Two close quark exchange gluons
colour force field
University of Birmingham
Master class,23rd April 2008
Ravjeet Kour
Properties
Each quark has one of the colour
Red + blue +green = colour neutral
(baryon)
Gluon (emission + absorption)
changes colour
Colour is conserved
University of Birmingham
Master class,23rd April 2008
Ravjeet Kour
What holds it together
Murray Gell-Mann (b. 1929)
University of Birmingham
Master class,23rd April 2008
Ravjeet Kour
what hold it Together
Four fundamental forces
• Electromagnetism
• Strong
• Weak
• Gravity
University of Birmingham
Master class,23rd April 2008
Ravjeet Kour
University of Birmingham
Master class,23rd April 2008
Ravjeet Kour
Electromagnetism
• Force between the two charges
• unlike charge attract
• like charge repel
• Carrier particle are photons
• Photons has zero mass
& travel with speed of light
University of Birmingham
Master class,23rd April 2008
Ravjeet Kour
Strong forces
Attractive force between the
nucleons
This force overcome the repulsive
force within an nucleus
Hold the quarks together
to form hadrons
Carrier particles are called
Gluons (8 gluons)
University of Birmingham
Master class,23rd April 2008
Ravjeet Kour
Weak forces
Causes massive quarks &
leptons to decay into lighter
ones
Force carriers are W+,W- & Z
Responsible for flavour
change ( when quark or lepton
changes type)
University of Birmingham
Master class,23rd April 2008
Ravjeet Kour
Gravity
• Acts between all particles
with mass
• Carrier are the
Gravitons ??
University of Birmingham
Master class,23rd April 2008
Ravjeet Kour
conclusion
University of Birmingham
Master class,23rd April 2008
Ravjeet Kour
Need for accelerators &
detectors
University of Birmingham
Master class,23rd April 2008
Ravjeet Kour
Any questions ?
University of Birmingham
Master class,23rd April 2008
Ravjeet Kour
Leptons
• Six type which come in three pair
• without color
• Tau and muon
heavier than
electron
• Spin ½ particles
University of Birmingham
Master class,23rd April 2008
Ravjeet Kour
University of Birmingham
Master class,23rd April 2008
Ravjeet Kour
Gluons
• gluon animation
(a). As the quark propagates through nuclear matter, it loses energy
by emitting gluons
(b) and creating pairs of quarks and anti-quarks
(c). As the system begins to return to equilibrium, two-quark systems
(pions) are formed
University of Birmingham
Master class,23rd April 2008
Ravjeet Kour
Gluons
• Carry colour / anticolour pair
• 8 gluons
University of Birmingham
Master class,23rd April 2008
Ravjeet Kour
University of Birmingham
Master class,23rd April 2008
Ravjeet Kour