Aim: How can we
describe Fundamental
Particles?
Four Fundamental
forces
•
•
•
•
1)
2)
3)
4)
Gravitational
Electromagnetic
Strong Nuclear force
Weak Nuclear force
Classification of Matter and
Particles of the Standard
Model Reference Tables
• Look at Classification of Matter
reference table to see how matter is
classified.
• Look at Particles of the Standard
Model table to go beyond the “dead
ends”: quarks and leptons.
Facts to know:
• Quarks and leptons are fundamental
particles – everything is made of them.
• Protons and neutrons are baryrons,
composed of three quarks.
• Electrons are leptons (very light particles,
not made of quarks).
• For each particle there is an antiparticle
with a charge opposite to its associated
particle, and designated with a “bar” over
the associated particle.
C. Classification of
Subatomic Particles
• 1. Hadrons – particles that interact
through the strong nuclear force.
•
Examples: protons, neutrons.
•
2. Leptons – particles that do not
interact through the strong nuclear
force. Have less mass than a proton.
•
Example: electrons
•
See reference table
• 3. Hadrons are divided in to baryons
and mesons
• a. Baryon – heavy particle; can be
transformed into a proton or neutron
and some number of lighter particles.
• b. Meson – particle of intermediate
mass.
• 4. Antiparticle •
A particle having mass, lifetime and
spin identical to the associated particle, but
with an opposite charge.
•
Is denoted with a particle sign with a
bar over the sign.
•
Antimatter is material consisting of
atoms composed of antiprotons, antineutrons
and positrons.
D. Quarks
• 1. Baryons and mesons are composed
of quarks
• 2. A quark is one of the basic particles
• 3. Elementary charges are built up from
quarks
• 4. Charges on quarks: ±2/3 e, ±1/3 e
• 5. Names: up, down, charm, strange,
top, bottom
Quarks
• 6. Antiquark – antiparticle of a quark, having
opposite charge of associated quark.
• 7. Baryon – composed of three quarks
• a. charges add to (0e, +1e or –1e)
• b. proton = uud
• c. neutron = udd
• 8. Meson – composed of a quark and an
antiquark. (charges add to 0e, +1e, or -1e)
• Determine the charge on a
strange quark in coulombs.
Examples:
• A proton is composed of what
combination of up and down
quarks?
• 2 up, 1 down (charge: +1)
• A neutron is composed of what
combination of up and down
quarks?
• 1 up, 2 down (charge: 0)
• How can we classify a particle
consisting of an up quark and an
anti-down quark?
• It’s a meson.
• What kind of particle is a muon
neutrino?
• A lepton.
• What is its charge?
• 0.
• What particles make up an antiproton?
• Anti-up, anti-up, anti-down.
• What particles make up a tau
neutrino?
• None – it is a lepton, a
fundamental particle itself.
• A particle has a quark
composition of sc and
classification of the particle.