Particle Physics Flashcards
what is a nucleus
made up of protons and neutrons
orbited by electrons
in the center of an atom
what’s the mass of a proton/neutron
1.6x10-27
what’s the mass of an electron
9.11x10-31
whats the charge of a proton/electron
1.6x10-19
whats the charge of a neutron
0
what are the 3 nuclide notations
A- proton number
Z- nucleon number
X- element name
what happens when you change each subatomic particle
proton- new element
neutron- new isotope
electron- new ion
what is isotopic data
using the amount of isotopes in a material you can estimate its age (carbon dating)
what is specific charge
the amount of charge something has per kg
what are the four fundamental forces and there corresponding exchange particles
gravity- graviton (theory)
SNF- gluons/pions
WNF- W+/W- bosons
electromagnetic- virtual photon
what is the strong nuclear force
holds the nucleons together. only works at short ranges and can be attractive or repulsive depending on its distance
Information on an SNF graph
0-0.5fm repulsive
0.5-3fm- attractive
beyond 3fm (no effect)
what is a neutrino
it has no mass or charge but it carries kinetic energy when a decay occurs
what is a photon
“packets” of electromagnetic waves all travelling at the speed of light
what are the differences in photons of red light vs blue light
because red light is longer wavelength it has a lower frequency so it transfers less energy per second
what is antimatter
every particle has a corresponding antiparticle with exact opposite values (except for mass)
what is annihilation
when matter and antimatter meet they annihilate and releases all there rest mass (internal energy) in 2 photons in opposite directions to conserve momentum
what is pair production
- the exact opposite of annihilation
-if a photon has enough energy they can collide with another to create matter - to produce an particle and antiparticle you need there combined rest energies in the photon
what happens in pair production with more energetic photons
heavier particles are produced
particles have a higher kinetic energy
or lots of smaller particles
what is the particle classification system
a system to organise different types of particles (and subatomic particles)
what are the 4 main classes of particles
hadrons
leptons
mesons
baryons
what is a hadron
it can feel the SNF
can be split into quarks
what is a lepton
cannot feel the SNF
they are fundamental
can feel WNF
what are the difference between baryons and mesons
baryons- 3 quarks (protons)
mesons- 2 quarks (pions)
what are quantum numbers
fundamental properties that always needs to be conserved between an interaction
what quantities need to be conserved in an interaction
charge
baryon number
lepton number (electron/muon)
strangeness (depends)
what are mesons
hadrons with only 2 quarks
they are very unstable
pions and kaons (+,0,-)
what are the most important leptons
muons- eventually decay into electrons
electrons
electron neutrino
muon neutrino
(and there antiparticles)
what to kaons eventually decay into
protons
what are the 6 quarks
u d s (anti) u d s
what are the 4 meson rules
1 quark and 1 anti quark
charge must add to +1,0-1
Strangeness is 0= pion
strangeness isnt 0= kaon
what is quark confinement
the idea of having a quark on its own
this isn’t possible
the amount of energy needed to split up a pion would cause pair production
what is the quark change in beta minus decay
neutron–>proton
down quark —> up quark
this is a weak interaction
what is the quark change in beta plus decay
proton –> neutron
up quark—> down quark
this is a weak interaction
what are the problems with discovering new particles
- its getting more expensive
- scientists are still looking for gaps in patterns or missing properties
what particle has strangeness
kaons
k+/k0–> +1
k-/(anti)k0 —> -1
when is strangeness conserved
its always conserved in an SNF interaction (baryons and mesons)
its sometimes conserved in an WNF interaction
what is a strong interaction
caused by SNF
cant involve leptons
only hadrons
strangeness is conserved
what is a weak interaction
caused by WNF
Probably involves leptons
usually 1 particle decaying into 2
strangeness probably not conserved
what are exchange particles
transmit forces between particles via momentum and energy
sometimes called gauge bosons
Feynman diagrams
beta minus decay
beta plus decay
electromagnetic repulsion
electron capture
electron/proton collision
