Particles and Quantum Phenomena Flashcards
isotope
atoms with the same number of protons but a different number of neutrons
equation for specific charge
charge/mass
units of specific charge
C kg ^-1
particle with greatest specific charge
electron
what is an alpha particle
2 protons and 2 neutrons
beta minus particle
a fast moving electron formed through the conversion of a neutron to a proton
beta plus particle
a fast moving electron formed through the conversion of a proton to a neutron
gamma particle
a high energy photon
nuclear equation for alpha decay
azX –> a-4 z-2 Y + 42α
nuclear equation for beta minus decay
azX –> a z+1Y + 0-1β- + v-e (anti)
nuclear equation for beta plus decay
azX –> a z-1Y + 0+1β+ ve
need for neutrinos
conservation of lepton number and energy. they have zero charge and nearly zero mass
feynman diagram beta minus decay
n→p ; W- ; v-e and β-
feynman diagram beta plus decay
p→n ; W+ ; ve and β+
feynman diagram electron capture
p→n ; W+ ; e→ve
feynman diagram for proton electron capture
p→n ; W- ; e→ve
axes of a feynman diagram
vertical axis - time
horizontal axis - space
forces and corresponding exchange particles
strong force - gluon or pion
weak force - W boson
electromagnetic force - virtual photon
gravitational force - graviton
strong nuclear force function and ranges
- keeps nucleus stable
- attractive up to 3 fm
- repulsive up to 0.5 fm
- very short range
can quarks change type
only in weak interaction
pair production
- when a gamma photon changes into a particle and its corresponding antiparticle (move in opposite directions)
- only happens if the energy of the photon > 2mc^2 (rest mass)
annihilation
when a particle and its antiparticle meet, they destroy each other and release 2 gamma photons travelling in opposite directions with the energy of the photons equivalent to the mass of the 2 particles
anti matter
particles with the same rest mass but equal and opposite charge as its corresponding particles
what do exchange particles transfer
- momentum
- energy
- force
- charge (in weak interactions)
difference between hadrons and leptons
hadrons experience the strong force, leptons do not
hadron subgroups
baryons and mesons
baryon
- 3 quarks (baryon) or 3 antiquarks (antibaryon)
- strangeness = 0