Particles Flashcards
(62 cards)
What is the SNF
Fundamental force, keeps the nucleus stable by counteracting the electrostatic force of repulsion between protons
State a use of radioactive isotopes
Carbon Dating - the amount of carbon 14 in a material can be used to estimate its age
What is the range of the strong nuclear force
Repulsive : <0.5 fm
Attractive: 0.5-3 fm
negligible: >3 fm
what makes a nucleus unstable
Too many protons or nuetrons or both that means the SNF and Elctrostatic force do not balance
how do nuclei with too many neutrons decay
Beta minus
how do nuclei with to many nucleons decay
Alpha decay
What exchange particle is used in beta minus decay
W minus boson
How was the exitance of the neutrino hypothesized
- Energy before and after beta minus decay was no conserved therefore another particle had to exist to which this energy was transfered too
how does a nuclei decay with too many Protons
Beta plus decay
what is an antiparticle
particle with the same rest energy and mass but all other properties are opposite
what particles have antiparticles
every particle
What is the antiparticle of a pion 0
pion 0
what is annihilation
When particle and its antiparticle meet the mass + KE of the particles is converted into 2 gamma rays which go in opposite directions to conserve momentum
what is pair production
photon is converted into equal matter and antimatter. Photon energy must be greater or equal to than the total rest energy of both particles.
Excess photon energy is converted to kinetic energy of particles
what are the exchange particles and ranges of the four fundamental forces
- SNF - Pion - 3 fm
- WNF - W boson - x10-18
- EM - Virtual photon - infinite
- Gravity - Graviton - infinite
Name the two mesons
Pions, Kaons
what is a hadron
Hadrons are particles made of quarks that experience the SNF. They consist of Baryons and Mesons
what is the quark structure of mesons
quark - antiquark pair
Property’s conserved in particle interactions
Energy
charge
baryon number
lepton number
momentum
when is strangeness conserved
during the SNF
what is the exchange particle for Beta plus decay
W plus boson
what is the exchange particle for electron proton collision
w minus boson
what is the exchange particle for electron capture
W + boson
what does a muon decay into
electron and two types of nutrino