1. Particles Flashcards
Describe the Strong Nuclear Force
- Repulsive for distances less than 0.5fm
- Attractive and larger than the electrostatic repulsion between 0.5-3.0 fm
- SNF falls to 0 and has no effect after 3fm
What is the maximum value of attraction for the SNF?
1fm
In what kind of nuclei does alpha decay usually occur?
Very large ones
Describe an alpha particle
2 protons, 2 neutrons
What particle is also released during beta decay?
an anti neutrino
Describe beta minus decay
neuton —> proton + electon + electron antineutrino
Describe beta plus decay
proton —> neuton + positron + electron neutrino
Describe pair production
A photon is converted into a particle and its corresponding antiparticle
What type of photons have enough energy for pair production?
Gamma ray photons
What it the minimum energy required for a photon to undergo pair production equal to?
The total rest energies of the particles produced
What is the opposite of pair production?
Annihilation
Describe annihilation?
A particle and antiparticle meet and get converted into a pair of gamma ray photons
During annihilation, why are two gamma ray photons produced?
To conserve momentum
What is a photon?
A packet of electromagnetic energy
What is 1eV equivalent to?
1.6x10-19 j
How many joules is 1 meV equivalent to?
1.6x10-13
What is intensity?
The number of photons per second
What is the exchange particle of the electromagnetic force?
Virtual photon
What is the exchange particle of the weak interaction?
W+ / W- boson
What is the exchange particle of the strong nuclear force?
The pion / gluon
What quarks is a proton made of?
UUD
What quarks is a neutron made of?
UDD
What force do hadrons feel?
Strong nuclear force
What are the two types of hadrons?
Baryons and Mesons
What type of particle is a proton?
Baryon
What type of particle is a neutron?
Baryon
What is the only stable baryon?
The proton
all baryons except protons decay to a proton
all baryons except protons decay to a proton
Name 2 mesons
Pions and Kaons
During what type of interaction is strangeness conserved in?
Strong interaction
How many quarks are baryons made from?
3
What is the quark combination of mesons?
Quark antiquark pair
Do kaons have strangeness?
Yes
Why are exchange particles needed?
To transfer energy/ momentum)
