P1 - Particle physics Flashcards
what is the nucleon number?
the nucleon number is the top number and shows the number of neutrons and protons in an atom
what is the atomic number?
the atomic number is the bottom number and shows the number of protons and electrons
what’s an isotope?
Isotopes are atoms of the same element that contain different numbers of neutrons.
what 2 ways can light be seen as? what does c, lander and f mean? what does h stand for?a
Light can be thought of as an electromagnetic wave. Like all electromagnetic waves, light travels at a constant speed, c, in a vacuum.
Light can also be thought of as a particle. The energy of the electromagnetic wave is emitted in short bursts called photons.
λ is wavelength
c is the speed of light
f is the frequency
h is the Planck constant
what is an electron volt?
how do you change something from eV or MeV to joules?
The energy of a particle or an antiparticle is usually expressed in electron volts (eV) or mega electron volts (MeV).
Times It!!!!!!! - by the magnitude of charge of an electron
what are neutrinos?
Neutrinos and their antiparticles, antineutrinos, come in three different types, two of which are: electron neutrinos νe and νe and muon neutrinos νμ and νμ.
what are mesons? (kaons and pions)
what are the properties of kaons?
Mesons are quark anti quark pairs. pi mesons (pions) and K mesons (kaons). Strangeness is a property of particles, with strange particles like K mesons being assigned a strangeness number of +1.
what is specific charge?
specific charge is a atoms ratio of charge to its mass given in coulombs per kg.
specific charge = charge/mass (C kg^-1)
what are the forces that act in an atom? explain effect they have
Electromagnetic force- causes the positively charged protons in the nucleus to repel each other
Gravitational force - causes the nucleons to attract but very weak compared to electromagnetic
Strong nuclear force - an attractive force that must be stronger than the electromagnetic force to hold everything together
How does the strong nuclear force work?- facts about the strong nuclear force
has a very short range, beyond this range the strength falls down very quickly
repulsive up to 0.5 fm, between 0.5 and 3 is attractive, above 3 fm it falls to 0 very quickly.
The force works equally among all nucleons.
why does nuclear decay happen?
to make ana atom more stable an atom can randomly decay
what is the alpha decay prcoess?
A nuclei emits an alpha particle from itself. When released the nuclei’s nucleon number decreases by 4 and proton number decreases by 2 as this is what the alpha particle is made up off.
what is the beta minus decay process? whats relreased?
When a electron (electron is b^-) and antinuetrino is released, Happens in isotopes that are ‘neutron rich’. a neutrom changes into a proton. Proton numbrr increases by one
what is an antiparticle?
Each particle type has a corresponding antiparticle with the same mass and rest energy but opposite charge
what is pair production??
When energy turns into mass, you get equal amounts of matter and antimatter
What is the minum energy needed for pair production?
The minimun energy needed for pair production is the combined rest energy thats gonna be produced
what is annihilation?? whats it converted to?
When a particle meets its antiparticle the result is annhailation. All the mass of the particle and antiparticle is converted back to energy in the form of two gamma ray photons
whats a hadron?
What they spilt into?
Atoms that feel the strong nuclear force are hadrons.
Not fundamental as they are made up of quarks.
Are split into baryons and mesons
whats a nucleon?
whats a baryon? what atoms are?
what do baryons decay too? unless?
A nucleon is a way to class protons and neutrons together
protons and neutrons are baryons
All baryons expect a free proton decay to other things, eventually decay to a proton
what is the process in neutrom decay?
neutron decays and forms a protn and an electron and an antineutrino
whats a hadron?
hadrons are everything that feel the strong force
Baryons, mesons
whats a lepton?
What particles?
what do muons decay too?
Leptons are fundamental particles and they dont feel the string nuclear force.
Only intearct with other particles via the weak interaction
electrons
muons
muins ceentualy decay to electrons
whats a strange particle?
Which interaction they created by?
How do strange particles decay? what changes?
Particles with the strangeness property
created via strong interaction
Weak interaction
Strangeness NOT conserved when decayed
what’s always conserved in particle interactions?
when is strangeness conserved/ not?
energy, momentum, baryon number, lepton number
conserved for strong interactions, sometimes not conserved in weak interactions
How do you work out the quark composition of a proton and neutron?
Use the data sheet, LOL
whats the general quark compositoon rule for mesons?
one quark anti quark pair
what are exchange particles?
what type of guage bosons is it for strong interaction? weak? electromagnetic?
exchange particles are virtual particles that show how forces react between interactions. they are types of bosons
pions for strong (Pie +, pie 0, pie -)
W+, W-, for weak interactions
virtual photon for electromagnetic
How do fennyon diagrams work?
Incoming partciles start at the bottom of the diagram and move upwards
The baryons stay on one side and the leptons stay on the other side.
The W bosons carry charge to make things balanced.
W- going left has same effe t as W+ going right
outgoing partciles are at top, straight lines for particles.
what are the parts in beta minus decay? - for fennyonem diagram
what kind of boson?
neutron in, proton out, electron out, antineurno out. W- boson as it is negative transfer across
what are the parts for beta + decay? for fennyenam diagram
what boson?
beta PPPPostive decay so
proton changes to neutron, w+ boson, positron out, neutrino out
what are the parts for electron capture? - to draw fenyam diagram, what boson?
proton and electron in, W+ boson, neutron and neutrino out
what dircetion does the Boson come from? - when drawning fenyanm diagrams
the direction from the partcile thats acting
whats the difference in electron capture and electron proton collesions? - generaly and when drawing a fennyam diagram
electron capture is where a proton captures an electron from the atom.
An electron proton collesin is where an electrom collides with a proton.
The only diagram difference is in electron capture the w + boson goes from the proton where as in electron proton collesiun the W- boson comes from the electron as thats the acting particle in that situation.
Remeber W- is same as W+ in opposite direction
whats electromagnetic repulsion collesion? - when drawning fennyan diagram, whats in middle?
when wo equal charged particles get close they repel, exchange psrtcile of a virtual photon
