particle physics

what is the specific charge formula?

specific charge= charge/mass

what is an isotope?

atoms of the same element that have the same number of protons but a different number of neutrons

what is a common use of isotopic data?

carbon dating of achaeological artifacts, all living things contain the same percentage of carbon 14, once the organism dies the carbon 14 decays. scientists can calculate age by using isotopic data to find the percentage of carbon 14 left..

what is alpha decay?

when a nucleus emits an alpha particle, made up of 2 protons and 2 neutrons (identical to helium nucleus). common in large unstable nuclei.

what is beta minus decay?

when a neutron turns into a proton and a beta minus particle which is a high energy electron, and an anti electron neutrino is emitted from the nucleus.

what is beta plus decay?

when a proton turns into a neutron and a beta plus particle which is a high energy positron, and an electron neutrino is emitted from the nucleus.

how were neutrinos hypothesised?

by wolfgang pauli in 1930, in order to save the law of conservation of energy during beta decay. he hypothesised a third body that escaped detection but could take away energy not given to beta particle.

how do antiparticles compare to their particles?

they have the same mass but an opposite charge.

what is a photon?

a massless packet of electromagnetic energy.

what is the equation for photon energy?

E=hf (energy of a photon=frequency*plancks constant)

what is annihilation?

when a particle meets its antiparticle, they are both destroyed and their mass is converted into energy in the form of 2 photons.

what is the minimum energy of one photon after annihilation?

the total rest mass energy of one of the particles.

what is pair production?

when a photon interacts with a nucleus or atom and the energy of the photon is used to create a particle-entiparticle pair. the photon must have an ergy equal to the total rest mass energy of the particles produced.

in annihilation and pair production why do the 2 photons and the partcile and antiparticle move in opposite directions?

to conserve momentum.

what should be conserved in particle interactions?

charge, baryon number, lepton number, strangeness.

how is strangeness conserved?

it is conserved in all interactions, except weak interaction where it can change by 1,0, or -1.

what is the feynman diagram for electron repulsion?

what is the Feynman diagram for beta-minus decay?

what is the feynman diagram for beta plus decay?

what is the feynman diagram for electron capture?

what is the feynman diagram for electron proton collision?

what are the fundamental forces?

gravity, elecromagnetic, weak nucleur, strong nucleur.

what particles does the strong nucleur affect?

hadrons

what particles does the weak nucleur affect?

all particles

what particles does the electromagnetic force affect?

charged particles

what is the gauge boson for the electromagnetic force?

virtual photon

what is the gauge boson for the strong nuclear force?

pions (particles), gluons (quarks)

what is the gauge boson for the weak nucleur force?

w+, w-, boson.

what are the properties of a photon?

it has no mass, it has no charge, it is its own antiparticle

what forces act on the nucleus?

electrostatic- very repulsive, gravity- very weak, strong nucleur- overpowers electrostatic, keeps nucleons together.

what is the range of the strong nuclear force?

below 0.5 fm it's repulsive, and attractive up to 3fm.

how does the range of strong nucleur compare to electromagnetic?

electromagnetic has a much larger range

how to tell the difference between strong interactions and weak interactions?

strong interaction- strangeness conserved, weak interaction- quark change, neutrino produced

what is weak interaction responsible for?

radioactive decay of atoms

what are muons?

leptons slightly heavier than electrons, typically decay through weak interacion (w- boson) into electrons, (antimuons decay into positrons).

what are leptons?

fundamental particle, doesnt feel strong force, examples: electron, electron neutrino, muon, muon neutrino (and all antiparticles).

what are hadrons?

particles made up of quarks, that feel the strong force. two classes: baryons and mesons.

what are baryons?

hadrons made up of three quarks or three antiquarks (known as anti baryons), examples: proton, neutron, sigma, omega, lambda.

what is the quark structure of a proton and neutron?

proton=uud neutron=udd

how do baryons decay?

all baryons decay into protons since they are the most stable and lightest baryon.

what are mesons?

hadrons made up of a quark anti-quark pair, examples: pions, kaons.

what are pions?

the lightest and most stable meson, originally discovered in cosmic rays and is observed in a cloud chamber. it is a virtual particle and the exchange particle for the strong force.

what are kaons?

a meson that contains a strange particle.

how do kaons decay?

they are heavy and unstable and usually decay into pions and neutrinos. they are produced through strong interaction but decay through weak interaction.

what is the equation for percentage uncertainty?

(uncertainty of measurement/measurement)*100

what is the strangeness of a K0 particle?

-1

what is the strangness of a K+ particle?

1

what is the strangeness of a K- particle?

-1

how do muons decay?

they decay through weak interaction into an electron, a muon neutrino and an electron antineutrino.

how do pions decay?

charged pions through the weak nucleur and neutral pions through the electromagnetic. charged pions decay into muons and and muon neutrinos (or antineutrinos) while neutral pions decay into two gamma rays.

How do you find the specific charge of an ion?

charge = total number of electrons added/removed * 1.6*10^-19/ mass- total number of nucleons * 1.67 ×10 ^-27

in annihilation what do you do if they ask for min frequency?

find values for 1 photon

effect of particle exchange on momentum?

when an exchange particle is emitted or absorbed, it carries away or delivers momentum, creating a recoil effect that changes the momentum of the interacting particles while keeping total momentum conserved.

why is progress in particle physics- slow?

international collaboration is required, expensive equipment is required.

How to tell the difference between electron proton collision and electron capture?

electron capture- nucleu interacts with electron, radioactive decay, inner shell decay

electron proton collision- electron collides with proton, electron beam, fired/scattering experiments.

when to use electromagnetic vs electrostatic

electromagnetic force- particle physics- or exchange particles

electrostatic repulsion- nucleus stability or Rutherford scattering

in particle interactions where does missing rest energy go?

if reactants have more rest energy then missing rest energy os converted into kinetic energy of products

if products have more rest energy then missing rest energy was converted from kinetic energy of reactants into rest energy of products