chapter 2.1-2 - quarks and leptons

cosmic rays

high energy particles that travel through space from stars

muon / heavy electron, u

a negatively charged particle with a rest mass over 200 times that of the electron

pion / pi meson

a particle that can be positively charged, negatively charged, or neutral; and that has a rest mass greater than a muon, but less than a proton

kaon / k meson

a particle which can be positively charged, negatively charged, or neutral; and that has a rest mass greater than a pion, but less than a proton

how kaons decay

via the weak interaction, as kaons are strange particles

what a kaon can decay into

pions;

a muon + an antineutrino;

an antimuon + a neutrino

what a charged pion can decay into

a muon + an antineutrino;

an antimuon + a neutrino

what an uncharged pion can decay into

high energy photons

what a muon can decay into

an electron + an antineutrino

what an antimuon can decay into

a positron + a neutron

what conservation rules do decays always observe

the conservation rules for energy, momentum, and charge

hadrons, + examples of hadrons

particles and antiparticles that interact through the strong interaction e.g. protons, neutrons, pions, kaons

leptons, + examples of leptons

particles and antiparticles that don't interact through the strong interaction e.g. electrons, muons, neutrinos

interactions of leptons

weak; gravitational; electromagnetic if charged

interactions of hadrons

all 4 fundamental interactions - but only strong + electromagnetic if charged

what interaction do hadrons tend to decay through

the weak interaction - apart from the proton, which is stable

antiparticles

particles with the same mass but opposite charge - annihilates with its positive pair

baryons

protons, and all other hadrons (including neutrons) that decay into protons, either directly or indirectly

mesons

hadrons that don't include protons in their decay products