Particles, Decays, Interactions, and Rules

Flashcards covering particle physics: particles, decays, interactions, and conservation rules.

Electron (e⁻)

A light, fundamental lepton with a charge of -1.

Neutrino (electron) (νₑ)

A lepton with tiny mass and a charge of 0.

Up (u)

A quark with a charge of +2/3 found in protons.

Down (d)

A quark with a charge of –1/3 found in neutrons.

Strange (s)

A quark with a charge of –1/3 that has strangeness.

Proton

A baryon made of 3 quarks (uud) with a charge of +1.

Neutron

A baryon made of 3 quarks (udd) with a charge of 0.

Beta-minus decay

Neutron decays into a proton, electron, and anti-neutrino.

Beta-plus decay

Proton decays into a neutron, positron, and neutrino.

Strong interaction

No neutrinos involved; strangeness is conserved; involves hadrons only.

Weak interaction

Neutrinos are involved.

Beta decay

A lepton comes out.

Charge conserved

Total charge before = after.

Baryon number conserved

B = +1 for protons/neutrons (e.g., proton → stays +1).

Lepton number conserved

L = +1 for electrons, 0 for hadrons; watch for neutrinos (+1) and antineutrinos (-1)

Strangeness conserved

Conserved in strong interactions only; not always conserved (e.g., kaon decay = weak).

muon decay

electron, electron antineutrino, and muon neutrino.

muon is

a type of lepton, weak interactions

pion is

a type of meson, strong interactions.

pion decays into

muon and muon antineutrino

kaon is

a type of meson, weak interactions.

kaon decays into

pions