BRAINCAKEFundamental Particles
Revision notes for Fundamental Particles in OCR Physics A (H556). Read the start of any lesson here, then sign in free for the whole lesson, the R.E.C.I.P.E. recall steps and the quiz.
- Fundamental ParticlesA fundamental particle is a particle that has no internal structure: it is not made of any smaller particles.
- AntiparticlesEvery particle has a corresponding antiparticle.
- Hadrons and LeptonsParticles can be sorted into two main groups according to whether or not they feel the strong nuclear force.
- The Strong Nuclear ForceThe nucleus contains positively charged protons, which repel each other electrostatically.
- Quarks and AntiquarksQuarks are fundamental particles that make up hadrons.
- Quark Composition of Protons and NeutronsA proton is made of two up quarks and one down quark: uud. charge = (+2⁄3) + (+2⁄3) + (−1⁄3) = +1e A neutron is made of one up quark and two down…
- Baryons and MesonsHadrons are particles made of quarks.
- Beta-Minus Decay and QuarksIn beta-minus (β−) decay a neutron in a neutron-rich nucleus changes into a proton.
- Beta-Plus Decay and QuarksIn beta-plus (β+) decay a proton in a proton-rich nucleus changes into a neutron.
- The Weak InteractionThere are four fundamental interactions: gravitational, electromagnetic, strong and weak.
- Conservation of Charge, Baryon Number and Lepton NumberIn every particle interaction and decay, three quantities are always conserved: charge Q, baryon number B and lepton number L.