2.5 Conversation rules Flashcards
What conservation rules apply to all changes in science?
» Energy
» Charge
» Momentum
What conservation rules are used only for particle and antiparticle interactions and decays?
» Conservation of strangeness
» Conservation of lepton number
» Conservation of baryon number
What is the conservation of the lepton number rule?
» The total lepton number for each lepton branch before the change is equal to total lepton number for that branch after the change
What is the conservation of strangeness?
» In any strong interaction strangeness is always conserved
What is the baryon number of a baryon?
» +1
» -1 for any antibaryon
The following reaction cannot occur, state and explain which conservation law would be broken by this reaction: Pie+ + n > p + Pie-
» Charge, as the charge is unbalanced on both sides
The following reaction cannot occur, state and explain which conservation law would not be broken by this reaction: Pie+ + n > p + Pie-
» Baryon number
Describe what happens when a proton and an antiproton collide.
» They annihilate one another and their mass is converted into energy, and gamma energy is released as 2 photons are produced
During Beta - decay of a nucleus, both the nucleon composition and the quark composition change, state the quark composition change
» A down quark changes to an up quark
What is the unique family of particles to which the kaon and pions belong to?
» Mesons
Why do Kaons have a long lifetime?
» Because of strange particles
What is the exchange particles involved in the strong interaction of the kaon?
» Gluons and pions
Which groups are contained in the hadron family?
» Baryons and mesons
Which groups are contained in the lepton family?
» Electrons, neutrinos, muons
