Standard Model for Sub-atomic Particles

Elementary & Fundamental Particles Democritus introduced the word which in English translates as atom Elementary Particles The name given to protons, neutrons and electrons Today we use the term "fundamental" for the six types of quarks and the six leptons

Quarks Quarks are fundamental matter particles that are constituents of neutrons and protons and other hadrons Proton -- composed of two up quarks and a down quark Neutron -- composed of two down quarks and an up quark

Classification of Matter Hadrons: Particles made of quarks. Protons, Neutrons and their Anti-particles Hadrons are further broken into Baryons and Mesons. ( both break down into Quarks) Leptons: Are NOT made of sub particles. Electrons are examples of Leptons

Hadrons Hadrons break down into two groups Baryons are made of 3 Quarks Mesons made up of 2 quarks and anti-quarks, or 1 of each ***(charge must add up to an integer not a fraction)

THE STANDARD MODEL

Leptons Leptons are fundamental particles that have no strong interactions Lepton is Greek for "light particle” Ex. The electron, but there are heavier leptons The first to be found was the muon

Sample Problem A Baryon may have a charge of Correct answer is 0e (all types of matter must have an integer charge)

FROM THE TEXTBOOK (i) allowed (charge and lepton number conserved) 9. a) the Weak Nuclear Force is responsible for proton decay into a neutron b) According to Hideki Yukawa, the W+ boson particle mediates this decay. c) electron neutrino, νₑ 10. a) (i) u⁻ → e⁻ + γ (ii) p + n → p + π⁰ (iii) P → π⁺ + π⁻ (i) allowed (charge and lepton number conserved) (ii) not allowed (baryon number not conserved) (iii) not allowed (charge and baryon number not conserved b) exchange particles in the Weak Interaction can be W+ , W- , or Z bosons Hideki Yukawa (1907-1981) Tokyo & Kyoto Prefecture. Book, “Tabibito”

Neutrinos (type of Lepton) These particles are so small that they pass right through the Earth without interacting with a single atom.

Strong Force Quarks and Gluons have a type of charge that is NOT electromagnetic The “color” charged particles are very powerful (STRONG) Quarks are glued together with GLUONS (Nuclear Energy)

Weak Force The stable matter of the universe is made up of the two least massive quarks: UP and Down and the least massive Lepton, the electron ( A Hydrogen Atom) When a quark or lepton changes type (muons changing to an electron), this is called a “flavor” weak interaction

11. Negative Kaon collides with a proton K⁻ + p K⁰ + K⁺ + X a) Kaons belong to the meson (middle) family, with 2 quark structure b) proton quark structure is uud (⅔ ⅔ -⅓) = +1 FROM THE TEXTBOOK c) baryon number (1 = 1) and strangeness both conserved 12. a) exchange particle carries the force between particles; said to be virtual because it is not detected during exchange b) W- boson (since diagram shows β – decay)

Reference Chart : Standard Model