SPH4U Elementary Particles

The 4 forces of Nature Weak Electromagnetic weak charge Electric Beta-decay pp fusion Electromagnetic TV, PCs Magnets e- e+ creation weak charge Electric charge Strong Quark binding Gravity Responsible of Keeping us well-planted on earth strong charge mass

From the atom to the quark How small are the smallest constituents of matter? <10-18 m <10-1 8 m ~ 10-14 m ~ 10-10 m ~ 10-15 m Atoms and sub-atomic particles are much smaller than visible light wave-length Therefore, we cannot really “see” them (all graphics are artist’s impressions) To learn about the sub-atomic structure we need particle accelerators

Protons and neutrons in the quark model Quarks have fractional electric charge! u electric charge + 2/3 d electric charge -1/3 proton (charge +1) neutron (charge 0) u u u d So we know now that protons and neutrons are made of quarks. d d

Force Particles (summary) Particles interact and/or decay thanks to forces Forces are also responsible of binding particles together Strong: gluons Only quarks (because of their colour charge) Weak: W+, W-, Z0 Leptons and quarks (only force for neutrinos) Electromagnetic:g Quarks and charged leptons (no neutrinos) Gravity: graviton? Still to be discovered Negligible effects on particles

The Standard Model Framework which includes: Not gravity! No quantum Matter 6 quarks 6 leptons Grouped in three generations Forces Electroweak: g (photon) Z0, W± Strong g (gluon) Not gravity! No quantum field theory of gravity yet.. H= the missing ingredient: the Higgs Boson Very successful to describe all observed phenomena in the subatomic world so far. But there ought to be more..