The energy produced in these collisions can be used to create other particles. The particles are made to collide into a stationary target or head-on with each other. High voltages are used to accelerate charged particles (electrons, positrons, protons and antiprotons) to near light velocities. The first new particles to be detected were muons (1937), pions (1947) and kaons (1947).Ħ Accelerators These enable more controlled conditions than occur with cosmic radiation interactions. These new particles can be detected at ground level by cloud chambers and other detectors. The protons strike gas atoms in the upper atmosphere and produce new short lived particles and antiparticles. The necessary data will be provided in questions for particles outside those specified.Ĭosmic rays consist of high energy protons and nuclei emitted from stars including the Sun. Application of the conservation laws for charge, baryon number, lepton number and strangeness to particle interactions. Change of quark character in β - and β + decay. Combinations of quarks and antiquarks required for baryons (proton and neutron only), antibaryons (antiproton and antineutron only) and mesons (pion and kaon) only. Properties of quarks: charge, baryon number and strangeness. 3 to 5 Quarks and antiquarks Up (u), down (d) and strange (s) quarks only. Lepton numbers for the leptons will be given in the data booklet. Candidates will be expected to know baryon numbers for the hadrons. Leptons are subject to the weak interaction. Leptons: electron, muon, neutrino (electron and muon types). Candidates should know that the proton is the only stable baryon into which other baryons eventually decay in particular, the decay of the neutron should be known. Hadrons are subject to the strong nuclear force. Hadrons: baryons (proton, neutron) and antibaryons (antiproton and antineutron) and mesons (pion, kaon). 1 1.1b Particles & Radiation Quarks & Leptonsīreithaupt pages 18 to 27 April 8th, 2010Ģ AQA AS Specification Lessons Topics 1 & 2 Classification of particles
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