The document discusses the fundamental interactions and particles in physics according to the Standard Model. It describes the four fundamental interactions - gravitation, electromagnetism, weak nuclear force, and strong nuclear force. It outlines the development of theories of these interactions from classical mechanics to quantum field theory and the particles associated with each interaction, such as photons, electrons, quarks, and Higgs bosons. The Standard Model successfully explains most experimental data but leaves some questions unanswered.

1. TO THE STANDARD MODEL particles and interactions The Physics studies the fundamental interactions among the elementary constituents of the matter. Constituents: bodies, fluids, particles Interactions: forces, fields Prof. Dr. Ion I. Cotaescu DISCRET PARTICLES CONTINUOUS WAVES

2. The first fundamental interaction Gravitation ideal point-wise particles Isaac Newton (1643-1727) Classical Mechanics INERTIA inertial frames Galileo Galilei (1564-1642) The Galilei transformations x’ = x – V t, t’ = t absolute frame

3. Electricity and Magnetism Michael Faraday (1791-1867) Magnetic induction Carl Friedrich Gauss (1777-1855) Electric flux Andre-Marie Ampere (1775 -1836) Magnetic effects of electric currents Hans Christian Ørsted (1777-1851)

4. James Clerk Maxwell (1831 -1879) predict the E-M waves discovered by Hertz in Heinrich Hertz (1857-1894) Electrodynamics The Maxwell equations 1887 oscillator receiver

5. The second fundamental interaction Electromagnetism electron Electric charges and currents elementary particles: Electromagnetic field (proton) Luminiferous ETHER ???? The EM radiation Electric field Magnetic field

6. Albert Michelson (1852 -1931) Edward Morley (1838-1923) The Michaelson and Morley experiment The ETHER does not exist Hendrik Lorentz (1853-1928) The Lorentz transformations 1887

7. Albert Einstein (1879-1955) 1905 the theory of special relativity the theory of general relativity photon In 1905 Einstein explains the Photoelectric effect Max Planck (1858-1947) the theory of quanta c = c’

8. The discovery of the atom structure 1909 nucleus Ernst Rutherford (1871-1937) Niels Bohr (1885-1962) Arno Sommerfeld (1868 -1951) Bohr’s model 1913 the fine structure of atomic spectra

9. Quantum Mechanics 1926 -1934 Louis de Broglie (1892-1987) the Davisson and Germer experiment Erwin Schrodinger (1887-1961) Werner Heisenberg (1901-1976) the fundamental equation of the Quantum Machanics uncertainty relations wave-particle duality

10. Wolfgang Pauli (1900-1958) electronic spin the Stern-Gerlach experiment Relativistic Quantum Mechanics positron Paul A. M. Dirac (1902-1984) predicting the antimatter Spin 1/2 Exclusion principle Dirac’s equation

11. The neutron and the nuclear reactions and fission 1932-1934 James Chadwick (1881-1974) Enrico Fermi (1901-1954) the role of the neutrino in beta decay - weak force proton neutron neutrino the first nuclear reactor Spin 1/2 Spin ½ (massless) Hideki Yukawa (1907-1981) strong nuclear forces

12. Four fundamental interactions Gravitation Electromagnetic interaction Weak nuclear forces (decay) Strong nuclear forces … an argument for unification…. Hadrons Leptons Elementary particles

13. Quantum interactions The consequences of the wave-particle duality: the elementary particles are field quanta matter fields gauge fields FERMIONS (spin ½) BOSONS (spin 1) DIRAC equation MAXWELL equation (electron/positron) (foton) GAUGE SYMMETRY Coupled through the U(1) Each type of conserved charge is given by a different symmetry em

14. Chen Ning Yang (1922) Tsung-Dao Lee (1926) New gauge symmetries Non-Abelian gauge fields Yang-Mills 1954 Parity non-conservation Robert Mills (1927-1999) U(1) SU(n) 1 charge n charges

15. The Quantum Theory of Fields 1950 - 1970 1950-1960 The Quantum Electrodynamics (QED) quarks Richard P. Feynman (1918-1988) Julian S. Schwinger (1918-1994) The (internal) unitary symmetry of hadrons: SU(3) flavor Murray Gell-Mann (1929) Spin 1/2 (leptons: electron/positron) 1962

16. Steven Weinberg (1933) Abdus Salam (1926-1996) Sheldom Glashow (1932) The Electro-Weak model SU(2) x U(1) 1970 - 1980 L

17. The Higgs mechanism of spontaneously breaking the gauge symmetry SU(2) x U(1) Peter Higgs (1929) L

18. leptons: neutrino, electron // positron Higgs field gauge bosons after the symmetry breaking the remaining symmetry is U(1) The theory of the gauge model SU(2) x U(1) L em

19. Quantum Chromodynamics Makoto Kobayashi (1944) Toshihide Maskawa (1940) Yoichiro Nambu (1921) The hadrons are constituted by quarks (antiquarks) : u, d, s, c, b, t The gauge particles are gluons SU(3) COLOR

20. The particles of the SU(3) QCD C quarks // antiquarks gluons Matter fields color // anticolor color - anticolor Gauge fields (strong forces) Fermions: Spin 1/2 Bosons: Spin 1 q = -1/3, 2/3 // 1/3, -2/3 massless and neutral massive with electric charges The color charges of the strong interaction (8 combinations) 2/3 -1/3 q = 0 etc…

21. Hadrons: baryons & mesons Baryons: Fermions Spin 1/2 Mesons: Bosons Spin 0

22. Standard Model SU(3) x SU(2) x U(1) Strong : gluon Weak : W, Z E-M : photon leptons interact E-M, W quarks interact E-M, W, S C L 3 generations L L

23. The masses of elementary particles Masa protonului ----- --- proton mass

24. Interactions – Feynman diagrams

25. THE STANDARD MODEL explains all the experimental data we know Unsolved problems 1. Where are the Higgs bosons? 2. Why the generations are independent ? 3. New particles may appear ? e.g. exotic quarks (with charges -4/3 and 5/3) or doubly charged bosons ?

26. Where we are…? New experimental data NON-RELATIVISTIC RELATIVISTIC SP. RELATIVISTIC G. CLASSICAL QUANTUM… Non-relativistic Classical Physics (mechaniacs E-M, etc....) Relativistic Classical Physics (relativistic classical fields) General relativity Cosmology Non-relativistic Quantum Mechanics Relativistic Quantum Fields Standard Model quantum gravity ? new sub -quantum level ? very high energies ? STRINGS ? M THEORY ?

27. The hope: The Large Hadron Collider (2010) principal ring - 27 km CERN

29. The detector ATLAS

30. We are waiting for new data Simulating the Hawking radiation (jets produced by the black-holes evaporation) ? Simulating a Higgs event ? ?