Quarks dans le proton

1. Quarks dans le proton Mariusz Sapinski Groupe d`Astroparticules de Montpellier

2. sommaire • History from Greece to atoms • Atom components • Some quantum mechanics • Nucleon components – quarks • Standard Model

4. Interactive: particle physics, a keyhole to the birth of time

5. What is the matter made of? Four elements: earth, water, air and fire la terre, l'eau, l'air et le feu Four states of matter: solid , liquid, gas and plasma Solid,liquid and gas – interaction between atoms What is plasma? ionized atoms... What is atom? How the conception of atom has been born?

6. What is an atom? The smallest possible part of a substance-element. Mendeleev 1871

7. Is atom the smallest possible amout of matter at all? 1827- Thomson discoveries that electric charge is quantified A particle smaller then atom exists - electron

8. electron

9. Rutheford experiment Particles in the nucleai - protons (1905) Planetary model of atom

10. we need quantas! Bohr

11. Physique quantique

12. Quantum numbers • In small scales physical quantities are quantified • charge is quantified (electron) • momentum is quantified • energy of bounded systems (atoms) • ... Others, except position... Example: number of electrons is a quantum number symmetrie => quantum numbers (usually quantum numbers are conserved)

13. spin

14. Performed a series of scattering experiments • with a-particles (recall a particles are He nucleus), • 42 He + 9 Be 12 C +10 n Protons and neutrons Picked up where Rutherford left off with more scattering experiments… (higher energy though!) • Chadwick postulated that the emergent radiation • was from a new, neutral particle, the neutron. Chadwick 1891-1974 Awarded the Nobel Prize in 1935

15. Discovery map 1 Discoveries of particles

16. Other particles Kaons, discovered in 1947 Do we need them?

17. In 1964, Murray Gell-mann & George Zweig (independently) came up with the idea that one could account for the entire “Zoo of Particles”, if there existed objects called quarks. MurrayGell-Mann GeorgeZweig We got a periodic table of particles! Lesson from history =>look for sub-particles

18. e- + p e- + X Are protons/neutrons fundamental ? In 1969, a Stanford-MIT Collaboration was performing scattering experiments (X = anything) What they found was remarkable; the results were as surprising as what Rutherford had found more than a half-century earlier! The number of high angle scatters was far in excess of what one would expect based on assuming a uniformly distributed charge distribution inside the proton. It’s as if the proton itself contained smaller constituents

19. Another experiments Observation of jets e quarks p And gluons: jet lot of particles originating from the same parton DESY, Hamburg 1979

20. Scales of length So, situation is:

21. Particle discoveries after quarks

22. freedom (asymptotic) Quarks - properties There are u-quarks, d-quarks and s-quarks (saveur) strong force - 3 charges (colours) electric charge -1/3, +2/3

23. So, how the proton looks like?

24. Is it so simple, ie. What really is in the proton? • Valence quarks • See quarks • gluons How they contribute to proton?

25. Spin of the proton vs spin of quarks polarisation

35. Modele Standard 1990s – discovery of the last quark (top) And discovery of tau-neutrino Still waiting for discovery of Higgs

36. Quark soup

37. Result

38. PHOBOS BRAHMS PHENIX Collider Rings STAR AGS-to-RHIC Transfer Line Polarized p-Source p-Linac Booster Synchrotron Alternating Gradient Synchrotron HITL Transfer Line Superconducting Magnet Facility Tandem Van de Graaff MP6 & MP7 RHIC Facility Configuration