1. cogilvie@iastate.edu1  Big questions  why are quarks confined inside protons ? artist’s view :)  what does the vacuum look like ?  can we use understanding of 2-body physics to describe complex behavior of n-body physics Nuclear Physics/Quantum Chromodynamics (QCD) 11/03/2009

2. cogilvie@iastate.edu2 Quantum Chromodynamics (QCD) Strong interaction/scattering by exchange of gluons quark t z Force between two quarks does not weaken as you separate them Completely counter-intuitive Gravity, electric, magnetic forces all are weaker at larger distances 11/03/2009

3. cogilvie@iastate.edu3 Confinement: A Partial Answer  Attractive interaction  try to separate quarks, force pulls them back  More complicated …… narrow “string” or color field / gluons try to separate quarks 11/03/2009

4. cogilvie@iastate.edu4 Confinement: The rest of the story “vacuum” is not empty!!, short-lived creation/destruction of particle pairs q q q q vacuum expels QCD field (gluons), Restricts gluons to be between quarks in “string” Confinement 1)Attractive force as you try to separate quarks 2)vacuum expels color field  quarks must stay “outside the vacuum” i.e. inside hadrons! 11/03/2009

5. cogilvie@iastate.edu5 Attack QCD on Multiple Fronts: ISU Program  Experiments that push our understanding of strong QCD  Form + study a bulk system of very hot quarks and gluons  Quark-gluon plasma  Melts the vacuum  Detailed study of the quarks, gluons inside a proton  Spin of a proton  Low-momentum region <= high density of gluons 11/03/2009

6. cogilvie@iastate.edu6 The Quark-Gluon Plasma  In all protons, neutrons, the quarks are confined to radius ~ 1x10 -15 m  Inside a nucleus, average separation between nucleons is ~ 2x10 -15 m  Increase density by compression or heating  nucleons significantly overlap  quarks, gluons no longer confined,  QGP : new form of hot, dense matter 11/03/2009

7. cogilvie@iastate.edu7 RHIC  Two independent accelerator rings  3.83 km in circumference  Accelerates everything, from p to Au  s p-p 500 GeV Au-Au 200 GeV BRAHM S PHOBO S PHENIX Long Island STAR

8. cogilvie@iastate.edu8 Au on Au Event at CM Energy 130 GeV*A STAR 11/03/2009

9. cogilvie@iastate.edu9 PHENIX at RHIC  2 central spectrometers  2 forward spectrometers West East South North 11/03/2009

10. cogilvie@iastate.edu10 Silicon Detector Upgrade to PHENIX Two layers of silicon pixel detectors Two layers of silicon strip detectors Tracks extropolate back to collision vertex Displaced vertices => charm (D), beauty (B) Requires ~ 50  m precision D  e+X Au e X B  e+X X    e  e  e e

11. 11/03/2009cogilvie@iastate.edu11 Nuclear Physics @ ISU  Many-body QCD  Experiment and theory  Densest, hottest matter: QGP, RHIC and LHC  Detailed study of the quarks, gluons inside a proton  Strongest gluon field possible in protons+nuclei  Large, active, enthusiastic group  Well-funded  Hardware experience  Exciting physics  Open invitation to join our group