Daniel Cebra - Physics Feb-04 Experimental Nuclear Physics at UC Davis PS… Check out our web page at FACULTY: Jim Draper (emeritus) Paul Brady (emeritus) Daniel Cebra Ramona Vogt STAFF: Juan Romero Tom Gutierrez GRAD STUDENTS: Roppon Picha (2005) Brooke Haag (2006) UNDERGRADS: David Cherney Stephen Baumgarten Matt Searle Orpheus Mall Come visit us on the fifth floor - WEST end

Daniel Cebra - Physics Feb-04 Recent Graduates Ian Johnson (2002) Postdoc LBNL Jenn Klay (2001) Postdoc LBNL Mike Heffner (2000) Postdoc LLNL Tom Gutierrez (2000) Postdoc UCD Bill Caskey (1999) Z-World, Davis CA Lynn Wood (1998) Z-World, Davis CA Doug Mayo (1997) Staff Scientist LANL Jason Dunn (1997) Professor - Idaho Christian Isaac Huang (1997) FunMail.com Jack Osbourn (1995) Professor - Sac State Jessica Kintner (1995) Professor - St. Mary’s

Daniel Cebra - Physics Feb-04 What Do We Do?

Daniel Cebra - Physics Feb-04 Basics Hadrons = Made of quarks Baryon = 3 q meson = q q p = uud n = udd  + = ud K+ = us

Daniel Cebra - Physics Feb-04 1) Goal: Use relativistic collisions of nuclear to create hot dense matter which reproduces the earliest stages of the universe Relativistic Heavy Ion Physics: Creating Mini-`Big Bangs’ in the Laboratory PS… Check out our web page at ucdavis.edu 2) Now, how do we do this? (In Theory)

Daniel Cebra - Physics Feb-04 Brief History of the RHIC Project 1947 BNL founded 1952 Cosmotron 1960 AGS 1970 Tandem 1979 ISABELLE 1983 CBA canceled 1983 RHIC proposed 1991 RHIC approved 1992 STAR approved 1999 First Beams 2000 First collisions GeV collisions 2003 d+Au collisions STAR PHOBOSBRAHMS PHENIX

Daniel Cebra - Physics Feb-04

Daniel Cebra - Physics Feb-04 3) How do we really do this?

Daniel Cebra - Physics Feb-04 Data sets Au+Au  s=130 GeV N Event =0.7 M Au+Au  s=200 GeV N Event = 3.2 M Au+Au  s=19.6 GeV N Event =~20k d+Au  s=200 GeV N Event =35 M jet pp un-polarized vertical pol. 391/nb longitudinal pol. 373/nb (spin flip snake) Level-3 trigger, rare probes EMC jet trigger Particle Identification: dE/dx resolution ~8% cold partonic/nuclear matter hot partonic/nuclear matter ?

Daniel Cebra - Physics Feb-04 First, have we created ‘Matter’? Local Kinetic Equilibrium Bulk Properties If so, does it have the properties of the QGP low T, high entropy (compared to hadron gas) opaque to jets large fluctuations/droplets at transition low pressure chiral symmetry The Relevant Questions

Daniel Cebra - Physics Feb-04 Local Thermal Equilibrium? T thermal source explosive source T,  pTpT light heavy pTpT light heavy Fits assuming a hubble-like expansion yields temperatures of 90 MeV and average radial expansion velocities of 0.6c ~½m 2 Conclusion: The Final freeze-out state has reached a local thermal equilibrium.

Daniel Cebra - Physics Feb-04 The Hottest matter in the Universe Scientists have recently set records for both the highest and lowest measured temperatures. The high temperatures approach those of the early stage of the Big Bang. Room Temperature 300 K Coldest place on Earth 184 K (Vostock Station - Antarctica) Air turns to liquid 73 K Coldest place in the solar system (Triton) 38K Helium turns to liquid 4.2 K Dilution Refrigeration.002 K Magnetic Cooling 90  K Ion Trapping 10 nK (1999) Relativistic Heavy Ion Collisions 1.3x10 12 K (2002) Thermonuclear Fusion Device 3x10 6 K The surface of the Sun 5800 K The hottest place in the Solar system (Io) 2000 K The highest recorded temperature on earth (Libya) 330 K Relativistic Heavy Ion Collider Brookhaven National Laboratory Upton, New York

Daniel Cebra - Physics Feb-04 Is it the Right Temperature ? Phase boundary lattice QCD: Allton et al. hep-lat/ T c =160  3.5 MeV  b =725  35 MeV  = GeV/fm 3 At RHIC, we see evidence that the quarks freeze-out at the expected QPG transition temperature hep-lat/ Statistical fit Result: T=176 MeV  B =41 MeV (130 GeV), T=177 MeV  B =29 MeV (200 GeV)  T=2.1·10 12 K Sun 15.6·10 6 K Supernova ~10 9 K Plasma fusion 55·10 6 K Laser fusion 4·10 6 K

Daniel Cebra - Physics Feb-04 Bulk Properties 1: Directed Flow or V1 X Z XZ – the reaction plane Picture: © UrQMD rapidity or v1   Developed early - pre - equilibrium !   Sensitive to the EOS   As important as radial flow   Well studied at lower energies   Hard to be measured at RHIC because it is small STAR Data

Daniel Cebra - Physics Feb-04 Bulk Properties 2: Elliptic Flow or V2 Significant v2 up to ~7 GeV/c in pt, the region where hard scattering begins to dominate. Expected Hydrodynamical Behavior Hard Scattering dominate d region, but still showing some V2 Profile of Source 

Daniel Cebra - Physics Feb-04 Jets at RHIC p+p  jet+jet Au+Au  ??? nucleon parton jet Find this……….in this pQCD estimate E T >1 GeV N Jet ~500

Daniel Cebra - Physics Feb-04 Strong suppression of back-to-back correlations in central Au+Au Azimuthal distributions in Au+Au Au+Au peripheralAu+Au central Near-side: peripheral and central Au+Au similar to p+p pedestal and flow subtracted Phys Rev Lett 90, ?

Daniel Cebra - Physics Feb-04 Have we found the Quark Gluon Plasma at RHIC? We now know that Au+Au collisions generate a medium that is hot => 175 MeV => the QGP transition temperature is dense (pQCD theory: many times cold nuclear matter density) is dissipative, jets lose energy. exhibits strong collective behavior We have yet to do: Study the properties of the QGP matter Relate these properties to the nature of the Universe (Big Bang) This represents significant progress in our understanding of strongly interacting matter

Daniel Cebra - Physics Feb-04 The ‘Bozons’ 2002 Softball Champions IM - Grad-Staff-Faculty League Record: Undeated! [outscored opponents 75-21]