Quark-Gluon Plasma Presented by: Paul Pryor and Michael Byrd December 8, 2010

Overview  Definitions  Theory  Signatures  Detection  Results 2

Quark-Gluon Plasma  Increasing the temperature of the hadronic system eventually leads to complete dissociation of quarks and gluons 3 full-energy collisions between gold ions at Brookhaven Lab's Relativistic Heavy Ion Collider (RHIC), as captured by the Solenoidal Tracker at RHIC (STAR) detector.

Where do we stand? 4  Atoms  Protons, neutrons, and electrons  Baryons and mesons  quarks Interaction Particles AffectedRange Relative Strength Particles ExchangedRole in Universe Strong Quarks ~ m1 Gluons Holds quarks together to form nucleons HadronsMesons Holds nucleons together to form atomic nuclei Electro- magnetic Charged particles ∞~10 -2 mPhotons Determines structures of atoms, molecules, solids, and liquids; is important factor in astronomical universe Weak Quarks and leptons ~ m~10 -5 m Intermediate bosons Mediates transformation of quarks and leptons; helps determine compositions of atomic nuclei GravitationalAll∞~ mGravitons Assembles matter into planets, stars, and galaxies

Strong force 5  Primary expression  The level between quarks  Produces quark confinement  color  gluons  Secondary expression  The level between baryons  flavor  mesons

Baryons and Mesons 6  Baryons  Mass carriers  Composed of three quarks  Mesons  Composed of a quark antiquark pair  Alternative charge (flavor) carriers

There is an octet of ½ + baryons (1/2= spin, + = odd parity): - isospins of the same multiplet 7

Quarks and Gluons  Quarks  Fermions  Carry Color charge  charges of ± 1/3e or ± 2/3e  Gluons  massless  the mediator of color interactions  carries color-anticolor charge quanta  Absolute confinement 8

Plasma  A fully ionized gas 9

Quantum Chromodynamics (QCD)  The dynamical theory of quarks and gluons that describes color interactions  Parton model 10

QCD Phase Diagram 11

Theory of strong interactions 12  QCD  4D SU (3) gauge theory  Describes the interactions of quarks and gluons  QCD is defined through the Lagrangian D - Dirac operator N f - Flavors Ψ f - Quark fields

Hydrodynamics  Perfect liquid  Perfect gas 13

Signatures 14  Enhancement of strangeness  forward angles  large rapidity measurements y= 5 – 8  Observables give information about different stages of the collision

Post-plasma Observable 15  Detection of final state particles frozen out of the hot collision zone  Freeze out

Why look? 16  Help prove the validity of QCD  If QGP is a reality, its further study may give insight into the processes of the early universe

Experiment Signatures & Detection

 1. Jet Quenching Jet—a narrow cone of hadrons and other particles produced by the hadronization of a quark or gluon in a heavy ion experiment According to QCD, matter undergoing a phase crossover into quark gluon plasma losses significant energy, which effectively quenches the outgoing jet Strong suppression of inclusive hadron production Disappearance of the away-side jet Pedestal&flow subtracted Experimental Results 18

 2. Strangeness Strange quarks are not brought into the reaction by the colliding nuclei Strange quarks or antiquarks are made from the kinetic energy of colliding nuclei Strange quarks are naturally radioactive and decay by weak interactions into lighter quarks which can be detected relatively easily (Xi baryon(dss) into a pion(d) and a Lambda baryon(uds)) Experimental Results Cont. 19

Relativistic Heavy Ion Collider Complex 1.Tandem Van de Graaff2a. Tandem-to-Booster line (TTB)2b. Linear Accelerator (Linac)3. Booster Synchrotron - 37% the speed of light 4. Alternating Gradient Synchrotron % the speed of light 5. AGS-to-RHIC Line6. RHIC mile ring - six intersection points 20

Detectors 21

Solenoidal Tracker at RHIC (STAR) 22

 1. Time Projection Chamber Strong E-field: 130V/cm Multi-wire proportional chamber end caps Drift Gas: Argon/methane mixture 1atm.  2. Silicon Vertex Tracker Res.:18 million pixels (72576 channels x 256 time samples) capabilities below transverse momenta of 150 MeVIc Sub-detectors 23

 3. Electromagnetic Calorimeter (EMC) Energy Deposition Measurements  4. Time-of-Flight (TOF) Detector Shingle design Tiled outer TPC cage w/ 7716 single ended scintillators in 216 trays  5. External Time-Projection Chambers (TPC) Sub-detectors Cont. 24

What now? 25  Discovery of QGP not yet conclusive because signatures are indirect results predicted by theory  Develop methods and hardware for direct detection of total deconfinement  Determine if and where a definite transition exists  Charm production Charm quarks, unlike the strange quarks, are predicted to be produced early in QGP formation at sufficient energies Looking to the LHC at CERN for detection

STAR Collaboration Institutions (49)  Argonne National Laboratory, Argonne, Illinois 60439, USA  University of Bern, 3012 Bern, Switzerland  University of Birmingham, Birmingham, United Kingdom  Brookhaven National Laboratory, Upton, New York 11973, USA  California Institute of Technology, Pasadena, California 91125, USA  University of California, Berkeley, California 94720, USA  University of California, Davis, California 95616, USA  University of California, Los Angeles, California 90095, USA  Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA  Creighton University, Omaha, Nebraska 68178, USA  Nuclear Physics Institute AS CR, ˇ Reˇz/Prague, Czech Republic  Laboratory for High Energy (JINR), Dubna, Russia  Particle Physics Laboratory (JINR), Dubna, Russia  University of Frankfurt, Frankfurt, Germany  Institute of Physics, Bhubaneswar , India  Indian Institute of Technology, Mumbai, India  Indiana University, Bloomington, Indiana 47408, USA  Institut de Recherches Subatomiques, Strasbourg, France  University of Jammu, Jammu , India  Kent State University, Kent, Ohio 44242, USA  Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA  Massachusetts Institute of Technology, Cambridge, MA  Max-Planck-Institut f¨ur Physik, Munich, Germany  Michigan State University, East Lansing, Michigan 48824, USA  Moscow Engineering Physics Institute, Moscow Russia  City College of New York, New York City, New York 10031, USA  NIKHEF and Utrecht University, Amsterdam, The Netherlands  Ohio State University, Columbus, Ohio 43210, USA  Panjab University, Chandigarh , India  Pennsylvania State University, University Park, Pennsylvania 16802, USA  Institute of High Energy Physics, Protvino, Russia  Purdue University, West Lafayette, Indiana 47907, USA  University of Rajasthan, Jaipur , India  Rice University, Houston, Texas 77251, USA  Universidade de Sao Paulo, Sao Paulo, Brazil  University of Science & Technology of China, Anhui , China  Shanghai Institute of Applied Physics, Shanghai , China  SUBATECH, Nantes, France  Texas A&M University, College Station, Texas 77843, USA  University of Texas, Austin, Texas 78712, USA  Tsinghua University, Beijing , China  Valparaiso University, Valparaiso, Indiana 46383, USA  Variable Energy Cyclotron Centre, Kolkata , India  Warsaw University of Technology, Warsaw, Poland  University of Washington, Seattle, Washington 98195, USA  Wayne State University, Detroit, Michigan 48201, USA  Institute of Particle Physics, CCNU (HZNU), Wuhan , China  Yale University, New Haven, Connecticut 06520, USA  University of Zagreb, Zagreb, HR-10002, Croatia 26

Sources  Adams, J. et al. The STAR Collaboration’s Critical Assessment of the Evidence from RHIC Collisions. Tech Print  Beddo, M. E. et al. STAR Conceptual Design Report. Tech. no Print.  Braun-Munzinger, Peter, and Johanna Stachel. "The Quest for the Quark– gluon Plasma." Nature 448 (2007): Web. 15 Nov  "Quark–gluon Plasma." Online Reference - Information Articles & Reference Resources. Web. 22 Nov