The National Academies Press

Currently Skimming:

Pages 80-103

The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.

From page 80... ... 80 NUCLEAR PHYSICS: THE CORE OF MATTER, THE FUEL OF STARS 80 4 Matter at Extreme Densities INTRODUCTION The completion of the Relativistic Heavy Ion Collider (RHIC) in 1999 will open a new window on matter at the highest energy densities. Read the entire page →
From page 81... ... MATTER AT EXTREME DENSITIES 81 gluon description of matter, is inadequately understood. At RHIC, such highenergy densities will be created that the quarks and gluons are expected to become deconfined across a volume that is large compared to that of a hadron. Read the entire page →
From page 82... ... 82 NUCLEAR PHYSICS: THE CORE OF MATTER, THE FUEL OF STARS latent heat (first-order transition) , without a latent heat (second order) Read the entire page →
From page 83... ... MATTER AT EXTREME DENSITIES 83 nuclear droplets (small nuclei with nucleon number A in the range 6 to 50) should increase with temperature in the mixed-phase region. Read the entire page →
From page 84... ... 84 NUCLEAR PHYSICS: THE CORE OF MATTER, THE FUEL OF STARS BOX 4.1 The Liquid-Gas Phase Transition in Nuclear Matter Nuclear matter is expected, theoretically, to undergo a transition from a liquid to a gaseous phase at densities lower than those inside normal atomic nuclei. This phase transition should occur at a temperature of 1.7 × 1011 K or 15 MeV. Read the entire page →
From page 85... ... MATTER AT EXTREME DENSITIES 85 occurs should allow extraction of the thermodynamic properties of the liquid-gas phase transition. Some of the experimental evidence for the phase transition is shown in Figure 4.1.1, which illustrates the yield of light nuclei in collisions of Kr beams of different energies on a stationary Au target. Read the entire page →
From page 86... ... 86 NUCLEAR PHYSICS: THE CORE OF MATTER, THE FUEL OF STARS tional observables accessible. The RHIC collisions will have ten times the energy of the collisions at the SPS. Read the entire page →
From page 87... ... MATTER AT EXTREME DENSITIES 87 14 GeV/nucleon collisions, and up to 6 times at the SPS. The corresponding energy densities are about 10 times that of normal nuclei and 2 to 5 times the energy density inside a hadron. Read the entire page →
From page 88... ... 88 NUCLEAR PHYSICS: THE CORE OF MATTER, THE FUEL OF STARS BOX 4.2 Probing the Vacuum Although one usually thinks of the vacuum as space with nothing in it, quantum theory tells us that the vacuum is not really completely empty. It contains a "sea" of quark-antiquark pairs. Read the entire page →
From page 89... ... MATTER AT EXTREME DENSITIES 89 sion. This energy rises with the energy of the beam, as illustrated by Figure 4.3. Read the entire page →
From page 90... ... 90 NUCLEAR PHYSICS: THE CORE OF MATTER, THE FUEL OF STARS FIGURE 4.2 Schematic illustration of the different stages in a heavy-ion collision. The stages include (a) Read the entire page →
From page 91... ... MATTER AT EXTREME DENSITIES 91 collisions of very heavy ions have driven new developments in detectors, readout electronics, and data acquisition technology. Hot Dense Initial State The arrangement of the quarks and gluons making up the nucleons inside a nucleus has been studied with energetic electron, positron, and proton beams. Read the entire page →
From page 92... ... 92 NUCLEAR PHYSICS: THE CORE OF MATTER, THE FUEL OF STARS energy density should be significantly larger at RHIC than for AGS or SPS collisions, and the lifetime of the hot dense state should be longer. The gluons participate in a rapid cascade of subsequent collisions. Read the entire page →
From page 93... ... MATTER AT EXTREME DENSITIES 93 THERMAL DESCRIPTION OF THE FINAL STATE The latter phase of the collision, after the quarks coalesce into hadrons, appears to behave as a system of hadrons in thermal equilibrium. The equilibrium is unlikely to span the entire central region in the collision, as the hadrons scatter primarily with nearby neighbors. Read the entire page →
From page 94... ... 94 NUCLEAR PHYSICS: THE CORE OF MATTER, THE FUEL OF STARS experimental results awaited from RHIC is how the higher initial temperature affects the freezeout. SIGNATURES OF QUARK-GLUON PLASMA FORMATION Determining the nature of high-density matter and identifying the formation of a quark-gluon plasma are the major experimental challenges at RHIC. Read the entire page →
From page 95... ... MATTER AT EXTREME DENSITIES 95 TABLE 4.1 Predicted Signatures of Quark-Gluon Plasma Formation Signature Process Probed Experimental Observable Suppression of J/psi Screening of charm-anticharm Decreased probability for J/psi (meson consisting of the pair interaction by the production bound state of a charm- surrounding quarks anticharm quark pair) Charm enhancement Fusion of the many gluons Energetic single leptons and (increase in the total number produced early in the collision pairs of leptons; decays of of charm and anticharm into a charm and anticharm D-mesons quarks, regardless of quark pair whether they are bound) Read the entire page →
From page 96... ... 96 NUCLEAR PHYSICS: THE CORE OF MATTER, THE FUEL OF STARS FIGURE 4.5 Quark-gluon plasma and chiral symmetry signatures. This figure illustrates two different signatures of quark-gluon plasma formation and chiral symmetry restoration. Read the entire page →
From page 97... ... MATTER AT EXTREME DENSITIES 97 FIGURE 4.6 Lepton pair spectrum. The top panel shows a schematic view of the distribution of lepton pairs (either electrons or muons) Read the entire page →
From page 98... ... 98 NUCLEAR PHYSICS: THE CORE OF MATTER, THE FUEL OF STARS pairs; labeled 1 in Figure 4.6) provides direct information on the thermal history of the collision. Read the entire page →
From page 99... ... MATTER AT EXTREME DENSITIES 99 between pairs of jets. While the beam energy in experiments performed to date is too low for significant jet production, energy loss of jets is an important new signal to be studied at RHIC. Read the entire page →
From page 100... ... 100 NUCLEAR PHYSICS: THE CORE OF MATTER, THE FUEL OF STARS (which will continue to run, primarily to serve as an injector for RHIC) and brought one-sixth of the way around the RHIC ring. Read the entire page →
From page 101... ... MATTER AT EXTREME DENSITIES 101 FIGURE 4.7 The PHENIX detector for RHIC. Different components of the detector are labeled; each component provides information complementary to the others. Read the entire page →
From page 102... ... 102 NUCLEAR PHYSICS: THE CORE OF MATTER, THE FUEL OF STARS extend their capabilities have been identified. The data and new discoveries will determine which further studies and upgrades are required. Read the entire page →
From page 103... ... MATTER AT EXTREME DENSITIES 103 when the quarks coalesce into hadrons. As we begin to learn the nature of highenergy-density matter at RHIC, the experiments can be accordingly expanded and upgraded. Read the entire page →

From page 80...

... 80 NUCLEAR PHYSICS: THE CORE OF MATTER, THE FUEL OF STARS 80 4 Matter at Extreme Densities INTRODUCTION The completion of the Relativistic Heavy Ion Collider (RHIC) in 1999 will open a new window on matter at the highest energy densities.