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Title: High-density QCD and instantons

Journal Article · · Annals of Physics (New York)
 [1];  [2];  [1];  [3]
  1. Department of Physics and Astronomy, State University of New York, Stony Brook, New York 11794-3800 (United States)
  2. School of Natural Sciences, Institute for Advanced Study, Princeton, New Jersey 08540 (United States)
  3. Nuclear Theory Group, Brookhaven National Laboratory, Upton, New York 11973-5000 (United States)

Instantons generate strong nonperturbative interactions between quarks. In vacuum, these interactions lead to chiral symmetry breaking and generate constituent quark masses on the order of 300-400 MeV. The observation that the same forces also provide attraction in the scalar diquark channel leads to the prediction that cold quark matter is a color superconductor, with gaps as large as {approx}100 MeV. We provide a systematic treatment of color superconductivity in the instanton model. We show that the structure of the superconductor depends on the number of flavors. In the case of two flavors, we verify the standard scenario, and provide an improved calculation of the mass gap. For three flavors, we show that the ground state is color-flavor locked and calculate the chiral condensate in the high-density phase. We show that as a function of the strange quark mass, there is a sharp transition between the two phases. Finally, we go beyond the mean-field approximation and investigate the role of instanton/anti-instanton molecules, which--in addition to superconducting gap formation--provide a competitive mechanism for chiral restoration at finite density. (c) 2000 Academic Press, Inc.

OSTI ID:
20216171
Journal Information:
Annals of Physics (New York), Vol. 280, Issue 1; Other Information: PBD: 25 Feb 2000; ISSN 0003-4916
Country of Publication:
United States
Language:
English