Thermodynamics of lattice QCD with 2 flavours of color-sextet quarks : a model of walking/conformal technicolor.

Journal Article · Wed Jun 30 04:00:00 EDT 2010 · Phys. Rev. D

DOI:https://doi.org/10.1103/PhysRevD.81.114507· OSTI ID:985142

Sinclair, D K; Kogut, J B

QCD with two flavors of massless color-sextet quarks is considered as a model for conformal/walking technicolor. If this theory possesses an infrared fixed point, as indicated by 2-loop perturbation theory, it is a conformal (unparticle) field theory. If, on the other hand, a chiral condensate forms on the weak-coupling side of this would-be fixed point, the theory remains confining. The only difference between such a theory and regular QCD is that there is a range of momentum scales over which the coupling constant runs very slowly (walks). In this first analysis, we simulate the lattice version of QCD with two flavors of staggered quarks at finite temperatures on lattices of temporal extent N{sub t} = 4 and 6. The deconfinement and chiral-symmetry restoration couplings give us a measure of the scales associated with confinement and chiral-symmetry breaking. We find that, in contrast to what is seen with fundamental quarks, these transition couplings are very different. {beta} = 6/g{sup 2} for each of these transitions increases significantly from N{sub t} = 4 and N{sub t} = 6 as expected for the finite-temperature transitions of an asymptotically free theory. This suggests a walking rather than a conformal behavior, in contrast to what is observed with Wilson quarks. In contrast to what is found for fundamental quarks, the deconfined phase exhibits states in which the Polyakov loop is oriented in the directions of all three cube roots of unity. At very weak coupling the states with complex Polyakov loops undergo a transition to a state with a real, negative Polyakov loop.

• Research Organization: Argonne National Laboratory (ANL)
• Sponsoring Organization: SC; NSF
• DOE Contract Number: AC02-06CH11357
• OSTI ID: 985142
• Report Number(s): ANL-HEP-PR-09-95
• Journal Information: Phys. Rev. D, Journal Name: Phys. Rev. D Journal Issue: Jun. 30, 2010 Vol. 81; ISSN 1550-7998
• Country of Publication: United States
• Language: ENGLISH

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
CHIRAL SYMMETRY
CONDENSATES
CONFINEMENT
COUPLING CONSTANTS
PERTURBATION THEORY
QUANTUM CHROMODYNAMICS
QUARKS
THERMODYNAMICS