Berlin 2005 – scientific programme

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T: Teilchenphysik

T 707: QCD III

T 707.7: Talk

Wednesday, March 9, 2005, 15:30–15:45, TU H2037

Center vortex model for SU(3) Yang-Mills theory – the ’t Hooft loop operator — •Markus Quandt¹, Hugo Reinhardt¹, and Michael Engelhardt² — ¹Institut für Theoretische Physik, Universität Tübingen, 72076 Tübingen, Germany — ²Physics Department, New Mexico State University, Las Cruces, NM 88003, USA

We study the ’t Hooft loop operator in the center vortex model for the infrared sector of SU(3) Yang-Mills theory. This model is based on the assumption that the vortex world-surfaces, which are the relevant degrees of freedom in this regime, can be viewed as random surfaces in Euclidean space-time. The ’t Hooft loop is a vortex creation operator which implements twisted boundary conditions on a spacetime torus.

Our mesurements of the free energy of large spatial ’t Hooft loops confirm a temperature dependence dual to the usual Wilson loop: We find an area law with a dual string tension σ(T) for T>T_c, and a perimeter law, σ = 0, in the confinement phase below T_c. As we approach the critical temperature from above, we also observe a weak discontinuity in the free energy, √Δ σ ≈ 34 MeV, which is an indication of a weak first order phase transition for the gauge group G=SU(3). Our findings are in good agreement with recent lattice calculations.