Scaling study of pure SU(3) theory - the QCD-TARO collaboration

Lattice Monte Carlo data versus perturbation theory

“…Of course the (leading order) lattice distorted PT fits include one extra fitting parameter (X n,ν ) compared to the renormalised coupling fits, so it is tempting to argue that the former fits are more successful only for this reason. However, Sec.3 details the results from a renormalised coupling style fit with two extra fitting parameters that proved entirely unsuccessful [25].…”

“…The interpretation of the well-known discrepancy between g 0 -PT and Monte Carlo ∆β data has been problematic in the past. For example, in [8], a fit was attempted to their ∆β data using a coupling with two free parameters. A good fit was obtained only for an unphysical value of one of these parameters, leaving the explanation of the discrepancy open.…”

“…( 4) with the same constraints on the coefficients as mentioned above. We use the ∆β data from the QCD-Taro collaboration [25].…”

“…Note in [25], a fit was performed to their ∆β data using two free parameters. The first was a 3-loop coefficient δ 2 (see eq.…”

“…In all cases the 2-loop function f P T was used. The Monte Carlo data points are from[25]. Plot of a −1 /a −1 P T versus a 2 P T for the string tension, where a −1P T = Λ L /f P T (g 2 0 ).The value of Λ L = 5.85 MeV from table 2 was used and the 2loop form of f P T was used to define a P T .…”