1,721,025 research outputs found
A CONSISTENCY CHECK FOR RENORMALONS IN LATTICE GAUGE THEORY: BETA**(-10) CONTRIBUTIONS TO THE SU(3) PLAQUETTE
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THE N_f = 2 RESIDUAL MASS IN PERTURBATIVE LATTICE-HQET FOR AN IMPROVED DETERMINATION OF M_B(M_B)
No full textWe determine to order α3 the so-called residual mass in the lattice regularisation of the Heavy Quark Effective Theory for Nf = 2. Our (gauge-invariant) strategy makes use of Numerical Stochastic Perturbation Theory to compute the static interquark potential where the above mentioned mass term appears as an additive contribution. We discuss how the new coefficient we compute in the expansion of the residual mass can improve the determination of the (MS) mass of the b-quark from lattice simulations of the Heavy Quark Effective Theory
NUMERICAL STOCHASTIC PERTURBATION THEORY: CONVERGENCE AND FEATURES OF THE STOCHASTIC PROCESS, COMPUTATIONS AT FIXED (LANDAU) GAUGE
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NUMERICAL STOCHASTIC PERTURBATION THEORY FOR FULL QCD
No full textWe give a full account of the Numerical Stochastic Perturbation Theory method for Lattice Gauge Theories. Particular relevance is given to the inclusion of dynamical fermions, which turns out to be surprisingly cheap in this context. We analyse the underlying stochastic process and discuss the convergence properties. We perform some benchmark calculations and - as a byproduct - we present original results for Wilson loops and the 3-loop critical mass for Wilson fermions
Lefschetz thimbles and sign problem: first results in 0 and 4 dimensional field theories
No full textHigh-loop perturbative renormalization constants for Lattice QCD. I. Finite constants for Wilson quark currents.
No full textWe present a high order perturbative computation of the renormalization constants Z_V, Z_A and of the ratio Z_P/Z_S for Wilson fermions. The computational setup is the one provided by the RI'-MOM scheme. Three- and four-loop expansions are made possible by Numerical Stochastic Perturbation Theory. Results are given for various numbers of flavours and/or (within a finite accuracy) for generic n_f up to three loops. For the case n_f=2 we also present four-loop results. Finite size effects are well under control and the continuum limit is taken by means of hypercubic symmetric Taylor expansions. The main indetermination comes from truncation errors, which should be assessed in connection with convergence properties of the series. The latter is best discussed in the framework of Boosted Perturbation Theory, whose impact we try to assess carefully. Final results and their uncertainties show that high-loop perturbative computations of Lattice QCD RC's are feasible and should not be viewed as a second choice. As a by-product, we discuss the perturbative expansion for the critical mass, also for which results are for generic n_f up to three loops, while a four-loop result is obtained for n_f=2
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