Browsing by Author "Di Giacomo, A."

Now showing items 1-17 of 17

    • Article  

      Behaviour of the topological susceptibility across the deconfining phase transition 

      Di Giacomo, A.; Meggiolaro, E.; Panagopoulos, Haralambos G. (1992)
      We investigate the behaviour of the topological susceptibility of pure SU(2) gauge theory at the deconfining phase transition. The cooling method gives ambiguous results. The susceptibility, determined by the field theoretical ...
    • Article  

      Cooling and the string tension in lattice gauge theories 

      Campostrini, M.; Di Giacomo, A.; Maggiore, M.; Panagopoulos, Haralambos G.; Vicari, E. (1989)
      We explore the possibility of improving the determination of the string tension using the cooling method. We present preliminary results for the gauge group SU(2): We find that statistical errors are drastically reduced ...
    • Article  

      Field strength correlations in the QCD vacuum 

      Di Giacomo, A.; Panagopoulos, Haralambos G. (1992)
      We determine by numerical simulation on a lattice the correlation function of the gauge field strengths in the QCD vacuum. © 1992.
    • Article  

      Field strength correlators in QCD at zero and non-zero temperature 

      Di Giacomo, A.; Meggiolaro, E.; Panagopoulos, Haralambos G. (1997)
      We study, by numerical simulations on a lattice, the behaviour of the gauge-invariant field strength correlators in QCD both at zero temperature, down to a distance of 0.1 fm, and at finite temperature, across the deconfinement ...
    • Article  

      Gauge-invariant field strength correlations in QCD at zero and non-zero temperature 

      Di Giacomo, A.; Meggiolaro, E.; Panagopoulos, Haralambos G. (1997)
      We determine, by numerical simulations on a lattice, the gauge-invariant two-point correlation functions of the gauge field strengths in the QCD vacuum at zero temperature, down to a distance of 0.1 fm. We also study the ...
    • Article  

      Improved lattice operators: Case of the topological charge density 

      Christou, Chris; Di Giacomo, A.; Panagopoulos, Haralambos G.; Vicari, E. (1996)
      We analyze the properties of a class of improved lattice topological charge density operators, constructed by a smearinglike procedure. By optimizing the choice of the parameters introduced in their definition we find ...
    • Article  

      Improving the topological charge density operator on the lattice 

      Christou, Chris; Di Giacomo, A.; Panagopoulos, Haralambos G.; Vicari, E. (1996)
      We analyze the properties of a class of improved lattice topological charge density operators, constructed by a smearing-like procedure. By optimizing the choice of the parameters introduced in their definition, we find ...
    • Article  

      A lattice determination of the slope at q2 = 0 of the topological susceptibility in SU (3) Yang-Mills theory 

      Di Giacomo, A.; Meggiolaro, E.; Panagopoulos, Haralambos G. (1992)
      We determine the slope of the topological susceptibility at q2 = 0 by Monte Carlo simulations, for an SU(3) quenched gauge theory. The value is consistent with the phenomenological estimates, within the (large) errors. © 1992.
    • Article  

      A lattice determination of the slope of the topological susceptibility at q2=0 

      Briganti, G.; Di Giacomo, A.; Panagopoulos, Haralambos G. (1991)
      The slope of the topological susceptibility at q2=0 is determined by Monte Carlo simulation for an SU(2) quenched gauge theory. Both the sign and the magnitude agree with the sum rule phenomenological determinations. © 1991.
    • Article  

      The proton matrix element of the topological charge in quenched QCD 

      Allés, B.; Campostrini, M.; Del Debbio, L.; Di Giacomo, A.; Panagopoulos, Haralambos G.; Vicari, E. (1994)
      We compute on the lattice the on-shell proton matrix element of the topological charge density in the quenched approximation. Our calculation makes use of a nonperturbative means of determining the multiplicative renormalization ...
    • Article  

      String tension and flux tubes on the lattice 

      Campostrini, M.; Di Giacomo, A.; Maggiore, M.; Olejník, S.; Panagopoulos, Haralambos G.; Vicari, E. (1990)
      We use the cooling technique to study the string tension in pure SU(2) gauge theory. We find that statistical errors are drastically reduced and at the same time the string tension is preserved through many cooling steps. ...
    • Article  

      Topological charge density renormalization in the presence of dynamical fermions 

      Allés, B.; Di Giacomo, A.; Panagopoulos, Haralambos G.; Vicari, E. (1995)
      We study the renormalization group behaviour of the topological charge density in full QCD on the lattice. We propose a way of extracting the necessary renormalization functions from Monte Carlo simulations. © 1995.
    • Article  

      Topological charge, renormalization and cooling on the lattice 

      Campostrini, M.; Di Giacomo, A.; Panagopoulos, Haralambos G.; Vicari, E. (1990)
      We show that a definition of the topological susceptibility χ on the lattice in terms of local fields, with the proper additive and multiplicative renormalizations, is well defined, self-consistent and compatible with ...
    • Article  

      The topological susceptibility and lattice universality 

      Di Giacomo, A.; Panagopoulos, Haralambos G.; Vicari, E. (1990)
      We study the topological susceptibility χ on the lattice, using four different actions from the mixed fundamental adjoint family. To measure χ we employ on the one hand a field theoretic approach, which requires the ...
    • Article  

      The topological susceptibility of the pure SU(3) Yang-Mills vacuum on the lattice 

      Campostrini, M.; Di Giacomo, A.; Gündüc, Y.; Lombardo, M. P.; Panagopoulos, Haralambos G.; Tripiccione, R. (1990)
      Using a "field theoretic" approach, we compute the topological susceptibility χ of the pure gauge SU(3) theory on the lattice. We also apply an algorithm of gradual cooling, and use these two approaches as a cross-check ...
    • Article  

      The topological susceptibility on the lattice 

      Campostrini, M.; Di Giacomo, A.; Panagopoulos, Haralambos G. (1988)
      We study the multiplicative renormalization of the topological charge operator on the lattice with respect to the continuum. Apparent discrepancies between different methods of determination of the topological charge on ...
    • Article  

      Universality and the parameter on a body-centered hypercubic lattice 

      Di Giacomo, A.; Maggiore, M.; Panagopoulos, Haralambos G. (1987)
      We calculate the relationship between the coupling constants of the simple hypercubic and the body-centered hypercubic lattice, to one-loop order, using the background-field method. This corresponds to determining the ratio ...