Browsing by Author "de Forcrand, Ph"

Now showing items 1-10 of 10

    • Article  

      Calculation of the N to Δ electromagnetic transition matrix element 

      Alexandrou, Constantia; de Forcrand, Ph; Lippert, Th; Neff, H.; Negele, J. W.; Schilling, K.; Schroers, W.; Tsapalis, Antonios (2003)
      We present results on the ratio of electric quadrupole to magnetic dipole amplitudes, REM = GE2/GM1, for the transition γN → Δ from lattice QCD. We consider both the quenched and the 2-flavor theory.
    • Article  

      Full QCD with the Lüscher local bosonic action 

      Alexandrou, Constantia; Borrelli, A.; de Forcrand, Ph; Galli, A.; Jegerlehner, F. (1995)
      We investigate Lüscher's method of including dynamical Wilson fermions in a lattice simulation of QCD with two quark flavours. We measure the accuracy of the approximation by comparing it with Hybrid Monte Carlo results ...
    • Article  

      Gauge-invariant two- and three- density correlators 

      Alexandrou, Constantia; de Forcrand, Ph; Tsapalis, Antonios (2003)
      Gauge-invariant spatial correlations between two and three quarks inside a hadron are measured within quenched and unquenched QCD. These correlators provide information on the shape and multipole moments of the pion, the ...
    • Article  

      The ground state of three quarks 

      Alexandrou, Constantia; de Forcrand, Ph; Jahn, O. (2003)
      We measure the static three-quark potential in SU(3) lattice gauge theory with improved accuracy, by using all available technical refinements, including Lüscher-Weisz exponential variance reduction. Together with insight ...
    • Article  

      Hadron wave functions and the issue of nucleon deformation 

      Alexandrou, Constantia; de Forcrand, Ph; Tsapalis, Antonios (2003)
      Using gauge invariant hadronic two- and three- density correlators we extract information on the spatial distributions of quarks in hadrons, and on hadron shape and multipole moments within quenched lattice QCD. Combined ...
    • Article  

      The matter density distribution for mesons and baryons 

      Alexandrou, Constantia; de Forcrand, Ph; Tsapalis, Antonios (2004)
      The matter density distribution inside a hadron is evaluated using gauge-invariant correlation functions within the quenched and the unquenched theory. Comparison with the charge density distribution suggests that hadron ...
    • Article  

      Momentum dependence of the N to Δ transition form factors 

      Alexandrou, Constantia; de Forcrand, Ph; Neff, H.; Negele, J. W.; Schroers, W.; Tsapalis, Antonios (2005)
      We present a new method to determine the momentum dependence of the N to Δ transition form factors and demonstrate its effectiveness in the quenched theory at β = 6.0 on a 323 × 64 lattice. We address a number of technical ...
    • Article  

      Phase structure of one-flavour QCD 

      Alexandrou, Constantia; Boriçi, A.; Feo, A.; de Forcrand, Ph; Galli, A.; Jegerlehner, F.; Takaishi, T. (1999)
      We present a study of the deconfinement phase transition of one-flavour QCD, using the multiboson algorithm. The mass of the Wilson fermions relevant for this study is moderately large and the non-Hermitian multiboson ...
    • Article  

      Static three- and four-quark potentials 

      Alexandrou, Constantia; de Forcrand, Ph; Tsapalis, Antonios (2002)
      We present results for the static three- and four- quark potentials in SU(3) and SU(4) respectively. Using a variational approach, combined with multi-hit for the time-like links, we determine the ground state of the ...
    • Article  

      γN → Δ transition form factors in Quenched and NF = 2 QCD 

      Alexandrou, Constantia; de Forcrand, Ph; Lippert, Th; Neff, H.; Negele, J. W.; Schilling, K.; Schroers, W.; Tsapalis, Antonios (2004)
      Calculations of the magnetic dipole, electric quadrupole and Coulomb quadrupole amplitudes for the transition γN → Δ are presented both in quenched QCD and with two flavours of degenerate dynamical quarks. © 2004 Published ...