Browsing by Author "Skouroupathis, A."
Now showing items 1-13 of 13
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Article
Additive and multiplicative renormalization of topological charge with improved gluon and fermion actions: A test case for 3-loop vacuum calculations, using overlap or clover fermions
Skouroupathis, A.; Panagopoulos, Haralambos G. (2005)We calculate perturbative renormalization properties of the topological charge, using the standard lattice discretization given by a product of twisted plaquettes. We use the overlap and clover action for fermions, and the ...
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Article
BK-parameter from Nf=2 twisted mass lattice QCD
Constantinou, Martha G.; Dimopoulos, Petros; Frezzotti, R.; Jansen, K.; Gimenez, V.; Lubicz, V.; Mescia, F.; Panagopoulos, Haralambos G.; Papinutto, M.; Rossi, G. C.; Simula, S.; Skouroupathis, A.; Stylianou, Fotos S.; Vladikas, A. (2011)We present an unquenched Nf=2 lattice computation of the B K parameter which controls K0-K̄0 oscillations. A partially quenched setup is employed with two maximally twisted dynamical (sea) light Wilson quarks, and valence ...
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Article
Erratum: Two-loop renormalization of scalar and pseudoscalar fermion bilinears on the lattice (Physical Review D - Particles, Fields, Gravitation and Cosmology (2007) 76 (094514))
Skouroupathis, A.; Panagopoulos, Haralambos G. (2008)
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Free energy and plaquette expectation value for gluons on the lattice, in three dimensions
Panagopoulos, Haralambos G.; Skouroupathis, A.; Tsapalis, Antonios (2006)We calculate the perturbative value of the free energy in lattice QCD in three dimensions, up to three loops. Our calculation is performed using the Wilson formulation for gluons in SU(N) gauge theories. The free energy ...
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Article
Improved perturbation theory for improved lattice actions
Constantinou, Martha G.; Panagopoulos, Haralambos G.; Skouroupathis, A. (2006)We study a systematic improvement of perturbation theory for gauge fields on the lattice
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Conference Object
Optimized interpolations and nonlinearity in numerical studies of woodwind instruments
Skouroupathis, A.; Panagopoulos, Haralambos G. (2005)We study the impedance spectra of woodwind instruments with arbitrary axisymmetric geometry. We perform piecewise interpolations of the instruments' profile, using interpolating functions amenable to analytic solutions of ...
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Article
Perturbative renormalization factors and O(a2) corrections for lattice four-fermion operators with improved fermion/gluon actions
Constantinou, Martha G.; Dimopoulos, Petros; Frezzotti, R.; Lubicz, V.; Panagopoulos, Haralambos G.; Skouroupathis, A.; Stylianou, Fotos S. (2011)In this work we calculate the corrections to the amputated Green's functions of four-fermion operators, in 1-loop lattice perturbation theory. One of the novel aspects of our calculations is that they are carried out to ...
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Article
Two-loop additive mass renormalization with clover fermions and Symanzik improved gluons
Skouroupathis, A.; Constantinou, Martha G.; Panagopoulos, Haralambos G. (2008)We calculate the critical value of the hopping parameter, κc, in lattice QCD, up to two loops in perturbation theory. We employ the Sheikholeslami-Wohlert (clover) improved action for fermions and the Symanzik improved ...
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Conference Object
Two-loop renormalization of fermion bilinears on the lattice
Skouroupathis, A.; Panagopoulos, Haralambos G. (2009)We compute the renormalization functions on the lattice, in the RI′ scheme, of local bilinear quark operators ψ̄ Γψ, where Γ = Î, γ5, γμ, γ5, γμ, γ5 σμν. This calculation is carried out to two loops for the first time. We ...
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Article
Two-loop renormalization of scalar and pseudoscalar fermion bilinears on the lattice
Skouroupathis, A.; Panagopoulos, Haralambos G. (2007)We compute the two-loop renormalization functions, in the RI′ scheme, of local bilinear quark operators ψ̄Γψ, where Γ denotes the scalar and pseudoscalar Dirac matrices, in the lattice formulation of QCD. We consider both ...
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Article
Two-loop renormalization of vector, axial-vector, and tensor fermion bilinears on the lattice
Skouroupathis, A.; Panagopoulos, Haralambos G. (2009)We compute the two-loop renormalization functions, in the RI′ scheme, of local bilinear quark operators ψ̄Γψ, where Γ corresponds to the vector, axial-vector, and tensor Dirac operators, in the lattice formulation of QCD. ...
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Article
θ Dependence of the spectrum of SU(N) gauge theories
Del Debbio, L.; Manca, G. M.; Panagopoulos, Haralambos G.; Skouroupathis, A.; Vicari, E. (2006)We study the θ dependence of the spectrum of four-dimensional SU(N) gauge theories, where θ is the coefficient of the topological term in the Lagrangian, for N 3 and in the large-N limit. We compute the O(θ2) terms of the ...
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Article
Λ-parameter of lattice QCD with Symanzik improved gluon actions
Skouroupathis, A.; Panagopoulos, Haralambos G. (2007)We compute the ratio ΛL/ΛMS̄, where the scale parameter ΛL is associated with a lattice formulation of QCD. We consider a 3-parameter family of gluon actions, which are most frequently used for O(a) improvement à la Symanzik. ...