• 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 ...
    • Conference Object  

      The chromomagnetic operator on the lattice 

      Constantinou, Martha G.; Costa, M. G.; Frezzotti, R.; Lubicz, V.; Martinelli, G.; Meloni, D.; Panagopoulos, Haralambos G.; Simula, S. (Proceedings of Science (PoS), 2013)
      We study matrix elements of the "chromomagnetic" operator on the lattice. This operator is contained in the strangeness-changing effective Hamiltonian which describes electroweak effects in the Standard Model and beyond. ...
    • Article  

      Non-perturbative renormalization of quark bilinear operators with N f = 2 (tmQCD) Wilson fermions and the tree-level improved gauge action 

      Constantinou, Martha G.; Dimopoulos, Petros; Frezzotti, R.; Herdoiza, G.; Jansen, K.; Lubicz, V.; Panagopoulos, Haralambos G.; Rossi, G. C.; Simula, S.; Stylianou, Fotos S.; Vladikas, A. (2010)
      We present results for the renormalization constants of bilinear quark operators obtained by using the tree-level Symanzik improved gauge action and the N f = 2 twisted mass fermion action at maximal twist, which guarantees ...
    • Article  

      O(a 2) corrections to the one-loop propagator and bilinears of clover fermions with Symanzik improved gluons 

      Constantinou, Martha G.; Lubicz, V.; Panagopoulos, Haralambos G.; Stylianou, Fotos S. (2009)
      We calculate corrections to the fermion propagator and to the Green's functions of all fermion bilinear operators of the form , to one-loop in perturbation theory. We employ the Wilson/clover action for fermions and the ...
    • 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 ...
    • Article  

      Renormalization and mixing in lattice QCD: The case of the chromomagnetic operator 

      Constantinou, Martha G.; Costa, M. G.; Frezzotti, R.; Lubicz, V.; Martinelli, G.; Meloni, D.; Panagopoulos, Haralambos G.; Simula, S. (2014)
      We study matrix elements of the "chromomagnetic" operator on the lattice. This operator is contained in the strangeness-changing effective Hamiltonian which describes electroweak effects in the Standard Model and beyond. ...
    • Article  

      Renormalization of the chromomagnetic operator on the lattice 

      Constantinou, Martha G.; Costa, M. G.; Frezzotti, R.; Lubicz, V.; Martinelli, G.; Meloni, D.; Panagopoulos, Haralambos G.; Simula, S. (2015)
      We present our study of the renormalization of the chromomagnetic operator, OCM, which appears in the effective Hamiltonian describing ΔS=1 transitions in and beyond the Standard Model. We have computed, perturbatively to ...