BK-parameter from Nf=2 twisted mass lattice QCD
Date
2011Author
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.
ISSN
1550-7998Source
Physical Review D - Particles, Fields, Gravitation and CosmologyVolume
83Issue
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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 quarks of both the maximally twisted and the Osterwalder-Seiler variety. Suitable combinations of these two kinds of valence quarks lead to a lattice definition of the BK parameter which is both multiplicatively renormalizable and O(a) improved. Employing the nonperturbative RI-MOM scheme, in the continuum limit and at the physical value of the pion mass we get BKRGI=0.729±0.030, a number well in line with the existing quenched and unquenched determinations. © 2011 American Physical Society.