PT Journal
AU Constantinou, M
   Dimopoulos, P
   Frezzotti, R
   Jansen, K
   Gimenez, V
   Lubicz, V
   Mescia, F
   Panagopoulos, H
   Papinutto, M
   Rossi, GC
   Simula, S
   Skouroupathis, A
   Stylianou, F
   Vladikas, A
TI B-K-parameter from N-f=2 twisted mass lattice QCD
SO Physical Review D
JI Phys. Rev. D
PY 2011
BP 014505
EP 20pp
VL 83
IS 1
DI 10.1103/PhysRevD.83.014505
LA English
AB We present an unquenched N-f = 2 lattice computation of the B-K parameter which controls K-0 – (K) over bar (0) 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 B-K 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 B-K(RGI) = 0.729 +/- 0.030, a number well in line with the existing quenched and unquenched determinations.
ER