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.
BK-parameter from Nf=2 twisted mass lattice QCD / M., Constantinou; P., Dimopoulos; R., Frezzotti; K., Jansen; V., Gimenez; V., Lubicz; F., Mescia; H., Panagopoulos; Papinutto, MAURO LUCIO; G. c., Rossi; S., Simula; A., Skouroupathis; F., Stylianou; A., Vladikas. - In: PHYSICAL REVIEW D, PARTICLES, FIELDS, GRAVITATION, AND COSMOLOGY. - ISSN 1550-7998. - 83:1(2011), p. 014505. [10.1103/physrevd.83.014505]
BK-parameter from Nf=2 twisted mass lattice QCD
PAPINUTTO, MAURO LUCIO;
2011
Abstract
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.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
