2026-04-13T07:24:48Zhttps://recercat.cat/oai/request

oai:recercat.cat:2445/1317952025-12-05T16:48:59Zcom_2072_1057col_2072_478823col_2072_478917

00925njm 22002777a 4500 dc Constantinou, M. author Dimopoulos, P. author Frezzotti, R. author Jansen, K. author Gimenez, V. author Lubicz, V. author Mescia, Federico author Panagopoulos, H. author Papinutto, M. author Rossi, G. C. author Simula, S. author Skouroupathis, A. author Stylianou, F. author Vladikas, A. author ETM Collaboration author 2019-04-08T12:11:20Z 2019-04-08T12:11:20Z 2011-01-01 2019-04-08T12:11:20Z We present an unquenched N f = 2 lattice computation of the B K parameter which controls K 0 − ¯¯¯¯ K 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 RGI K = 0.729 ± 0.030 , a number well in line with the existing quenched and unquenched determinations. Física de partícules Experiments Particle physics Experiments BK-parameter from Nf = 2 twisted mass lattice QCD