We present preliminary results at {\beta} = 1.95 (a = 0.077 fm) on the first unquenched N_f=2+1+1 lattice computation of the B_K parameter which controls the neutral kaon oscillations in the Standard Model. Using N_f=2+1+1 maximally twisted sea quarks and Osterwalder-Seiler valence quarks we achieve O(a) improvement and a continuum-like renormalization pattern for the four-fermion operator. Our results are extrapolated/interpolated to the physical light/strange quark mass but not yet to the continuum limit. The computation of the relevant renormalization constants is performed non perturbatively in the RI'-MOM scheme using dedicated simulations with N_f=4 degenerate sea quark flavours produced by the ETM collaboration. We get B_K^{RGI} (a = 0.077) = 0.747(18), which when compared to our previous unquenched N_f=2 determination and most of the existing results, suggests a rather weak B_K^{RGI} dependence on the number of dynamical flavours. We are at the moment analysing lattice data at two additional {\beta} values which will allow us to perform an extrapolation to the continuum limit.

Carrasco, N., Gimenez, V., Dimopoulos, P., Frezzotti, R., Palao, D., Rossi, G., et al. (2011). K^0-\bar{K}^0 mixing in the Standard Model from Nf=2+1+1 Twisted Mass Lattice QCD. ??????? it.cilea.surplus.oa.citation.tipologie.CitationProceedings.prensentedAt ??????? 29th International Symposium on Lattice Field Theory (Lattice 2011), Squaw Valley, Lake Tahoe, California.

K^0-\bar{K}^0 mixing in the Standard Model from Nf=2+1+1 Twisted Mass Lattice QCD

FREZZOTTI, ROBERTO;ROSSI, GIANCARLO;
2011-01-01

Abstract

We present preliminary results at {\beta} = 1.95 (a = 0.077 fm) on the first unquenched N_f=2+1+1 lattice computation of the B_K parameter which controls the neutral kaon oscillations in the Standard Model. Using N_f=2+1+1 maximally twisted sea quarks and Osterwalder-Seiler valence quarks we achieve O(a) improvement and a continuum-like renormalization pattern for the four-fermion operator. Our results are extrapolated/interpolated to the physical light/strange quark mass but not yet to the continuum limit. The computation of the relevant renormalization constants is performed non perturbatively in the RI'-MOM scheme using dedicated simulations with N_f=4 degenerate sea quark flavours produced by the ETM collaboration. We get B_K^{RGI} (a = 0.077) = 0.747(18), which when compared to our previous unquenched N_f=2 determination and most of the existing results, suggests a rather weak B_K^{RGI} dependence on the number of dynamical flavours. We are at the moment analysing lattice data at two additional {\beta} values which will allow us to perform an extrapolation to the continuum limit.
29th International Symposium on Lattice Field Theory (Lattice 2011)
Squaw Valley, Lake Tahoe, California
2011
29
P. Vranas
Rilevanza internazionale
contributo
2011
Settore FIS/02 - FISICA TEORICA, MODELLI E METODI MATEMATICI
English
http://inspirehep.net/record/944838
Intervento a convegno
Carrasco, N., Gimenez, V., Dimopoulos, P., Frezzotti, R., Palao, D., Rossi, G., et al. (2011). K^0-\bar{K}^0 mixing in the Standard Model from Nf=2+1+1 Twisted Mass Lattice QCD. ??????? it.cilea.surplus.oa.citation.tipologie.CitationProceedings.prensentedAt ??????? 29th International Symposium on Lattice Field Theory (Lattice 2011), Squaw Valley, Lake Tahoe, California.
Carrasco, N; Gimenez, V; Dimopoulos, P; Frezzotti, R; Palao, D; Rossi, G; Lubicz, V; Papinutto, M; Sanfilippo, F; Simula, S
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2108/80035
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