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We calculate the B-parameters for operators arising in theories of new physics beyond the standard model (BSM) using HYP-smeared improved staggered fermions on the MILC asqtad lattices with N_f = 2+1 flavors. We use three different lattice…

We present results for the matrix elements of the additional $\Delta S=2$ operators that appear in models of physics beyond the Standard Model (BSM), expressed in terms of four BSM $B$-parameters. Combined with experimental results for…

We present updated results for kaon B-parameters for operators arising in models of new physics. We use HYP-smeared staggered quarks on the $N_f = 2+1$ MILC asqtad lattices. During the last year we have added new ensembles, which has…

We present results for kaon mixing parameter $B_K$ calculated using HYP-smeared improved staggered fermions on the MILC asqtad lattices. We use three lattice spacings ($a\approx 0.12$, $0.09$ and $0.06\;$fm), ten different valence quark…

High Energy Physics - Lattice · Physics 2011-01-17 Taegil Bae , Yong-Chull Jang , Chulwoo Jung , Hyung-Jin Kim , Jongjeong Kim , Kwangwoo Kim , Weonjong Lee , Stephen R. Sharpe , Boram Yoon

We present results for the kaon mixing parameter $B_K$ obtained using improved staggered fermions on a much enlarged set of MILC asqtad lattices. Compared to our previous publication, which was based largely on a single ensemble at each of…

We present a calculation of the kaon $B$-parameter, $B_K$, using lattice QCD. We use improved staggered valence and sea fermions, the latter generated by the MILC collaboration with $N_f=2+1$ light flavors. To control discretization errors,…

The use of improved staggered actions (HYP, Asqtad) has been proved to reduce the scaling corrections that affected previous calculations of B_K with unimproved (standard) staggered fermions in the quenched approximation. This improved…

High Energy Physics - Lattice · Physics 2008-11-26 E. Gamiz , S. Collins , C. T. H. Davies , G. P. Lepage , J. Shigemitsu , M. Wingate

We present results from a calculation of beyond the standard model (BSM) kaon mixing including data physical with light quark masses. We simulate $N_f=2+1$ QCD with Iwasaki gauge and domain wall fermion action on 8 ensembles, spanning 3…

High Energy Physics - Lattice · Physics 2018-12-18 Peter Boyle , Nicolas Garron , Renwick James Hudspith , Andreas Juttner , Julia Kettle , Ava Khamseh , Justus Tobias Tsang

We give a progress report on the calculation of B meson mixing matrix elements, focusing on contributions that could arise beyond the Standard Model. The calculation uses asqtad (light quark) and Fermilab (heavy quark) valence actions and…

High Energy Physics - Lattice · Physics 2011-05-18 C. Bouchard , A. X. El-Khadra , E. D. Freeland , E. Gamiz , A. S. Kronfeld

We study the improvement of staggered fermions using hypercubically smeared (HYP) links. We calculate the strange quark mass and the kaon B-parameter, $B_K$, in quenched QCD on a $16^3 \times 64$ lattice at $\beta=6.0$. We find…

High Energy Physics - Lattice · Physics 2014-11-17 Weonjong Lee , Tanmoy Bhattacharya , George T. Fleming , Rajan Gupta , Gregory Kilcup , Stephen R. Sharpe

I describe a calculation of B meson mixing at one-loop in staggered chiral perturbation theory, for the complete set of Standard Model and beyond-the-Standard Model operators. The particular lattice representation of the continuum operators…

High Energy Physics - Lattice · Physics 2012-11-02 C. Bernard

We compute non-perturbatively the B-parameters of the complete basis of four-fermion operators needed to study the Kaon oscillations in the SM and in its supersymmetric extension. We perform numerical simulations with two dynamical…

High Energy Physics - Lattice · Physics 2010-02-10 V. Bertone , P. Dimopoulos , R. Frezzotti , V. Gimenez , V. Lubicz , F. Mescia , D. Palao , M. Papinutto , G. C. Rossi , S. Simula , A. Vladikas

A recent numerical lattice calculation of the kaon mixing matrix elements of general $\Delta S=2$ four-fermion operators using staggered fermions relied on two auxiliary theoretical calculations. Here we describe the methodology and present…

High Energy Physics - Lattice · Physics 2014-07-16 Jongjeong Kim , Weonjong Lee , Jaehoon Leem , Stephen R. Sharpe , Boram Yoon

We report on recent progress in the calculation of $B_K$ using HYP-smeared staggered fermions on the MILC asqtad lattices. Our main focus is on the continuum extrapolation, which is done using (up to) four different lattice…

We report updated results for $B_K$ calculated using HYP-smeared staggered fermions on the MILC asqtad 2+1 flavor lattices. We use four different lattice spacings ($a \approx$ 0.12, 0.09, 0.06 and 0.045 fm) to control the continuum…

We present a lattice QCD computation of the b-quark mass, the B and B_s decay constants, the B-mixing bag parameters for the full four-fermion operator basis as well as determinations for \xi and f_{Bq}\sqrt{B_i^{(q)}} extrapolated to the…

We present a preliminary calculation of B_K using domain-wall valence quarks and 2+1 flavors of improved staggered sea quarks. Both the size of the residual quark mass, which measures the amount of chiral symmetry breaking, and of the mixed…

High Energy Physics - Lattice · Physics 2011-03-23 Christopher Aubin , Jack Laiho , Ruth S. Van de Water

We report on recent progress in the calculation of $B_K$ using HYP-smeared improved staggered fermions on the MILC asqtad lattices. We have added measurements on fine ($a\sim 0.09 $fm) and superfine ($a\sim 0.06 $fm) ensembles at different…

Models of new physics induce K-Kbar mixing operators having Dirac structures other than the "left-left" form of the Standard Model. We calculate the functional form of the corresponding B-parameters at next-to-leading order in both SU(3)…

High Energy Physics - Lattice · Physics 2013-05-30 Jon A. Bailey , Hyung-Jin Kim , Weonjong Lee , Stephen R. Sharpe

We calculate the kaon B-parameter, B_K, in chiral perturbation theory for a partially quenched, mixed action theory with Ginsparg-Wilson valence quarks and staggered sea quarks. We find that the resulting expression is similar to that in…

High Energy Physics - Lattice · Physics 2014-11-17 C. Aubin , Jack Laiho , Ruth S. Van de Water
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