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Related papers: Calculation of BSM Kaon B-parameters using Stagger…

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We demonstrate the viability of improved staggered light quarks in studies of heavy-light systems. Our method for constructing heavy-light operators exploits the close relation between naive and staggered fermions. The new approach is…

High Energy Physics - Lattice · Physics 2009-11-07 Matthew Wingate , Junko Shigemitsu , Christine T. H. Davies , G. Peter Lepage , Howard D. Trottier

We calculate the bag parameters for neutral $B$-meson mixing in and beyond the Standard Model, in full four-flavour lattice QCD for the first time. We work on gluon field configurations that include the effect of $u$, $d$, $s$ and $c$ sea…

High Energy Physics - Lattice · Physics 2019-12-04 R. J. Dowdall , C. T. H. Davies , R. R. Horgan , G. P. Lepage , C. J. Monahan , J. Shigemitsu , M. Wingate

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 progress on an ongoing calculation of the $B_s\to D_s^{(*)} l \nu$ form factors calculated on the $n_f=2+1+1$ MILC ensembles and using the Highly Improved Staggered Quark action for all valence quarks. We perform the calculation…

High Energy Physics - Lattice · Physics 2019-01-16 E. McLean , C. T. H. Davies , A. T. Lytle , J. Koponen

We calculate the neutral kaon mixing parameter B_K in unquenched lattice QCD using asqtad-improved staggered sea quarks and domain-wall valence quarks. We use the "2+1" flavor gauge configurations generated by the MILC Collaboration, and…

High Energy Physics - Lattice · Physics 2010-04-28 C. Aubin , Jack Laiho , Ruth S. Van de Water

We calculate---for the first time in three-flavor lattice QCD---the hadronic matrix elements of all five local operators that contribute to neutral $B^0$- and $B_s$-meson mixing in and beyond the Standard Model. We present a complete error…

We present our results of lattice calculations of $B$ parameters, which parameterize $\Delta B$=2 transition amplitudes together with the leptonic decay constant. Calculations are made in the quenched approximation at $\beta$=5.7, 5.9, 6.0…

We present an update of the MILC studies of the physics of light pseudoscalars using improved staggered fermions. New runs at lighter quark mass, as well as increased statistics for older sets, are enabling us to improve the results for…

We give the first accurate results for $B$ and $B_s$ meson masses from lattice QCD including the effect of $u$, $d$ and $s$ sea quarks, and we improve an earlier value for the $B_c$ meson mass. By using the Highly Improved Staggered Quark…

A status report on the theory and phenomenology of rare radiative $B$ decays in the standard model is presented with emphasis on the measured decays $B \to X_s \gamma$ and $B \to K^* \gamma$. Standard model is in agreement with experiments…

High Energy Physics - Phenomenology · Physics 2007-05-23 Ahmed Ali

We calculate one-loop matching factors for bilinear operators composed of improved staggered fermions. We compare the results for different improvement schemes used in the recent literature, all of which involve the use of smeared links.…

High Energy Physics - Lattice · Physics 2009-11-07 Weonjong Lee , Stephen R. Sharpe

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…

High Energy Physics - Lattice · Physics 2011-11-08 N. Carrasco , V. Gimenez , P. Dimopoulos , R. Frezzotti , D. Palao , G. C. Rossi , V. Lubicz , M. Papinutto , F. Sanfilippo , S. Simula

We present an update of the MILC investigation of the properties of light pseudoscalar mesons using three flavors of improved staggered quarks. Results are presented for the $\pi$ and $K$ leptonic decay constants, the CKM matrix element…

We study the $B \to K^{(\ast)} \nu \bar{\nu}$ decays within the Standard Model (SM) by using the relevant transition form factors obtained from the covariant confined quark model (CCQM) developed by us. The $B \to K$ and $B\to K^\ast$…

High Energy Physics - Phenomenology · Physics 2023-05-17 Aidos Issadykov , Mikhail A. Ivanov

A brief review of the current state of observed deviations of theoretical predictions from experimental data in semileptonic decays of $B$ and $B_c$ mesons is given. A theoretical analysis of these decays is carried out, taking into account…

High Energy Physics - Phenomenology · Physics 2023-07-19 Aidos Issadykov , Mikhail A. Ivanov

We calculate for the first time all four-quark hadronic matrix elements of local operators possibly contributing to $K\to\pi\pi$ decays and in particular to the ratio $\epsilon'/\epsilon$ beyond the Standard Model (BSM). To this end we use…

High Energy Physics - Phenomenology · Physics 2019-02-20 Jason Aebischer , Andrzej J. Buras , Jean-Marc Gerard

We present results for one-loop perturbative matching factors using bilinear operators composed of improved staggered fermions, using unimproved (Wilson) and improved (Symanzik, Iwasaki, and DBW2) gluon actions. We consider two fermions…

High Energy Physics - Lattice · Physics 2012-01-25 Jongjeong Kim , Weonjong Lee , Stephen R. Sharpe

We report on the calculation of the kaon B-parameter using two dynamical flavours of domain wall fermions. Our analysis is based on three ensembles of configurations, each consisting of about 5,000 HMC trajectories, with a lattice spacing…

High Energy Physics - Lattice · Physics 2007-05-23 Chris Dawson

We compute O(alpha_s) lattice-to-continuum perturbative matching coefficients for the Delta S=2 flavor changing four-quark operators for the Asqtad improved staggered action. In conjunction with lattice simulations with three flavors of…

High Energy Physics - Lattice · Physics 2008-11-26 Thomas Becher , Elvira Gamiz , Kirill Melnikov

We report on the status of our calculation of the hadronic matrix elements for neutral $B$-meson mixing with asqtad sea and valence light quarks and using the Wilson clover action with the Fermilab interpretation for the $b$ quark. We…

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