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Oleg Loktik

Publications and source records attributed to Oleg Loktik.

5 recordsLinked to original sources
arXiv2011

One-loop operator matching in the static heavy and domain-wall light quark system with O(a) improvement

We discuss perturbative O(g^2a) matching with static heavy quarks and domain-wall light quarks for lattice operators relevant to B-meson decays and $B^0$-$\bar{B}^0$ mixing. The chiral symmetry of the light domain-wall quarks does not prohibit operator mixing at O(a) for these operators. The O(a) corrections to physical quantities are non-negligible and must be included to obtain high-precision simulation results for CKM physics. We provide results using plaquette, Symanzik, Iwasaki and DBW2 gluon actions and applying APE, HYP1 and HYP2 link-smearing for the static quark action.

hep-lat↗
arXiv2010

Neutral B-meson mixing from unquenched lattice QCD with domain-wall light quarks and static b-quarks

We demonstrate a method for calculating the neutral B-meson decay constants and mixing matrix elements in unquenched lattice QCD with domain-wall light quarks and static b-quarks. Our computation is performed on the "2+1" flavor gauge configurations generated by the RBC and UKQCD Collaborations with a lattice spacing of a approx 0.11 fm (a^-1 = 1.729 GeV) and a lattice spatial volume of approximately (1.8 fm)^3. We simulate at three different light sea quark masses with pion masses down to approximately 430 MeV, and extrapolate to the physical quark masses using a phenomenologically-motivated fit function based on next-to-leading order heavy-light meson SU(2) chiral perturbation theory. For the b-quarks, we use an improved formulation of the Eichten-Hill action with static link-smearing to increase the signal-to-noise ratio. We also improve the heavy-light axial current used to compute the B-meson decay constant to O(alpha_s p a) using one-loop lattice perturbation theory. We present initial results for the SU(3)-breaking ratios f_{B_s}/f_{B_d} and xi = f_{B_s} sqrt{B_{B_s}}/f_{B_d} sqrt{B_{B_d}}, thereby demonstrating the viability of the method. For the ratio of decay constants, we find f_{B_s}/f_{B_d} = 1.15(12) and for the ratio of mixing matrix elements, we find xi = 1.13(12), where in both cases the errors reflect the combined statistical and systematic uncertainties, including an estimate of the size of neglected O(1/m_b) effects.

hep-lat↗
arXiv2007

The Static Approximation to B Meson Mixing using Light Domain-Wall Fermions: Perturbative Renormalization and Ground State Degeneracies

We discuss the theoretical input into the current RBC-UKQCD calculation of $f_{B_{d, s}}$ and $B_{B_{d, s}}$ using a smeared static heavy quark propagator, light domain-wall quarks and the Iwasaki gauge action. We present the complete one-loop, mean-field improved matching of heavy-light current and four-fermion lattice operators onto the static continuum theory renormalized in $\bar{\text{MS}}$(NDR). The large degeneracies present in a static calculation are addressed, and a method for extracting $f_B$ and $B_B$ using only box sources is described; implications for future calculations are discussed.

hep-lat↗
arXiv2005

Lattice calculation of SU(3) flavor breaking ratios in B - anti-B mixing

We present an unquenched lattice calculation for the SU(3) flavor breaking ratios of the heavy-light decay constants and the $ΔB = 2$ matrix elements. The calculation was performed on $16^3 \times 32$ lattices with two dynamical flavors of domain-wall quarks and inverse lattice spacing $1/a = 1.69(5)$ GeV. Heavy quarks were implemented using an improved lattice formulation of the static approximation. In the infinite heavy-quark mass limit we obtain $f_{B_s}/f_{B_d} = 1.29(4)(6)$, $B_{B_s}/B_{B_d} = 1.06(6)(4)$, $ξ= 1.33(8)(8)$ where the first error is statistical and the second systematic.

hep-lat↗