10 papers found.

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Quantum field theories at finite matter densities generically possess a partition function that is exponentially suppressed with the volume compared to that of the phase quenched analog. The smallness arises from an almost uniform distribution for the phase of the fermion determinant. Large cancellations upon integration is the origin of a poor signal to noise ratio. We study three ...

We compute the renormalisation factors (Z-matrices) of the ΔF = 2 four-quark operators needed for Beyond the Standard Model (BSM) kaon mixing. We work with n f = 2+1 flavours of Domain-Wall fermions whose chiral-flavour properties are essential to maintain a continuum-like mixing pattern. We introduce new RI-SMOM renormalisation schemes, which we argue are better behaved compared ...

QCD at finite densities of heavy quarks is investigated using the density-of-states method. The phase factor expectation value of the quark determinant is calculated to unprecedented precision as a function of the chemical potential. Results are validated using those from a reweighting approach where the latter can produce a significant signal-to-noise ratio. We confirm the ...

We compute the hadronic matrix elements of the four-quark operators relevant for \( {K}^0-{\overline{K}}^0 \) mixing beyond the Standard Model. Our results are from lattice QCD simulations with n f = 2 + 1 flavours of domain-wall fermion, which exhibit continuum-like chiral-flavour symmetry. The simulations are performed at two different values of the lattice spacing (a ∼ 0.08 and ...

We study the heavy quark mass dependence of selected observables constructed from heavy-light meson correlation functions in small-volume two-flavour lattice QCD after taking the continuum limit. The light quark mass is tuned to zero, whereas the range of available heavy quark masses m h covers a region extending from around the charm to beyond the bottom quark mass scale. This ...

We present two-flavor lattice QCD estimates of the hadronic couplings \(g_{B^*_0 B \pi }\) and \(g_{B_1^* B_0^* \pi }\) that parametrize the non-leptonic decays \(B^*_0 \rightarrow B \pi \) and \(B^*_1 \rightarrow B_0^* \pi \). We use CLS two-flavor gauge ensembles. Our framework is the Heavy Quark Effective Theory (HQET) in the static limit and solving a Generalized Eigenvalue ...

We report on a non-perturbative determination of the parameters of the lattice Heavy Quark Effective Theory (HQET) Lagrangian and of the time component of the heavy-light axial-vector current with N f = 2 flavors of massless dynamical quarks. The effective theory is considered at the 1/m h order, and the heavy mass m h covers a range from slightly above the charm to beyond the ...

We determine non-perturbatively the parameters of the lattice HQET Lagrangian and those of the time component of the heavy-light axial-vector current in the quenched approximation. The HQET expansion includes terms of order 1/m b. Our results allow to compute, for example, the heavy-light spectrum and B-meson decay constants in the static approximation and to order 1/m b in HQET. ...

We report on the computation of the Bs meson decay constant in Heavy Quark Effective Theory on the lattice. The next to leading order corrections in the HQET expansion are included non-perturbatively. We estimate higher order contributions to be very small. The results are extrapolated to the continuum limit, the main systematic error affecting the computation is therefore the ...

Using Heavy Quark Effective Theory with non-perturbatively determined parameters in a quenched lattice calculation, we evaluate the splittings between the ground state and the first two radially excited states of the Bs system at static order. We also determine the splitting between first excited and ground state, and between the B s * and Bs ground states to order 1/m b . The ...