Related papers: Four-quark operators in hadrons
Using the relation between the harmonic oscillator wave function and the light quark scattering form factor, the expectation values of colour-straight four-quark operators are evaluated and found to be directly proportional to the cubic…
By introducing an external spin operator to the fermion action, the quark spin fractions of hadrons are determined from the linear response of the hadron energies using the Feynman-Hellmann (FH) theorem. At our SU(3)-flavour symmetric…
The B-$\bar B$ mixing, B-meson lifetimes, the $B_{s}$-$\bar{B}_{s}$ lifetime difference and SUSY FCNC effects in $\Delta B=2$ processes are very important measurable quantities in B-meson phenomenology whose theoretical predictions depend…
We study efficiency of higher order integrator schemes for the hybrid Monte Carlo (HMC) algorithm. Numerical tests are performed for Quantum Chromo Dynamics (QCD) with two flavors of Wilson fermions. We compare 2nd, 4th and 6th order…
Physics from beyond the Standard Model, such as leptoquarks, can induce four fermion operators involving a quark, an anti-quark, a lepton and an anti-lepton. We update the (flavour dependent) constraints on the coefficients of such…
We look at the contribution of Quark-Mass-dependent twist-4 operators to the second moments of spin averaged structure functions and the Bjorken sum rule. Its contribution is non-negligible in the former case due to large Wilson…
We review two lattice calculations involving charm hadrons: a determination of the vector and scalar form factors of the semileptonic $D \to \pi \ell \nu$ decays, which are relevant for the extraction of the CKM matrix element $\lvert…
We study the light-quark mass and spatial volume dependence of the matrix elements of $\Delta B=0$ four-quark operators relevant for the determination of $V_{ub}$ and the lifetime ratios of single-$b$ hadrons. To this end, one-loop diagrams…
We present the status of a lattice calculation for the K-->pipi matrix elements of the (delta S=1) effective weak Hamiltonian, directly with two pion in the final state. We study the energy shift of two pion in a finite volume both in the…
We show how to compute electromagnetic polarizabilities of charged hadrons using four-point functions in lattice QCD. The low-energy behavior of Compton scattering amplitude is matched to matrix elements of current-current correlation…
The renormalization factor and O(a) improvement coefficient of four-quark operators are calculated perturbatively for the improved Wilson fermion action with clover term and the Iwasaki gauge action. With an application to the $K\to\pi\pi$…
This talk summarizes the status of the calculations of $B_K$, $B_7$, $B_8$, and $B_s$, done in collaboration with T. Bhattacharya, G. Kilcup, and S. Sharpe. Results for staggered, Wilson, and Clover fermions are presented.
Status report is made of our quenched study of heavy-light matrix elements employing the Wilson quark action for heavy quark. Results obtained up to now with 200 configurations at $\beta=6.1$ on a $24^3\times64$ lattice and with 100…
Heavy quark expansion can nicely explain the lifetime of $\Lambda_{b}$. However, there still exist sizable uncertainties from the four-quark operator matrix elements of $\Lambda_{b}$ in $1/m_{b}^{3}$ corrections, which describe the…
We present results of a lattice simulation of quantum chromodynamics with two degenerate flavors of dynamic Wilson fermions at $6/g^2=5.3$ at each of two dynamical fermion hopping parameters, $\kappa=0.1670$ and 0.1675, corresponding to…
We have technically improved the non-perturbative renormalization method, proposed by Martinelli et al., by using quark momentum sources and sinks. Composite two-fermion operators up to three derivatives have been measured for Wilson…
Numerical simulations of processes of three and four top quark hadroproduction are carried out in the SMEFT model framework. The simulated data are used to derive expected theoretical constraints on Wilson coefficients of relevant SMEFT…
We compute the hadronic matrix elements of the four-quark operators needed for the study of $K^0-{\bar K^0}$ mixing beyond the Standard Model. We have used $n_f=2+1$ flavours of domain wall fermion (DWF) at two values of the lattice spacing…
It has been suggested to use the production of Lambda hyperons for investigating the nucleon spin structure. The viability of this idea depends crucially on the spin structure of the Lambda. Using nonperturbatively O(a) improved Wilson…
Renormalization factors of four-quark operators are perturbatively calculated for the improved Wilson fermion with clover term and the Iwasaki gauge action. A main application shall be the $K\to\pi\pi$ decay amplitude and the calculation is…