Related papers: How much do charm sea quarks affect the charmonium…
In charged current deep inelastic scattering charm is dominantly produced in scattering events on strange quarks, thereby allowing for an experimental determination of the nucleon's strange sea density. A measurement of the energy spectrum…
Lattice quantum chromodynamics provides first principles calculations for hadrons containing heavy quarks -- charm and bottom quarks. Their mass spectra, decay rates, and some hadronic matrix elements can be calculated on the lattice in a…
The spin-singlet P-wave state of charmonium, hc(1P1), has been observed in the decay psi(2S) -> pi0 hc followed by hc -> gamma etac. Inclusive and exclusive analyses of the M(hc) spectrum have been performed. Two complementary inclusive…
Hyperfine interactions in the light meson and baryon sectors are generalized to the charm and bottom systems. It is pointed out that an attempt to increase the value of the wave function at the origin to account for the unusual ratio of…
We report here our lattice simulation on the charmonium spectra in the quenched approximation. Because the full adjustment on the nonperturbative parameters such as $C_E$, $C_B$, $m_0a_s$ and $r_s$ needs many calculation time, we only…
We present results of lattice QCD simulations with mass-degenerate up and down and mass-split strange and charm (Nf=2+1+1) dynamical quarks using Wilson twisted mass fermions at maximal twist. The tuning of the strange and charm quark…
We report on an estimate of \alpha_s, renormalised in the MSbar scheme at the tau and Z^0 mass scales, by means of lattice QCD. Our major improvement compared to previous lattice calculations is that, for the first time, no perturbative…
We use overlap fermions as valence quarks to calculate meson masses in a wide quark mass range on the $2+1$-flavor domain-wall fermion gauge configurations generated by the RBC and UKQCD Collaborations. The well-defined quark masses in the…
We present results from an ongoing lattice study of the lowest lying charmonium and bottomonium level splittings using the Fermilab heavy quark formalism. Our objective is to test the performance of this action on MILC-collaboration…
We present results for the static energy in ($2+1+1$)-flavor QCD over a wide range of lattice spacings and several quark masses, including the physical quark mass, with ensembles of lattice-gauge-field configurations made available by the…
In this work, the charm quark mass is obtained from a QCD sum rule analysis of the charmonium system. In our investigation we include results from non-relativistic QCD at next-to-next-to-leading order. Using the pole mass scheme, we obtain…
We discuss the internal structure of radially excited charmonium mesons based on the equal-time and Coulomb gauge Bethe-Salpeter (BS) amplitudes, which are obtained in lattice QCD. Our simulations are performed with a relativistic…
Charmonium is an attractive system for the application of lattice QCD methods. While the sub-threshold spectrum has been considered in some detail in previous works, it is only very recently that excited and higher-spin states and further…
The process of charm quark fragmentation is studied using $D^{*\pm}$ meson production in deep-inelastic scattering as measured by the H1 detector at HERA. Two different regions of phase space are investigated defined by the presence or…
The presence of strange sea quark pairs may have a significant impact of the pattern of chiral symmetry breaking : in particular large differences can occur between the chiral limits of two and three massless flavours (i.e., whether $m_s$…
Dependence of a/r_c (inverse Sommer parameter in units of lattice spacing a) on am_q (quark mass in lattice unit) has been observed in all lattice QCD simulations with sea quarks including the ones with improved actions. How much of this…
We study charmonium properties at non-zero temperature in the temperature range 153 MeV $<T<$ 305 MeV using lattice QCD. We use HISQ action for dynamical quarks and Wilson clover action for valence charm quarks and calculate the correlation…
We present the results of a partially quenched lattice QCD calculation of light quark masses with $N_f=2$ degenerate dynamical flavors. Numerical simulations are carried out using the plaquette gauge action and the Wilson quark action at…
We outline a strategy to efficiently include the electromagnetic interactions of the sea quarks in QCD+QED. When computing iso-spin breaking corrections to hadronic quantities at leading order in the electromagnetic coupling, the sea-quark…
We present a progress report on our calculation of the decay constants $f_B$ and $f_{B_s}$ from lattice-QCD simulations with highly-improved staggered quarks. Simulations are carried out with several heavy valence-quark masses on…