arXiv subjects

Marcus Petschlies

Publications and source records attributed to Marcus Petschlies.

59 records · Page 4Linked to original sources

arXiv2011

Charm Current-Current Correlators in Twisted Mass Lattice QCD

The current correlator method has been shown to be a practical tool to extract the charm quark mass and strong coupling constant from Lattice QCD data as an alternative to the sum rule approach using experimental electron-positron annihilation cross section data. We report on the progress of an investigation of charm current-current correlators in N_f=2 Twisted Mass Lattice QCD. Upon determining the temporal moments of the current correlators we compare to the low-energy expansion of the moments in perturbative QCD and calculate the charm quark mass and strong coupling constant and in case of the vector current correlator directly compare both methods.

hep-lat↗

arXiv2011

Two-flavor QCD correction to lepton magnetic moments at leading-order in the electromagnetic coupling

We present a reliable nonperturbative calculation of the QCD correction, at leading order in the electromagnetic coupling, to the anomalous magnetic moment of the electron, muon, and tau leptons using two-flavor lattice QCD. We use multiple lattice spacings, multiple volumes, and a broad range of quark masses to control the continuum, infinite-volume, and chiral limits. We examine the impact of the commonly ignored disconnected diagrams and introduce a modification to the previously used method that results in a well-controlled lattice calculation. We obtain 1.513(43) 10^(-12), 5.72(16) 10^(-8), and 2.650(54) 10^(-6) for the leading-order two-flavor QCD correction to the anomalous magnetic moment of the electron, muon, and tau, respectively, each accurate to better than 3%.

hep-lat↗

arXiv2011

Leading-order hadronic contribution to g-2 from lattice QCD

We calculate the leading-order hadronic correction to the anomalous magnetic moments of each of the three charged leptons in the Standard Model: the electron, muon and tau. Working in two-flavor lattice QCD, we address essentially all sources of systematic error: lattice artifacts, finite-size effects, quark-mass extrapolation, momentum extrapolation and disconnected diagrams. The most significant remaining systematic error, the exclusion of the strange and charm quark contributions, will be addressed in our four-flavor calculation. We achieve a statistical accuracy of 2% or better for the physical values for each of the three leptons and the systematic errors are at most comparable.

hep-lat↗

arXiv2010

Pseudoscalar decay constants from N_f=2+1+1 twisted mass lattice QCD

We present first results for the pseudoscalar decay constants $f_K$, $f_D$ and $f_{D_s}$ from lattice QCD with N_f=2+1+1 flavours of dynamical quarks. The lattice simulations have been performed by the European Twisted Mass collaboration (ETMC) using maximally twisted mass quarks. For the pseudoscalar decay constants we follow a mixed action approach by using so called Osterwalder-Seiler fermions in the valence sector for strange and charm quarks. The data for two values of the lattice spacing and several values of the up/down quark mass is analysed using chiral perturbation theory.

hep-lat↗

arXiv2010

Leading order hadronic contribution to g-2 from twisted mass QCD

We calculate the leading order hadronic contribution to the muon anomalous magnetic moment using twisted mass lattice QCD. The pion masses range from 330 MeV to 650 MeV. We use two lattice spacings, a=0.079 fm and 0.063 fm, to study lattice artifacts. Finite-size effects are studied for two values of the pion mass, and we calculate the disconnected contributions for four ensembles. Particular attention is paid to the dominant contributions of the vector mesons, both phenomenologically and from our lattice calculation.

hep-lat↗