arXiv subjects

Konstantin Ottnad

Publications and source records attributed to Konstantin Ottnad.

78 records · Page 5Linked to original sources

arXiv2013

Investigating a mixed action approach for η and η' mesons in Nf=2+1+1 lattice QCD

We present results for a test of a mixed action approach with Osterwalder-Seiler valence quarks on a Wilson twisted mass sea for the example η, η' mesons. Flavour singlet pseudoscalar mesons obtain significant contributions from disconnected diagrams and are, therefore, expected to be particularly sensitive to mixed regularisations. We employ different procedures for matching valence and sea quark actions and show that the results agree in the continuum limit.

hep-lat↗

arXiv2013

η and η' masses and decay constants from lattice QCD with 2+1+1 quark flavours

We investigate the masses and decay constants of eta and eta' mesons using the Wilson twisted mass formulation with N_f=2+1+1 dynamical quark flavours based on gauge configurations of ETMC. We show how to efficiently subtract excited state contributions to the relevant correlation functions and estimate in particular the eta' mass with improved precision. After investigating the strange quark mass dependence and the continuum and chiral extrapolations, we present our results for masses and mixing angle(s) at the physical point. Using chiral perturbation theory we also extract the decay constants f_l and f_s and use them to estimate the decay widths of eta,η' to gamma gamma and the transition form factor in the limit of large momentum transfer.

hep-lat↗

arXiv2013

η and η' mixing from Lattice QCD

We present a lattice QCD computation of $η$ and $η^\prime$ masses and mixing angles, for the first time controlling continuum and quark mass extrapolations. The results for the eta mass 551(8)(6) MeV (first error statistical, second systematic) and the eta' mass 1006(54)(38)(+61) MeV (third error from our method) are in excellent agreement with experiment. Our data show that the mixing in the quark flavour basis can be described by a single mixing angle of 46(1)(3) degree indicating that the eta' is mainly a flavour singlet state.

hep-lat↗

arXiv2013

Properties of pseudoscalar flavour-singlet mesons from 2+1+1 twisted mass lattice QCD

We study properties of pseudoscalar flavour-singlet mesons from Wilson twisted mass lattice QCD with Nf=2+1+1 dynamical quark flavors. Results for masses are presented at three values of the lattice spacing and light quark masses corresponding to values of the pion mass from 230 MeV to 500 MeV. We briefly discuss scaling effects and the light and strange quark mass dependence of the eta mass. In addition we present an exploratory study using Osterwalder-Seiler type strange and charm valence quarks. This approach avoids some of the complications of the twisted mass heavy doublet. We present first results for matching valence and unitary actions and a comparison of statistical uncertainties.

hep-lat↗

arXiv2013

Determination of Low-Energy Constants of Wilson Chiral Perturbation Theory

By matching Wilson twisted mass lattice QCD determinations of pseudoscalar meson masses to Wilson Chiral Perturbation Theory we determine the low-energy constants $W'_6$, $W'_8$ and their linear combination $c_2$. We explore the dependence of these low-energy constants on the choice of the lattice action and on the number of dynamical flavours.

hep-lat↗

arXiv2011

Eta and eta' meson masses from Nf=2+1+1 twisted mass lattice QCD

We determine mass and flavour content of eta and eta' states using Nf=2+1+1 Wilson twisted mass lattice QCD. We describe how those flavour singlet states need to be treated in this lattice formulation. Results are presented for two values of the lattice spacing, a~0.08 fm and a~0.09 fm, with a range of light quark masses corresponding to values of the pion mass from 270 to 500 MeV and fixed bare strange and charm quark mass values.

hep-lat↗