Wed·Aug 18, 2021Wednesday·August 18, 2021

1. 01*

   About the solution of the numerical instability for topological solitons with long range interaction

   Fabian Anmasser · Dominik Theuerkauf · Manfried Faber🇦🇹

   The computations of solutions of the field equations in the Model of Topological Particles, formulated with a scalar SU(2)-field, have shown instabilities leading to discrepancies between the numerical and analytical solutions. We identify the origin of these deviations in misalignments of the rotational axes corresponding to the SU(2) elements. The system of a single soliton we use as an example to show that a constraint suppressing the wave-like disturbances is able to lead to excellent agreement between the result of the numerical minimisation procedure and the analytical solution.

   hep-latFew Body Syst.(2021)·2 citations
2. 02*

   Mellin moments of spin dependent and independent PDFs of the pion and rho meson

   Marius Löffler🇩🇪 · Philipp Wein🇩🇪 · Thomas Wurm🇩🇪 · Simon Weishäupl🇩🇪 · Daniel Jenkins🇩🇪 · Rudolf Rödl🇩🇪 · Andreas Schäfer🇩🇪 · Lisa Walter (for the RQCD Collaboration)🇩🇪

   We compute the second moments of pion and rho parton distribution functions (PDFs) in lattice QCD with $N_f=2+1$ flavors of improved Wilson fermions. We determine both singlet and non-singlet flavor combinations and, for the first time, take disconnected contributions fully into account. In the case of the rho, we also calculate the additional contribution arising from the $b_1$ structure function. The numerical analysis includes 26 ensembles, mainly generated by the CLS effort, with pion masses ranging from 420MeV down to 214MeV and with 5 different lattice spacings in the range of 0.1fm to 0.05fm. This enables us to take the continuum limit, as well as to resolve the quark mass dependencies reliably. Additionally we discuss the contaminations of rho correlation functions by two-pion states.

   hep-latPRD(2022)·25 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.