相关论文: Hadronic contribution to g-2 from twisted mass fer…
We study isospin-1 P-wave $\pi\pi$ scattering in lattice QCD with two flavours of O($a$) improved Wilson fermions. For pion masses ranging from $m_\pi=265$ MeV to $m_\pi=437$ MeV, we determine the energy spectrum in the centre-of-mass frame…
Knowledge of the electric polarizability is crucial to understanding the interactions of hadrons with electromagnetic fields. The neutron polarizability is very sensitive to the quark mass and is expected to diverge in the chiral limit.…
Polarizabilities reveal valuable information on the internal structure of hadrons in terms of charge and current distributions. For neutral hadrons, the standard approach is the background field method. But for a charged hadron, its…
The Boer-Mulders transverse momentum-dependent parton distribution (TMD) characterizes polarized quark transverse momentum in an unpolarized hadron. Techniques previously developed for lattice calculations of nucleon TMDs are applied to the…
We present a lattice calculation of the Euclidean position-space windows contributing to the leading-order hadronic vacuum polarization term of the muon anomalous magnetic moment $a_\mu$. Short-, intermediate- and long-distance windows are…
The anomalous magnetic moment of the muon, $g_\mu-2$, is one of the most promising observables to identify hints for physics beyond the Standard Model. QCD contributions are currently responsible for the largest fraction of the overall…
We present the status of the MUonE experimental proposal which aims at determining the leading order hadronic contribution to the muon g-2 by measuring the hadronic part of the photon vacuum polarization in the spacelike region. The…
We compare overlap fermions, which are chirally invariant, and Wilson twisted mass fermions in the approach to the chiral limit. Our quenched simulations reveal that with both formulations of lattice fermions pion masses of O(250 MeV) can…
We review the present status of the theoretical evaluation of the anomalous magnetic moment of the the muon within the Standard Model. We mainly focus on the hadronic contributions in the muon g-2 due to vacuum polarization effects,…
We review and compare recent calculations of hadronic vacuum polarization effects. In particular, we consider the anomalous magnetic moments g-2 of the leptons and alpha(M_Z), the effective fine structure constant at the Z--resonance.
We present an update on the ongoing calculations by the Fermilab Lattice, HPQCD, and MILC Collaboration of the leading-order (in electromagnetism) hadronic vacuum polarization contribution to the anomalous magnetic moment of the muon. Our…
We calculate the electromagnetic form factor of the pion in quenched lattice QCD. The non-perturbatively improved Sheikoleslami-Wohlert lattice action is used together with the consistently O(a) improved current. We calculate the pion form…
We present results for Monte Carlo calculations of the electromagnetic vector and scalar form factors of the pion in a quenched simulation. We work at a lattice spacing of 0.15 fm and use two lattice volumes up to a spatial size of 2.4 fm.…
This work presents a complete re-evaluation of the hadronic vacuum polarisation contributions to the anomalous magnetic moment of the muon, $a_{\mu}^{\rm had, \, VP}$ and the hadronic contributions to the effective QED coupling at the mass…
I suggest a new approach to the determination of the hadronic vacuum polarization (HVP) contribution to the anomalous magnetic moment of the muon $a_{\mu}^{\rm HVP}$ in lattice QCD. It is based on properties of the Mellin transform of the…
We present a high-statistics lattice QCD determination of the valence parton distribution function (PDF) of the pion, with a mass of 300 MeV, using two very fine lattice spacings of $a=0.06$ fm and 0.04 fm. We reconstruct the $x$-dependent…
We summarise status and recent results of the European Twisted Mass collaboration (ETMC). The collaboration has generated gauge configurations for three different values of the lattice spacing smaller or equal 0.1 fm and values of the…
We present a comprehensive investigation of light meson physics using maximally twisted mass fermions for two mass-degenerate quark flavours. By employing four values of the lattice spacing, spatial lattice extents ranging from 2.0 fm to…
Measurements and theoretical calculations of meson form factors are essential for our understanding of internal hadron structure and QCD, the dynamics that bind the quarks in hadrons. The pion electromagnetic form factor has been measured…
The leading-order hadronic contribution to the muon anomalous magentic moment, $a_\mu^{\rm LO,HVP}$, can be expressed as an integral over Euclidean $Q^2$ of the vacuum polarization function. We point out that a simple trapezoid-rule…