Towards a precise lattice determination of the leading hadronic contribution to (g-2)_mu

por Michele della Morte (Universität Mainz (Germany))

martes 24 jul. 2012 12:00 → 13:00 Europe/Madrid

Sala Seminarios IFIC (Edf. Institutos de Investigación)

We report on a recent computation of the leading hadronic contribution to the anomalous magnetic moment of the muon using two dynamical flavours of non-perturbatively O(a) improved Wilson fermions. The strange quark is introduced in the quenched approximation. Partially twisted boundary conditions are applied to improve the momentum resolution in the relevant convolution integral. Our results, obtained at three different values of the lattice spacing allow for a preliminary study of discretization effects. We explore a wide range of lattice volumes, namely 2.2 fm < L < 3.3 fm, with pion masses from 580 to 250 MeV and discuss different chiral extrapolations to the physical point. We observe a non-trivial dependence of a mu^{HLO} on m_pi especially for small pion masses. Our result is obtained by considering the quark connected contribution only to the vacuum polarization (as all other existing ones from the lattice), and therefore has an uncertainty which can be estimated around 10%. It will be discussed in some detail how such an estimate can be obtained in Chiral Perturbation Theory