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We compute the spectrum of the low-lying mesonic states with vector, scalar and pseudoscalar quantum numbers in QCD with one flavour. With three colours the fundamental and the two-index anti-symmetric representations of the gauge group coincide. The latter is an orientifold theory that maps into the bosonic sector of $\mathcal{N} = 1$ super Yang-Mills theory in the large number of colours limit. We employ Wilson fermions along with tree-level improvement in the gluonic and fermionic parts of the action. In this setup the Dirac operator can develop real negative eigenvalues. We therefore perform a detailed study in order to identify configurations where the fermion determinant is negative and eventually reweight them. We finally compare results with effective field theory predictions valid in the large $N_C$ limit and find reasonably consistent values despite $N_C$ being only three. Additionally,the spin-one sector provides a novel window for supersymmetric dynamics., Version accepted and published by PRD (Phys. Rev. D 107, 114506)

We present results of calculations of the hadronic vacuum polarisation contribution to the muon anomalous magnetic moment. Specifically, we focus on controlling the infrared regime of the vacuum polarisation function. Our results are corrected for finite-size effects by combining the Gounaris-Sakurai parameterisation of the timelike pion form factor with the Lüscher formalism. The impact of quark-disconnected diagrams and the precision of the scale determination is discussed and included in our final result in two-flavour QCD, which carries an overall uncertainty of 6%. We present preliminary results computed on ensembles with N f = 2 + 1 dynamical flavours and discuss how the long-distance contribution can be accurately constrained by a dedicated spectrum calculation in the iso-vector channel.

We nonperturbatively determine the renormalization factor of the axial vector current in lattice QCD with Nf=3 flavors of Wilson-clover fermions and the tree-level Symanzik-improved gauge action. The (by now standard) renormalization condition is derived from the massive axial Ward identity, and it is imposed among Schrödinger functional states with large overlap on the lowest lying hadronic state in the pseudoscalar channel, in order to reduce kinematically enhanced cutoff effects. We explore a range of couplings relevant for simulations at lattice spacings of ≈0.09 fm and below. An interpolation formula for ZA(g02), smoothly connecting the nonperturbative values to the 1-loop expression, is provided together with our final results.

We present a study of the B spectrum performed in the framework of Heavy Quark Effective Theory expanded to next-to-leading order in 1/m and non-perturbative in the strong coupling. Our analyses have been performed on Nf=2 lattice gauge field ensembles corresponding to three different lattice spacings and a wide range of pion masses. We obtain the Bs-meson mass and hyperfine splittings of the B- and Bs-mesons that are in good agreement with the experimental values and examine the mass difference m_{Bs}-m_B as a further cross-check of our previous estimate of the b-quark mass. We also report on the mass splitting between the first excited state and the ground state in the B and Bs systems.

We report our final estimate of the b-quark mass from Nf=2 lattice QCD simulations using Heavy Quark Effective Theory non-perturbatively matched to QCD at O(1/mh). Treating systematic and statistical errors in a conservative manner, we obtain m¯bMS¯(2 GeV)=4.88(15) GeV after an extrapolation to the physical point.

Bernardoni, Fabio et al., We report our final estimate of the b-quark mass from Nf=2 lattice QCD simulations using Heavy Quark Effective Theory non-perturbatively matched to QCD at O(1/mh). Treating systematic and statistical errors in a conservative manner, we obtain View the MathML source after an extrapolation to the physical point., This work is supported in part by the SFB/TR 9, by grant HE 4517/2-1 (P.F. and J.H.) and HE 4517/3-1 (J.H.), of the Deutsche Forschungsgemeinschaft, and by the European Community through EU Contract MRTN-CT-2006-035482, “FLAVIAnet”. It was also partially supported by the Spanish Minister of Education and Science project RyC-2011-08557 (M.D.M.). P.F. and R.S. thank the ECT* in Trento for support during the workshop “Beautiful Mesons and Baryons on the Lattice”. We thank our colleagues in the CLS effort for the joint production and use of gauge configurations. We gratefully acknowledge the computer resources granted by the John von Neumann Institute for Computing (NIC) and provided on the supercomputer JUROPA at Jülich Supercomputing Centre (JSC) and by the Gauss Centre for Supercomputing (GCS) through the NIC on the GCS share of the supercomputer JUQUEEN at JSC, with funding by the German Federal Ministry of Education and Research (BMBF) and the German State Ministries for Research of Baden–Württemberg (MWK), Bayern (StMWFK) and Nordrhein–Westfalen (MIWF), as well as within the Distributed European Computing Initiative by the PRACE-2IP, with funding from the European Community's Seventh Framework Programme (FP7/2007–2013) under grant agreement RI-283493, by the Grand Équipement National de Calcul Intensif at CINES in Montpellier under the allocation 2012-056808, by the HLRN in Berlin, and by NIC at DESY, Zeuthen.

We report on our ongoing project to calculate the leading hadronic contribution to the anomalous magnetic moment of the muon a_mu^HLO using two dynamical flavours of non-perturbatively O(a) improved Wilson fermions. In this study, we changed the vacuum polarisation tensor to a combination of local and point-split currents which significantly reduces the numerical effort. Partially twisted boundary conditions allow us to improve the momentum resolution of the vacuum polarisation tensor and therefore the determination of the leading hadronic contribution to (g-2)_mu. We also extended the range of ensembles to include a pion mass below 200 MeV which allows us to check the non-trivial chiral behaviour of a_mu^HLO., 7 pages, 3 figures, 1 table, talk presented at the 30th International Symposium on Lattice Field Theory (Lattice2012), Cairns, Australia

A non perturbative method to compute the mass of the b quark including the 1/m term in HQET has been presented in a companion talk. Following this strategy, we find in the MS bar scheme m_b^{stat}(m_b) = 4.350(64) GeV for the leading term, and m_b^{(1)}(m_b) = -0.049(29) GeV for the next to leading order correction. This method involves several steps, including the simulation of the relativistic theory in a small volume, and of the effective theory in a big volume. Here we present some numerical details of our calculations., 7 pages, 5 figures, talk presented at Lattice 2005 (Heavy quark physics), PoS style. Add reference to hep-lat/0510048

We consider HQET including the first order correction in 1/m. A strategy for the computation of the b-quark mass is discussed. Only two quantities Phi_1/2 have to be considered in order to match QCD and HQET, since the spin-dependent interaction is easily eliminated due to the spin symmetry of the static theory. Quite simple formulae relate the renormalization group invariant b-quark mass (M_b) to the B-meson mass. All entries in these formulae are non-perturbatively defined and can be computed in the continuum limit of the lattice regularized theory. For the numerically most critical part, we illustrate the cancellation of power divergences by a numerical example. Numerical results for the 1/m correction to M_b, are presented in a companion talk., Talk presented at Lattice 2005 (Heavy quark physics), 5 pages

The coefficient c_A required for O(a) improvement of the axial current in lattice QCD with N_f=3 flavors of Wilson fermions and the tree-level Symanzik-improved gauge action is determined non-perturbatively. The standard improvement condition using Schroedinger functional boundary conditions is employed at constant physics for a range of couplings relevant for simulations at lattice spacings of ~ 0.09 fm and below. We define the improvement condition projected onto the zero topological charge sector of the theory, in order to avoid the problem of possibly insufficient tunneling between topological sectors in our simulations at the smallest bare coupling. An interpolation formula for c_A(g_0^2) is provided together with our final results., Comment: 16 pages including figures and tables, latex2e; version published in Nucl. Phys. B, small additions to the text and references added, results unchanged

We present a calculation of the hadronic vacuum polarization contribution to the muon anomalous magnetic moment, aμhvp, in lattice QCD employing dynamical up and down quarks. We focus on controlling the infrared regime of the vacuum polarization function. To this end we employ several complementary approaches, including Padé fits, time moments and the time-momentum representation. We correct our results for finite-volume effects by combining the Gounaris-Sakurai parameterization of the timelike pion form factor with the Lüscher formalism. On a subset of our ensembles we have derived an upper bound on the magnitude of quark-disconnected diagrams and found that they decrease the estimate for aμhvp by at most 2%. Our final result is ahvpμ=(654±32+21−23)·10−10, where the first error is statistical, and the second denotes the combined systematic uncertainty. Based on our findings we discuss the prospects for determining aμhvp with sub-percent precision., Journal of High Energy Physics, 2017 (10), ISSN:1126-6708, ISSN:1029-8479