相关论文: The Vacuum Polarization: Power Corrections beyond …
We have reported elsewhere in this conference on our continuing project to determine non-perturbative Wilson coefficients on the lattice, as a step towards a completely non-perturbative determination of the nucleon structure. In this talk…
We study the simultaneous effect of finite volume and finite lattice spacing corrections in the framework of chiral perturbation theory (ChPT) in the epsilon regime, for both the Wilson and staggered formulations. In particular the finite…
The vacuum--polarization contributions of ${\cal O}(b^{n-1} \al_s^n)$ to the relation between the pole--mass $M$ of a quark and the \MS parameter $\mh (M)$ are evaluated by a straightforward method. They are found to approximate very well…
We study a systematic improvement of perturbation theory for gauge fields on the lattice; the improvement entails resumming, to all orders in the coupling constant, a dominant subclass of tadpole diagrams. This method, originally proposed…
We consider electroweak (EW) virtual corrections to $2\to 2$ fermion scattering processes mediated by a vector boson $V$ ($V=W^\pm,Z$) in the pole approximation. As is well known, the computation can be organised into factorisable and…
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…
We present new results for light quark masses. The calculations are performed using two flavours of $O(a)$ improved Wilson fermions. We have reached lattice spacings as small as $a \sim 0.07$fm and pion masses down to $m_{\pi} \sim 340$MeV…
We present a lattice calculation of the charged/neutral pion mass difference $M_{\pi^{+}}-M_{\pi^{0}}$ at order $\mathcal{O}(\alpha_{em})$ using the gauge configurations produced by the Extended Twisted Mass Collaboration with $N_{f}=2+1+1$…
We construct the chiral effective Lagrangian for two lattice theories: one with Wilson fermions and the other with Wilson sea fermions and Ginsparg-Wilson valence fermions. For each of these theories we construct the Symanzik action through…
We compute the electric screening mass in lattice QCD with Wilson fermions at finite temperature and chemical potential to one-loop order, and show that lattice artefacts arising from a finite lattice spacing result in an enhancement of the…
We present the results of a non-perturbative determination of the improvement coefficient $c_\mathrm{V}$ and the renormalisation factor $Z_\mathrm{V}$, which define the renormalised vector current in three-flavour $\mathrm{O}(a)$ improved…
Recent experiments have shown the transfer of orbital angular momentum (OAM) from a non-resonant laser onto an exciton-polariton condensate, despite earlier views that the phase information of such a laser should be lost during the process…
We characterize spin-polarized lasing in a two-dimensional photonic lattice fabricated from a GaAs/InGaAs semiconductor microcavity sample. The lattice is defined by a staggered arrangement of rounded rectangular micrometric mesas that…
We present preliminary numerical results from a lattice study of the two-dimensional O(3) non-linear sigma model. In the continuum this model possesses N=2 supersymmetry. The lattice formulation we use retains an exact (twisted)…
Nucleon structure functions can be observed in Deep Inelastic Scattering experiments, but it is an outstanding challenge to confront them with fully non-perturbative QCD results. For this purpose we investigate the product of…
We show, within the framework of the Euclidean $\phi^4$-quantum field theory in four dimensions, that the Wilson operator product expansion (OPE) is not only an asymptotic expansion at short distances as previously believed, but even…
We provide a compendium of techniques that can be used to compute $O(N_f\alpha^2)$ corrections to low-energy electroweak processes. Specifically, these are the 2-loop electroweak corrections containing a light fermion loop. It is shown that…
As several lattice collaborations agree on the result for the window quantity of the hadronic vacuum polarization (HVP) contribution to $(g-2)_\mu$, whilst being in tension with the calculation using the dispersive approach, further effort…
The energy levels of the $n=1$ and $n=2$ bound states of the $\mu^+\mu^-$ atom (true muonium) are calculated starting from a previously derived potential that correctly describes positronium to order $\alpha^5$ supplemented by the known…
We present analytical results to guide numerical simulations with Wilson fermions in higher representations of the colour group. The ratio of $\Lambda$ parameters, the additive renormalization of the fermion mass, and the renormalization of…