A5006530789- Particle physics theoretical and experimental studies
- Quantum Chromodynamics and Particle Interactions
- High-Energy Particle Collisions Research
- Computational Physics and Python Applications
University of Southampton
2018-2023
Johannes Gutenberg University Mainz
2016-2018
We review the present status of Standard Model calculation anomalous magnetic moment muon. This is performed in a perturbative expansion fine-structure constant $\alpha$ and broken down into pure QED, electroweak, hadronic contributions. The QED contribution by far largest has been evaluated up to including $\mathcal{O}(\alpha^5)$ with negligible numerical uncertainty. electroweak suppressed $(m_\mu/M_W)^2$ only shows at level seventh significant digit. It two loops known better than one...
The anomalous magnetic moment of the muon currently exhibits a discrepancy about three standard deviations between experimental value and recent Standard Model predictions. theoretical uncertainty is dominated by hadronic vacuum polarization light-by-light (HLbL) scattering contributions, where latter has so far only been fully evaluated using different models. To pave way for lattice calculation HLbL, we present an expression HLbL contribution to $g-2$ that involves multidimensional...
Hadronic light-by-light scattering is one of the virtual processes that causes gyromagnetic factor $g$ muon to deviate from value two predicted by Dirac's theory. This process makes largest contributions uncertainty Standard Model prediction for $(g-2)$. Lattice QCD allows a first-principles approach computing this non-perturbative effect. In order avoid power-law finite-size artifacts generated photons in lattice simulations, we follow coordinate-space involving weighted integral over...
The well-known discrepancy in the muon $g-2$ between experiment and theory demands further investigations view of upcoming new experiments. One leading uncertainties lies hadronic light-by-light scattering contribution (HLbL), that we address with our position-space approach. We focus on exploratory studies pion-pole a simple model fermion loop without gluon exchanges continuum infinite volume. These provide us useful information for planned computation HLbL using full QCD.
Hadronic light-by-light scattering in the anomalous magnetic moment of muon a_\mu <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mi>a</mml:mi><mml:mi>μ</mml:mi></mml:msub></mml:math> is one two hadronic effects limiting precision Standard Model prediction for this observable, and hence new-physics discovery potential direct experimental determinations . In contribution, I report on recent progress calculation effect achieved both via dispersive...
We report calculations of hadronic light-by-light scattering amplitudes via lattice QCD evaluation Euclidean four-point functions vector currents.These initial results include only the fully quark-connected contribution.Particular attention is given to case forward scattering, which can be related dispersion relations γ * → hadrons cross section, and thus allows data compared with phenomenology.We also present a strategy for computing contribution muon anomalous magnetic moment.
We briefly review several activities at Mainz related to hadronic light-by-light scattering (HLbL) using lattice QCD. First we present a position-space approach the HLbL contribution in muon g-2, where focus on exploratory studies of pion-pole simple model and lepton loop QED continuum infinite volume. The second part describes calculation double-virtual pion transition form factor F_{pi^0 gamma^* gamma^*}(q_1^2, q_2^2) spacelike region with photon virtualities up 1.5 GeV^2 which paves way...
The measurement of the anomalous magnetic moment muon and its prediction allow for a high-precision test Standard Model (SM). In this proceedings article we present ongoing work combining lattice QCD continuum QED in order to determine an important SM contribution moment, hadronic light-by-light contribution. We compute quark-connected Mainz position-space approach investigate long-distance part our data using calculations $\pi^0$-pole charged pion loop contributions.