A5050480452- Quantum Chromodynamics and Particle Interactions
- Particle physics theoretical and experimental studies
- High-Energy Particle Collisions Research
- Black Holes and Theoretical Physics
- Cold Atom Physics and Bose-Einstein Condensates
- Physics of Superconductivity and Magnetism
- Criminal Law and Policy
- Theoretical and Computational Physics
- Pulsars and Gravitational Waves Research
- Computational Physics and Python Applications
- Superconducting Materials and Applications
- Atomic and Subatomic Physics Research
- Social Media and Politics
- Quantum and electron transport phenomena
- Graphene research and applications
- Taxation and Legal Issues
- Corporate Taxation and Avoidance
- Law and Political Science
- Quantum many-body systems
- Historical and Archaeological Studies
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- Linguistic research and analysis
- Particle accelerators and beam dynamics
- Impact of Technology on Adolescents
- Medical and Health Sciences Research
Justus-Liebig-Universität Gießen
2016-2025
GSI Helmholtz Centre for Heavy Ion Research
2009-2025
Institut für Hochschulforschung
2020-2025
University of Tübingen
2001-2024
University of Münster
2022-2024
Frankfurt School of Finance & Management
2023
German Meteorological Service
2023
Charité - Universitätsmedizin Berlin
2023
Heidelberg University
2004-2022
Giessen School of Theology
2013-2022
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...
I review recent results on the infrared properties of QCD from Dyson–Schwinger equations. The topics include exponents one-particle irreducible Green's functions, fixed point behaviour running coupling at zero momentum, pattern dynamical quark mass generation and light mesons.
We investigate the impact of unquenching effects on QCD Green's functions, in form quark-loop contributions to both gluon propagator and three-gluon vertex, a three-loop inspired truncation three-particle irreducible (3PI) effective action. The fully coupled system Dyson-Schwinger equations for quark-gluon-, ghost-gluon- vertices, together with quark propagator, are solved self-consistently; our only input ghost propagators themselves that constrained by calculations within Lattice QCD. find...
The coupled system of renormalized Dyson-Schwinger equations for the quark, gluon, and ghost propagators Landau gauge QCD is solved within truncation schemes. These employ bare as well nonperturbative Ans\"atze vertices such that running coupling quark mass function are independent renormalization point. one-loop anomalous dimensions all reproduced. Dynamical chiral symmetry breaking found; dynamically generated agrees with phenomenological values, corresponding results from lattice...
We explore the analytic structure of gluon and quark propagators Landau gauge QCD from numerical solutions coupled system renormalized Dyson-Schwinger equations fits to lattice data. find sizable negative norm contributions in transverse propagator indicating absence physical spectrum. A simple for is proposed. For we evidence a masslike singularity on real timelike momentum axis, with mass 350 500 MeV. Within Green's function approach that employed, identify crucial term quark-gluon vertex...
We investigate the phase structure of QCD at finite temperature and light-quark chemical potential. improve upon earlier results for N_f=2+1 dynamical quark flavors effects charm quarks in an extension to N_f=2+1+1. determine condensate Polyakov loop potential using solutions a coupled set (truncated) Dyson-Schwinger equations gluon propagators Landau gauge QCD. At zero we find excellent agreement with from lattice-QCD. With input fixed physical observables only very small influence on...
The analytic structure of the nonperturbative gluon propagator contains information on absence gluons from physical spectrum theory. We study this numerical solutions in complex momentum plane and ghost Dyson-Schwinger equations Landau gauge Yang-Mills resulting propagators are apart a distinct cut real, timelike axis. violates Osterwalder-Schrader positivity condition, confirming asymptotic
We investigate the phase structure of QCD at finite temperature and chemical potential by solving a coupled set truncated Dyson-Schwinger equations for quark gluon propagator. In contrast to previous calculations we take into account full back-reaction quarks onto Yang-Mills sector include effects strange quarks. discuss resulting thermal mass unquenched propagator extract order parameters chiral deconfinement transition from Our result dependence condensate zero agrees well with...
We present a shortened and simplified version of our proof [C. S. Fischer J. M. Pawlowski, Phys. Rev. D 75, 025012 (2007).] the uniqueness scaling solution for infrared asymptotics Green functions in Landau gauge Yang-Mills theory. The simplification relates to new renormalization group--invariant arrangement applicable general theories. As before relies on necessary consistency between Dyson-Schwinger equations functional group equations. also demonstrate existence specific both, equations,...
We investigate masses and decay constants of light mesons from a coupled system Dyson-Schwinger Bethe-Salpeter equations. explicitly take into account dominant non-Abelian contributions to the dressed quark-gluon vertex stemming gluon self-interaction. construct corresponding kernel that satisfies axial-vector Ward-Takahashi identity. Our numerical treatment fully includes all momentum dependencies with equations solved completely in complex plane. This approach goes well beyond...
We present results for the charged kaon-box contributions to hadronic light-by-light (HLBL) correction of muon's anomalous magnetic moment. To this end we determine kaon electromagnetic form factor within functional approach QCD using Dyson-Schwinger and Bethe-Salpeter equations evaluate contribution as defined in dispersive HLBL. As an update previous work also reevaluate pion-box taking effects due isospin breaking into account. Our are...
We present results for fluctuations of the baryon number QCD at nonzero temperature and chemical potential. These are extracted from solutions to a coupled set truncated Dyson-Schwinger equations quark gluon propagators Landau-gauge with ${N}_{\mathrm{f}}=2+1$ flavors, that has been studied previously. discuss changes ratios thereof up fourth order several temperatures potential beyond critical endpoint. In context preliminary STAR data skewness kurtosis ratios, compatible scenario endpoint...
We solve a truncated system of coupled Dyson-Schwinger equations for the gluon and ghost propagators in $\mathrm{SU}{(N}_{c})$ Yang-Mills theories Faddeev-Popov quantization on four-torus. This compact space-time manifold provides an efficient mean to without any angular approximations. verify that analytically two powerlike solutions very far infrared seem possible. However, only one these can be matched numerical solution nonvanishing momenta. For bare ghost-gluon vertex this implies...
We investigate dynamical chiral symmetry breaking in unquenched ${\mathrm{Q}\mathrm{E}\mathrm{D}}_{3}$ using the coupled set of Dyson-Schwinger equations for fermion and photon propagators. For fermion-photon interaction we employ an ansatz which satisfies its Ward-Green-Takahashi identity. present self-consistent analytical solutions infrared as well numerical results all momenta. In Landau gauge, find a phase transition at critical number flavors...
We uniquely determine the infrared asymptotics of Green functions in Landau gauge Yang-Mills theory. They have to satisfy both Dyson-Schwinger equations and functional renormalization group equations. Then, requirement consistency fixes relation between power laws these functions. discuss consequences for interpretation recent results from lattice QCD.
We study the dual quark condensate as a signal for confinement-deconfinement phase transition of QCD. This order parameter center symmetry has been defined recently by Bilgici et al. within framework lattice In this work we determine ordinary and with functional methods using formulation Dyson-Schwinger equations propagator on torus. The temperature dependence these condensates serves to investigate interplay between chiral deconfinement transitions quenched
We determine the mass of tetraquark bound states from a coupled system covariant Bethe-Salpeter equations. Similar in spirit to quark-diquark model nucleon, we approximate full four-body equation for by set two-body equations with meson and diquark constituents. These are calculated their quark gluon substructure using phenomenologically well-established quark-gluon interaction. For lightest scalar find order 400 MeV wave function dominated pion-pion Both results agreement molecule picture...
We determine the quark condensate and dressed Polyakov loop from finite temperature Landau gauge propagator evaluated with $U(1)$-valued boundary conditions in an approximation to quenched QCD. These invariant quantities allow for investigation of chiral deconfinement transitions. compare results Dyson-Schwinger equations on a lattice infinite volume continuum study mass dependence both quantities. In particular we investigate limit. also consider alternative order parameter transition, dual...