Related papers: The perturbative QCD gradient flow to three loops
Normalizing flows can be used to construct unbiased, reduced-variance estimators for lattice field theory observables that are defined by a derivative with respect to action parameters. This work implements the approach for observables…
The temporal component of the heavy-light axial vector current is constructed to one-loop order in perturbation theory and to order 1/M, where M is the heavy quark mass, in terms of operators suitable for use in lattice simulations of B and…
Reaching next-to-leading order accuracy in perturbative calculations of particle production in QCD at high energy is essential for reliable phenomenological applications. In recent years, the Color Glass Condensate effective theory (the…
Precision tests of QCD perturbation theory are not readily available from experimental data. The main reasons are systematic uncertainties due to the confinement of quarks and gluons, as well as kinematical constraints which limit the…
The following topics in perturbative QCD are reviewed: recent theoretical progress in higher-order calculations; soft-gluon resummation for hard-scattering processes at large $E_T$ and high $x$; low-$x$ behaviour of structure functions and…
The lattice gauge theory technique for non-perturbative calculations in QCD is reviewed. The extraction of the continuum limit of lattice results is discussed with particular examples appropriate to hadron spectroscopy (the light hadrons…
The main theoretical tool to provide precise predictions for scattering cross sections of strongly interacting particles is perturbative QCD. Starting at next-to-leading order (NLO) the calculation suffers from unphysical IR-divergences…
Infrared safe differential cross sections, such as event shape distributions, can be measured over wide kinematic ranges, from regions where fixed order calculations are adequate to regions where nonperturbative dynamics dominate. Such…
A short survey of the renormalization problem in QCD and its non-perturbative solution by means of numerical simulations on the lattice is given. Most emphasis is on scale dependent renormalizations, which can be reliably addressed via a…
We compute all helicity amplitudes for four-particle scattering in massless QCD with $n_f$ fermion flavours to next-to-next-to-leading order (NNLO) in perturbation theory. In particular, we consider all possible configurations of external…
We evaluate the three-loop corrections to the matching coefficient of the vector current between Quantum Chromodynamics (QCD) and non-relativistic QCD. The result is presented in the MSbar scheme where large perturbative corrections are…
The calculations for the production of heavy quarks in deeply inelastic scattering (DIS) can be seen as an illustrative example in the framework of perturbative Quantum Chromo Dynamics (pQCD). In this thesis, I give an overview of all steps…
High-energy particles traversing a medium experience modified dispersion. In the Quark-Gluon Plasma, such dispersion affects jet propagation and transport properties and should be determined better. Above $\sim 2T_c$ we expect strongly…
We calculated next-to-leading-order (NLO) QCD perturbative contributions to a $J^{PC}=0^{+-}$, $d u\bar d\bar u$ tetraquark (diquark-antidiquark) correlator in the chiral limit of massless $u$ and $d$ quarks. At NLO, there are four quark…
We present a high order perturbative computation of the renormalization constants Z_V, Z_A and of the ratio Z_P/Z_S for Wilson fermions. The computational setup is the one provided by the RI'-MOM scheme. Three- and four-loop expansions are…
The gradient-flow formalism provides a framework for the direct determination of moments of parton distribution functions (PDFs) from lattice QCD calculations. Their conversion from the gradient-flow scheme to $\overline{\text{MS}}$…
Using stochastic quantization method we derive gauge-invariant equations, connecting multilocal vacuum correlators of nonperturbative field configurations immersed into the quantum background. Three alternative methods of stochastic…
The translation of experimental limits on the neutron electric dipole moment into constraints on heavy $CP$-violating physics beyond the Standard Model requires knowledge about non-perturbative matrix elements of effective operators, which…
We present the result for the first moment of the scalar and axial-vector current correlator in third order of the strong coupling constant alpha_s and give the details of a recent evaluation of the pseudo-scalar correlator. The results can…
We compare the perturbatively calculated QCD potential to that obtained from lattice calculations in the theory without light quark flavours. We examine E_tot(r) = 2 m_pole + V_QCD(r) by re-expressing it in the MSbar mass m =…