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Markus Wobisch

Publications and source records attributed to Markus Wobisch.

6 recordsLinked to original sources
arXiv2022

50 Years of Quantum Chromodynamics

This paper presents a comprehensive review of both the theory and experimental successes of Quantum Chromodynamics, starting with its emergence as a well defined theory in 1972-73 and following developments and results up to the present day. Topics include a review of the earliest theoretical and experimental foundations; the fundamental constants of QCD; an introductory discussion of lattice QCD, the only known method for obtaining exact predictions from QCD; methods for approximating QCD, with special focus on effective field theories; QCD under extreme conditions; measurements and predictions of meson and baryon states; a special discussion of the structure of the nucleon; techniques for study of QCD at high energy, including treatment of jets and showers; measurements at colliders; weak decays and quark mixing; and a section on the future, which discusses new experimental facilities or upgrades currently funded. The paper is intended to provide a broad background for Ph.D. students and postdocs starting their career. Some contributions include personal accounts of how the ideas or experiments were developed.

hep-ph↗
arXiv2018

Determination of the strong coupling constant from inclusive jet cross section data from multiple experiments

Inclusive jet cross section measurements from the ATLAS, CDF, CMS, D0, H1, STAR, and ZEUS experiments are explored for determinations of the strong coupling constant $α_{\text{s}}(M_{\text{Z}})$. Various jet cross section data sets are reviewed, their consistency is examined, and the benefit of their simultaneous inclusion in the $α_{\text{s}}(M_{\text{Z}})$ determination is demonstrated. Different methods for the statistical analysis of these data are compared and one method is proposed for a coherent treatment of all data sets. While the presented studies are based on next-to-leading order in perturbative quantum chromodynamics (pQCD), they lay the groundwork for determinations of $α_{\text{s}}(M_{\text{Z}})$ at next-to-next-to-leading order.

hep-ph↗
arXiv2012

New features in version 2 of the fastNLO project

Standard methods for higher-order calculations of QCD cross sections in hadron-induced collisions are time-consuming. The fastNLO project uses multi-dimensional interpolation techniques to convert the convolutions of perturbative coefficients with parton distribution functions and the strong coupling into simple products. By integrating the perturbative coefficients for a given observable with interpolation kernels, fastNLO can store the results of the time-consuming folding integrals in tables, which subsequently are used for very fast rederivations of the same observable for arbitrary parton distribution functions, different scale choices, or alpha_s(M_Z). Various tables with code for their evaluation are available for numerous jet measurements at the LHC, the TeVatron, and HERA. FastNLO is used in publications of experimental results by the ATLAS, CMS, CDF, D0, and H1 collaborations, and in all recent global PDF analyses by MSTW, CTEQ, and NNPDF. This article focuses on developments implemented in the new version 2 of fastNLO, enhancing and broadening its functionality.

hep-ph↗
arXiv2004

Recent Run II QCD Results from DO

We present recent QCD results from the D0 experiment at the Fermilab Tevatron Collider in pp-bar collisions at sqrt(s)=1.96 TeV. Results are presented for the inclusive jet and dijet cross sections, a measurement of dijet azimuthal decorrelations, studies of elastic scattering, and a search for diffractively produced Z bosons.

hep-ex↗
arXiv1999

Direct determination of the gluon density in the proton from jet cross sections in deep-inelastic scattering

A QCD analysis of jet production in deep-inelastic scattering is presented. The studies are based on recent measurements of jet cross sections in the H1 experiment at HERA which are directly sensitive to the gluon density in the proton. The inclusion of H1 data on the inclusive deep-inelastic scattering cross section enables us to perform a consistent, simultaneous determination of the quark and gluon densities in the proton. The gluon density has been determined at fairly large values of $0.01 < x < 0.1$ at a scale of the order of the transverse jet energies $μ^2_f = 200\GeV^2$. The result is consistent with indirect determinations from HERA structure function data and extends their range of sensitivity to larger $x$-values.

hep-ph↗