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Related papers: QCD Studies at LEP I

200 papers

We review the long term project of the ALPHA collaboration to compute in QCD the running coupling constant and quark masses at high energy scales in terms of low energy hadronic quantities. The adapted techniques required to numerically…

High Energy Physics - Lattice · Physics 2015-01-09 Rainer Sommer , Ulli Wolff

We present a determination of the strange, charm and bottom quark masses as well as the strong coupling constant in 2+1 flavor lattice QCD simulations using highly improved staggered quark action. The ratios of the charm quark mass to the…

High Energy Physics - Lattice · Physics 2016-09-06 Y. Maezawa , P. Petreczky

We study the quark number susceptibility of the hot quark-gluon plasma at zero and non-zero quark number density, using lattice Monte Carlo simulations of an effective theory of QCD, electrostatic QCD (EQCD). Analytic continuation is used…

High Energy Physics - Lattice · Physics 2009-12-15 Ari Hietanen , Kari Rummukainen

Selected, recent results, primarily from collider experiments but including some fixed target experiments, are presented as a survey of Quantum Chromodynamics (QCD). The concepts of leading order and next-to-leading order QCD are…

High Energy Physics - Experiment · Physics 2011-03-23 Gerald C. Blazey

The four LEP experiments and the SLD detector have measured the Z partial widths for Z decays into b and c quarks and the corresponding forward-backward asymmetries at centre-of-mass energies close to the Z boson mass. The results yield a…

High Energy Physics - Experiment · Physics 2019-08-14 Wolfgang Liebig

We present a comparison of local multiplicity fluctuations in angular phase-space intervals with first-order QCD predictions. The data are based on 810k hadronic events at 91.2 GeV collected with the L3 detector at LEP during 1994.

High Energy Physics - Experiment · Physics 2007-05-23 S. V. Chekanov

We discuss the flavor of leading jet partons as a valuable probe of nuclear matter. We point out that the coupling of jets to nuclear matter naturally leads to an alteration of jet chemistry even at high transverse momentum $p_T$. In…

Nuclear Theory · Physics 2008-11-26 W. Liu , R. J. Fries

Average charged multiplicities have been measured separately in $b$, $c$ and light quark ($u,d,s$) events from $Z^0$ decays measured in the SLD experiment. Impact parameters of charged tracks were used to select enriched samples of $b$ and…

High Energy Physics - Experiment · Physics 2008-11-26 K. Abe

Fragmentation functions for charged particles in Z -> qq(bar) events have been measured for bottom (b), charm (c) and light (uds) quarks as well as for all flavours together. The results are based on data recorded between 1990 and 1995…

High Energy Physics - Experiment · Physics 2008-11-26 The OPAL Collaboration , K. Ackerstaff et al

The `XIIIth Quark Confinement and the Hadron Spectrum' conference (Confinement 2018) contained a `Round Table Discussion' on the status of the determinations of the strong coupling $\alpha_s(m_Z)$ as well as prospects for future…

High Energy Physics - Phenomenology · Physics 2018-12-17 Antonio Pich , Juan Rojo , Rainer Sommer , Antonio Vairo

Recent LHC data suggest that perturbative QCD provides a qualitatively consistent picture of jet quenching. Constrained to RHIC pi0 suppression, zero parameter WHDG energy loss predictions agree quantitatively with the charged hadron v2 and…

Nuclear Theory · Physics 2015-06-05 W. A. Horowitz

New results on the measurements of the hadronic final state in neutral-current deep-inelastic scattering at HERA are presented. A combination of reduced charm and beauty cross sections is presented and the masses of the heavy quarks are…

High Energy Physics - Experiment · Physics 2017-05-16 Daniel Britzger

We present a new determination of the QCD strong coupling constant based on precise lattice calculations of the $\Upsilon$ spectrum. The largest systematic uncertainty in previous such determinations resulted from the absence of vacuum…

High Energy Physics - Phenomenology · Physics 2009-10-28 C. T. H. Davies , K. Hornbostel , G. P. Lepage , A. Lidsey , J. Shigemitsu , J. Sloan

We use the available data on e+ e- -> hadrons to determine the value of the QED coupling at the Z pole. The inclusion of recent preliminary BES-II data in the analysis is found to reduce the ambiguity in the determination of the coupling,…

High Energy Physics - Phenomenology · Physics 2009-10-31 A. D. Martin , J. Outhwaite , M. G. Ryskin

An update is described of a model independent method to determine the hadronic contribution to the QED running coupling at the Z-boson mass scale, $\Delta\alpha_{\text{HAD}}(M_{Z}^{2})$. The major source of uncertainty is from the…

High Energy Physics - Phenomenology · Physics 2022-03-29 Cesareo A. Dominguez , Luis A. Hernández

The modern status of basic low energy QCD parameters is reviewed. It is demonstrated, that the recent data allows one to determine the light quark mass ratios with an accuracy 10-15%. The general analysis of vacuum condensates in QCD is…

High Energy Physics - Phenomenology · Physics 2010-04-06 B. L. Ioffe

A fundamental characteristic of hadron colliders is the abundant production of jets, which then are studied to learn about hard QCD, the proton structure, or nonperturbative effects. In the following the latest results and developments from…

High Energy Physics - Experiment · Physics 2013-05-28 Klaus Rabbertz

I review the status of lattice-QCD calculations relevant to quark flavor physics. The recent availability of physical-mass ensembles with large physical volumes generated by a growing number of lattice collaborations is an exciting…

High Energy Physics - Lattice · Physics 2014-03-28 Aida X. El-Khadra

The strong coupling $\alpha_\mathrm{s}$ can be obtained from the static energy as shown in previous lattices studies. For short distances, the static energy can be calculated both on the lattice with the use of Wilson line correlators, and…

The quartic gauge coupling (QGC) of the electroweak interaction can be used as a probe for physics beyond the Standard Model and has been previously measured at the Large Hadron Collider. However, to achieve sensitivity to small deviations…

High Energy Physics - Experiment · Physics 2020-02-26 Jakob Beyer , Jenny List