Related papers: QCD Studies at LEP I

We present a determination of the QCD parameter Lambda in the quenched approximation (n_f=0) and for two flavours (n_f=2) of light dynamical quarks. The calculations are performed on the lattice using O(a) improved Wilson fermions and…

We study QCD with one flavor at finite baryon density. In the limit of very high baryon density the system is expected to be a color superconductor. In the case of one flavor, the order parameter is in a $\bar 3$ of color and has total…

This document is one of a series of whitepapers from the USQCD collaboration. Here, we discuss opportunities for lattice QCD in quark and lepton flavor physics. New data generated at Belle II, LHCb, BES III, NA62, KOTO, and Fermilab E989,…

Data from e+e- annihilation into hadrons collected by the JADE experiment at centre-of-mass energies between 14 and 44 GeV were used to study the 4-jet rate using the Durham algorithm as well as the first five moments of event shape…

We present results showing that the strong coupling constant measured in two-flavor full QCD with dynamical Kogut-Susskind quarks at $\beta=5.7$ exhibit a 15\% increase due to sea quarks over that for quenched QCD at the scale $\mu\approx…

Hadron colliders offer a unique opportunity to test perturbative QCD because, rather than producing events at a specific beam energy, the dynamics of the hard scattering is probed simultaneously at a wide range of momentum transfers. This…

A survey is presented of recent measurements in jet physics, and improved determinations of the QCD coupling constant alpha_s that these have made possible.

Perturbative QCD formula for inclusive energy spectra of heavy quarks from heavy quark initiated jets which takes into account collinear and/or soft logarithms in all orders, the exact first order result and two-loop effects is applied to…

We demonstrate that sea quark effects of a magnitude expected from renormalization group considerations are clearly visible in the strong coupling constant measured in current full QCD simulations. Building on this result an estimate of…

We present a strong coupling constant extraction at Next-to-Leading Order QCD accuracy using ATLAS Z+2,3,4 jets data. This is the first extraction using processes with a dependency to high powers of the coupling constant. We obtain values…

We obtain a determination of the strong coupling alpha_s in quantum chromodynamics, by comparing perturbative calculations for the short-distance part of the static energy with lattice computations. Our result reads…

Precision studies of flavour-changing processes involving quarks and leptons provide a number of ways to improve knowledge of the Standard Model and search for physics beyond it. There are excellent short- and mid-term prospects for…

We demonstrate that a Quark-Gluon Plasma (QGP) with a dilute admixture of heavy quarks has, in general, a lower speed of sound than a "pure" QGP without effects from heavy flavors. The change in the speed of sound is sensitive to the…

In the domain of Nuclear reactions at intermediate energies, the QCD coupling constant $\alpha_s$ is large enough ($\sim$ 0.3 - 0.5) to render the perturbative calculational techniques inapplicable. In this regime the quarks are confined…

Heavy-flavour hadrons, containing at least one charm or beauty quark, are excellent probes of the deconfined medium created in ultra-relativistic heavy-ion collisions, known as quark-gluon plasma. Results in smaller collision systems, such…

The production of beauty and charm quarks in ep interactions has been studied with the ZEUS detector at HERA for exchanged four-momentum squared 5 < Q^2 < 1000 GeV^2 using an integrated luminosity of 354 pb^{-1}. The beauty and charm…

The value of $\alpha_s (M_Z)$ emerging from the so called global fits based mainly on the data at the $Z$ peak (and assuming the standard model) is three standard deviations higher than the one stemming from the low-energy phenomenology.…

The early production of heavy-flavor (HF, charm and beauty) quarks makes them an excellent probe of the dynamical evolution of quantum chromodynamics (QCD) systems. Jets tagged by the presence of a HF hadron give access to the kinematics of…

The top quark mass is one of the fundamental parameters of the Standard Model. In these proceedings, recent measurements of the top quark mass in $pp$ collisions at centre-of-mass energies of $\sqrt s=7$ and 8~TeV data in Run I of the Large…

A selection of results from the 2010 data taking period of the ATLAS and CMS experiments at the LHC at a proton-proton centre-of-mass energy of 7 TeV is presented. These results comprise differential jet cross sections for varying jet…