Experimental Tests of QCD

The first very successful LHC running period has been finished. At 7 TeV centre-of-mass energy about 5/fb of data have been collected and at 8 TeV even 20/fb. Many detailed analyses of these data are still going on. The latest measurements on photon, weak boson plus jet, and jet production are compared against the most recent theory predictions. They are complemented by new results reported by the experiments at the Tevatron and HERA colliders. Finally, several new determinations of the strong coupling constant from jet data are presented.Comment: On behalf of the ATLAS and CMS Collaborations, 8 pages, 8 figures, pdflatex, to be published in the Proceedings of the Rencontres du Vietnam, Inaugural Conference of ICISE on "Windows on the Universe", Quy Nhon, Vietnam, August 11-17, 201

Top Spin and Experimental Tests

We examine pair mass dependence near threshold as a means to measure the spin of the top quark in hadron collisions, and we discuss the possibility that a top squark signal could be hidden among the top events.Comment: 9 pages, RevTeX, 3 figures. Contribution to the Thinkshop on Top-Quark Physics for the Tevatron Run II, Fermilab, October 16 - 18, 199

Experimental Tests of Asymptotic Freedom

Measurements which probe the energy dependence of $\alpha_s$, the coupling strength of the strong interaction, are reviewed. Jet counting in $e^+ e^-$ annihilation, combining results obtained in the centre of mass energy range from 22 to 133 GeV, provides direct evidence for an asymptotically free coupling, without the need to determine explicit values of $\alpha_s$. Recent results from jet production in $e p$ and in $p \overline{p}$ collisions, obtained in single experiments spanning large ranges of momentum transfer, $Q^2$, are in good agreement with the running of $\alpha_s$ as predicted by QCD. Mass spectra of hadronic decays of $\tau$-leptons are analysed to probe the running $\alpha_s$ in the very low energy domain, $0.7 GeV^2 < Q^2 < M_\tau^2$. An update of the world summary of measurements of $\alpha_s(Q^2)$ consistently proves the energy dependence of $\alpha_s$ and results in a combined average of $\alpha_s(M_Z) = 0.118 \pm 0.006$.Comment: 11 pages, 8 Figures, LaTeX. To appear in Proc. of QCD Euroconference 96 at Montpellier, France, July 199

Experimental Tests of Asymptotic Freedom

Quantum Chromodynamics (QCD), the gauge field theory of the Strong Interaction, has specific features, asymptotic freedom and confinement, which determine the behaviour of quarks and gluons in particle reactions at high and at low energy scales. QCD predicts that the strong coupling strength \as decreases with increasing energy or momentum transfer, and vanishes at asymptotically high energies. In this review, the history and the status of experimental tests of asymptotic freedom are summarised. The world summary of measurements of \as is updated, leading to an unambiguous verification of the running of \as and of asymptotic freedom, in excellent agreement with the predictions of QCD. Averaging a set of measurements balanced between different particle processes and the available energy range, results in a new and improved world average of \amz = 0.1189 \pm 0.0010 .Comment: 38 pages, 18 figure

Experimental Tests of General Relativity

Einstein's general theory of relativity is the standard theory of gravity, especially where the needs of astronomy, astrophysics, cosmology and fundamental physics are concerned. As such, this theory is used for many practical purposes involving spacecraft navigation, geodesy, and time transfer. Here I review the foundations of general relativity, discuss recent progress in the tests of relativistic gravity in the solar system, and present motivations for the new generation of high-accuracy gravitational experiments. I discuss the advances in our understanding of fundamental physics that are anticipated in the near future and evaluate the discovery potential of the recently proposed gravitational experiments.Comment: revtex4, 30 pages, 10 figure

Recent Experimental Tests of Special Relativity

We review our recent Michelson-Morley (MM) and Kennedy-Thorndike (KT) experiment, which tests Lorentz invariance in the photon sector, and report first results of our ongoing atomic clock test of Lorentz invariance in the matter sector. The MM-KT experiment compares a cryogenic microwave resonator to a hydrogen maser, and has set the most stringent limit on a number of parameters in alternative theories to special relativity. We also report first results of a test of Lorentz invariance in the SME (Standard Model Extension) matter sector, using Zeeman transitions in a laser cooled Cs atomic fountain clock. We describe the experiment together with the theoretical model and analysis. Recent experimental results are presented and we give a first estimate of components of the $\tilde{c}^p$ parameters of the SME matter sector. A full analysis of systematic effects is still in progress, and will be the subject of a future publication together with our final results. If confirmed, the present limits would correspond to first ever measurements of some $\tilde{c}^p$ components, and improvements by 11 and 14 orders of magnitude on others.Comment: 29 pages. Contribution to Springer Lecture Notes, "Special Relativity - Will it survive the next 100 years ?", Proceedings, Potsdam, 200

Experimental Tests of Particle Flow Calorimetry

Precision physics at future colliders requires highly granular calorimeters to support the Particle Flow Approach for event reconstruction. This article presents a review of about 10 - 15 years of R\&D, mainly conducted within the CALICE collaboration, for this novel type of detector. The performance of large scale prototypes in beam tests validate the technical concept of particle flow calorimeters. The comparison of test beam data with simulation, of e.g.\ hadronic showers, supports full detector studies and gives deeper insight into the structure of hadronic cascades than was possible previously.Comment: 55 pages, 83 figures, to appear in Reviews of Modern physic

Experimental Tests of the Standard Model

Four lectures on experimental test of the standard model presented at the Advanced Summer Institute on Techniques and Concepts of High Energy Physics.Comment: 46 page LaTeX with 35 figures included using epsf, requires crckapb.sty. For publication in Proceedings of the NATO Advanced Study Institute on Techniques and Concepts of High Energy Physics (1998: St. Croix, V. I.) Ed. T. Ferbe