Related papers: Do LEP results suggest that quarks have integer el…
LEP offers an excellent opportunity to measure two photon processes over a large kinematical range and thus study the complex nature of the photon. This article reviews the experimental status of ``Two Photon Physics'' at LEP. The recent…
Within the context of the Standard Model, quarks are placed in a $(\mathbf{3},\mathbf{2})\oplus (\mathbf{3},\bar{\mathbf{2}})$ matter field representation of $U_{EW}(2)$. Although the quarks carry unit intrinsic electric charge in this…
A remarkable number of studies have been performed at LEP in the field of two-photon physics in the last four years. These results represent a very important contribution to the understanding of strong interactions at low energies. In…
The LEP experiments are making real progress in understanding the structure of the photon, though the results do not yet give such clear demonstrations of QCD in action as the proton structure has done. Other new results are reported,…
This review covers selected results from the LEP experiments on the structure of quasi-real and virtual photons. The topics discussed are the total hadronic cross-section for photon-photon scattering, hadron production, jet cross-sections,…
The LEP experiments measure the QED and QCD structure of the photon in deep-inelastic electron-photon scattering. The status of these measurements is discussed in this short review.
Experimental tests performed in the past to determine quark charges are reviewed. It is pointed out that only experiments involving two real photons can really distinguish between the Gell-Mann-Zweig scheme of fractional charges from the…
In this contribution we discuss recent measurements by the LEP experiments on photon structure functions.
Recent developments in the field of Two Photon Physics at LEP, and their contribution to QCD are reviewed.
Next-to-leading order QCD corrections to three jet heavy quark production in $e^+ e^-$ collisions, including quark mass effects, are presented. The extraction of the b-quark mass form LEP data is considered and the first experimental…
We analyse numerically manifestations of the radiative amplitude zero (RAZ) effect in single leptoquark production associated with hard photon emission. We present some quantitative conclusions on the possibility to distinguish leptoquark…
Two photon collisions offer a variety of physics studies that can be performed at the future electron-positron colliders. Using the planned CEPC parameters as a benchmark we consider several topics to be studied in the two-photon…
We perform a detailed analyses of the CERN Large Hadron Collider (LHC) capability to discover first generation vector leptoquarks through their pair production. We study the leptoquark signals and backgrounds that give rise to final states…
In two-photon collisions at LEP2 and a future $e^+e^-$ linear collider heavy quarks (mainly charm) will be pair-produced rather copiously. The production via direct and resolved photons can be distinguished experimentally via a remnant-jet…
Data from LEP2 on hadron production in gamma gamma interactions at high pT exceed the predictions of QCD by about an order of magnitude. The amplitude for the process is asymptotically proportional to the sum of the squares of the charges…
Starting with the premise that the electric charge associated with fundamental fermions (quarks and leptons) can, under certain circumstances, be appropriately represented as a real \emph{internal} 2-vector, the mathematical ``machinery''…
I review recent QCD results from LEP. The emphasis is on results that represent new studies and on puzzling disagreements of theory and experiment. Further results are nevertheless mentioned by reference. The new studies discussed in more…
Studies of hadronic final states of $e^+e^-$ annihilations at LEP are reviewed. The topics included cover hadronic event shapes, measurements of $\alpha_s$, determinations of QCD colour factors and tests of the non-Abelian gauge structure…
We study the potentiality of the CERN Large Hadron Collider (LHC) to unravel the existence of first generation scalar leptoquarks. Working with the most general $SU(2)_L \otimes U(1)_Y$ invariant leptoquark interactions, we analyze in…
The minimal model of spontaneously broken leptonic colour and discrete quark-lepton symmetry predicts that charged leptons have the same masses as their partner charge $+2/3$ quarks up to small radiative corrections. By invoking a different…