相关论文: Hard Photons in W Pair Production at LEP 2
The production of photon pairs in $e^+e^-\rightarrow f \bar f \gamma\gamma$ processes is studied using exact helicity amplitudes at tree level. Total cross sections, including initial state radiation effects, are given. They are presented…
Hadronic interactions of two quasi-real photons have been studied extensively both during the LEP1 and the LEP2 data taking periods. The higher energies available at LEP2 in particular opened regions of phase space where hadronic processes…
The production of four fermions plus a visible photon in electron-positron collisions is analyzed, with particular emphasis on the LEP2 energy range. The study is based on the calculation of exact matrix elements, including the effect of…
High intensity back-scattered laser beams will allow the efficient conversion of a substantial fraction of the incident lepton energy into high energy photons, thus significantly extending the physics capabilities of an electron-electron or…
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…
The search for new physics in single- and multi-photon final states with large missing energy at LEP and future e^+ e^- colliders requires precise predictions for the Standard Model irreducible background. While at LEP1 the theoretical…
Recent tests of the electroweak Standard Model are reviewed, covering the precise measurements of Z decays at LEP I and SLC and measurements of fermion pair production at higher energies at LEP II. Special emphasis is given to new results…
A study of W+W- events accomanied by hard photon radiation produced in e+e- collisions at LEP is presented. Events consistent with being two on-shell W bosons and an isolated photon are selected from 681 pb^-1 of data recorded at 180 GeV <…
A study of W+W- events accompanied by hard photon radiation produced in e+e- collisions at LEP is presented. Events consistent with two on-shell W-bosons and an isolated photon are selected from 183pb^-1 of data recorded at root{s}=189GeV.…
A study of the radiative neutrino counting reaction $e^+ e^- \to \nu {\bar \nu} \gamma$ at LEP1 and LEP2 energies is presented. An approximate expression for the spectrum of the observed photon is derived within the framework of the…
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…
After the first observations of W bosons in leptonic interactions, about 4000 WW candidate events per experiment have been collected at LEP2. This data allows the measurement of the WW production cross section at different centre-of-mass…
After 12 years of glorious data taking LEP has been shut down. During the past two years an incredible effort has been devoted to get more accurate predictions and estimates of the related theoretical uncertainties. Many of the theoretical…
The production of invisible pairs of lightest neutralinos accompanied by a large-angle hard photon in the reaction $e^+ e^- \to \chi^0_1 \chi^0_1 \gamma$ is studied at LEP2 energies. The most general gaugino/higgsino composition of the…
The unique nature of the photon can be investigated in hitherto unexplored kinematic regions at LEP2. We discuss the theoretical significance of deep inelastic measurements and present a prescription that allows a theoretically and…
The process of electron-positron pair production is investigated within the phase-space Wigner formalism. The similarities between atomic ionization and pair production for homogeneous, but time-dependent linearly polarized electric fields…
The emission of $\nu\bar\nu$ pairs off electrons in a polarized ultra-intense electromagnetic (e.g.\ laser) wave field is analyzed. We elaborate on the significance of non-linear electrodynamics effects (i.e., multi-photon processes) and…
Production of particle-antiparticle pairs by a high-energy probe photon propagating through a high-intensity laser field is considered in the nonperturbative interaction regime. The laser field consists of a strong low-frequency and a weak…
High-energy photon-proton interactions at the LHC offer interesting possibilities for the study of top properties. Using a fast simulation of a LHC-like detector, first results on the measurement of the |V_{tb}| matrix element using Wt…
We study at LEP II and Next Linear Collider energies Higgs production via the bremsstrahlung channel $e^+e^-\ar ZH$, with $Z\ar \mu^+\mu^-$ and $H\ar b\bar b$, and the corresponding irreducible background, in presence of hard photon…