Unstable particles in One Loop Calculations

We present a gauge invariant way to compute one loop corrections to processes involving the production and decay of unstable particles.Comment: 21 pages latex, <A HREF=http://pss058.psi.ch/preprints/unstablefull.ps>ps file, PSI-PR-93-22, REVISED. (Completely rewritten due to many complaints about the unclear exposition.

Light Fermion Mass Effects in e^+e^- -> 4 Fermions

We investigated the effect of the light fermion masses on cross sections for e^+e^- into 4 fermions in the Fermion Loop scheme defined in hep-ph/9612260, and approximations to it. The effects are found to be very small, except of course in the collinear region of single W-boson production where the electron mass acts as the cut-off.Comment: 8 pages, latex, 3 ps figs include

Fully automated calculation in fermion scattering

The package aITALC has been developed for fully automated calculations of two fermion production at e+ e- collider and other similar reactions. We emphasize the connection and interoperability between the different modules required for the calculation and the external tools Diana, Form and LoopTools. Results for e+ e- -> f anti-f, e+ e- are presented.Comment: 5 pages, 2 tables, 2 figures. Contribution to the X International Workshop on Advanced Computing and Analysis Techniques in Physics Research, ACAT 2005, May 22-27, 2005, Zeuthen (Germany

Signature of exotic particles in light by light scattering

We discuss the implications on light by light scattering of two kind of exotic particles: doubly charged scalar bosons and doubly charged fermions; the virtual effects of a nonstandard singly charged gauge boson are also examined. These particles, if their masses lie in the range 0.1--1.0 TeV, will have a clear signature in the future linear colliders. The present analysis has the advantage that it depends only on electromagnetic symmetry, so it is applicable to any model which predicts this class of particles. In particular, our results have interesting consequences on left-right models and their supersymmetric extension.Comment: 6 eps figures. Requires elsevier.cl

EEWW: a generator for e+e−→W+W−e^+e^- \to W^+W^- including one-loop and leading photonic two-loop corrections

We describe a generator for the process $e^+e^- \to W^+W^-$ including all one-loop and leading log photonic two-loop contributions. It includes polarization of the beam and $W$ bosons, and the possibility to study the effect of anomalous couplings.Comment: 13 pages latex with 2 figures ps; also available as http://pss058.psi.ch/preprints/eewwmc.ps; PSI-PR-94-16 (added two references

Haunted Archives: Presence and Absence in the Audio-visual Record of Conflict in Bosnia-Herzegovina

This paper examines the potential consequences of the loss of raw rushes of historical events on collective memory. It examines two sets of rushes from 21 August 1993 that survived against the odds, of the arrival of the first humanitarian aid convoy in the besieged enclave of east Mostar, Bosnia-Herzegovina. These rushes were compared with edited accounts and examined for elements that, in the words of Dai Vaughan, could generate “meanings oblique, peripheral or even antagonistic to the text as understood.”&nbsp; According to a well-worn maxim, “journalism is the first rough draft of history”. This is certainly true for audio-visual media: typically, archives preserve edited, “finished” films, and rushes often get lost from the record. This highlights a sometimes overlooked form of exclusion from the archive: the selection of footage in the editing room. In commercial news archives economic pressures determine which footage will be digitised, and a diminishing pool of well-known images tend to be re-used in a “feedback loop of historical footage”.&nbsp; Examining the rushes of the aid convoy to Mostar reveals how much the news coverage is coloured by the media spectacle accompanying the convoy. The clear emphasis on the humanitarian aspects of the story downplays the political stakes of the warring parties, and incongruous jokes to the camera provide unexpected glimpses of the pressures and the privileges of the international journalists and aid workers producing the images. These are insights that could only have been gleaned from the raw rushes of the situation, and are an indication of the kind of insights into comparable events that may have been “narrativised” out of the historical record, and lost on the cutting room floor.&nbsp