Energy Electron-positron Collider Research Articles

Triplet Higgs bosons at e+e− colliders

We investigate the possibility of probing the triplet Higgs boson sector via single charged Higgs production in the process e + e − → H + lν l , at high energy electron-positron colliders, using the tree level H + W − Z coupling which is a unique feature of such models. We find that even LEP-200 can give nontrivial information up to M H ± ⋍ 120 GeV if the doublet -triplet mixing is not restricted by the current value of the ϱ parameter. Further we point out that in such models, the 4-body, tree level decay H + → W ∗Z ∗ → 4 fermions dominates and hence provides a very clean signal. At NLC the discovery range for the charged Higgs in triplet models via this process is ∼ 400 GeV.

A fast track finding trigger processor for the BES detector

The Beijing Spectrometer (BES) is being designed and constructed for use at the Beijing 2 × 2.8 GeV center-of-mass energy electron-positron collider (BEPC). The BES detector will have approximately 20 K channels of electronics, and the beam collision rate will be 1.25 MHz, corresponding to a luminosity of 10 30−10 31 cm −2 s −1. A fast programmable track finding processor to be used in the second level trigger is described. This processor, mainly consisting of 3 out of 4 logic and track finding logic, is simple and flexible. Only 96 pieces of 4K × 1 bit random access memory (RAM) chips are used for the track finding logic on 4 layers of the main drift chamber.

Higgs boson production and the scattering of longitudinally polarized vector bosons at very high energy electron-positron colliders

A detailed discussion is presented of rates and backgrounds for studying Higgs boson production and W LW L, Z LZ L, W LZ L scattering at very high energy e +e − colliders. The e ̄ e → e ̄ eWW , γγWW backgrounds limit the reach for discovering Higgs bosons. Strong interaction effects, which must develop for invariant masses above 1 TeV if there is no Higgs boson or if M H is very large, would best be seen in final states involving two Z's which decay to charged leptons, for which backgrounds are small. Quantitative studies of strong interaction effects should be possible for √s ⪆ 5 TeV .

CAMAC crate controller on a FASTBUS cable segment

A CAMAC crate controller that can be attached to a FASTBUS cable segment has been designed to incorporate CAMAC systems into a FASTBUS environment. The controller meets the multiple controller specification of CAMAC. The block transfer modes are enhanced with functional shares with a FASTBUS master activity. The controllers are installed in the TOPAZ data acquisition system for the TRISTAN high energy electron-positron collider at KEK, Japan.