https://cds.cern.ch/record/245580/files/cer-000161656.pdf

Study of D+ and D− Feynman's x distributions in π−-nucleus interactions at the SPS

The last decade has seen substantial progress in the use of solid state detectors, which are now exploited on a large scale in high energy physics experiments for precise positional measurements. This article surveys the major classes of detector and the methods employed to construct them and instrument the large systems presently in use for particle tracking. Some of the most topical areas of current research and an indication of future important applications are described.

https://iopscience.iop.org/article/10.1088/0034-4885/57/5/002/pdf

Semiconductor particle tracking detectors

We report on a high statistics search for the ${\ensuremath{\Xi}}^{\ensuremath{-}\ensuremath{-}}(1860)$ resonance in ${\ensuremath{\Sigma}}^{\ensuremath{-}}$-nucleus collisions at $340\phantom{\rule{0.3em}{0ex}}\mathrm{GeV}∕c$. No evidence for this resonance is found in our data sample which contains 676000 ${\ensuremath{\Xi}}^{\ensuremath{-}}$ candidates above background. For the decay channel ${\ensuremath{\Xi}}^{\ensuremath{-}\ensuremath{-}}(1860)\ensuremath{\rightarrow}{\ensuremath{\Xi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{\ensuremath{-}}$ and the kinematic range $0.15l{x}_{F}l0.9$ we find a $3\ensuremath{\sigma}$ upper limit for the production cross section of 3.1 and $3.5\phantom{\rule{0.3em}{0ex}}\ensuremath{\mu}\mathrm{b}$ per nucleon for reactions with carbon and copper, respectively.

/pdf/search-for-the-exotic-x-1860-resonance-in-340-gev-c-s-22glsv2kk4.pdf

Search for the exotic Ξ––(1860) resonance in 340 GeV/c Σ –-nucleus interactions

Nuclear dependence of charm production by a 340 GeV π- beam

A study of the semileptonic decay

A high-intensity hyperon beam was constructed at CERN to deliver Σ− to experiment WA89 at the Omega facility and operated from 1989 to 1994. The setup allowed rapid changeover between hyperon and conventional hadron beam configurations. The beam provided a Σ− flux of 1.4×105 per burst at mean momenta between 330 and 345 GeV/c produced by about 3×1010 protons of 450 GeV/c. At the experiment target the beam had a Σ−/π− ratio close to 0.4 and a size of 1.6×3.7cm2. The beam particle trajectories and their momenta were measured with a scintillating fibre hodoscope in the beam channel and a silicon microstrip detector at the exit of the channel. A fast transition radiation detector was used to identify the pion component of the beam.

The High intensity hyperon beam at CERN

The implementation of a trigger aimed at selecting those nuclear interactions which contain a charm particle is described. The trigger uses a fast emulator of the PDP-11 which calculates the impact parameter of the decaying charged tracks originating from the charm decay. An enrichment factor of 15 is thereby obtained. The results obtained show that, in its present implementation, this trigger, while giving a good enrichment factor, performs a correct rejection, since it does not eliminate many good events that would have been retained by the more sophisticated selection of the offline programs. >

/pdf/results-on-heavy-quark-selection-through-an-impact-parameter-4vd72i3vgc.pdf

M. Zavertiaev

Papers

The High intensity hyperon beam at CERN

Results on heavy quark selection through an impact parameter trigger