JETSET Experiment Research Articles

A partial wave analysis of proton-antiproton annihilation above threshold for ϕϕ production in the JETSET experiment

The JETSET experiment (PS202) conducted at CERN was designed to search for gluonic resonances in the mass range between 2.1 and 2.4 GeV using the channel p̄p → ϕϕ. This channel is OZI suppressed, thus any observed enhancement of the cross section beyond expections of theOZI rule could indicate possible resonating gluonic degrees of freedom. Infact, the measured cross section is two orders of magnitude beyond OZI expections. Subsequent spin-parity analyses have suggested a resonance with adominant J = 2 spin component and a parity of +1. Recently, another spin-parity analysis has been performed. This analysis includes the possibility of coherent interference with a scaler background. It will be summarized that the overall fit quality improves when coherent interference is included. A dominant spin component of J = 2 still emerges but a J = 4 component is also present.

A luminosity monitor system for the JETSET experiment at LEAR

Abstract A luminosity-monitor system for the JETSET experiment at LEAR is described. Four silicon-strip detectors are used as position sensitive devices to monitor the elastic p p-scattering. The design concept, data-acquisition and results of the detector system are presented. On-line monitoring is used to assure the proper operation of the JETSET experiment.

A new Fastbus-VMEbus interface and its use in the JETSET experiment at LEAR

A set of VMEbus modules has been developed, its primary purpose being to provide the experimenter with a high-speed data sink for Fastbus digitisers and a sequencer-controlled interface between Fastbus and VMEbus. One application of these modules is the parallel detector readout implemented for the PS202 (JETSET) experiment at CERN-LEAR. Operation and performance of the new devices as an integral part of the data-acquisition system are described. For a full Fastbus crate loaded with ADCs or TDCs, complete readout and subevent buffering is accomplished within a few hundred microseconds.

Calculation of $$\bar pp \to \phi \phi$$ using two-meson intermediate states

We study the two-meson intermediate state contributions to the¯ pp →φφ reaction. The estimated cross section from the ¯KK intermediate states is close to the recent preliminary data of the JETSET experiment at LEAR. We have also analysedpp intermediate states and ω-φ mixing mechanisms. Their contributions are found to be much smaller than the ¯KK contribution. Implications for the search of gluonic intermediate states are discussed. Results on similar intermediate two-meson contributions to ¯pp →φπ at rest are also briefly presented.

A fast RICH detector for JETSET

A fast RICH is being prepared for installation in the forward region of the JETSET experiment at LEAR. In the absence of a magnetic field for momentum analysis, the RICH is intended to measure charged particle velocities in the range 0.68 < β < 1, where dE/dx is decreasingly effective. A segment of the RICH detector, consisting of a modular wire chamber operating at room temperature and pressure with a He/C2H6/TMAE gas mixture, has been tested with a planar quartz radiator in a p/π beam of 1.0–3.5 GeV/c momentum. The analysis of the events and the resulting velocity resolution is presented. The measured photoelectron multiplicity is compared with Monte Carlo calculations. The measurements show a good efficiency and a low background for UV photon detection.