Glueballs, Hybrids, Multiquarks. Experimental facts versus QCD inspired concepts

http://cds.cern.ch/record/954903/files/0609101.pdf

Heavy-Flavour Hadro-Production from Fixed-Target to Collider Energies

The main characteristics of the COMPASS experimental setup for physics with hadron beams are described. This setup was designed to perform exclusive measurements of processes with several charged and/or neutral particles in the final state. Making use of a large part of the apparatus that was previously built for spin structure studies with a muon beam, it also features a new target system as well as new or upgraded detectors. The hadron setup is able to operate at the high incident hadron flux available at CERN. It is characterised by large angular and momentum coverages, large and nearly flat acceptances, and good two and three-particle mass resolutions. In 2008 and 2009 it was successfully used with positive and negative hadron beams and with liquid hydrogen and solid nuclear targets. This paper describes the new and upgraded detectors and auxiliary equipment, outlines the reconstruction procedures used, and summarises the general performance of the setup.

The COMPASS Setup for Physics with Hadron Beams

The spectroscopy of light and heavy mesons is reviewed with emphasis on glueballs, hybrids, and tetraquarks.

Measurements of charmed-meson production in interactions between 350 GeV/c π− particles and nuclei

We describe the detectors and trigger system used in the CERN WA92 experiment. The experiment was designed to study the production and decay of beauty particles from 350 GeV/ c π − interactions in copper and tungsten targets. Charged particle tracking is performed using the omega spectrometer. Silicon microstrip detectors are used to provide precise tracking information in the region of the production and the decay of heavy-flavoured particles and to trigger on the resulting high impact parameter tracks. The precision of vertex reconstruction corresponds to ±3.7% of the mean B-decay proper lifetime. Lepton and high transverse momentum hadron signals are also used in the trigger, which accepts 23% of B-decays and rejects 98.4% of non-beauty interactions.

/pdf/wa92-a-fixed-target-experiment-to-trigger-on-and-identify-idlcmznu5o.pdf

R. Gessaroli

Papers

WA92: A fixed target experiment to trigger on and identify beauty particle decays

Search for the decay D0 → μ+μ−