Kaonic atoms and the Λ(1405) Weise, W.; Tauscher, L.
Physics letters. B,
2000, Letnik:
64, Številka:
4
Journal Article
Recenzirano
Kaonic shifts and widths for
12C and
32S are analysed using an optical potential, which selectively incorporates nuclear shell structure aspects as well as effects of Λ(1405) dynamics inside the ...nucleus. Good agreement with data is found and suggests a moderately repulsive interaction of the Λ(1405) with surrounding nucleons.
The CPLEAR electromagnetic calorimeter Adler, R.; Backenstoss, G.; Bal, F. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
05/1997, Letnik:
390, Številka:
3
Journal Article
Recenzirano
Odprti dostop
A large-acceptance lead/gas sampling electromagnetic calorimeter (ECAL) was constructed for the CPLEAR experiment to detect photons from decays of π
0s with momentum
p
π
0 ≤ 800 MeV/
c. The main ...purpose of the ECAL is to determine the decay vertex of neutral-kaon decays K
0 → π
0π
0 → 4γ and K
0 → π
0π
0π
0 → 6γ. This requires a position-sensitive photon detector with high spatial granularity in
r−,
ϕ−, and
z−coordinates. The ECAL - a barrel without end-caps located inside a magnetic field of 0.44 T - consists of 18 identical concentric layers. Each layer of
1
3
radiation length (
X
0) contains a converter plate followed by small cross-section high-gain tubes of 2640 mm active length which are sandwiched by passive pick-up strip plates. The ECAL, with a total of 6
X
0 has an energy resolution of
α(E)
E
≈
13%
(E(
GeV)
and a position resolution of 4.5 mm for the shower foot. The shower topology allows separation of electrons from pions. The design, construction, read-out electronics, and performance of the detector are described.
DIRAC: A high resolution spectrometer for pionium detection Adeva, B.; Afanasyev, L.; Benayoun, M. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
12/2003, Letnik:
515, Številka:
3
Journal Article
Recenzirano
Odprti dostop
The DIRAC spectrometer has been commissioned at CERN with the aim of detecting π+π− atoms produced by a 24GeV/c high intensity proton beam in thin foil targets. A challenging apparatus is required to ...cope with the high interaction rates involved, the triggering of pion pairs with very low relative momentum and the measurement of the latter with resolution around 0.6MeV/c. The general characteristics of the apparatus are explained and each part is described in some detail. The main features of the trigger system, data-acquisition, monitoring and set-up performances are also given.
We study ππ correlations in the exclusive reaction pp → 2π+2π− at rest measured by the CPLEAR experiment. Avoiding the introduction of an arbitrary reference sample, we analyse differential ...distributions for equal charge pion pairs removing the phase-space factor event by event. A peak at small relative momenta is most pronounced for large total momentum of the pair. The physical implications of bosonic symmetrization for the properties of the pion source, in particular its radius, are briefly discussed. The two extremes considered are the chaotic Hanbury-Brown-Twiss mechanism and the coherent Skyrmion model.
A new first-level trigger for the L3 experiment at LEP (CERN) is presented. It is using the inner time expansion chamber of the detector. The event selection is based on identifying sectors ...containing genuine tracks originating from the interaction point. The sector identification uses a neural network algorithm tuned to identify single tracks in a sector (hadronic jets are also selected). The hardware for this trigger is built around existing custom made neural network digital modules. The decision time is less than 100
ns and the final rate of accepted events is 1–5
Hz depending on the beam luminosity.
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