We present the result of a direct search for the decay KS→e+e−, obtained with a sample of e+e−→ϕ→KSKL events produced at DAΦNE, the Frascati ϕ-factory, for an integrated luminosity of 1.9 fb−1. The ...search has been performed using a pure KS beam tagged by the simultaneous detection of a KL interaction in the calorimeter. Background rejection has been optimized by using both kinematic and particle identification cuts. We find BR(KS→e+e−)<9×10−9 at 90% CL, which improves by an order of magnitude on the previous best limit.
Offline analysis of HEP events by “dynamic perceptron” neural network Perrone, A.L; Basti, G; Messi, R ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
04/1997, Volume:
389, Issue:
1
Journal Article
Peer reviewed
In this paper we start from a critical analysis of the fundamental problems of the parallel calculus in linear structures and of their extension to the partial solutions obtained with non-linear ...architectures. Then, we present shortly a new dynamic architecture able to solve the limitations of the previous architectures through an automatic redefinition of the topology. This architecture is applied to real-time recognition of particle tracks in high-energy accelerators.
Calibration and performances of the KLOE calorimeter Ambrosino, F.; Antonelli, A.; Antonelli, M. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
2009, 2009-1-00, Volume:
598, Issue:
1
Journal Article
Peer reviewed
The KLOE experiment uses a fine sampling lead-scintillating fibre calorimeter to measure energy, time and position of neutral and charged particles. The overall detector consists of 88 modules ...organised in a barrel and two end-caps, for a total granularity of 2440 cells, read-out by photo-multipliers at both fibre ends. The chosen design of a high sampling fraction with the usage of thin lead layers and fast scintillating fibres allows to reach good efficiency for photon energies down to few
MeV, good energy resolution and excellent time resolution. The design, calibration and performances of the calorimeter on efficiency, time/position/energy resolution and particle identification is reviewed. The overall calorimeter impact on kaon tagging and on physics results is also presented.
The full-length prototype of the KLOE drift chamber Andryakov, A.; Avanzini, C.; Bacci, C. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
1998, Volume:
404, Issue:
2
Journal Article
Peer reviewed
The main goal of the KLOE experiment is the study of CP violation in the K mesons system, with an accuracy of 10
−4 in the measurement of
Re(
ε′
ε
)
. This task imposes strong constraints on the ...design and operation of the drift chamber, which must reconstruct the charged decays of low momentum K
L's and K
S's with high efficiency and high resolution. A full-length prototype of the chamber has been built and tested on a 50 GeV/
c beam. The analysis of the large sample of data has allowed a detailed study of the time to distance relations as a function of the track parameters and of the peculiar geometry of the drift cell. The detector performance, in terms of efficiency, spatial resolutions and
dE
dχ
resolution, is illustrated and discussed.
We have measured the radiative decays
φ→
ηγ,
φ→
η′
γ selecting
π
+
π
−
γγγ final state in a sample of ∼5×10
7
φ-mesons produced at the Frascati
φ-factory DA
ΦNE. We obtain
Γ(
φ→
η′
γ)/
Γ(
φ→
...ηγ)=(4.70±0.47±0.31)×10
−3. From this result we derive new accurate values for the branching ratio BR(
φ→
η′
γ)=(6.10±0.61±0.43)×10
−5 and the mixing angle of pseudoscalar mesons in the flavour basis
ϕ
P
=(41.8
+1.9
−1.6)°.
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