Using the ARGUS detector at the
e
+
e
− storage ring DORIS II, we have searched for the real and imaginary part of the electric dipole formfactor
d
τ
of the
τ lepton in the production of
τ pairs at
q
...2=100
GeV
2
. This is the first direct measurement of this
CP
violating formfactor. We applied the method of optimised observables which takes into account all available information on the observed
τ decay products. No evidence for
CP
violation was found, and we derive the following results:
Re(d
τ)=(1.6±1.9)·10
−16
e
cm
and
Im(d
τ)=(−0.2±0.8)·10
−16
e
cm
, where statistical and systematic errors have been combined.
The construction of a micro-pattern gas detector of dimensions
40×10
cm
2
is described. Two gas electron multiplier foils (GEM) provide the internal amplification stages. A two-layer readout ...structure was used, manufactured using the same technology as the GEM foils. The strips of each layer cross at an effective crossing angle of 6.7° and have a
406
μm
pitch. The performance of the detector has been evaluated in a muon beam at CERN using a silicon telescope as reference system. The position resolutions of two orthogonal coordinates are measured to be
50
μm
and
1
mm
, respectively. The muon detection efficiency for two-dimensional space points reaches 96%.
Drift chamber readout with 1 Gsample/s full signal digitization Cerrito, L; Gatta, M; Imhof, M ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
11/1999, Letnik:
436, Številka:
3
Journal Article
Recenzirano
Odprti dostop
This paper describes the performances of a large volume drift chamber with complete digitization of the output pulses. The electronics used in this test include wide-band (700
MHz) amplifiers and ...fast (1 Gsample/s) digitizers. The gas mixture selected for drift chamber operation (80% He–20% CH
4) and the signal processing mentioned above allow the measurement of the primary ionization clusters. The improvement in the (wire) impact parameter evaluation of the primary particle is sizeable.
We report on the performance of a large micro-pattern detector with two gas electron multiplier foils and a two-layer readout structure at ground potential. The two readout layers each have a
406
μm
...pitch and cross at an effective angle of 6.7°. This structure allows for two orthogonal coordinates to be determined. Using a muon beam at CERN together with a silicon tracking system, the position resolutions of the two coordinates are measured to be
50
μm
and 1
mm respectively (1 standard deviation). The muon detection efficiency for the two-dimensional space points reaches 96%. The detector was found to be well operational over a wide range in the settings of the different electrical fields.
For the first time an electrostatic method of wire tension measurement (WTM) is used for drift chamber construction. It became possible due to the use of a digital approach to sense the wire ...oscillations induced by an alternating potential. The method has excellent signal-to-noise ratio, high accuracy which is well above the stringing requirements and reasonable measuring time. The WTM system implemented in a CAMAC–Machintosh–Labview environment is now in use for the KLOE drift chamber stringing control and for monitoring the end-plate deformation.
The KLOE Drift Chamber construction Bencivenni, G.; Andryakov, A.; Antonelli, A. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
12/1998, Letnik:
419, Številka:
2-3
Journal Article
Recenzirano
The tracking detector of the KLOE experiment is a large volume drift chamber designed to contain most of the decays of KL produced at the DAFNE Φ factory. The design of the chamber, choice of ...materials, stringing technique are described in detail as well as the quality tests performed during the construction.
dE/dx measurement in a He-based gas mixture Andryakov, A; Antonelli, A; Baldini-Ferroli, R ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
05/1998, Letnik:
409, Številka:
1-3
Journal Article
Recenzirano
The performance of a prototype drift chamber operating in a He-based gas mixture as a specific ionisation detector is presented. In spite of the small number of primary ions, Helium performs quite ...satisfactorily in measuring energy losses for charged particles: with 50GeV/c pions, we have measured in a 90%He–10%iC4H10 mixture a relative energy loss resolution of 3.1% with 75 samples 3cm long, using a modified Truncated Mean technique with 80% accepted fraction.
The dependence of the resolution on several parameters such as the operating voltage, the truncation fraction, the number and length of the samples is discussed.
The ARGUS vertex trigger Koch, N.; Kolander, M.; Kolanoski, H. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
05/1996, Letnik:
373, Številka:
3
Journal Article
Recenzirano
Odprti dostop
A fast second level trigger has been developed for the ARGUS experiment which recognizes tracks originating from the interaction region. The processor compares the hits in the ARGUS micro vertex ...drift chamber to 245 760 masks stored in random access memories. The masks which are fully defined in three dimensions are able to reject tracks originating in the wall of the narrow beampipe of 10.5 mm radius.
Results from the full-length prototype of the KLOE Drift Chamber Andryakov, A.; Antonelli, A.; Baldini-Ferroli, R. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
05/1998, Letnik:
409, Številka:
1-3
Journal Article
Recenzirano
A full-size prototype of the KLOE drift chamber has been built and successfully exposed to a 50GeV/c pion beam at CERN. The performances of the detector are presented.
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