The straw tube technology for the LHCb outer tracking system Bachmann, S.; Bagaturia, I.; Deppe, H. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
12/2004, Volume:
535, Issue:
1
Journal Article
Peer reviewed
Open access
For the outer tracking system of the LHCb spectrometer 53.760 straws of 2.5
m length will be used. They are arranged in detector modules of 5
m length and 0.34
m width. The envisaged spatial ...resolution over the entire active area is 200
μ
m resulting in stringent requirements on the accuracy for the module construction.
In this paper we discuss the optimisation of the straws, design and construction of detector modules. The long-term operation properties of straws in two different counting gases, Ar/CO
2
(70/30) and Ar/CO
2
/CF
4
(75/10/15), are compared.
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.
A maximum likelihood analysis of ARGUS data on two-photon production of
π
+
π
+
π
0
π
0
π
−
π
− is presented. A small fraction of events is due to the production of omega pairs. The
γγ →
ωω cross ...section has its maximum value close to threshold.
Using the ARGUS detector at the e
+e
− storage ring DORIS II at DESY, we have searched for decays
b →
s
gluon through full reconstruction of a whole event. Two B
B
decays were found with one of B ...meson decaying into a final state without charmed particles. We also obtained an upper limit of
Br(B
+ →
τ
+
ν
τ
) of 1.04% at 90%
CL.
Using the detector ARGUS at the
e
+
e
− storage ring DORIS II at DESY, we have observed the decays
Λ
c
+ →
Ξ
−
K
+
π
+ and
Λ
c
+ → Ξ
∗0K
+
and obtained evidence for the decay
Ξ
c
0 →
ΛK
s
0. All ...three of these decays are of interest as they provide information about
W-exchange processes. The products of cross sections and branching ratios for
Λ
c
+ →
Ξ
−
K
+
π
+ and
Λ
c
+ → Ξ
∗0K
+
are (1.7±0.3±0.3) pb and (0.6±0.2±0.1) pb, respectively, which implies that (35±17) % of the
Ξ
−
K
+
π
+ final state is generated through a two-body decay via intermediate
W-exchange. The product of production cross section and branching ratio for
Ξ
c
0 →
Λ
K
s
0 is (2.1 ± 1.0 ± 0.6) pb.
The straw tube technology for the LHCb outer tracking system BACHMANN, S; BAGATURIA, I; DEPPE, H ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
12/2004, Volume:
535, Issue:
1-2
Journal Article
The design and construction of the BaBar electromagnetic calorimeter are reviewed. Recent results on the expected sensitivity of the CsI(TI) to radiation damage are discussed. The performance of the ...calorimeter in the first PEP-II run is presented. Particular emphasis is placed on operational experience and the measured degradation due to radiation damage. Correlation of radiation damage with the dose recorded in a novel large-scale array of radiation sensitive FETs are presented. The consequences for the long-term performance of a CsI(TI) calorimeter operating in a high background environment are discussed.
Using the ARGUS detector at the
e
+
e
− storage ring DORIS II at DESY, we have found evidence for the production of the excited charmed baryon state
Λ
c
(2593)
+ in the channel
Λ
c
+
π
+
π
−. Its ...mass was determined to be (2594.6±0.9±0.4) MeV/c
2, and the natural width measured to be Γ = (2.9
−2.1−1.4
+2.9+1.8) MeV. The production cross section times the branching ratios of
σ(
e
+
e
− →
Λ
c
(2593)
+
X) ×
Br(
Λ
c
(2593)
+ →
Λ
c
+
π
+
π
−) ×
Br(
Λ
c
+ →
pK
−
π
+) was measured to be (0.25
−0.13
+0.24 ±0.13) pb. The fractions of
Λ
c
(2593)
+ decays proceeding through the
Σ
c
0
π
+ and
Σ
c
++
π
− channels were determined to be 0.29±0.10±0.11 and 0.37±0.12±0.13, respectively.
Results from the BABAR electromagnetic calorimeter beam test Barlow, Roger J.; Bernet, Roland; Bowdery, Christopher K. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
1999, 1999-1-00, Volume:
420, Issue:
1
Journal Article
Peer reviewed
Open access
We present results from the PSI test beam run for the electromagnetic calorimeter of the BABAR experiment. A system of 25 CsI(Tl) crystals was tested with electrons and pions in the momentum range ...from 100 to 405
MeV/
c. Results are presented on crystal light output, on coherent and incoherent noise, on energy resolution and on spatial resolution. The design energy resolutions of the Technical Design Report of BABAR were achieved.
Using the ARGUS detector at the
e
+
e
− storage ring DORIS II, we have measured the Michel parameters
ρ,
ξ, and
ξδ for
τ
±→l
±ν
ν
̄
decays in
τ-pair events produced at center of mass energies in the ...region of the
ϒ resonances. Using
τ
∓→
ρ
∓
ν as spin analyzing tags, we find
ρ
e
=0.68±0.04±0.08,
ξ
e
=1.12±0.20±0.09,
ξδ
e
=0.57±0.14±0.07,
ρ
μ
=0.69±0.06±0.08,
ξ
μ
=1.25±0.27±0.14 and
ξδ
μ
=0.72±0.18±0.10. In addition, we report the combined ARGUS results on
ρ,
ξ, and
ξδ using this work und previous measurements.
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