At the Belle II experiment a Time-of-Propagation (TOP) counter is used for particle identification in the barrel region. This novel type of particle identification device combines the Cherenkov ring ...imaging technique with the time-of-flight and therefore it relies on a precise knowledge of the time of collision in each triggered event. We discuss the performance of the counter and present a maximum likelihood based method for the determination of event collision time from the measured data.
At the Belle II spectrometer a Time-of-Propagation (TOP) counter is used for particle identification in the barrel region. The Belle II TOP counter consists of sixteen 2.7m long modules positioned in ...the space between the central drift chamber and the electromagnetic calorimeter. We discuss the methods for the alignment and calibration of the TOP counter with measured data.
Performance studies of the Belle II TOP counter Staric, M
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
12/2014, Letnik:
766
Journal Article
Recenzirano
We present the performance studies of the Belle II time-of-propagation (TOP) counter. The studies are performed with the Belle II software that includes Geant4 full detector simulation, realistic ...digitizers, track finding and fitting, and other reconstruction algorithms. We also compare a Geant4 based Monte Carlo simulation with the recently taken test beam data.
Pattern recognition for the time-of-propagation counter Staric, M
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
05/2011, Letnik:
639, Številka:
1
Journal Article
Recenzirano
In the barrel region at the Belle II detector, a time-of-propagation (TOP) counter is foreseen for particle identification. In this counter the particle identity is determined from a complicated ...pattern in the time and the position of Cherenkov photon hits. We present an extended likelihood method for particle identification, which is based on an analytical construction of the likelihood function.
We present a search for lepton-flavor-violating τ decays into three leptons (electrons or muons) using 782 fb−1 of data collected with the Belle detector at the KEKB asymmetric-energy e+e− collider. ...No evidence for these decays is observed and we set 90% confidence level upper limits on the branching fractions between 1.5×10−8 and 2.7×10−8.
The Belle II experiment at the SuperKEKB e+e− accelerator is preparing for taking first collision data next year. For the success of the experiment it is essential to have information about varying ...conditions available in the simulation, reconstruction, and analysis code. The interface to the conditions data in the client code was designed to make the life for developers as easy as possible. Two classes, one for single objects and one for arrays of objects, provide a type-safe access. Their interface resembles that of the classes for the access to event- level data with which the developers are already familiar. Changes of the referred conditions objects are usually transparent to the client code, but they can be checked for and functions or methods can be registered that are called back whenever a conditions data object is updated. The framework behind the interface fetches objects from the back-end database only when needed and caches them while they are valid. It can transparently handle validity ranges that are shorter than the finest granularity for the validity of payloads in the database. Besides an access to the central database the framework supports local conditions data storage which can be used as fallback solution or to overwrite values in the central database with custom ones.
Track based maximum likelihood ring search algorithm Starič, M.
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
09/2008, Letnik:
595, Številka:
1
Journal Article
Recenzirano
A track based maximum likelihood algorithm, unbiased to any mass hypothesis, has been developed for the HERA-B RICH to search for deuterons produced in 920
GeV proton–nucleus collisions. Clear ...signals of deuterons and anti-deuterons have been observed in data recorded by the HERA-B spectrometer. We present the algorithm, discuss its performance and show some preliminary results of an ongoing data analysis.
A
bstract
We present measurements of absolute branching fractions of hadronic and lep-tonic
$ D_s^{+} $
decays to
K
−
K
+
π
+
,
$ {{\overline{K}}^0} $
K
+
,
ηπ
+
,
μ
+
ν
μ
and
τ
+
ν
τ
and report a ...search for the leptonic
$ D_s^{+} $
→
e
+
ν
e
decays. The results are obtained from a data sample of 913 fb
−1
collected at or near the
$ \varUpsilon $
(4
S
) and
$ \varUpsilon $
(5
S
) resonances with the Belle detector at the KEKB asymmetric-energy
e
+
e
−
collider. The branching fractions of hadronic decays are measured to be
$ \begin{array}{*{20}{c}} {\mathcal{B}\left( {D_s^{+}\ \to\ {K^{-}}{K^{+}}{\pi^{+}}} \right) = \left( {5.06\pm 0.15\pm 0.21} \right)\%,} \\ {\mathcal{B}\left( {D_s^{+}\ \to\ {{\overline{K}}^0}{K^{+}}} \right) = \left( {2.95\pm 0.11\pm 0.09} \right)\%,} \\ {\mathcal{B}\left( {D_s^{+}\ \to\ \eta {\pi^{+}}} \right) = \left( {1.82\pm 0.14\pm 0.07} \right)\%,} \\ \end{array} $
where the first and second uncertainties are statistical and systematic, respectively. The branching fractions of leptonic decays are measured to be
$ \begin{array}{*{20}{c}} {\mathcal{B}\left( {D_s^{+}\ \to\ {\mu^{+}}{\nu_{\mu }}} \right)=\left( {0.531\pm 0.028\pm 0.020} \right)\%,} \\ {\mathcal{B}\left( {D_s^{+}\to {\tau^{+}}{\nu_{\tau }}} \right)=\left( {5.70\pm 0.21_{-0.30}^{-0.31 }} \right)\%,} \\ \end{array} $
which are combined to determine the
$ D_s^{+} $
meson decay constant
$ {f_{{{D_s}}}=\left( {255.5\pm 4.2\pm 5.1} \right)\ \mathrm{MeV}. $
We find no significant signal for
$ D_s^{+} $
→
e
+
ν
e
decays and set an upper limit of
$ \mathcal{B}\left( {D_s^{+}\ \to\ {e^{+}}{\nu_e}} \right) $
<
1
.
0(0
.
83)
×
10
−4
at 95% (90%) confidence level.
We report on a search for the lepton flavor violating τ−→μ−γ and τ−→e−γ decays based on 535 fb−1 of data accumulated at the Belle experiment. No signal is found and we set 90% confidence level upper ...limits on the branching ratios B(τ−→μ−γ)<4.5×10−8 and B(τ−→e−γ)<1.2×10−7.
Likelihood analysis of patterns in a time-of-propagation (TOP) counter Starič, M.; Inami, K.; Križan, P. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
09/2008, Letnik:
595, Številka:
1
Journal Article
Recenzirano
For the upgrade of the Belle spectrometer, a Time-Of-Propagation (TOP) counter is planned in the barrel region. In this contribution, an analytical likelihood function to analyze the time dependent ...patterns on the image plane of the counter is presented.
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