Study of τ−→KSπ−ντ decay at Belle Epifanov, D.; Aihara, H.; Aulchenko, V. ...
Physics letters. B,
10/2007, Letnik:
654, Številka:
3-4
Journal Article
Recenzirano
We present a study of the decay τ−→KSπ−ντ using a 351 fb−1 data sample collected with the Belle detector. The analysis is based on 53,110 lepton-tagged signal events. The measured branching fraction ...B(τ−→KSπ−ντ)=(0.404±0.002(stat.)±0.013(syst.))% is consistent with the world average value and has better accuracy. An analysis of the KSπ− invariant mass spectrum reveals contributions from the K∗(892)− as well as other states. For the first time the K∗(892)− mass and width have been measured in τ decay: M(K∗(892)−)=(895.47±0.20(stat.)±0.44(syst.)±0.59(mod.)) MeV/c2, Γ(K∗(892)−)=(46.2±0.6(stat.)±1.0(syst.)±0.7(mod.)) MeV. The K∗(892)− mass is significantly different from the current world average value.
HERA-B is a fixed target spectrometer which uses
920
GeV
protons incident on various target materials. The experiment is aimed to study various aspects of beauty and charm physics. The detector is ...designed to operate at high interaction rates with an average of 4–5 interactions per event. The First-Level Trigger (FLT) is required to reduce the input rate by more than two orders of magnitude while keeping high efficiency for beauty and charm channels. The trigger performs online track reconstruction and takes decisions based on particle momenta or pair masses. A pipeline architecture is implemented on about 100 pipelined hardware processors to perform this job. The working principle and first results of the FLT performance based on the data acquired during the run in the year 2000 are described.
The excellent jet energy resolution required for precise physics measurements at ILC is achievable using a Particle Flow Method and highly granular calorimeters. As it was shown by CALICE ...international R&D collaboration, the silicon-tungsten imaging electromagnetic calorimeter provides the best granularity, stability and resolution of jet energy measurement. After proving the calorimeter concept with physical prototypes in 2005–2011, an emphasis is now moved to building a technological prototype satisfying challenging requirements. All chosen technologies should be reliable and scalable for a mass production of a future detector. We report on the current status of R&D, in particular, on beam and charge injection tests of the technological prototype and on the tests of ECAL mechanical structure. We also report on our plans to build a realistic prototype detector and test it together with an existing carbon fiber-tungsten mechanical structure. A similar silicon-tungsten calorimeter technology has been recently proposed for the Phase 2 upgrade of CMS end-cap calorimeter and future high energy circular collider projects.
We report on the design, construction and performance of a prototype for a high-granularity tile hadronic calorimeter for a future international linear collider detector. Scintillating tiles are read ...out via wavelength-shifting fibers that guide the scintillation light to a novel photodetector, the silicon photomultiplier. A prototype has been tested using a positron test beam at DESY. The results are compared with a reference prototype calorimeter equipped with multichannel vacuum photomultipliers. Detector calibration, noise, linearity and stability are discussed, and the energy response in a 1–6
GeV positron beam is compared with simulations. The present results demonstrate that the silicon photomultiplier is well-suited as photodetectors in calorimeters and thus has been selected for the construction of a
1
m
3
calorimeter prototype to operate in hadron beams.
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