We present a novel method for the reconstruction of events containing pairs of hadronically decaying tau leptons at collider experiments. This method relies on accurate knowledge of the tau production vertex and precise measurement of its charged dec
ay products. The method makes no assumptions about the centre-of-mass or invariant mass of the tau pair, and is insensitive to momentum loss along the beam direction. We demonstrate the method using e+e- -> mu+ mu- tau+ tau- events fully simulated in the ILD detector.
We describe an algorithm which has been developed to extract fine granularity information from an electromagnetic calorimeter with strip-based readout. Such a calorimeter, based on scintillator strips, is being developed to apply particle flow recons
truction to future experiments in high energy physics. Tests of this algorithm in full detector simulations, using strips of size 45 x 5 mm^2 show that the performance is close to that of a calorimeter with true 5 x 5 mm^2 readout granularity. The performance can be further improved by the use of 10 x 10 mm^2 tile- shaped layers interspersed between strip layers.
The International Large Detector (ILD) is a proposed detector for the International Linear Collider (ILC). It has been designed to achieve an excellent jet energy resolution by using Particle Flow Algorithms (PFA), which rely on the ability to separa
te nearby particles within jets. PFA requires calorimeters with high granularity. The ILD Electromagnetic Calorimeter (ECAL) is a sampling calorimeter with thirty tungsten absorber layers. The total thickness of this ECAL is about 24 X$_0$, and it has between 10 and 100 million channels to make high granularity. Silicon sensors are a candidate technology for the sensitive layers of this ECAL. Present prototypes of these sensors have 256 5.5$times$5.5 mm$^2$ pixels in an area of 9$times$9 cm$^2$.We have measured various properties of these prototype sensors: the leakage current, capacitance, and full depletion voltage. We have also examined the response to an infrared laser to understand the sensors response at its edge and between pixel readout pads, as well the effect of different guard ring designs. In this paper, we show results from these measurements and discuss future works.
We explore the fractal nature of particle showers using Monte-Carlo simulation. We define the fractal dimension of showers measured in a high granularity calorimeter designed for a future lepton collider. The shower fractal dimension reveals detailed
information of the spatial configuration of the shower. %the information hidden in the details of shower spatial configuration, It is found to be characteristic of the type of interaction and highly sensitive to the nature of the incident particle. Using the shower fractal dimension, we demonstrate a particle identification algorithm that can efficiently separate electromagnetic showers, hadronic showers and non-showering tracks. We also find a logarithmic dependence of the shower fractal dimension on the particle energy.
The precise measurement of hadronic jet energy is crucial to maximise the physics reach of a future Linear Collider. An important ingredient required to achieve this is the efficient identification of photons within hadronic showers. One configuratio
n of the ILD detector concept employs a highly granular silicon-tungsten sampling calorimeter to identify and measure photons, and the GARLIC algorithm described in this paper has been developed to identify photons in such a calorimeter. We describe the algorithm and characterise its performance using events fully simulated in a model of the ILD detector.
This paper presents mechanical R&D for the CALICE Silicon-tungsten electromagnetic calorimeter. After the physics ECAL prototype, tested in 2006 (DESY-CERN), 2007 (CERN), 2008 (FNAL) and before the design of different modules 0 (barrel and endcap) fo
r a final detector, a technological ECAL prototype, called the EUDET module, is under design in order to have a close to full scale technological solution which could be used for the final detector, taking into account future industrialisation of production.
