Tau-pair process has been analyzed in the ILD detector model as a benchmark process for LoI. Results of background rejection, forward-backward asymmetry and polarization measurements are obtained with full detector simulation. Impact of detector parameters for tau-pair analysis is also discussed in this paper.
The International Large Detector, ILD, is a detector concept which has been developed for the electron-positron collider ILC. The detector has been optimized for precision physics in a range of energies between 90 GeV and 1 TeV. ILD features a high precision, large volume combined silicon and gaseous tracking system, together with a high granularity calorimeter, all inside a 3.5 T solenoidal magnetic field. The paradigm of particle flow has been the guiding principle of the design of ILD. In this document the required performance of the detector, the proposed implementation and the readiness o…
The process $e^- e^+ \to τ^- τ^+$ is of particular interest because the tau lepton polarisation can be reconstructed, allowing its chiral nature to be probed. This note reports on a study of the reconstruction of the di-tau final state at ILC-500, its selection and the reduction of backgrounds, the identification of the tau lepton's decay mode, and on the extraction of the tau leptons' polarisation. The performance of this analysis is studied in two models of the ILD detector, one larger (IDR-L) the other smaller (IDR-S), which differ in the outer radius of the TPC and of the subdetectors beyo…
The long slab is a new prototype for the SiW-Ecal, a silicon tungsten electromagnetic calorimeter for the ILD detector of the future International Linear Collider. This new prototype has been designed to demonstrate the ability to build a full length detecting layer (1.60m for the ILD barrel). Indeed, this length induces difficulties for clock and signal propagation and data integrity. The design used for short length slabs had to be adapted on the basis of a simulation study. The long slab performance has been tested with cosmics, radioactive source and with 3 GeV electrons in the beam tests …
The Particle Flow Algorithms adopted for future $e^{+}e^{-}$ colliders detectors and phase-II CMS upgrade require very high granularity calorimeters to deconvolve the individual contributions of particles in jets. This is especially true for electromagnetic calorimeters (ECAL). For a realistic large detector many technological requirements have to be fulfilled: modularity for industrialization; compact integration of an embedded very front-end electronics featuring large dynamics, low-power and self-triggering; mechanical structure and cooling systems with minimal dead zones. The technological…
Feasibility study of the forward-backward asymmetry of the e+e- -> t tbar process in all-hadronic decay modes at sqrt(s) = 500 GeV with the ILD detector
Although the LHC experiments have searched for and excluded many proposed new particles up to masses close to 1 TeV, there are many scenarios that are difficult to address at a hadron collider. This talk will review a number of these scenarios and present the expectations for searches at an electron-positron collider such as the International Linear Collider. The cases discussed include the light Higgsino, the stau lepton in the coannihilation region relevant to dark matter, and heavy vector bosons coupling to the s-channel in e$^+$e$^-$ annihilation. The studies are based on the ILD concept a…
The ILD detector is proposed for an electron-positron collider with collision centre-of-mass energies from 90~\GeV~to about 1~\TeV. It has been developed over the last 10 years by an international team of scientists with the goal to design and eventually propose a fully integrated detector, primarily for the International Linear Collider, ILC. In this report the fundamental ideas and concepts behind the ILD detector are discussed and the technologies needed for the realisation of the detector are reviewed. The document starts with a short review of the science goals of the ILC, and how the goa…
This study showcases the approaches towards lepton identification and $γγ$ mitigation at center-of-mass energy $\sqrt{s} = 500$ GeV for semileptonic WW decays at the ILC. The analysis is performed using fully simulated Standard Model Monte Carlo events with the ILD detector concept and emphasizes the measurement of the W mass. The mass measurement is performed through the identification of a lepton and treatment of the remaining system as the hadronic W-boson. Only the most favorable beam polarization scenario for WW production is considered. The resulting detector performance benchmark obtain…
We study the prospects for discovering an extra scalar boson $S^0$ at the International Linear Collider (ILC) based on a full simulation of the International Large Detector (ILD). In order to provide results in an as model-independent way as possible, the analysis uses the recoil of the scalar against a $Z$ boson decaying into a pair of muons, $e^+e^- \to μμS^{0}$. This process serves as a physics benchmark for the ILD detector performance at $\sqrt{s}=500$ GeV, specifically for the muon ID and momentum resolution, as well as for the identification of initial state radiation photons and their …
The International Large Detector: Letter of Intent
国际大型探测器(International Large Detector,ILD)是国际直线对撞机(International Linear Collider,ILC)的一个探测器概念。ILC将以最初500 GeV的能量碰撞电子和正电子,可扩展到1 TeV。ILC有一个雄心勃勃的物理计划,它将扩展和补充大型强子对撞机(LHC)。ILC物理学的一个特点是精确。轻子对撞机干净的初始状态和相对良好的环境非常适合高精度的测量。为了充分利用ILC的物理潜能,对探测器的性能提出了很高的要求。ILD的设计受这些要求驱动。出色的量热和跟踪相结合,以获得最佳的整体事件重建,包括重建单个粒子射流的粒子流量热的能力。这要求所有探测器系统都具有出色的空间分辨率。高度颗粒化的热量计系统与强调冗余和效率的中央跟踪器相结合。此外,有效的次顶点重构和良好的带电粒子动量分辨率是ILC探测器的基本条件。ILC的相互作用区域被设计成容纳两个探测器,这两个探测器可以通过推挽方案移动到光束位置。ILD的机械设计和子探测器的整体集成考虑了这些操作条件。
Standard three-flavor neutrino oscillations have well explained by a wide range of neutrino experiments. However, the anomalous results, such as electron-antineutrino excess seen by LSND and MiniBooNE do not fit the three-flavor paradigm. This can be explained by an additional fourth flavor sterile neutrino at a larger scale than the existing three flavor neutrinos. The NOvA experiment consists of two finely segmented, liquid scintillator detectors operating 14 .6 mrad off-axis from the NuMI muon-neutrino beam. The Near Detector is located on the Fermilab campus, 1 km from the NuMI target, whi…
The Super Tau-Charm Facility (STCF) is a future electron-positron collider proposed in China with a peak luminosity of above 0.5$\times$10$^{35}$ cm$^{-2}$s$^{-1}$ and center-of-mass energy ranging from 2 to 7 GeV. An excellent particle identification (PID) capability is one of the most important requirements for the detector at the STCF. A 3$σ$ $π$/K separation power at the momentum of up to 2 GeV/c is required within the detector acceptance. A DIRC-like time-of-flight (DTOF) detector is proposed to meet the PID requirement for the endcap region of the STCF. The conceptual design of the DTOF …
A highly granular silicon-tungsten electromagnetic calorimeter (SiW-ECAL) is the reference design of the ECAL of the International Large Detector (ILD) concept, one of the two detector concepts for the detector(s) at the future International Linear Collider. Prototypes for this type of detector are developed within the CALICE Collaboration. During the last year a highly compact digital readout system has been built. The system has been used for the first time in a beam test in Summer 2019 at DESY. This article summarises the main features of the system and report on its performance during the …
The design of detector concepts has been driven for a long time by requirements on transverse momentum, impact parameter and jet energy resolutions, as well as hermeticity. Only rather recently it has been realised that the ability to idenfity different types of charged hadrons, in particular kaons and protons, could have important applications at Higgs factories like the International Linear Collider (ILC), ranging from improvements in tracking, vertexing and flavour tagging to measurements requiring strangeness-tagging. While detector concepts with gaseous tracking, like a time projection ch…
The design of detector concepts has been driven for a long time by requirements on transverse momentum, impact parameter and jet energy resolutions, as well as hermeticity. Only rather recently it has been realised that the ability to idenfity different types of charged hadrons, in particular kaons and protons, could have important applications at Higgs factories like the International Linear Collider (ILC), ranging from improvements in tracking, vertexing and flavour tagging to measurements requiring strangeness-tagging. While detector concepts with gaseous tracking, like a time projection ch…
The quartic gauge coupling (QGC) of the electroweak interaction can be used as a probe for physics beyond the Standard Model and has been previously measured at the Large Hadron Collider. However, to achieve sensitivity to small deviations the couplings must be measured with precision beyond the capability of a hadron collider. An electron-positron collider with center-of-mass energies in the TeV range can precisely probe the QGC and test a variety of models. The International Linear Collider is such a collider project with a possible extension to $1\,$TeV. In this note the critical reconstruc…
This paper describes a novel algorithm for tagging jets originating from the hadronisation of strange quarks (strange-tagging) with the future International Large Detector (ILD) at the International Linear Collider (ILC). It also presents the first application of such a strange-tagger to a Higgs to strange ($h \rightarrow s\bar{s}$) analysis with the $P(e^-,e^+) = (-80\%,+30\%)$ polarisation scenario, corresponding to 900 fb$^{-1}$ of the initial proposed 2000 fb$^{-1}$ of data which will be collected by ILD during its first 10 years of data taking at $\sqrt{s} = 250$ GeV. Upper limits on the …
Search for events with large missing transverse momentum, jets, and at least two tau leptons in 7 TeV proton-proton collision data with the ATLAS detector