arXiv subjects

Henri Videau

Publications and source records attributed to Henri Videau.

6 recordsLinked to original sources

arXiv2024

Cluster time measurement with CEPC calorimeter

We have developed an algorithm dedicated to timing reconstruction in highly granular calorimeters(HGC). The performance of this algorithm is evaluated on an electromagnetic calorimeter (ECAL) with geometries comparable to the electromagnetic compartment (CE-E) of the CMS endcap calorimeter upgrade at HL-LHC and conceptual Particle Flow oriented ECAL's for future Higgs factories. The time response of individual channel is parameterized according to the CMS experimental result. The particle Time-of-Flight (ToF) can be measured with a resolution of $5\sim20 \;\rm{ps}$ for electromagnetic (EM) showers and $80\sim 160 \;\rm{ps}$ for hadronic showers above 1 GeV. The presented algorithm provides comparable reconstruction with the $E_{\mathrm{hit}}^2$ weighting strategy and can significantly improve the time resolution compared to a simple averaging of the fast component of the time spectrum. The effects of three detector configurations are also quantified in this study. ToF resolution depends linearly on the timing resolution of a single silicon sensor and improves statistically with increasing incident particle energy. The timing layers at depth of $6\sim 9$ radiation lengths provide higher timing performance for EM showers. A clustering algorithm that vetoes isolated hits improves ToF resolution.

physics.ins-det↗

arXiv2020

Higgs to $ττ$ analysis in the future $e^{+}e^{-}$ Higgs factories

The Circular Electron Positron Collider and International Linear Collider are two electron positron Higgs factories. They are designed to operate at center-of-mass energy of 240 and 250 GeV and accumulate 5.6 and 2 $ab^{-1}$ of integrated luminosity. Using CEPC official samples, the signal strength for Higgs to $ττ$ events are analyzed. The combined accuracy of the signal strength for $H\rightarrow ττ$ at CEPC achieves 0.8\%. Extrapolating this analysis to the ILC setup, we conclude the ILC can reach a relative accuracy of 1.1\% or 1.2\%, corresponding to two benchmark settings of the beam polarization.

hep-ex↗

arXiv2018

Reconstruction of physics objects at the Circular Electron Positron Collider with Arbor

After the Higgs discovery, precise measurements of the Higgs properties and the electroweak observables become vital for the experimental particle physics. A powerful Higgs/Z factory, the Circular Electron Positron Collider(CEPC) is proposed. The Particle Flow oriented detector design is proposed to the CEPC and a Particle Flow algorithm, Arbor is optimized accordingly. We summarize the physics object reconstruction performance of the Particle Flow oriented detector design with Arbor algorithm and conclude that this combination fulfills the physics requirement of CEPC.

hep-ex↗

arXiv2017

Lepton identification at particle flow oriented detector for the future $e^{+}e^{-}$ Higgs factories

The lepton identification is essential for the physics programs at high-energy frontier, especially for the precise measurement of the Higgs boson. For this purpose, a Toolkit for Multivariate Data Analysis (TMVA) based lepton identification (LICH) has been developed for detectors using high granularity calorimeters. Using the conceptual detector geometry for the Circular Electron-Positron Collider (CEPC) and single charged particle samples with energy larger than 2 GeV, LICH identifies electrons/muons with efficiencies higher than 99.5% and controls the mis-identification rate of hadron to muons/electrons to better than 1%/0.5%. Reducing the calorimeter granularity by 1-2 orders of magnitude, the lepton identification performance is stable for particles with E > 2 GeV. Applied to fully simulated eeH/$μμ$H events, the lepton identification performance is consistent with the single particle case: the efficiency of identifying all the high energy leptons in an event, is 95.5-98.5%.

physics.ins-det↗

arXiv2016

Reconstruction and classification of tau lepton decays with ILD

Tau-lepton decays with up to two $π^0$'s in the final state, $τ^+ \to π^+ \barν_τ$, $ρ^+ (π^+π^0) \barν_τ$, $a^+_1 (π^+π^0π^0) \barν_τ$, are used to study the performance of the barrel part of the silicon-tungsten electromagnetic calorimeter (Si-W ECAL) of the International Large Detector (ILD) at the future $e^+-e^-$ International Linear Collider. A correct reconstruction of the tau decay mode is crucial for constraining the tau spin state and measuring the Higgs boson CP state in $H\to τ^+τ^-$ decays. About 95% of $π^+ \barν_τ$ and 90% of $ρ^+\barν_τ$ and $a^+_1\barν_τ$ decays from $e^+e^-\to Z^0\to τ^+τ^-$ reaction at $e^\pm$-beam energy of 125 GeV are correctly reconstructed. In a smaller ILD detector, with Si-W ECAL radius reduced by about 20% these numbers degrade by at most 2%. The $π^0$ mass resolution stays below 10%. Since the failures in the tau-lepton reconstruction are mainly due to photons, the increase of the ILD magnetic field from 3.5 T to 4 T does not bring any significant improvement.

physics.ins-det↗

arXiv2013

Fractal Dimension of Particle Showers Measured in a Highly Granular Calorimeter

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.

physics.ins-det↗