arXiv subjects

Jean-Claude Brient

Publications and source records attributed to Jean-Claude Brient.

12 recordsLinked to original sources

arXiv2023

The International Linear Collider: Report to Snowmass 2021

The International Linear Collider (ILC) is on the table now as a new global energy-frontier accelerator laboratory taking data in the 2030s. The ILC addresses key questions for our current understanding of particle physics. It is based on a proven accelerator technology. Its experiments will challenge the Standard Model of particle physics and will provide a new window to look beyond it. This document brings the story of the ILC up to date, emphasizing its strong physics motivation, its readiness for construction, and the opportunity it presents to the US and the global particle physics community.

physics.acc-ph↗

arXiv2021

A combined fit to the Higgs Branching Ratios at ILD

Higgs decay branching ratios at future Higgs factories can be measured by directly exploiting class numeration. Given the clean environment at a lepton collider, it is possible to build an event sample highly enriched in Higgs bosons and essentially unbiased for any decay mode. The sample can be partitioned into categories using event properties linked to the expected Higgs decay modes. The counts per category are used to fit the Higgs branching ratios in a model independent way. The result of the fit is the set of branching ratios, independent from a Higgs production mode measurement. We present a simplified study on simulated data for the International Linear Detector (ILD) at the International Linear Collider (ILC) at 250 GeV center-of-mass energy.

hep-ex↗

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↗

arXiv2020

Inclusive Higgsstrahlung cross section measurements with the new reference sample method

An accurate determination of the Higgsstrahlung cross section is one of the main objectives at a future electron-positron collider. It allows for the only Higgs boson decay model independent measurement of the total Higgs width. Current results use the recoil mass shape method. That technique can be applied to Higgsstrahlung events with Z boson decays into muons, into electrons and, with reservations, into quarks. The samples built from Higgsstrahlung events with Z boson decays into taus and neutrinos are not used in previous analyses. We present here a new method, the reference sample method. It extends the recoil mass method to be usable with the tau and neutrino samples as well. The extension promises a model independent determination of the inclusive Higgsstrahlung cross section with a 2.1-2.2% uncertainty from each of the two ILC polarization scenarios at $\sqrt{s}$=250 GeV with an integrated luminosity of 250 $\mathrm{fb^{-1}}$. This represents an improvement of 20-30% on the accuracy from the application of the new approach without additional data collection.

hep-ex↗

arXiv2019

ILD Silicon Tungsten Electromagnetic Calorimeter First Full Scale Electronic Prototype

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 at DESY, Hamburg. The results of the per-channel calibration of the detector are presented. In DESY beam tests we have accumulated data for both normal and inclined incidence of the beam. With the latter one particle can sometimes traverse two pixels and deposit less energy per pixel. We show how this can be used to measure the position of the trigger threshold. This new prototype gives us a lot of hints on how to improve the design of the front-end electronics. It is also a convenient tool to estimate the key characteristics of ILD SiW-Ecal (like power consumption, cooling, readout time etc.) and to optimize the future design of the detector.

physics.ins-det↗

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↗

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↗

arXiv2012

GARLIC: GAmma Reconstruction at a LInear Collider experiment

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 configuration 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.

physics.ins-det↗

arXiv2010

Status of Simulation Tools for the ILD ScECAL

The scintillator-strip electromagnetic calorimeter (ScECAL) is one of the calorimeter technic for the ILC. To achieve the fine granularity from the strip-segmented layers the strips in odd layers are orthogonal with respect to those in the even layers. In order to extract the best performance from such detector concept, a special reconstruction method and simulation tools are being developed in ILD collaboration. This manuscript repots the status of developing of those tools.

physics.ins-det↗

arXiv2009

GARLIC - GAmma Reconstruciton for the LInear Collider

In order to profit from the high granularity of the calorimeters proposed for the ILC that are suitable for the Particle Flow Approach, specialised clustering algorithms have to be developped. GARLIC is such an algorithm with the goal to find and identify pointing photons in the electromagnetic calorimeter. This would help to improve the energy resolution on the photon contribution in jets.

hep-ex↗

arXiv2004

Improving the Jet Reconstruction with the Particle Flow Method; an Introduction

At the future electron-positron TeV linear collider, the reachable physics will be strongly dependent on the detector capability to reconstruct high energy jets in multi-jet environment. At LEP, SLD experiments, a technique combining charged tracks and calorimetric information has been used to improve the jet energy/direction reconstruction. Starting from this experience, it has been proposed to go from partial individual particle reconstruction to complete (or full) individual reconstruction. Different studies have shown that the reachable resolution is far beyond any realistic hope from calorimetric-only measurement.

physics.ins-det↗