391 research outputs found
Higgs measurement at e+e- circular colliders
Now that the mass of the Higgs boson is known, circular electron positron
colliders, able to measure the properties of these particles with high
accuracy, are receiving considerable attention. Design studies have been
launched (i) at CERN with the Future Circular Colliders (FCC), of which an e+e-
collider is a potential first step (FCC-ee, formerly caller TLEP) and (ii) in
China with the Circular Electron Positron Collider (CEPC). Hosted in a tunnel
of at least 50 km (CEPC) or 80-100 km (FCC), both projects can deliver very
high luminosity from the Z peak to HZ threshold (CEPC) and even to the top pair
threshold and above (FCC-ee). At the ZH production optimum, around 240 GeV, the
FCC-ee (CEPC) will be able to deliver 10 (5) ab-1 integrated luminosity in 5
(10) years with 4 (2) interaction points: hence to produce millions of Higgs
bosons through the Higgsstrahlung process and vector boson fusion processes.
This sample opens the possibility of subper- cent precision absolute
measurements of the Higgs boson couplings to fermions and to gauge-bosons, and
of the Higgs boson width. These precision measurements are potentially
sensitive to multi-TeV range new physics interacting with the scalar sector.
The ZH production mechanism also gives access to the invisible or exotic
branching ratios down to the per mil level, and with a more limited precision
to the triple Higgs coupling. For the FCC-ee, the luminosity expected at the
top pair production threshold (sqrt(s) ~ 340-350 GeV) further improves some of
these accuracies significantly, and is sensitive to the Higgs boson coupling to
the top quark.Comment: 6 pages. Report at ICHEP 201
Semi-DHCAL software developments: Digitization and Display
GRPC Semi-Digital HCAL is a solid option for the PFA oriented calorimetry of
the International Linear Collider. Together with the hardware, the software
developments is progressing steadily. The stauts and plans for the GRPC SDHCAL
software development are presented, as well the first order digitization module
for the GRPC and the display program DRUID (Display Root module Used for ILD)
have been introduced.Comment: Proceeding of LCWS 2010, Beijin
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.Comment: 4 pages, 5 figure
Requirement analysis for dE/dx measurement and PID performance at the CEPC baseline detector
The Circular Electron-Positron Collider (CEPC) can be operated not only as a
Higgs factory but also as a Z-boson factory, offering great opportunities for
flavor physics studies where Particle Identification (PID) is critical. The
baseline detector of the CEPC could record TOF and dE/dx information that can
be used to distinguish particles of different species. We quantify the physics
requirements and detector performance using physics benchmark analyzes with
full simulation. We conclude that at the benchmark TOF performance of ps,
the dE/dx resolution should be better than 3% for incident particles in the
barrel region with a relevant energy larger than GeV/c. This performance
leads to an efficiency/purity of identification 97%/96%, reconstruction 68.19%/89.05%, and reconstruction
82.26%/77.70%, providing solid support for relevant CEPC flavor physics
measurements
Fast simulation of the CEPC detector with Delphes
Fast simulation tools are highly appreciated in particle physics
phenomenology studies, especially in the exploration of the physics potential
of future experimental facilities. The Circular Electron Positron Collider is a
proposed Higgs and Z factory that can precisely measure the Higgs boson
properties and the electroweak precision observables. A fast-simulation toolkit
dedicated to the CEPC detector has been developed using Delphes. The comparison
shows that this fast simulation tool is highly consistent with the full
simulation, on a set of benchmark distributions. Therefore, we recommend this
fast simulation toolkit for CEPC phenomenological investigations
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