374 research outputs found
The ILC Potential for Discovering New Particles
The LHC did not discover new particles beyond the Standard Model Higgs boson
at 7 and 8 TeV, or in the first data samples at 13 TeV. However, the
complementary nature of physics with collisions still offers many
interesting scenarios in which new particles can be discovered at the ILC.
These scenarios take advantage of the capability of collisions to
observe particles with missing energy and small mass differences, to observe
mono-photon events with precisely controlled backgrounds, and to observe the
full range of exotic decay modes of the Higgs boson. The searches that an
collider makes possible are particularly important for models of dark
matter involving a dark sector with particles above the modest energy reach of
fixed-target experiments. In this talk, we will review the opportunities that
the ILC offers for new particle discovery.Comment: on behalf of the LCC Physics W
Polarimetry at the ILC
At the ILC, the luminosity-weighted average polarization at the IP needs to
be determined at the permille-level. In order to reach this goal, the combined
information from the polarimeter and the collision data is required. In this
study, a unified approach will be presented, which for the first time combines
the cross section measurements with the expected constraints from the
polarimeters. Hereby, the statistical and systematical uncertainties are taken
into account, including their correlations. This study shows that a fast spin
flip frequency is required because it easily reduces the systematic
uncertainty, while a non-perfect helicity reversal can be compensated for
within the unified approach. The final goal is to provide a realistic
estimation of the luminosity-weighted average polarization at the IP to be used
in the physic analyses.Comment: 8 pages, conference proceedings LCWS 2016 Morioka Japa
Improvements to the ILC Upstream Polarimeter
The physics programme of the ILC requires polarimetry with yet unprecedented
precision. This note focusses on aspects of the upstream polarimeter as
described in the ILC Reference Design Report which are not compatible with the
extraordinary precision goals. In conclusion, recommendations for improving the
design are given.Comment: to appear in the proceedings of LCWS 200
A Calibration System for Compton Polarimetry at Linear Colliders
Polarimetry with permille-level precision is essential for future
electron-positron linear colliders. Compton polarimeters can reach negligible
statistical uncertainties within seconds of measurement time. The dominating
systematic uncertainties originate from the response and alignment of the
detector which records the Compton scattered electrons. The robust baseline
technology for the Compton polarimeters foreseen at future linear colliders is
based on an array of gas Cherenkov detectors read out by photomultipliers. In
this paper, we will present a calibration method which promises to monitor
nonlinearities in the response of such a detector at the level of a few
permille. This method has been implemented in an LED-based calibration system
which matches the existing prototype detector. The performance of this
calibration system is sufficient to control the corresponding contribution to
the total uncertainty on the extracted polarisation to better than .Comment: 27 pages, 17 figure
A Quartz Cherenkov Detector for Compton-Polarimetry at Future e+e- Colliders
Precision polarimetry is essential for future e+ e- colliders and requires
Compton polarimeters designed for negligible statistical uncertainties. In this
paper, we discuss the design and construction of a quartz Cherenkov detector
for such Compton polarimeters. The detector concept has been developed with
regard to the main systematic uncertainties of the polarisation measurements,
namely the linearity of the detector response and detector alignment.
Simulation studies presented here imply that the light yield reachable by using
quartz as Cherenkov medium allows to resolve in the Cherenkov photon spectra
individual peaks corresponding to different numbers of Compton electrons. The
benefits of the application of a detector with such single-peak resolution to
the polarisation measurement are shown for the example of the upstream
polarimeters foreseen at the International Linear Collider. Results of a first
testbeam campaign with a four-channel prototype confirming simulation
predictions for single electrons are presented
Model-independent WIMP Characterisation using ISR
The prospects of measuring the parameters of WIMP dark matter in a model
independent way at the International Linear Collider are investigated. The
signal under study is direct WIMP pair production with associated initial state
radiation. The analysis is performed in full simulation of the ILD detector
concept. With an integrated luminosity of L = 500 fb-1 and realistic beam
polarizations the helicity structure of the WIMP couplings to electrons can be
determined, and the masses and cross sections can be measured to the percent
level. The systematic uncertainties are dominated by the polarization
measurement and the luminosity spectrum.Comment: 7 pages, 4 figures, International Workshop on Future Linear Colliders
LCWS1
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