223 research outputs found
How Well Can We Reconstruct the ttbar System Near its Threshold at Future e+e- Linear Colliders?
We developed a new method for full kinematical reconstruction of the ttbar
system near its threshold at future linear e+e- colliders. In the core of the
method lies likelihood fitting which is designed to improve measurement
accuracies of the kinematical variables that specify the final states resulting
from ttbar decays. The improvement is demonstrated by applying this method to a
Monte-Carlo ttbar sample generated with various experimental effects including
beamstrahlung, finite acceptance and resolution of the detector system, etc. In
most cases the fit brings a broad non-Gaussian distribution of a given
kinematical variable to a nearly Gaussian shape, thereby justifying
phenomenological analyses based on simple Gaussian smearing of parton-level
momenta. The standard deviations of the resultant distributions of various
kinematical variables are given in order to facilitate such phenomenological
analyses. A possible application of the kinematical fitting method and its
expected impact are also discussed.Comment: 14 pages, LaTeX, 11 figure
A study of the measurement precision of the Higgs boson decaying into tau pairs at the ILC
We evaluate the measurement precision of the production cross section times
the branching ratio of the Higgs boson decaying into tau lepton pairs at the
International Linear Collider (ILC). We analyze various final states associated
with the main production mechanisms of the Higgs boson, the Higgs-strahlung and
WW-fusion processes. The statistical precision of the production cross section
times the branching ratio is estimated to be 2.6% and 6.9% for the
Higgs-strahlung andWW-fusion processes, respectively, with the nominal
integrated luminosities assumed in the ILC Technical Design Report; the
precision improves to 1.0% and 3.4% with the running scenario including
possible luminosity upgrades. The study provides a reference performance of the
ILC for future phenomenological analyses.Comment: 10 pages, 6 figures, 9 tables, revised from v
A feasibility study of the measurement of Higgs pair creation at a Photon Linear Collider
We studied the feasibility of the measurement of Higgs pair creation at a
Photon Linear Collider (PLC). From the sensitivity to the anomalous
self-coupling of the Higgs boson, the optimum collision energy
was found to be around 270 GeV for a Higgs mass of 120 GeV/. We found that
large backgrounds such as and
, can be suppressed if correct assignment of tracks to parent
partons is achieved and Higgs pair events can be observed with a statistical
significance of by operating the PLC for 5 years.Comment: 7 pages, 8 figures, 5 table
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