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Implementation of polarization diversity pulse-pair technique using airborne W-band radar
This work describes the implementation of polarization diversity on the National Research Council Canada W-band Doppler radar and presents the first-ever airborne Doppler measurements derived via polarization diversity pulse-pair processing. The polarization diversity pulse-pair measurements are interleaved with standard pulse-pair measurements with staggered pulse repetition frequency, this allows a better understanding of the strengths and drawbacks of polarization diversity, a methodology that has been recently proposed for wind-focused Doppler radar space missions. Polarization diversity has the clear advantage of making possible Doppler observations of very fast decorrelating media (as expected when deploying Doppler radars on fast-moving satellites) and of widening the Nyquist interval, thus enabling the observation of very high Doppler velocities (up to more than 100âmâsâ1 in the present work). Crosstalk between the two polarizations, mainly caused by depolarization at backscattering, deteriorated the quality of the observations by introducing ghost echoes in the power signals and by increasing the noise level in the Doppler measurements. In the different cases analyzed during the field campaigns, the regions affected by crosstalk were generally associated with highly depolarized surface returns and depolarization of backscatter from hydrometeors located at short ranges from the aircraft. The variance of the Doppler velocity estimates can be well predicted from theory and were also estimated directly from the observed correlation between the H-polarized and V-polarized successive pulses. The study represents a key milestone towards the implementation of polarization diversity in Doppler space-borne radars
Determination of the muon Yukawa coupling at high energy e+e- linear colliders
The perspectives for the observation of the rare decay H -> mumu decay and
the determination of the muon Yukawa coupling at a TeV-class and at a multi-TeV
e+e- linear colliders are discussed. The signal for the decay can be obtained
at 0.8 TeV and a first estimate of the coupling derived. A linear collider
operating at 3 TeV, with high luminosity, is able to improve the accuracy on
this couplings to 4% to 11% for 120 GeV < M_H < 150 GeV.Comment: 3 pages, 2 figures, to appear on the proceedings of the Snowmass 2001
Summer Study, Snowmass CO, June-July 200
Light neutralino dark matter in MSSM
Three dark matter direct detection experiments, DAMA, COGENT and CRESST, have
reported a possible signal of WIMP interaction corresponding to very light
particles, close to the edge of the XENON 100 and CDMS sensitivity. Imposing
the latest constraints from colliders, flavour physics, electroweak precision
tests and direct and indirect dark matter searches, we show that viable MSSM
scenarios with a light neutralino, in agreement with all the present data, are
feasible. An analysis of the characteristics of the resulting scenarios will be
presented.Comment: 6 pages, 2 figures, contribution to the ICHEP 2012 Conference
proceedings, 4-11 July 2012, Melbourne, Australi
Study of e+e- -> H+H- at a 800 GeV Linear Collider
The production and decay of heavy charged Higgs bosons at a 800 GeV e+e-
linear collider have been studied. The analysis of the H+H- -> tb tb, expected
to be dominant in the MSSM, and H+H- -> W+h0 W-h0 decay modes leading to the
same final state consisting of two W bosons and four b quarks, provides with a
determination of the boson mass to 1 GeV and of the production cross section
with 10% accuracy for 500 fb-1 of data.Comment: 4 pages, 1 figure, to appear in the Proceedings of the 5th Linear
Collider Workshop Fermilab, October 200
B2 and G2 Toda systems on compact surfaces: a variational approach
We consider the B2 and G2 Toda systems on compact surfaces. We attack the
problem using variational techniques. We get existence and multiplicity of
solutions under a topological assumption on the surface and some generic
conditions on the parameters. We also extend some of the results to the case of
general systems.Comment: 28 pages, accepted on Journal of Mathematical Physic
Implications of LHC Higgs and SUSY searches for MSSM
The implications of the LHC SUSY searches as well as the discovery of a new
bosonic state compatible with the lightest Higgs boson will be discussed in the
context of constrained and general MSSM scenarios. Exploring the MSSM through
the Higgs sector is an alternative and complementary path to direct searches,
and tight constraints on the MSSM parameter space can be obtained.Comment: 7 pages, 5 figures, contribution to the ICHEP 2012 Conference
proceedings, 4-11 July 2012, Melbourne, Australi
An update of the constraints on the phenomenological MSSM from the new LHC Higgs results
Updated results on the search of Higgs bosons at the LHC with up to 17/fb of
data have just been presented by the ATLAS and CMS collaborations. New
constraints are provided by the LHCb and XENON experiments with the observation
of the rare decay B_s -> mu+mu- and new limits on dark matter direct detection.
In this paper, we update and extend the results on the implications of these
data on the phenomenological Minimal Supersymmetric extension of the Standard
Model (pMSSM) by using high statistics, flat scans of its 19 parameters. The
new LHC data on bb and tau tau decays of the lightest Higgs state and the new
CMS limits from the tau tau searches for the heavier Higgs states set stronger
constraints on the pMSSM parameter space.Comment: 14 pages, 8 figures. This update is based on results presented at HCP
2012 and the December 2012 CERN Council LHC Jamboree. It features larger scan
statistics and additional plot
Hybrid Pixel Detector Development for the Linear Collider Vertex Tracker
In order to fully exploit the physics potential of the future high energy
e+e- linear collider, a Vertex Tracker able to provide particle track
extrapolation with very high resolution is needed. Hybrid Si pixel sensors are
an attractive technology due to their fast read-out capabilities and radiation
hardness. A novel pixel detector layout with interleaved cells has been
developed to improve the single point resolution. Results of the
characterisation of the first processed prototypes by electrostatic
measurements and charge collection studies are discussed.Comment: 5 pages, 1 figure, to appear in the Proceedings of the 9th Int.
Workshop on Vertex Detectors, Lake Michigan MI (USA), September~200
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