253 research outputs found
Chopper-controlled discharge life cycling studies on lead-acid batteries
State-of-the-art 6 volt lead-acid golf car batteries were tested. A daily charge/discharge cycling to failure points under various chopper controlled pulsed dc and continuous current load conditions was undertaken. The cycle life and failure modes were investigated for depth of discharge, average current chopper frequency, and chopper duty cycle. It is shown that battery life is primarily and inversely related to depth of discharge and discharge current. Failure mode is characterized by a gradual capacity loss with consistent evidence of cell element aging
CP Studies of the Higgs Sector
The CP structure of the Higgs sector will be of great interest to future
colliders. The measurement of the CP properties of candidate Higgs particles
will be essential in order to distinguish models of electroweak symmetry
breaking, and to discover or place limits on CP-violation in the Higgs sector.
In this report we briefly summarize various methods of determining the CP
properties of Higgs bosons at different colliders and identify areas where more
study is required. We also provide an example of a synergy between the LHC, an
e+e- Linear Collider and a Photon Collider, for the examination of CP-violation
in a Two-Higgs-Doublet-Model.Comment: A contribution to the LHC / LC Study Group document; 9 pages, 2
figure
SUSY-QCD corrections to stop and sbottom decays into Higgs bosons
We calculate the order(\alpha_s) SUSY-QCD corrections to the widths of stop
and sbottom decays into Higgs bosons within the Minimal Supersymmetric Standard
Model. We give the complete analytical formulae paying particular attention to
the on-shell renormalization of the soft SUSY-breaking parameters. We also
perform a detailed numerical analysis of both stop and sbottom decays into all
Higgs bosons h^0, H^0, A^0, and H^\pm. We find that the SUSY-QCD corrections
are significant, mostly negative and of the order of a few ten percent.Comment: revised version, one figure and a few comments adde
Light Sneutrino Dark Matter at the LHC
In supersymmetric (SUSY) models with Dirac neutrino masses, a weak-scale
trilinear A-term that is not proportional to the small neutrino Yukawa
couplings can induce a sizable mixing between left and right-handed sneutrinos.
The lighter sneutrino mass eigenstate can hence become the lightest SUSY
particle (LSP) and a viable dark matter candidate. In particular, it can be an
excellent candidate for light dark matter with mass below ~10 GeV. Such a light
mixed sneutrino LSP has a dramatic effect on SUSY signatures at the LHC, as
charginos decay dominantly into the light sneutrino plus a charged lepton, and
neutralinos decay invisibly to a neutrino plus a sneutrino. We perform a
detailed study of the LHC potential to resolve the light sneutrino dark matter
scenario by means of three representative benchmark points with different
gluino and squark mass hierarchies. We study in particular the determination of
the LSP (sneutrino) mass from cascade decays involving charginos, using the mT2
variable. Moreover, we address measurements of additional invisible sparticles,
in our case the lightest neutralino, and the question of discrimination against
the MSSM.Comment: 25 pages, 16 figure
Sfermion Pair Production at Colliders
We discuss pair production of stops, sbottoms, staus and tau--sneutrinos at a
collider. We present the formulae for the production cross
sections and perform a detailed numerical analysis within the Minimal
Supersymmetric Standard Model. In particular, we consider sfermion production
near and .Comment: 21 pages, Latex, uses Revtex (included), 8 figures (included as
PS-files
Long-lived stops in MSSM scenarios with a neutralino LSP
This work investigates the possibility of a long-lived stop squark in
supersymmetric models with the neutralino as the lightest supersymmetric
particle (LSP). We study the implications of meta-stable stops on the sparticle
mass spectra and the dark matter density. We find that in order to obtain a
sufficiently long stop lifetime so as to be observable as a stable R-hadron at
an LHC experiment, we need to fine tune the mass degeneracy between the stop
and the LSP considerably. This increases the stop-neutralino coanihilation
cross section, leaving the neutralino relic density lower than what is expected
from the WMAP results for stop masses ~1.5 TeV/c^2. However, if such scenarios
are realised in nature we demonstrate that the long-lived stops will be
produced at the LHC and that stop-based R-hadrons with masses up to 1 TeV/c^2
can be detected after one year of running at design luminosity
Gauge dependence of the on-shell renormalized mixing matrices
It was recently pointed out that the on-shell renormalization of the
Cabibbo-Kobayashi-Maskawa (CKM) matrix in the method by Denner and Sack causes
a gauge parameter dependence of the amplitudes. We analyze the gauge dependence
of the on-shell renormalization of the mixing matrices both for fermions and
scalars in general cases, at the one-loop level. We then show that this gauge
dependence can be avoided by fixing the counterterms for the mixing matrices in
terms of the off-diagonal wave function corrections for fermions and scalars
after a rearrangement, in a similar manner to the pinch technique for gauge
bosons. We finally present explicit calculation of the gauge dependence for two
cases: CKM matrix in the Standard Model, and left-right mixing of scalar quarks
in the minimal supersymmetric standard model.Comment: 16 pages, minor correction
Summary of the SUSY Working Group of the 1999 Les Houches Workshop
The results obtained by the Working Group on Supersymmetry at the 1999 Les
Houches Workshop on Collider Physics are summarized. Separate chapters treat
"general" supersymmetry, R-parity violation, gauge mediated supersymmetry
breaking, and anomaly mediated supersymmetry breaking.Comment: LaTeX, 110 pages with numerous .ps and .eps files. proc.tex is main
tex fil
Three-Body Decays of Top and Bottom Squarks
We investigate the decays of third generation scalar quarks in the Minimal
Supersymmetric extension of the Standard Model, focusing on the three-body
modes. We calculate the partial widths of the decays of heavier top and bottom
squarks into the lighter ones and a fermion pair [through virtual vector boson,
Higgs boson or gaugino exchanges] and the partial widths of the three-body
decays of both top squarks into bottom quarks and a pair of fermion and scalar
fermion [we consider the case of lighter or states]
and into a bottom quark, the lightest neutralino and a or a charged Higgs
boson . Some of these decay modes are shown to have substantial
branching ratios in some areas of the parameter space.Comment: 24 pages with 4 psfigures, late
THE TOOLS AND MONTE CARLO WORKING GROUP Summary Report from the Les Houches 2009 Workshop on TeV Colliders
This is the summary and introduction to the proceedings contributions for the
Les Houches 2009 "Tools and Monte Carlo" working group.Comment: 144 Pages. Workshop site
http://wwwlapp.in2p3.fr/conferences/LesHouches/Houches2009/ . Conveners were
Butterworth, Maltoni, Moortgat, Richardson, Schumann and Skand
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