5,200 research outputs found
Recharge unit provides for optimum recharging of battery cells
Percent recharge unit permits each cell of a rechargeable battery to be charged to a preset capacity of the cell. The unit automatically monitors and controls a rechargeable battery subjected to charge-discharge cycling tests
Effects of systemic and non-systemic stresses on the thermal characteristics of corn
Experiments were conducted on corn plants using a calibrated spectroradiometer under field conditions in the indium antimonide channel (InSb, 2.8 to 5.6 mm) and the mercury cadmium telluride channel (HgCdTe, 7 to 14 mm). A ground cover experiment, an experiment on nonsystemic corn plants, and an experiment on systemic-stressed corn plants were included. The average spectral radiance temperature of corn plant populations was found (1) to be statistically significantly different for four healthy corn plant populations, (2) to increase with increased blight severity, and (3) to be statistically significantly different for varying rates of nitrogen applications
Multi-parameter approach to R-parity violating SUSY couplings
We introduce and implement a new, extended approach to placing bounds on
trilinear R-parity violating couplings. We focus on a limited set of leptonic
and semi-leptonic processes involving neutrinos, combining multidimensional
plotting and cross-checking constraints from different experiments. This allows
us to explore new regions of parameter space and to relax a number of bounds
given in the literature. We look for qualitatively different results compared
to those obtained previously using the assumption that a single coupling
dominates the R-parity violating contributions to a process (SCD). By combining
results from several experiments, we identify regions in parameter space where
two or more parameters approach their maximally allowed values. In the same
vein, we show a circumstance where consistency between independent bounds on
the same combinations of trilinear coupling parameters implies mass constraints
among slepton or squark masses. Though our new bounds are in most cases weaker
than the SCD bounds, the largest deviations we find on individual parameters
are factors of two, thus indicating that a conservative, order of magnitude
bound on an individual coupling is reliably estimated by making the SCD
assumption.Comment: 30 pages, 8 figures, 2 tables. Typos fixed, two references added and
references updated. Eq. (41) removed, Eq. (40) and text modified. Published
versio
Trileptons from Chargino-Neutralino Production at the CERN Large Hadron Collider
We study direct production of charginos and neutralinos at the CERN Large
Hadron Collider. We simulate all channels of chargino and neutralino production
using ISAJET 7.07. The best mode for observing such processes appears to be
pp\to\tw_1\tz_2\to 3\ell +\eslt. We evaluate signal expectations and
background levels, and suggest cuts to optimize the signal. The trilepton mode
should be viable provided m_{\tg}\alt 500-600~GeV; above this mass, the decay
modes \tz_2\to\tz_1 Z and \tz_2\to H_{\ell}\tz_1 become dominant, spoiling
the signal. In the first case, the leptonic branching fraction for decay is
small and additional background from is present, while in the second case,
the trilepton signal is essentially absent. For smaller values of ,
the trilepton signal should be visible above background, especially if
and m_{\tell}\ll m_{\tq}, in which case the leptonic
decays of \tz_2 are enhanced. Distributions in dilepton mass
can yield direct information on neutralino masses due to
the distribution cutoff at m_{\tz_2}-m_{\tz_1}. Other distributions that may
lead to an additional constraint amongst the chargino and neutralino masses are
also examined.Comment: preprint nos. FSU-HEP-940310 and UH-511-786-94, 13 pages (REVTEX)
plus 7 uuencoded figures attache
Hadronic Production with QCD Corrections and Leptonic Decays
The process , where
denotes a lepton, is calculated to order . Total and differential
cross sections, with acceptance cuts imposed on the leptons and photon, are
given for the Tevatron and LHC center of mass energies. In general, invariant
mass and angular distributions are simply scaled up in magnitude by the QCD
radiative corrections, whereas in transverse momentum distributions, the QCD
radiative corrections increase with the transverse momentum.Comment: 16 pages + 9 figures, UCD-94-29. A postscript version and 9
postscript figures are available via anonymous ftp to UCDHEP.UCDAVIS.EDU in
the directory [.ohnemus.ucd-94-29
Measurements in SUGRA Models with Large tan beta at LHC
We present an example of a scenario of particle production and decay in
supersymmetry models in which the supersymmetry breaking is transmitted to the
observable world via gravitational interactions. The case is chosen so that
there is a large production of tau leptons in the final state. It is
characteristic of large tan beta in that decays into muons and electrons may be
suppressed. It is shown that hadronic tau decays can be used to reconstruct
final states.Comment: 15 pages, 12 figure
Hidden SUSY at the LHC: the light higgsino-world scenario and the role of a lepton collider
While the SUSY flavor, CP and gravitino problems seem to favor a very heavy
spectrum of matter scalars, fine-tuning in the electroweak sector prefers low
values of superpotential mass \mu. In the limit of low \mu, the two lightest
neutralinos and light chargino are higgsino-like. The light charginos and
neutralinos may have large production cross sections at LHC, but since they are
nearly mass degenerate, there is only small energy release in three-body
sparticle decays. Possible dilepton and trilepton signatures are difficult to
observe after mild cuts due to the very soft p_T spectrum of the final state
isolated leptons. Thus, the higgsino-world scenario can easily elude standard
SUSY searches at the LHC. It should motivate experimental searches to focus on
dimuon and trimuon production at the very lowest p_T(\mu) values possible. If
the neutralino relic abundance is enhanced via non-standard cosmological dark
matter production, then there exist excellent prospects for direct or indirect
detection of higgsino-like WIMPs. While the higgsino-world scenario may easily
hide from LHC SUSY searches, a linear e^+e^- collider or a muon collider
operating in the \sqrt{s}\sim 0.5-1 TeV range would be able to easily access
the chargino and neutralino pair production reactions.Comment: 20 pages including 12 .eps figure
The Reach of CERN LEP2 and Fermilab Tevatron Upgrades for Higgs Bosons in Supersymmetric Models
Luminosity upgrades of the Fermilab Tevatron pbar-p collider have been shown
to allow experimental detection of a Standard Model (SM) Higgs boson up to
GeV via events. This limit
nearly saturates the parameter space for many models of weak scale
supersymmetry (SUSY) with a minimal particle content. It is therefore
interesting to examine the SUSY Higgs reach of future Tevatron experiments.
Contours are presented of Higgs boson reach for CERN LEP2 and Tevatron
luminosity upgrades for three models of weak scale SUSY: the Minimal
Supersymmetric Standard Model (MSSM), the minimal Supergravity model (mSUGRA)
and a simple Gauge Mediated SUSY Breaking Model (GMSB). In each case we find a
substantial gain in reach at the Tevatron with integrated luminosity increasing
from 10 fb^{-1} to 25-30 fb^{-1}. With the larger integrated luminosity, a
Higgs search at the Tevatron should be able to probe essentially the entire
parameter space of these models. While a discovery would be very exciting, a
negative result would severely constrain our ideas about how weak scale
supersymmetry is realized.Comment: 12 pages + 7 figures. Uses REVTEX and epsf macros. Several references
added, stated value of A-parameters corrected, note added reguarding sgn(mu)
dependence in MSSM case. To appear in Physical Review
Target dark matter detection rates in models with a well-tempered neutralino
In the post-LEP2 era, and in light of recent measurements of the cosmic
abundance of cold dark matter (CDM) in the universe from WMAP, many
supersymmetric models tend to predict 1. an overabundance of CDM and 2.
pessimistically low rates for direct detection of neutralino dark matter.
However, in models with a ``well-tempered neutralino'', where the neutralino
composition is adjusted to give the measured abundance of CDM, the neutralino
is typically of the mixed bino-wino or mixed bino-higgsino state. Along with
the necessary enhancement to neutralino annihilation rates, these models tend
to give elevated direct detection scattering rates compared to predictions from
SUSY models with universal soft breaking terms. We present neutralino direct
detection cross sections from a variety of models containing a well-tempered
neutralino, and find cross section asymptotes with detectable scattering rates.
These asymptotic rates provide targets that various direct CDM detection
experiments should aim for. In contrast, in models where the neutralino mass
rather than its composition is varied to give the WMAP relic density via either
resonance annihilation or co-annihilation, the neutralino remains essentially
bino-like, and direct detection rates may be below the projected reaches of all
proposed experiments.Comment: 13 pages including 1 EPS figur
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