65 research outputs found
The Effect of Carbon Dioxide Anaesthesia on Collembola
Excerpt: In a contribution to the Michigan Entomologist by Snider, Shaddy and Butcher (1969), a method of carbon dioxide anaesthesia for some soil arthropods was described as an alternative to etherization which frequently gives rise to unpredictable mortality. They stated (page 359) that CO, has very little long-range effect on most species.
Anaesthetization by carbon dioxide has been used on various species of Collembola, particularly of the genus Folsomia Willem, 1902, by myself and my associates for about fifteen years. Until recently no ill effects on the cultures, as a result of this treatment, has been observed or suspected.
As part of an investigation into the cause of sudden and fairly frequent sporadic increases in the incidence in our cultures of numerous abnormal specimens, such as those described, for example, in Goto and Ogel (1961), the effect of regular daily anaesthetization with carbon dioxide was examined. Although more extensive experimentation is needed, a brief comment is given here as a warning of possible side effects that might cause serious misinterpretation of quantitative data derived from specimens that have been subjected to carbon dioxide anaesthesia in cultur
Can the polarization of the strange quarks in the proton be positive ?
Recently, the HERMES Collaboration at DESY, using a leading order QCD
analysis of their data on semi-inclusive deep inelastic production of charged
hadrons, reported a marginally positive polarization for the strange quarks in
the proton. We argue that a non-negative polarization is almost impossible.Comment: 6 pages, latex, minor changes in the discussion after Eq. (9
Lepton polarization correlations in
In this work we will study the polarizations of both leptons () in the
decay channel . In the case of the dileptonic inclusive
decay , where apart from the polarization asymmetries
of single lepton , one can also observe the polarization asymmetries of
both leptons simultaneously. If this sort of measurement is possible then we
can have, apart from decay rate, FB asymmetry and the six single lepton
polarization asymmetries (three each for and ), nine more
double polarization asymmetries. This will give us a very useful tool in more
strict testing of SM and the physics beyond. We discuss the double polarization
asymmetries of leptons in the decay mode within
the SM and the Minimal Supersymmetric extensions of it.Comment: 21 pages, 21 figures; version to match paper to appear in PR
Collider signals from slow decays in supersymmetric models with an intermediate-scale solution to the mu problem
The problem of the origin of the mu parameter in the Minimal Supersymmetric
Standard Model can be solved by introducing singlet supermultiplets with
non-renormalizable couplings to the ordinary Higgs supermultiplets. The
Peccei-Quinn symmetry is broken at a scale which is the geometric mean between
the weak scale and the Planck scale, yielding a mu term of the right order of
magnitude and an invisible axion. These models also predict one or more singlet
fermions which have electroweak-scale masses and suppressed couplings to MSSM
states. I consider the case that such a singlet fermion, containing the axino
as an admixture, is the lightest supersymmetric particle. I work out the
relevant couplings in several of the simplest models of this type, and compute
the partial decay widths of the next-to-lightest supersymmetric particle
involving leptons or jets. Although these decays will have an average proper
decay length which is most likely much larger than a typical collider detector,
they can occasionally occur within the detector, providing a striking signal.
With a large sample of supersymmetric events, there will be an opportunity to
observe these decays, and so gain direct information about physics at very high
energy scales.Comment: 24 pages, LaTeX, 4 figure
Enhancement of Loop Induced Vertex in Two Higgs-doublet Model
The non-decoupling effects of heavy Higgs bosons as well as fermions on the
loop-induced vertex are discussed in the general two Higgs
doublet model. The decay width of the process is calculated
at one-loop level and the possibility of its enhancement is explored both
analytically and numerically. We find that the novel enhancement of the decay
width can be realized by the Higgs non-decoupling effects with large
mass-splitting between the charged Higgs boson and the CP-odd one. This is due
to the large breakdown of the custodial invariance in the Higgs
sector. The branching ratio can amount to for GeV within the constraint from the present experimental data. Hence this
mode may be detectable at LHC or future linear colliders.Comment: 31+1 pages, Latex with 8 eps-file
A Complete Theory of Grand Unification in Five Dimensions
A fully realistic unified theory is constructed, with SU(5) gauge symmetry
and supersymmetry both broken by boundary conditions in a fifth dimension.
Despite the local explicit breaking of SU(5) at a boundary of the dimension,
the large size of the extra dimension allows precise predictions for gauge
coupling unification, alpha_s(M_Z) = 0.118 \pm 0.003, and for Yukawa coupling
unification, m_b(M_Z) = 3.3 \pm 0.2 GeV. A complete understanding of the MSSM
Higgs sector is given; with explanations for why the Higgs triplets are heavy,
why the Higgs doublets are protected from a large tree-level mass, and why the
mu and B parameters are naturally generated to be of order the SUSY breaking
scale. All sources of d=4,5 proton decay are forbidden, while a new origin for
d=6 proton decay is found to be important. Several aspects of flavor follow
from an essentially unique choice of matter location in the fifth dimension:
only the third generation has an SU(5) mass relation, and the lighter two
generations have small mixings with the heaviest generation. The entire
superpartner spectrum is predicted in terms of only two free parameters. The
squark and slepton masses are determined by their location in the fifth
dimension, allowing a significant experimental test of the detailed structure
of the extra dimension. Lepton flavor violation is found to be generically
large in higher dimensional unified theories with high mediation scales of SUSY
breaking. In our theory this forces a common location for all three neutrinos,
predicting large neutrino mixing angles. Rates for mu -> e gamma, mu -> e e e,
mu -> e conversion and tau -> mu gamma are larger in our theory than in
conventional 4D supersymmetric GUTs. Proposed experiments probing mu -> e
transitions will probe the entire interesting parameter space of our theory.Comment: 51 pages, late
MSSM Higgs sector CP violation at photon colliders: Revisited
We present a comprehensive analysis on the MSSM Higgs sector CP violation at
photon colliders including the chargino contributions as well as the
contributions of other charged particles. The chargino loop contributions can
be important for the would-be CP odd Higgs production at photon colliders.
Polarization asymmetries are indispensable in determining the CP properties of
neutral Higgs bosons.Comment: 24 pages, 40 figure
Supersymmetric effects on Forward Backward asymmetries of
Leptonic and semi-leptonic rare decays of B-mesons are very clean (both
theoretically and experimentally) signatures of any new physics beyond the
Standard Model (SM). More specifically the decay \btokll has been theoretically
observed to be very sensitive to new physics as the Forward Backward (FB)
asymmetry in this decay mode vanishes in the SM. Supersymmetry, however,
predicts a non-vanishing value of this asymmetry. In this work we will study
the polarized lepton pair FB asymmetry, i.e. the FB asymmetry of the lepton
when one (or both) final state lepton(s) are polarized. We will study these
asymmetries both within the SM and for Supersymmetric corrections to the SM.Comment: 18 pages, RevTeX file including 21 eps figures; version accepted for
publication in Phys. Rev. D. Some references adde
Colliders and Cosmology
Dark matter in variations of constrained minimal supersymmetric standard
models will be discussed. Particular attention will be given to the comparison
between accelerator and direct detection constraints.Comment: Submitted for the SUSY07 proceedings, 15 pages, LaTex, 26 eps figure
The Forward Backward asymmetries of in the MSSM
The relatively clean theoretical probes of the Standard Model (SM), and the
various theories beyond the SM, provided by radiative, semi-leptonic and
(purely) leptonic decays of B-mesons have become increasingly important. Due to
the large number of possible distributions in the semi-leptonic decays based on
the quark level transition (not just the branching
ratio), these transitions have become very useful. A study of the
Forward-Backward asymmetries for the inclusive decay () is carried out in this paper. This study shall be performed in the SM
and a minimal supersymmetric extensions of the SM, namely the mSUGRA model.Comment: 14 pages, 4 figures (5 eps files); modified to JHEP format, accepted
in JHEP, references adde
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