10,381 research outputs found
Monte Carlo simulation of baryon and lepton number violating processes at high energies
We report results obtained with the first complete event generator for
electroweak baryon and lepton number violating interactions at supercolliders.
We find that baryon number violation would be very difficult to establish, but
lepton number violation can be seen provided at least a few hundred L violating
events are available with good electron or muon identification in the energy
range 10 GeV to 1 TeV.Comment: 40 Pages uuencoded LaTeX (20 PostScript figures included),
Cavendish-HEP-93/6, CERN-TH.7090/9
An intermediate state between the kagome-ice and the fully polarized state in DyTiO
DyTiO is at present the cleanest example of a spin-ice material.
Previous theoretical and experimental work on the first-order transition
between the kagome-ice and the fully polarized state has been taken as a
validation for the dipolar spin-ice model. Here we investigate in further depth
this phase transition using ac-susceptibility and dc-magnetization, and compare
this results with Monte-Carlo simulations and previous magnetization and
specific heat measurements. We find signatures of an intermediate state between
the kagome-ice and full polarization. This signatures are absent in current
theoretical models used to describe spin-ice materials.Comment: 7 pages, 4 figure
Discipline-Specific Compared to Generic Training of Teachers in Higher Education
A recurrent theme arising in the higher education sector is the suitability and effectiveness of generic versus discipline-specific training of university teachers, who are often recruited based on their disciplinary specialties to become teachers in higher education. We compared two groups of participants who had undergone training using a generic post-graduate certificate in higher education (PGCertGeneric) versus a discipline-specific course in veterinary education (PGCertVetEd). The study was conducted using a survey that allowed comparison of participants who completed PGCertGeneric (n=21) with PGCertVetEd (n=22). Results indicated that participants from both PGCertGeneric and PGCertVetEd considered teaching to be satisfying and important to their careers, valued the teaching observation component of the course, and identified similar training needs. However, the participants of the PGCertVetEd felt that the course made them better teachers, valued the relevance of the components taught, understood course design better, were encouraged to do further courses/reading in teaching and learning, changed their teaching as a result of the course, and were less stressed about teaching as compared to the PGCertGeneric participants (p<.05). It is likely that the PGCertVetEd, which was designed and developed by veterinarians with a wider understanding of the veterinary sector, helped the participants perceive the training course as suited to their needs
Charge Symmetry Violation Effects in Pion Scattering off the Deuteron
We discuss the theoretical and experimental situations for charge symmetry
violation (CSV) effects in the elastic scattering of pi+ and pi- on deuterium
(D) and 3He/3H. Accurate comparison of data for both types of targets provides
evidence for the presence of CSV effects. While there are indications of a CSV
effect in deuterium, it is much more pronounced in the case of 3He/3H. We
provide a description of the CSV effect on the deuteron in terms of single- and
double- scattering amplitudes. The Delta-mass splitting is taken into account.
Theoretical predictions are compared with existing experimental data for pi-d
scattering; a future article will speak to the pi-three nucleon case.Comment: 16 pages of RevTeX, 7 postscript figure
A Search for Instantons at HERA
A search for QCD instanton (I) induced events in deep-inelastic scattering
(DIS) at HERA is presented in the kinematic range of low x and low Q^2. After
cutting into three characteristic variables for I-induced events yielding a
maximum suppression of standard DIS background to the 0.1% level while still
preserving 10% of the I-induced events, 549 data events are found while
363^{+22}_{-26} (CDM) and 435^{+36}_{-22} (MEPS) standard DIS events are
expected. More events than expected by the standard DIS Monte Carlo models are
found in the data. However, the systematic uncertainty between the two
different models is of the order of the expected signal, so that a discovery of
instantons can not be claimed. An outlook is given on the prospect to search
for QCD instanton events using a discriminant based on range searching in the
kinematical region Q^2\gtrsim100\GeV^2 where the I-theory makes safer
predictions and the QCD Monte Carlos are expected to better describe the
inclusive data.Comment: Invited talk given at the Ringberg Workshop on HERA Physics on June
19th, 2001 on behalf of the H1 collaboratio
The Flexi Planar Fuel Cell
The Flexi Planar fuel cell is a new type of lightweight polymer electrolyte fuel cell design. The approach utilises standard, reliable and low cost printed circuit board fabrication processes. An iterative approach is adopted and feasibility along with excellent test characteristics for short modules have been successfully demonstrated
Satellite holmium M-edge spectra from the magnetic phase via resonant x-ray scattering
Developing an expression of resonant x-ray scattering (RXS) amplitude which
is convenient for investigating the contributions from the higher rank tensor
on the basis of a localized electron picture, we analyze the RXS spectra from
the magnetic phases of Ho near the absorption edges. At the
edge in the uniform helical phase, the calculated spectra of the absorption
coefficient, the RXS intensities at the first and second satellite spots
capture the properties the experimental data possess, such as the spectral
shapes and the peak positions. This demonstrates the plausibility of the
adoption of the localized picture in this material and the effectiveness of the
spectral shape analysis. The latter point is markedly valuable since the
azimuthal angle dependence, which is one of the most useful informations RXS
can provides, is lacking in the experimental conditions. Then, by focusing on
the temperature dependence of the spectral shape at the second satellite spot,
we expect that the spectrum is the contribution of the pure rank two profile in
the uniform helical and the conical phases while that is dominated by the rank
one profile in the intermediate temperature phase, so-called spin slip phase.
The change of the spectral shape as a function of temperature indicates a
direct evidence of the change of magnetic structures undergoing. Furthermore,
we predict that the intensity, which is the same order observed at the second
satellite spot, is expected at the fourth satellite spot from the conical phase
in the electric dipolar transition.Comment: 24 pages, 5 figure
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