9,643 research outputs found
Discovery potential of the Standard Model Higgs in CMS at the LHC
This thesis presents the discovery potential of the Standard Model Higgs boson in the CMS experiment at the LHC. Detailed studies have been carried out to evaluate the detector performance in the difficult channel. The electromagnetic crystal calorimeter is of main importance in this channel and it has been designed according stringent performance requirements. Test beam data of lead tungstate crystals have been analysed and it is shown that the performance of the crystals can meet the requirements. The Higgs decay into two photons has been studied with full detector simulation and the Higgs mass has been reconstructed. A potential danger for the photon measurement are the photon conversions in the detector material in front of the electromagnetic calorimeter. Different methods to recover these converted photons are developed and it is shown that, including the recovered conversions does not degrade the Higgs mass resolution. To complete the full Standard Model Higgs discovery range, studies of the other decay channels are reviewed and updated taking into account the next to leading order corrections to the cross-sections. A new study for the l2 channel shows that it can give an important contribution above m\sb{\rm H} = 400 GeV. An estimate of the integrated luminosity needed for an observable Higgs signal is derived. It is shown that a fast discovery (integrated luminosity less than 10 fb\sp{-1}) can be expected if the Higgs mass is in the range of 130-550 GeV. The most difficult regions are the low mass range (m\sb{\rm H}600 GeV). With 100 fb\sp{-1} of integrated luminosity the full mass range can be covered
Fiscal sustainability and policy rules: Under changing demographic forecasts
All practical evaluations of fiscal sustainability that include the effects of population ageing must utilize demographic forecasts. It is well known that such forecasts are uncertain, and that has been taken into account in some studies by using stochastic population projections jointly with economic models. We develop this approach further by introducing regular demographic forecast revisions that are embedded in stochastic population projections. This allows us to separate systematically, in each demographic outcome and under different policy rules, the expected and the actualized effects of population ageing on public finances. We show that the likelihood of sustainability risks is significant, and that it would be wise to consider policies that reduce the likelihood of getting highly indebted. Furthermore, although demographic forecasts are uncertain, they seem to contain enough information to be useful in forward-looking policy rules
Quark cluster signatures in deuteron electromagnetic interactions
A suggestion is made for distinguishing 2N and 6q short range correlations
within the deuteron. The suggestion depends upon observing high momentum
backward nucleons emerging from inelastic electromagnetic scattering from a
deuteron target. A simple model is worked out to see the size of effects that
may be expected.Comment: 18 pages (3 figures available as hard copy), WM-94-10
Evaluation of bis-GMA/MMA resin adhesion to silica-coated and silanized titanium
The effects of pH value and alcohol solvent type of a silane solution on the bonding of an experimental resin to the silica-coated titanium (Ti) surface were studied. First, Ti surfaces underwent tribochemical Rocatec ™ treatment followed by silanization of the surface with 3-methacryloxypropyltrimethoxysilane (MPS). Then, resin stubs based on a mixture of bisphenol-A-glycidyl dimethacrylate and methyl methacrylate were bonded and light-cured onto each silica-coated Ti surface (n = 6 per group). Two different solvents for MPS, namely iso-propanol (i-PrOH)/H2O and ethanol (EtOH)/H2O were used, at pH values of 4.5, 5.0, and 5.5, and shear bond strengths were tested both under dry storage conditions and after water sorption induced by accelerated aging (i.e. thermo-cycling). The shear bond strengths were also re-determined after the silane solutions had been stored at 4°C for 15 weeks before the silanization step. For dry samples, the shear bond strengths ranged from 7.5 to 10.6 MPa (ANOVA, p < 0.05) when the Ti surface had been silanized with MPS in i-PrOH/H2O, and from 6.5 to 12.4 MPa (ANOVA, p < 0.05) when the Ti surface had been silanized with MPS in EtOH/H2O at pH 4.5. Fifteen weeks of storage of the silane solution increased the shear bond strength of dry samples by ca. 1-4 MPa per test group. In contrast, thermo-cycling reduced the shear bond strength in both solvent systems. The weight of the test sample stubs increased by ca. 3.5 wt% after 187 days of being subjected to the water sorption test. © 2009 VSP.postprin
An Introduction to Silanes and Their Clinical Applications in Dentistry
Purpose: This overview presents a description of organofunctional trialkoxysilane coupling agents (silanes), their chemistry, properties, use, and some of the main clinical experiences in dentistry. Materials and Methods: The main emphasis was on major dental journals that have been reviewed from 1958 up to the latest research news from 2002. A MEDLINE search with the key words “dental silanes” was used. Special silane literature and journals outside dentistry were also cited. Results: The main emphasis is on the use of silanes in prosthetic and restorative dentistry. Clinical relevance was based mainly on either short- or long-term tests. The interpretation of various results is not given, mainly because of controversial observations that may be very difficult to explain. Nevertheless, the majority of the clinical results pointed to silanes playing a significant role in the adhesion process. Silane reaction mechanisms were not entirely understood, and there exist several theories for bonding mechanisms for silanes and substrates. Conclusion: Dental materials offer a continuously challenging forum for silanes, and silanes will play an essential role in material developmen
Three-pion exchange: a gap in the nucleon-nucleon potential
The leading contribution to the three-pion exchange nucleon-nucleon potential
is calculated in the framework of chiral symmetry. It has pseudoscalar and
axial components and is dominated by the former, which has a range of about 1.5
fm and tends to enhance the OPEP. The strength of this force does not depend on
the pion mass and hence it survives in the chiral limit.Comment: 20 pages, 5 figures, 1 tabl
Microscopic Cluster Model for Exotic Nuclei
For a better understanding of the dynamics of exotic nuclei it is of crucial
importance to develop a practical microscopic theory easy to be applied to a
wide range of masses. Theoretically the basic task consists in formulating an
easy solvable theory able to reproduce structures and transitions of known
nuclei which should be then used to calculate the sparely known properties of
proton- or neutron-rich nuclei. In this paper we start by calculating energies
and distributions of A\leq4 nuclei withing a unitary correlation model
restricted to include only two-body correlations. The structure of complex
nuclei is then calculated extending the model to include correlation effects of
higher order.Comment: 10 pages, 4 figures. Final Version to be published in "Progress of
Particle and Nuclear Physics (2007
Peripheral N Scattering: A Tool For Identifying The Two Pion Exchange Component Of The NN Potential
We study elastic N scattering and produce a quantitative correlation
between the range of the effective potential and the energy of the system. This
allows the identification of the waves and energies for which the scattering
may be said to be peripheral. We then show that the corresponding phase shifts
are sensitive to the tail of the NN potential, which is due to the exchange of
two pions. However, the present uncertainties in the experimental phase shifts
prevent the use of N scattering to discriminate the existing models
for the NN interaction.Comment: 19 pages, 6 PostScript figures, RevTeX, to be appear in Phys. Rev.
Description of chlorophenol-degrading Pseudomonas sp. strains KF1T, KF3, and NKF1 as a new species of the genus Sphingomonas, Sphingomonas subarctica sp. nov
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