820 research outputs found
Tensor gauge field localization on a string-like defect
This work is devoted to the study of tensor gauge fields on a string-like
defect in six dimensions. This model is very successful in localizing fields of
various spins only by gravitational interaction. Due to problems of field
localization in membrane models we are motivated to investigate if a
string-like defect localizes the Kalb-Ramond field. In contrast to what happens
in Randall-Sundrum and thick brane scenarios we find a localized zero mode
without the addition of other fields in the bulk. Considering the local string
defect we obtain analytical solutions for the massive modes. Also, we take the
equations of motion in a supersymmetric quantum mechanics scenario in order to
analyze the massive modes. The influence of the mass as well as the angular
quantum number in the solutions is described. An additional analysis on the
massive modes is performed by the Kaluza-Klein decomposition, which provides
new details about the KK masses.Comment: 17 pages, 2 figures. To appear in Physics Letters
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Sensitivity of hydrological performance assessment analysis to variations in material properties, conceptual models, and ventilation models
The Yucca Mountain Site Characterization Project is studying Yucca Mountain in southwestern Nevada as a potential site for a high-level nuclear waste repository. Site characterization includes surface- based and underground testing. Analyses have been performed to support the design of an Exploratory Studies Facility (ESF) and the design of the tests performed as part of the characterization process, in order to ascertain that they have minimal impact on the natural ability of the site to isolate waste. The information in this report pertains to sensitivity studies evaluating previous hydrological performance assessment analyses to variation in the material properties, conceptual models, and ventilation models, and the implications of this sensitivity on previous recommendations supporting ESF design. This document contains information that has been used in preparing recommendations for Appendix I of the Exploratory Studies Facility Design Requirements document
Kalb-Ramond excitations in a thick-brane scenario with dilaton
We compute the full spectrum and eigenstates of the Kalb-Ramond field in a
warped non-compact Randall-Sundrum -type five-dimensional spacetime in which
the ordinary four-dimensional braneworld is represented by a sine-Gordon
soliton. This 3-brane solution is fully consistent with both the warped
gravitational field and bulk dilaton configurations. In such a background we
embed a bulk antisymmetric tensor field and obtain, after reduction, an
infinite tower of normalizable Kaluza-Klein massive components along with a
zero-mode. The low lying mass eigenstates of the Kalb-Ramond field may be
related to the axion pseudoscalar. This yields phenomenological implications on
the space of parameters, particularly on the dilaton coupling constant. Both
analytical and numerical results are given.Comment: 10 pages, 13 figures, and 2 tables. Final version to appear in The
European Physical Journal
Measurement of W Polarisation at LEP
The three different helicity states of W bosons produced in the reaction e+
e- -> W+ W- -> l nu q q~ at LEP are studied using leptonic and hadronic W
decays. Data at centre-of-mass energies \sqrt s = 183-209 GeV are used to
measure the polarisation of W bosons, and its dependence on the W boson
production angle. The fraction of longitudinally polarised W bosons is measured
to be 0.218 \pm 0.027 \pm 0.016 where the first uncertainty is statistical and
the second systematic, in agreement with the Standard Model expectation
Search for Anomalous Couplings in the Higgs Sector at LEP
Anomalous couplings of the Higgs boson are searched for through the processes
e^+ e^- -> H gamma, e^+ e^- -> e^+ e^- H and e^+ e^- -> HZ. The mass range 70
GeV < m_H < 190 GeV is explored using 602 pb^-1 of integrated luminosity
collected with the L3 detector at LEP at centre-of-mass energies
sqrt(s)=189-209 GeV. The Higgs decay channels H -> ffbar, H -> gamma gamma, H
-> Z\gamma and H -> WW^(*) are considered and no evidence is found for
anomalous Higgs production or decay. Limits on the anomalous couplings d, db,
Delta(g1z), Delta(kappa_gamma) and xi^2 are derived as well as limits on the H
-> gamma gamma and H -> Z gamma decay rates
Measurement of W Polarisation at LEP
The three different helicity states of W bosons produced in the reaction e+
e- -> W+ W- -> l nu q q~ at LEP are studied using leptonic and hadronic W
decays. Data at centre-of-mass energies \sqrt s = 183-209 GeV are used to
measure the polarisation of W bosons, and its dependence on the W boson
production angle. The fraction of longitudinally polarised W bosons is measured
to be 0.218 \pm 0.027 \pm 0.016 where the first uncertainty is statistical and
the second systematic, in agreement with the Standard Model expectation
Bose-Einstein Correlations of Neutral and Charged Pions in Hadronic Z Decays
Bose-Einstein correlations of both neutral and like-sign charged pion pairs
are measured in a sample of 2 million hadronic Z decays collected with the L3
detector at LEP. The analysis is performed in the four-momentum difference
range 300 MeV < Q < 2 GeV. The radius of the neutral pion source is found to be
smaller than that of charged pions. This result is in qualitative agreement
with the string fragmentation model
Z Boson Pair-Production at LEP
Events stemming from the pair-production of Z bosons in e^+e^- collisions are
studied using 217.4 pb^-1 of data collected with the L3 detector at
centre-of-mass energies from 200 GeV up to 209 GeV. The special case of events
with b quarks is also investigated.
Combining these events with those collected at lower centre-of-mass energies,
the Standard Model predictions for the production mechanism are verified. In
addition, limits are set on anomalous couplings of neutral gauge bosons and on
effects of extra space dimensions
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