351 research outputs found
Large Electric Dipole Moments of Heavy Leptons
In many models of CP violation, the electric dipole moments (EDMs) of leptons
scale as the cube of the lepton mass. In these models, the EDM of a 100 GeV
heavy lepton would be a billion times greater than that of the muon, and could
be as large as a 0.01 e-fermi. In other models, in which the heavy leptons have
different properties from the lighter generations, a similarly large EDM can be
obtained. A large EDM could dominate the electromagnetic properties of heavy
leptons. The angular distribution and production cross-section of both charged
and neutral heavy leptons with large dipole moments is calculated and
discussed. The interesting possibility that a heavy neutrino with a large EDM
could leave an ionization track in a drift chamber is investigated.Comment: Discussion expanded extensively to include model-dependence of
results. Calculations unchanged. Note Added To Acknowledgments: This paper is
dedicated to the memory of Nathan Isgu
Large Electric Dipole Moments of Heavy Neutrinos
In many models of CP violation, the electric dipole moment (EDM) of a heavy
charged or neutral lepton could be very large. We present an explicit model in
which a heavy neutrino EDM can be as large as e-cm, or even a factor
of ten larger if fine-tuning is allowed, and use an effective field theory
argument to show that this result is fairly robust. We then look at the
production cross section for these neutrinos, and by rederiving the Bethe-Block
formula, show that they could leave an ionization track. It is then noted that
the first signature of heavy neutrinos with a large EDM would come from
, leading to a very large rate for single photon plus
missing energy events, and the rate and angular distribution are found.
Finally, we look at some astrophysical consequences, including whether these
neutrinos could constitute the UHE cosmic rays and whether their decays in the
early universe could generate a net lepton asymmetry.Comment: 22 pages, 9 figure
Oil elite networks in a transforming global oil market
This article analyses oil elite formation in light of the wider transformation that is taking place in the global oil order due to the rise of powers from the Global South, including Russia: in particular, the expansion and integration of the state-owned oil companies into the global oil market. This is done by analysing the networks that the directors of the world's largest oil companies create through their affiliations with a) other corporations, b) policy planning bodies and c) with the state. The most important finding is that the increased cooperation between the Western private oil companies and the non-Western state-owned oil companies has not yet translated into increased integration between their respective elite networks. It is argued that this indicates we are witnessing a transition towards a more multi-polar global oil order that increasingly needs to take into account the rising powers of the Global South. © The Author(s) 2012
Approximation algorithms for general cluster routing problem
Graph routing problems have been investigated extensively in operations
research, computer science and engineering due to their ubiquity and vast
applications. In this paper, we study constant approximation algorithms for
some variations of the general cluster routing problem. In this problem, we are
given an edge-weighted complete undirected graph whose vertex set
is partitioned into clusters We are also given a subset
of and a subset of The weight function satisfies the
triangle inequality. The goal is to find a minimum cost walk that visits
each vertex in only once, traverses every edge in at least once and
for every all vertices of are traversed consecutively.Comment: In COCOON 202
Premorbid levels of high-sensitivity cardiac troponin T and natriuretic peptide and prognosis after incident myocardial infarction
High-sensitivity cardiac troponin T (hs-cTnT) and N-terminal pro-B-type natriuretic peptide (NT-proBNP) at the time of myocardial infarction (MI) are strong predictors of prognosis. However, whether their premorbid (before MI occurrence) levels are associated with prognosis after incident MI is unknown. Methods: In 1,054 participants from the Atherosclerosis Risk in Communities Study with incident MI, we evaluated premorbid levels of hs-cTnT and NT-proBNP measured on median 5.8 (interquartile interval 3.0-11.5 [mean 5.5]) years prior to incident MI and their associations with subsequent composite and individual outcomes of all-cause mortality, cardiovascular mortality, recurrent MI, heart failure, and stroke. Results: During a median follow-up of 3.0 years after MI, 801 participants developed the composite outcome. Both hs-cTnT and NT-proBNP were independently associated with the composite outcome after incident MI. Among individual outcomes, all-cause mortality, cardiovascular mortality, and heart failure showed significant associations with both cardiac markers. Overall, NT-proBNP demonstrated a more evident relationship than hs-cTnT. Indeed, the addition of premorbid NT-proBNP alone, but not hs-cTnT alone, to conventional predictors at incident MI significantly improved risk prediction of the composite outcome after incident MI (âc-statistic 0.013 [95% CI 0.005-0.022] from 0.691 with conventional predictors). Conclusions: Premorbid levels of hs-cTnT and NT-proBNP assessed on average 6 years prior to incident MI were associated with adverse outcomes after incident MI. These results further highlight the importance of cardiac health at an earlier stage of life
Slepton Flavor Nonuniversality, the Muon EDM and its Proposed sensitive Search at Brookhaven
We analyze the electric dipole moment of the electron (), of the neutron
() and of the muon () using the cancellation mechanism in the
presence of nonuniversalities of the soft breaking parameters. It is shown that
the nonuniversalities in the slepton sector produce a strong violation of the
scaling relation in the cancellation region. An
analysis of and under the constraints of the current
experimental limits on and and under the constraints of the recent
Brookhaven result on shows that in the non-scaling region
can be as large as ()ecm and thus within reach of the
recently proposed Brookhaven experiment for a sensitive search for at
the level of ecm.Comment: 24 pages, Latex, including 5 figures with additional reference
Higgs Low-Energy Theorem (and its corrections) in Composite Models
The Higgs low-energy theorem gives a simple and elegant way to estimate the
couplings of the Higgs boson to massless gluons and photons induced by loops of
heavy particles. We extend this theorem to take into account possible nonlinear
Higgs interactions resulting from a strong dynamics at the origin of the
breaking of the electroweak symmetry. We show that, while it approximates with
an accuracy of order a few percents single Higgs production, it receives
corrections of order 50% for double Higgs production. A full one-loop
computation of the gg->hh cross section is explicitly performed in MCHM5, the
minimal composite Higgs model based on the SO(5)/SO(4) coset with the Standard
Model fermions embedded into the fundamental representation of SO(5). In
particular we take into account the contributions of all fermionic resonances,
which give sizeable (negative) corrections to the result obtained considering
only the Higgs nonlinearities. Constraints from electroweak precision and
flavor data on the top partners are analyzed in detail, as well as direct
searches at the LHC for these new fermions called to play a crucial role in the
electroweak symmetry breaking dynamics.Comment: 30 pages + appendices and references, 12 figures. v2: discussion of
flavor constraints improved; references added; electroweak fit updated,
results unchanged. Matches published versio
Comparison of cardiovascular risk factors between sri lankans living in kandy and oslo
<p>Abstract</p> <p>Background</p> <p>South Asians living in western countries are known to have unfavourable cardiovascular risk profiles. Studies indicate migrants are worse off when compared to those living in country of origin. The purpose of this study was to compare selected cardiovascular risk factors between migrant Sri Lankans living in Oslo, Norway and Urban dwellers from Kandy, Sri Lanka.</p> <p>Methods</p> <p>Data on non fasting serum lipids, blood pressure, anthropometrics and socio demographics of Sri Lankan Tamils from two almost similar population based cross sectional studies in Oslo, Norway between 2000 and 2002 (1145 participants) and Kandy, Sri Lanka in 2005 (233 participants) were compared. Combined data were analyzed using linear regression analyses.</p> <p>Results</p> <p>Men and women in Oslo had higher HDL cholesterol. Men and women from Kandy had higher Total/HDL cholesterol ratios. Mean waist circumference and body mass index was higher in Oslo. Smoking among men was low (19.2% Oslo, 13.1% Kandy, P = 0.16). None of the women smoked. Mean systolic and diastolic blood pressure was significantly higher in Kandy than in Oslo.</p> <p>Conclusions</p> <p>Our comparison showed unexpected differences in risk factors between Sri Lankan migrants living in Oslo and those living in Kandy Sri Lanka. Sri Lankans in Oslo had favorable lipid profiles and blood pressure levels despite being more obese.</p
Two-loop electroweak corrections to the parameter beyond the leading approximation
We show that in the framework of the pinch technique the universal part of
the parameter can be meaningfully defined, beyond one loop. The
universal part so obtained satisfies the crucial requirements of
gauge-independence, finiteness, and process-independence, even when subleading
contributions of the top quark are included. The mechanism which enforces the
aforementioned properties is explained in detail, and several subtle field
theoretical issues are discussed. Explicit calculations of the sub-leading
two-loop corrections of order are carried
out in the context of an model, with , and various
intermediate and final results are reported.Comment: 40 pages, TeXsis, uu encoded ps files, 14 figures include
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