23 research outputs found
Heavy-Higgs Lifetime at Two Loops
The Standard-Model Higgs boson with mass decays almost
exclusively to pairs of and bosons. We calculate the dominant two-loop
corrections of to the partial widths of these decays. In
the on-mass-shell renormalization scheme, the correction factor is found to be
, where the second term is the
one-loop correction. We give full analytic results for all divergent two-loop
Feynman diagrams. A subset of finite two-loop vertex diagrams is computed to
high precision using numerical techniques. We find agreement with a previous
numerical analysis. The above correction factor is also in line with a recent
lattice calculation.Comment: 26 pages, 6 postscript figures. The complete paper including figures
is also available via WWW at
http://www.physik.tu-muenchen.de/tumphy/d/T30d/PAPERS/TUM-HEP-247-96.ps.g
Probing helium interfaces with light scattering : from fluid mechanics to statistical physics
We have investigated the formation of helium droplets in two physical
situations. In the first one, droplets are atomised from superfluid or normal
liquid by a fast helium vapour flow. In the second, droplets of normal liquid
are formed inside porous glasses during the process of helium condensation. The
context, aims, and results of these experiments are reviewed, with focus on the
specificity of light scattering by helium. In particular, we discuss how, for
different reasons, the closeness to unity of the index of refraction of helium
allows in both cases to minimise the problem of multiple scattering and obtain
results which it would not be possible to get using other fluids.Comment: 21 page
Two-loop corrections to the fermionic decay rates of the Higgs boson
We calculate the dominant two-loop
electroweak corrections to the fermi\-onic decay widths of a heavy Higgs boson
in the Standard Model. Use of the Goldstone-boson equivalence theorem reduces
the problem to one involving only the physical Higgs boson and the
Goldstone bosons and of the unbroken theory. The two-loop
corrections are opposite in sign to the one-loop electroweak corrections,
exceed the one-loop corrections in magnitude for , and
increase in relative magnitude as for larger values of . We
conclude that the perturbation expansion in powers of breaks down
for . We discuss briefly the QCD and the complete
one-loop electroweak corrections to , and
comment on the validity of the equivalence theorem. Finally we note how a very
heavy Higgs boson could be described in a phenomenological manner.Comment: 24 pages, RevTeX file, 4 figures in a separate compressed uuencoded
Postscript file or available by mail on request. Fig. 1 not included see
Figs. 1, 2 in Phys. Rev. D 48, 1061 (1993
Quantidade absorvida e concentrações de micronutrientes em tomateiro sob cultivo protegido
Biomarker signatures for progressive idiopathic pulmonary fibrosis
Background: Idiopathic pulmonary fibrosis (IPF) is a progressive lung disease in which circulatory biomarkers have the potential for guiding management in clinical practice. We assessed the prognostic role of serum biomarkers in three independent IPF cohorts: Australian Idiopathic Pulmonary Fibrosis Registry (AIPFR), Trent Lung Fibrosis (TLF) and Prospective Observation of Fibrosis in the Lung Clinical Endpoints (PROFILE). Methods: In the AIPFR cohort, candidate proteins were assessed by ELISA as well as in an unbiased proteomic approach. LASSO (least absolute shrinkage and selection operator) regression was used to restrict the selection of markers that best accounted for the progressor phenotype at 1 year in the AIPFR cohort, and subsequently prospectively selected for replication in the validation TLF cohort and assessed retrospectively in the PROFILE cohort. Four significantly replicating biomarkers were aggregated into a progression index model based on tertiles of circulating concentrations. Results 189 participants were included in the AIPFR cohort, 205 participants from the TLF cohort and 122 participants from the PROFILE cohort. Differential biomarker expression was observed by ELISA and replicated for osteopontin, matrix metallopeptidase-7, intercellular adhesion molecule-1 and periostin for those with a progressor phenotype at 1 year. Proteomic data did not replicate. The progression index in the AIPFR, TLF and PROFILE cohorts predicted risk of progression, mortality and progression-free survival. A statistical model incorporating the progression index demonstrated the capacity to distinguish disease progression at 12 months, which was increased beyond the clinical GAP (gender, age and physiology) score model alone in all cohorts, and significantly so within the incidence-based TLF and PROFILE cohorts. Conclusion: A panel of circulatory biomarkers can provide potentially valuable clinical assistance in the prognosis of IPF patients.Britt Clynick ... Paul N. Reynolds ... et. a