20 research outputs found
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
Search for jet extinction in the inclusive jet-pT spectrum from proton-proton collisions at s=8 TeV
Published by the American Physical Society under the terms of the Creative Commons Attribution 3.0 License. Further distribution of this work must maintain attribution to the author(s) and the published articles title, journal citation, and DOI.The first search at the LHC for the extinction of QCD jet production is presented, using data collected with the CMS detector corresponding to an integrated luminosity of 10.7 fb−1 of proton-proton collisions at a center-of-mass energy of 8 TeV. The extinction model studied in this analysis is motivated by the search for signatures of strong gravity at the TeV scale (terascale gravity) and assumes the existence of string couplings in the strong-coupling limit. In this limit, the string model predicts the suppression of all high-transverse-momentum standard model processes, including jet production, beyond a certain energy scale. To test this prediction, the measured transverse-momentum spectrum is compared to the theoretical prediction of the standard model. No significant deficit of events is found at high transverse momentum. A 95% confidence level lower limit of 3.3 TeV is set on the extinction mass scale
Searches for electroweak neutralino and chargino production in channels with Higgs, Z, and W bosons in pp collisions at 8 TeV
Searches for supersymmetry (SUSY) are presented based on the electroweak pair production of neutralinos and charginos, leading to decay channels with Higgs, Z, and W bosons and undetected lightest SUSY particles (LSPs). The data sample corresponds to an integrated luminosity of about 19.5 fb(-1) of proton-proton collisions at a center-of-mass energy of 8 TeV collected in 2012 with the CMS detector at the LHC. The main emphasis is neutralino pair production in which each neutralino decays either to a Higgs boson (h) and an LSP or to a Z boson and an LSP, leading to hh, hZ, and ZZ states with missing transverse energy (E-T(miss)). A second aspect is chargino-neutralino pair production, leading to hW states with E-T(miss). The decays of a Higgs boson to a bottom-quark pair, to a photon pair, and to final states with leptons are considered in conjunction with hadronic and leptonic decay modes of the Z and W bosons. No evidence is found for supersymmetric particles, and 95% confidence level upper limits are evaluated for the respective pair production cross sections and for neutralino and chargino mass values
Comparison of two coprological methods for the diagnosis of Eurytrema ssp. in cattle and sheep
Eurytrematosis is a disease caused by flukes of the genus Eurytrema. These parasites infect the
pancreatic ducts of a wide variety of species, including cattle, sheep and humans. Diagnosing
eurytrematosis through the analysis of faecal samples can be difficult because most of the available
techniques are considered of low sensitivity. In this context, a modification of the Dennis,
Stone and Swanson technique (Belem Sedimentation Technique, BST) was previously developed
to increase the probability of detecting infected animals; nevertheless, the values of eggs per
gram obtained using the modified technique are generally low. We proposed a modification
of the this technique (MBST), to increase the sensitivity and detection rate of infected animals.
The objective of this work was to describe MBST and compare it with BST. Faecal samples of
212 clinically healthy animals (174 from cattle and 38 from sheep) from 20 farms were taken by
the intra-rectal route and stored at 4°C. The samples were processed using BST and MBST.
Positive samples amounted to 55 (25.9%) using BST and 121 (57.1%) using MBST. In the simples
from cattle, 52 (29.8%) and 107 (61.4%) were positive in BST and MBST, respectively. In
sheep, three (7.8%) and 14 (36.8%) positive samples were obtained in BST and MBST,
respectively.The results obtained using the two methods were significantly different, indicating
a lack of agreement between their findings. The results suggest that MBST is a more sensitive
method to detect Eurytrema spp. eggs in faeces than BST.Instituto de Investigación Animal del Chaco SemiáridoFil: Olmos, Leandro Hipólito. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Investigación Animal del Chaco Semiárido. Área de Investigación en Salud Animal; ArgentinaFil: Olmos, Leandro Hipolito. Universidad Católica de Salta. Facultad de Ciencias Agrarias y Veterinarias; ArgentinaFil: Pantiu, Andrea Julia. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Montecarlo; ArgentinaFil: Avellaneda Cáceres, Agustín. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Avellaneda Cáceres, Agustín. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Investigación Animal del Chaco Semiárido. Área de Investigación en Salud Animal; ArgentinaFil: Avellaneda Cáceres, Agustín. Universidad Católica de Salta. Facultad de Ciencias Agrarias y Veterinarias; ArgentinaFil: Valencia, P.N. Instituto San Cayetano N° 8092. Tecnicatura Superior en Laboratorio; ArgentinaFil: Cayo, P.N. Instituto San Cayetano N° 8092. Tecnicatura Superior en Laboratorio; ArgentinaFil: Signorini Porchiett, Marcelo Lisandro. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Signorini Porchiett, Marcelo Lisandro. Instituto Nacional de Tecnología Agropecuaria (INTA).Estación Experimental Agropecuaria Rafaela; ArgentinaFil: Micheloud, Juan Francisco. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Investigación Animal del Chaco Semiárido. Área de Investigación en Salud Animal; ArgentinaFil: Micheloud, Juan Francisco. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Micheloud, Juan Francisco. Universidad Católica de Salta. Facultad de Ciencias Agrarias y Veterinarias; Argentin
Greater male variability in daily energy expenditure develops through puberty.
There is considerably greater variation in metabolic rates between men than between women, in terms of basal, activity and total (daily) energy expenditure (EE). One possible explanation is that EE is associated with male sexual characteristics (which are known to vary more than other traits) such as musculature and athletic capacity. Such traits might be predicted to be most prominent during periods of adolescence and young adulthood, when sexual behaviour develops and peaks. We tested this hypothesis on a large dataset by comparing the amount of male variation and female variation in total EE, activity EE and basal EE, at different life stages, along with several morphological traits: height, fat free mass and fat mass. Total EE, and to some degree also activity EE, exhibit considerable greater male variation (GMV) in young adults, and then a decreasing GMV in progressively older individuals. Arguably, basal EE, and also morphometrics, do not exhibit this pattern. These findings suggest that single male sexual characteristics may not exhibit peak GMV in young adulthood, however total and perhaps also activity EE, associated with many morphological and physiological traits combined, do exhibit GMV most prominently during the reproductive life stages