Perturbative reliability of the Higgs-boson coupling in the standard electroweak model

We apply Pade summation to the \beta(\lambda) function for the quartic Higgs coupling \lambda in the standard electroweak model. We use the \beta function calculated to five loops in the minimal subtraction scheme to demonstrate the improvement resulting from the summation, and then apply the method to the more physical on-mass-shell renormalization scheme where \beta is known to three loops. We conclude that the OMS \beta function and the running coupling \lambda(\mu) are reliably known over the range of energies and Higgs-boson masses of current interest.Comment: 14 pages, RevTeX, 6 figure

Statistical Properties of Fano Resonances in Atomic and Molecular Photoabsorption

Statistical properties of Fano resonances occurring in photoabsorption to highly excited atomic or molecular states are derived. The situation with one open and one closed channel is analyzed when the classical motion of the excited complex in the closed channel is chaotic. The closed channel subspace is modeled by random matrix theory. The probability distribution of the Fano parameter is derived both for the case of time reversal symmetry (TRS) and broken time reversal symmetry. For the TRS case the area distribution under a resonance profile relevant for low resolution experiments is discussed in detail.Comment: 4 pages, 4 figure

As múltiplas funções da agricultura familiar: um estudo no assentamento Monte Alegre, região de Araraquara (SP).

A partir da emergência da ideia de sustentabilidade, a agricultura adquiriu novas conotações, associadas não apenas ao aspecto produtivo, mas também à conservação dos recursos naturais e dos territórios rurais, em um reconhecimento de sua multifuncionalidade. Com base nesta noção, que valoriza as funções socioambientais desempenhadas pelas famílias rurais e pelas agriculturas praticadas, o presente artigo analisa um assentamento rural no estado de São Paulo, buscando identificar quais são e de que forma se expressam as funções para além da produção neste território particular. Por meio de uma metodologia de cunho quali-quantitativo, observou-se que, no assentamento em foco, a agricultura encerra em si questões de coesão territorial, manutenção da segurança alimentar, conservação da agrobiodiversidade e de fomento a outras atividades produtivas, sendo o elemento central da reconstrução de um modo de vida rural neste ambiente

Two-Loop O(αsGFmt2){\cal O}(\alpha_sG_Fm_t^2) Corrections to the Fermionic Decay Rates of the Standard-Model Higgs Boson

Low- and intermediate mass Higgs bosons decay preferably into fermion pairs. The one-loop electroweak corrections to the respective decay rates are dominated by a flavour-independent term of ${\cal O}(G_Fm_t^2)$. We calculate the two-loop gluon correction to this term. It turns out that this correction screens the leading high-$m_t$ behaviour of the one-loop result by roughly 10\%. We also present the two-loop QCD correction to the contribution induced by a pair of fourth-generation quarks with arbitrary masses. As expected, the inclusion of the QCD correction considerably reduces the renormalization-scheme dependence of the prediction.Comment: 14 pages, latex, figures 2-5 appended, DESY 94-08

Photoproduction of pions and properties of baryon resonances from a Bonn-Gatchina partial wave analysis

Masses, widths and photocouplings of baryon resonances are determined in a coupled-channel partial wave analysis of a large variety of data. The Bonn-Gatchina partial wave formalism is extended to include a decomposition of t- and u-exchange amplitudes into individual partial waves. The multipole transition amplitudes for $\gamma p\to p\pi^0$ and $\gamma p\to n\pi^+$ are given and compared to results from other analyses.Comment: 18 pages, 14 figure

P-wave excited baryons from pion- and photo-induced hyperon production

We report evidence for $N(1710)P_{11}$, $N(1875)P_{11}$, $N(1900)P_{13}$, $\Delta(1600)P_{33}$, $\Delta(1910)P_{31}$, and $\Delta(1920)P_{33}$, and find indications that $N(1900)P_{13}$ might have a companion state at 1970\,MeV. The controversial $\Delta(1750)P_{31}$ is not seen. The evidence is derived from a study of data on pion- and photo-induced hyperon production, but other data are included as well. Most of the resonances reported here were found in the Karlsruhe-Helsinki (KH84) and the Carnegie-Mellon (CM) analyses but were challenged recently by the Data Analysis Center at GWU. Our analysis is constrained by the energy independent $\pi N$ scattering amplitudes from either KH84 or GWU. The two $\pi N$ amplitudes from KH84 or GWU, respectively, lead to slightly different $\pi N$ branching ratios of contributing resonances but the debated resonances are required in both series of fits.Comment: 22 pages, 28 figures. Some additional sets of data are adde

Spectral modeling of scintillator for the NEMO-3 and SuperNEMO detectors

We have constructed a GEANT4-based detailed software model of photon transport in plastic scintillator blocks and have used it to study the NEMO-3 and SuperNEMO calorimeters employed in experiments designed to search for neutrinoless double beta decay. We compare our simulations to measurements using conversion electrons from a calibration source of $\rm ^{207}Bi$ and show that the agreement is improved if wavelength-dependent properties of the calorimeter are taken into account. In this article, we briefly describe our modeling approach and results of our studies.Comment: 16 pages, 10 figure

The COMPASS Experiment at CERN

The COMPASS experiment makes use of the CERN SPS high-intensitymuon and hadron beams for the investigation of the nucleon spin structure and the spectroscopy of hadrons. One or more outgoing particles are detected in coincidence with the incoming muon or hadron. A large polarized target inside a superconducting solenoid is used for the measurements with the muon beam. Outgoing particles are detected by a two-stage, large angle and large momentum range spectrometer. The setup is built using several types of tracking detectors, according to the expected incident rate, required space resolution and the solid angle to be covered. Particle identification is achieved using a RICH counter and both hadron and electromagnetic calorimeters. The setup has been successfully operated from 2002 onwards using a muon beam. Data with a hadron beam were also collected in 2004. This article describes the main features and performances of the spectrometer in 2004; a short summary of the 2006 upgrade is also given.Comment: 84 papes, 74 figure

Risk of End-Stage Renal Disease in HIV-Positive Potential Live Kidney Donors

New federal regulations allow HIV-positive individuals to be live kidney donors; however, potential candidacy for donation is poorly understood given the increased risk of end-stage renal disease (ESRD) associated with HIV infection. To better understand this risk, we compared the incidence of ESRD among 41 968 HIV-positive participants of North America AIDS Cohort Collaboration on Research and Design followed for a median of 5 years with the incidence of ESRD among comparable HIV-negative participants of National Health and Nutrition Examination III followed for a median of 14 years. We used risk associations from multivariable Cox proportional hazards regression to derive cumulative incidence estimates for selected HIV-positive scenarios (no history of diabetes, hypertension, AIDS, or hepatitis C virus coinfection) and compared these estimates with those from similarly selected HIV-negative scenarios. For 40-year-old HIV-positive individuals with health characteristics that were similar to those of age-matched kidney donors, viral load <400 copies/mL, and CD4+ count ≥500 cells/μL, the 9-year cumulative incidence of ESRD was higher than that of their HIV-negative peers, yet still low: 2.5 versus 1.1 per 10 000 among white women, 3.0 versus 1.3 per 10 000 among white men, 13.2 versus 3.6 per 10 000 among black women, and 15.8 versus 4.4 per 10 000 among black men. HIV-positive individuals with no comorbidities and well-controlled disease may be considered low-risk kidney donor candidates

Plasma copeptin as biomarker of disease progression and prognosis in cirrhosis

Lay summary: Copeptin is a fragment of the vasopressin precursor, a hormone that is known to be increased in patients with cirrhosis and that plays a role in the development of complications of the disease. Vasopressin is difficult to measure, but copeptin is a more stable molecule and is easier to measure in blood. Sola and Kerbert and colleagues have shown in a series of 361 patients that copeptin is markedly increased in patients with cirrhosis who develop complications during the following 3 months, compared to those patients who do not develop complications. Moreover, copeptin correlates with prognosis. (C) 2016 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.Cellular mechanisms in basic and clinical gastroenterology and hepatolog