21 research outputs found
Simultaneous decoupling of bottom and charm quarks
We compute the decoupling relations for the strong coupling, the light quark
masses, the gauge-fixing parameter, and the light fields in QCD with heavy
charm and bottom quarks to three-loop accuracy taking into account the exact
dependence on . The application of a low-energy theorem allows the
extraction of the three-loop effective Higgs-gluon coupling valid for
extensions of the Standard Model with additional heavy quarks from the
decoupling constant of .Comment: 30 page
High precision determination of the gluon fusion Higgs boson cross-section at the LHC
We present the most precise value for the Higgs boson cross-section in the gluon-fusion production mode at the LHC. Our result is based on a perturbative expansion through NLO in QCD, in an effective theory where the top-quark is assumed to be infinitely heavy, while all other Standard Model quarks are massless. We combine this result with QCD corrections to the cross-section where all finite quark-mass effects are included exactly through NLO. In addition, electroweak corrections and the first corrections in the inverse mass of the top-quark are incorporated at three loops. We also investigate the effects of threshold resummation, both in the traditional QCD framework and following a SCET approach, which resums a class of contributions to all orders. We assess the uncertainty of the cross-section from missing higher-order corrections due to both perturbative QCD effects beyond NLO and unknown mixed QCD-electroweak effects. In addition, we determine the sensitivity of the cross-section to the choice of parton distribution function (PDF) sets and to the parametric uncertainty in the strong coupling constant and quark masses. For a Higgs mass of and an LHC center-of-mass energy of , our best prediction for the gluon fusion cross-section is \[ \sigma = 48.58\,{\rm pb} {}^{+2.22\, {\rm pb}\, (+4.56\%)}_{-3.27\, {\rm pb}\, (-6.72\%)} \mbox{ (theory)} \pm 1.56 \,{\rm pb}\, (3.20\%) \mbox{ (PDF+)} \
Altered ion transporter expression in bronchial epithelium in mountaineers with high-altitude pulmonary edema
BACKGROUND: The prevalence of overweight and obesity defined as BMI>/=25kg/m(2) is increasing, also among head and neck cancer patients. It is unknown whether the presence of high BMI influences disease-related mortality, overall survival and recurrence in these patients. METHODS: We reviewed available literature using Pubmed and Web of Science. Human observational studies were included if they reported the impact of high BMI on mortality, recurrence or survival for head and neck cancer. RESULTS: Eleven full articles and two abstracts met the inclusion criteria: six prospective and seven retrospective cohort studies, which comprised 8.306 patients. Patients with higher BMI had increased overall survival and decreased disease-related mortality and recurrence rate compared with underweight and normal weight patients. Most studies were adjusted for potentially confounding variables, such as stage of disease and smoking habits. CONCLUSION: High BMI is associated with a better outcome in head and neck cancer