88 research outputs found
Scale dependence and collinear subtraction terms for Higgs production in gluon fusion at N3LO
The full, explicit, scale dependence of the inclusive N3LO cross section for
single Higgs hadroproduction is obtained by calculating the convolutions of
collinear splitting kernels with lower-order partonic cross sections. We
provide results for all convolutions of splitting kernels and lower-order
partonic cross sections to the order in epsilon needed for the full N3LO
computation, as well as their expansions around the soft limit. We also discuss
the size of the total scale uncertainty at N3LO that can be anticipated with
existing information.Comment: 27 pages, 8 figure, 1 table, 8 ancillary files. v2: added 4
references, changed labelling of contour plot
Higgs production cross-section in a Standard Model with four generations at the LHC
We present theoretical predictions for the Higgs boson production
cross-section via gluon fusion at the LHC in a Standard Model with four
generations. We include QCD corrections through NLO retaining the full
dependence on the quark masses, and the NNLO corrections in the heavy quark
effective theory approximation. We also include electroweak corrections through
three loops. Electroweak and bottom-quark contributions are suppressed in
comparison to the Standard Model with three generations.Comment: 6 pages, 2 Tables, to appear in the proceedings of the XLVIth
Rencontres de Moriond session devoted to Electroweak Interactions and Unified
Theorie
NNLO phase space master integrals for two-to-one inclusive cross sections in dimensional regularization
We evaluate all phase space master integrals which are required for the total
cross section of generic 2 -> 1 processes at NNLO as a series expansion in the
dimensional regulator epsilon. Away from the limit of threshold production, our
expansion includes one order higher than what has been available in the
literature. At threshold, we provide expressions which are valid to all orders
in terms of Gamma functions and hypergeometric functions. These results are a
necessary ingredient for the renormalization and mass factorization of
singularities in 2 -> 1 inclusive cross sections at NNNLO in QCD.Comment: 37 pages, plus 3 ancillary files containing analytic expressions in
Maple forma
Development of a GEM-TPC prototype
The use of GEM foils for the amplification stage of a TPC instead of a con-
ventional MWPC allows one to bypass the necessity of gating, as the backdrift
is suppressed thanks to the asymmetric field configuration. This way, a novel
continuously running TPC, which represents one option for the PANDA central
tracker, can be realized. A medium sized prototype with a diameter of 300 mm
and a length of 600 mm will be tested inside the FOPI spectrometer at GSI using
a carbon or lithium beam at intermediate energies (E = 1-3AGeV). This detector
test under realistic experimental conditions should allow us to verify the
spatial resolution for single tracks and the reconstruction capability for
displaced vertexes. A series of physics measurement implying pion beams is
scheduled with the FOPI spectrometer together with the GEM-TPC as well.Comment: 5 pages, 4 figures, Proceedings for 11th ICATTP conference in como
(italy
The fully differential hadronic production of a Higgs boson via bottom quark fusion at NNLO
The fully differential computation of the hadronic production cross section
of a Higgs boson via bottom quarks is presented at NNLO in QCD. Several
differential distributions with their corresponding scale uncertainties are
presented for the 8 TeV LHC. This is the first application of the method of
non-linear mappings for NNLO differential calculations at hadron colliders.Comment: 27 pages, 13 figures, 1 lego plo
Implications of early respiratory support strategies on disease progression in critical COVID-19: a matched subanalysis of the prospective RISC-19-ICU cohort.
Uncertainty about the optimal respiratory support strategies in critically ill COVID-19 patients is widespread. While the risks and benefits of noninvasive techniques versus early invasive mechanical ventilation (IMV) are intensely debated, actual evidence is lacking. We sought to assess the risks and benefits of different respiratory support strategies, employed in intensive care units during the first months of the COVID-19 pandemic on intubation and intensive care unit (ICU) mortality rates.
Subanalysis of a prospective, multinational registry of critically ill COVID-19 patients. Patients were subclassified into standard oxygen therapy â„10 L/min (SOT), high-flow oxygen therapy (HFNC), noninvasive positive-pressure ventilation (NIV), and early IMV, according to the respiratory support strategy employed at the day of admission to ICU. Propensity score matching was performed to ensure comparability between groups.
Initially, 1421 patients were assessed for possible study inclusion. Of these, 351 patients (85 SOT, 87 HFNC, 87 NIV, and 92 IMV) remained eligible for full analysis after propensity score matching. 55% of patients initially receiving noninvasive respiratory support required IMV. The intubation rate was lower in patients initially ventilated with HFNC and NIV compared to those who received SOT (SOT: 64%, HFNC: 52%, NIV: 49%, p = 0.025). Compared to the other respiratory support strategies, NIV was associated with a higher overall ICU mortality (SOT: 18%, HFNC: 20%, NIV: 37%, IMV: 25%, p = 0.016).
In this cohort of critically ill patients with COVID-19, a trial of HFNC appeared to be the most balanced initial respiratory support strategy, given the reduced intubation rate and comparable ICU mortality rate. Nonetheless, considering the uncertainty and stress associated with the COVID-19 pandemic, SOT and early IMV represented safe initial respiratory support strategies. The presented findings, in agreement with classic ARDS literature, suggest that NIV should be avoided whenever possible due to the elevated ICU mortality risk
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