6,966 research outputs found
MCFM for the Tevatron and the LHC
A summary is given of the current status of the next-to-leading order (NLO)
parton-level integrator MCFM. Some details are given about the Higgs + 2-jet
process and the production and decay of , both of which have
recently been added to the code. Using MCFM, comparisons between the Tevatron
running at ~TeV and the LHC running at ~TeV are made
for standard model process including the production of Higgs bosons. The case
for running the Tevatron until 16fb are accumulated by both detectors is
sketched.Comment: Talk presented by R.K Ellis at Loops and Legs in Quantum Field Theory
2010, Woerlitz, Germany, April 25-30, 2010, (6 pages and 4 figures
QCD corrections to the hadronic production of a heavy quark pair and a W-boson including decay correlations
We perform an analytic calculation of the one-loop amplitude for the W-boson
mediated process 0 \to d u-bar Q Q-bar l-bar l, retaining the mass for the
quark Q. The momentum of each of the massive quarks is expressed as the sum of
two massless momenta and the corresponding heavy quark spinor is expressed as a
sum of two massless spinors. Using a special choice for the heavy quark spinors
we obtain analytic expressions for the one-loop amplitudes which are amenable
to fast numerical evaluation. The full next-to-leading order (NLO) calculation
of hadron+hadron \to W(\to e nu) b b-bar with massive b-quarks is included in
the program MCFM. A comparison is performed with previous published work.Comment: 45 pages, 17 figure
Single top production and decay at next-to-leading order
We present the results of a next-to-leading order analysis of single top
production including the decay of the top quark. Radiative effects are included
both in the production and decay stages, using a general subtraction method.
This calculation gives a good treatment of the jet activity associated with
single top production. We perform an analysis of the single top search at the
Tevatron, including a consideration of the main backgrounds, many of which are
also calculated at next-to-leading order.Comment: 35 pages + 15 figures, revtex
The Energy Transfer Process in Planetary Flybys
We illustrate the energy transfer during planetary flybys as a function of
time using a number of flight mission examples. The energy transfer process is
rather more complicated than a monotonic increase (or decrease) of energy with
time. It exhibits temporary maxima and minima with time which then partially
moderate before the asymptotic condition is obtained. The energy transfer to
angular momentum is exhibited by an approximate Jacobi constant for the system.
We demonstrate this with flybys that have shown unexplained behaviors: i) the
possible onset of the "Pioneer anomaly" with the gravity assist of Pioneer 11
by Saturn to hyperbolic orbit (as well as the Pioneer 10 hyperbolic gravity
assist by Jupiter) and ii) the Earth flyby anomalies of small increases in
energy {\it in the geocentric system} (Galileo-I, NEAR, and Rosetta, in
additioon discussing the Cassini and Messenger flybys). Perhaps some small, as
yet unrecognized effect in the energy-transfer process can shed light on these
anomalies.Comment: 29 pages, 43 images combined into 13 figures. Additions to answer
comments of refere
Understanding the role of infant and toddler nutrition on population health : epidemiological resources in Australasia
The importance of understanding the relationship between weaning and toddler nutrition, which in turn impacts on health in later life, is highlighted. Emphasis is placed on the need for epidemiological research in Australasia for population-specific information on early life diet and health.Rebecca K Golley, Lisa G Smithers, Karen Campbell, and John Lync
Hemorrhage into an Occult Spinal Ependymoma after Epidural Anesthesia
Summary of Background Data: Five cases of hemorrhage into a spinal neoplasm after spinal or epidural anesthesia are reported in the literature. Presentation ranges from severe low back pain to acute cauda equina syndrome.
Methods: A case study of a patient who hemorrhaged into an intradural, extramedullary spinal cord mass was performed. A detailed literature review is also provided.
Results: A 27 year old female underwent epidural anesthesia for Cesarean section delivery. She presented with a 3 week history of increasing low back pain with bilateral radiculopathy. Imaging studies revealed a large hemorrhagic intradural mass compressing the lower conus medullaris and cauda equina, which operatively was confirmed to be a myxopapillary ependymoma.
Conclusions: We report a case of hemorrhage into a previously unrecognized ependymoma after epidural anesthesia. Underlying tumors may rarely complicate regional anesthesia in the lumbar spine
Discussion of âFormation of an Intermediate Layer Between Grains in Nickel-Based Superalloy Turbine Bladesâ*
Achirality in the low temperature structure and lattice modes of tris(acetylacetonate)iron(iii)
Tris(acetylacteonate) iron(III) is a relatively ubiquitous mononuclear inorganic coordination complex. The bidentate nature of the three acetylacteonate ligands coordinating around a single centre inevitably leads to structural isomeric forms, however whether or not this relates to chirality in the solid state has been questioned in the literature. Variable temperature neutron diffraction data down to T = 3 K, highlights the dynamic nature of the ligand environment, including the motions of the hydrogen atoms. The Fourier transform of the molecular dynamics simulation based on the experimentally determined structure was shown to closely reproduce the low temperature vibrational density of states obtained using inelastic neutron scattering
t \bar{t} W production and decay at NLO
We present results for the production of a top pair in association with a
W-boson at next-to-leading order. We have implemented this process into the
parton-level integrator MCFM including the decays of both the top quarks and
the W-bosons with full spin correlations. Although the cross section for this
process is small, it is a Standard Model source of same-sign lepton events that
must be accounted for in many new physics searches. For a particular analysis
of same-sign lepton events in which b-quarks are also present, we investigate
the effect of the NLO corrections as a function of the signal region cuts.Comment: 10 pages, 7 figure
Next-to-Leading order Higgs + 2 jet production via gluon fusion
We present phenomenological results for the production of a Higgs boson in
association with two jets at the LHC. The calculation is performed in the limit
of large top mass and is accurate to next-to-leading order in the strong
coupling, i.e. Comment: 13 pages, 6 figures; v2: references added, modified acknowledgments,
final version as published in JHE
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