8,866 research outputs found
Higgs Strahlung at the Large Hadron Collider in the 2-Higgs-Doublet Model
We present a calculation of all relevant contributions to associated
production of a Higgs boson with a weak gauge boson in the 2-Higgs-Doublet
Model (2HDM) at the LHC, , with and
. While for the mode, this mostly amounts to a simple
rescaling of the Standard Model (SM) cross section, the cross section
depends on several 2HDM parameters. The ratio ,
for which we present the currently most complete SM prediction, therefore
appears to be a sensitive probe of possible New Physics effects. We study its
numerical dependence on the top and bottom Yukawa couplings, including their
sign. Furthermore, we consider the ratio in exemplary 2HDM
scenarios and briefly address the effects in the boosted regime. Analogous
studies for other 2HDM scenarios will become possible with an upcoming version
of the program vh@nnlo which incorporates the 2HDM effects.Comment: 32 pages, 18 figures; v2: discussion of boosted regime added, typos
corrected, references added, version published in JHE
A nonsymmetric version of Okounkov's BC-type interpolation Macdonald polynomials
Symmetric and nonsymmetric interpolation Laurent polynomials are introduced
with the interpolation points depending on and a -tuple of parameters
. For the principal specialization
the symmetric interpolation Laurent polynomials reduce to
Okounkov's -type interpolation Macdonald polynomials and the nonsymmetric
interpolation Laurent polynomials become their nonsymmetric variants. We expand
the symmetric interpolation Laurent polynomials in the nonsymmetric ones. We
show that Okounkov's -type interpolation Macdonald polynomials can also be
obtained from their nonsymmetric versions using a one-parameter family of
actions of the finite Hecke algebra of type in terms of Demazure-Lusztig
operators. In the Appendix we give some experimental results and conjectures
about extra vanishing.Comment: 30 pages, 9 figures; v4: experimental results and conjectures added
about extra vanishin
Pharmacokinetic models for propofol-defining and illuminating the devil in the detail
The recently introduced open-target-controlled infusion (TCI) systems can be programmed with any pharmacokinetic model, and allow either plasma- or effect-site targeting. With effect-site targeting the goal is to achieve a user-defined target effect-site concentration as rapidly as possible, by manipulating the plasma concentration around the target. Currently systems are pre-programmed with the Marsh and Schnider pharmacokinetic models for propofol. The former is an adapted version of the Gepts model, in which the rate constants are fixed, whereas compartment volumes and clearances are weight proportional. The Schnider model was developed during combined pharmacokinetic-pharmacodynamic modelling studies. It has fixed values for V1, V3, k(13), and k(31), adjusts V2, k(12), and k(21) for age, and adjusts k(10) according to total weight, lean body mass (LBM), and height. In plasma targeting mode, the small, fixed V1 results in very small initial doses on starting the system or on increasing the target concentration in comparison with the Marsh model. The Schnider model should thus always be used in effect-site targeting mode, in which larger initial doses are administered, albeit still smaller than for the Marsh model. Users of the Schnider model should be aware that in the morbidly obese the LBM equation can generate paradoxical values resulting in excessive increases in maintenance infusion rates. Finally, the two currently available open TCI systems implement different methods of effect-site targeting for the Schnider model, and in a small subset of patients the induction doses generated by the two methods can differ significantly
Soft gluon resummation for gluon-induced Higgs Strahlung
We study the effect of soft gluon emission on the total cross section
predictions for the associated Higgs production process at the LHC.
To this end, we perform resummation of threshold corrections at the NLL
accuracy in the absolute threshold production limit and in the threshold limit
for production of a system with a given invariant mass. Analytical results
and numerical predictions for various possible LHC collision energies are
presented. The perturbative stability of the results is verified by including
universal NNLL effects. We find that resummation significantly reduces the
scale uncertainty of the contribution, which is the dominant source
of perturbative uncertainty to production. We use our results to evaluate
updated numbers for the total inclusive cross section of associated
production at the LHC. The reduced scale uncertainty of the
component translates into a decrease of the overall scale error by about a
factor of two.Comment: 22 pages, 4 figures, 2 table
Exact asymptotic behavior of magnetic stripe domain arrays
The classical problem of magnetic stripe domain behavior in films and plates
with uniaxial magnetic anisotropy is treated. Exact analytical results are
derived for the stripe domain widths as function of applied perpendicular
field, , in the regime where the domain period becomes large. The stripe
period diverges as , where is the critical (infinite
period) field, an exact result confirming a previous conjecture. The
magnetization approaches saturation as , a behavior which
compares excellently with experimental data obtained for a m thick
ferrite garnet film. The exact analytical solution provides a new basis for
precise characterization of uniaxial magnetic films and plates, illustrated by
a simple way to measure the domain wall energy. The mathematical approach is
applicable for similar analysis of a wide class of systems with competing
interactions where a stripe domain phase is formed.Comment: 4 pages, 4 figure
Recommended from our members
Turning on the alarm: the neural mechanisms of the transition from innocuous to painful sensation
The experience of pain occurs when the level of a stimulus is sufficient to elicit a marked affective response, putatively to warn the organism of potential danger and motivate appropriate behavioral responses. Understanding the biological mechanisms of the transition from innocuous to painful levels of sensation is essential to understanding pain perception as well as clinical conditions characterized by abnormal relationships between stimulation and pain response. Thus, the primary objective of this study was to characterize the neural response associated with this transition and the correspondence between that response and subjective reports of pain.
Towards this goal, this study examined BOLD response profiles across a range of temperatures spanning the pain threshold. 14 healthy adults underwent functional magnetic resonance imaging (fMRI) while a range of thermal stimuli (44-49oC) were applied. BOLD responses showed a sigmoidal profile along the range of temperatures in a network of brain regions including insula and mid- cingulate, as well as a number of regions associated with motor responses including ventral lateral nuclei of the thalamus, globus pallidus and premotor cortex. A sigmoid function fit to the BOLD responses in these regions explained up to 85% of the variance in individual pain ratings, and yielded an estimate of the temperature of steepest transition from non-painful to painful heat that was nearly identical to that generated by subjective ratings.
These results demonstrate a precise characterization of the relationship between objective levels of stimulation, resulting neural activation, and subjective experience of pain and provide direct evidence for a neural mechanism supporting the nonlinear transition from innocuous to painful levels along the sensory continuum
Comments and Suggestions for Improvement of the Archon Genomics X PRIZE Validation Protocol
This document is a comment on the X PRIZE validation protocol written by Kedes et al. (2011). We propose several modifications which we think will improve the fairness and transparency of the contest while keeping the cost of the validation process under control
Accurate supercapacitor modeling for energy-harvesting wireless sensor nodes
Supercapacitors are often used in energy-harvesting wireless sensor nodes (EH-WSNs) to store harvested energy. Until now, research into the use of supercapacitors in EH-WSNs has considered them to be ideal or over-simplified, with non-ideal behavior attributed to substantial leakage currents. In this brief, we show that observations previously attributed to leakage are predominantly due to redistribution of charge inside the supercapacitor. We confirm this hypothesis through the development of a circuit-based model which accurately represents non-ideal behavior. The model correlates well with practical validations representing the operation of an EH-WSN, and allows behavior to be simulated over long periods
Extended hierarchical search (EHS) algorithm for detection of gravitational waves from inspiraling compact binaries
Pattern matching techniques like matched filtering will be used for online
extraction of gravitational wave signals buried inside detector noise. This
involves cross correlating the detector output with hundreds of thousands of
templates spanning a multi-dimensional parameter space, which is very expensive
computationally. A faster implementation algorithm was devised by Mohanty and
Dhurandhar [1996] using a hierarchy of templates over the mass parameters,
which speeded up the procedure by about 25 to 30 times. We show that a further
reduction in computational cost is possible if we extend the hierarchy paradigm
to an extra parameter, namely, the time of arrival of the signal. In the first
stage, the chirp waveform is cut-off at a relatively low frequency allowing the
data to be coarsely sampled leading to cost saving in performing the FFTs. This
is possible because most of the signal power is at low frequencies, and
therefore the advantage due to hierarchy over masses is not compromised.
Results are obtained for spin-less templates up to the second post-Newtonian
(2PN) order for a single detector with LIGO I noise power spectral density. We
estimate that the gain in computational cost over a flat search is about 100.Comment: 6 pages, 6 EPS figures, uses CQG style iopart.cl
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