3,973 research outputs found
Threshold scans in diffractive W pair production via QED processes at the LHC
We propose a new set of measurements which can be performed at the LHC using
roman pot detectors. This new method is based on exploiting excitation curves
to measure kinematical properties of produced particles. We illustrate it in
the case of central diffractive W pair production.Comment: Accepted by Phys. Lett. B - 1 reference adde
Threshold scans in Central Diffraction at the LHC
We propose a new set of measurements which can be performed at the LHC using
roman pot detectors. The method exploits excitation curves in central
diffractive pair production, and is illustrated using the examples of the W
boson and top quark mass measurements. Further applications are mentioned.Comment: 11 page
Diffractive Production at the Tevatron and the LHC
We present predictions for the diffractive production of mesons in the
central rapidity region usually covered by collider detectors. The predicted
cross sections are based on the Bialas-Landshoff formalism for both exclusive
and inclusive production and makes use of the DPEMC Monte-Carlo simulation
adapted with kinematics appropriate for small-mass diffractive production. We
compare generator-level results with a CDF measurement for exclusive
production, and study background and other scenarios including the contribution
of inclusive production. The results agree with the Tevatron data and
are extrapolated, highlighting the exclusive \chic production at LHC
energies. A possible new measurement at the Tevatron using the D{\O}forward
detectors is investigated, taking advantage of the dominance of exclusive
production for high enough diffractive mass fraction.Comment: 9 pages, 2 figures, added akcnowledgment
Experimentally increased brood size accelerates actuarial senescence and increases subsequent reproductive effort in a wild bird population
The assumption that reproductive effort decreases somatic state, accelerating ageing, is central to our understanding of life‐history variation. Maximal reproductive effort early in life is predicted to be maladaptive by accelerating ageing disproportionally, decreasing fitness.
Optimality theory predicts that reproductive effort is restrained early in life to balance the fitness contribution of reproduction against the survival cost induced by the reproductive effort. When adaptive, the level of reproductive restraint is predicted to be inversely linked to the remaining life expectancy, potentially resulting in a terminal effort in the last period of reproduction.
Experimental tests of the reproductive restraint hypothesis require manipulation of somatic state and subsequent investigation of reproductive effort and residual life span. To our knowledge the available evidence remains inconclusive, and hence reproductive restraint remains to be demonstrated.
We modulated somatic state through a lifelong brood size manipulation in wild jackdaws and measured its consequences for age‐dependent mortality and reproductive success.
The assumption that lifelong increased brood size reduced somatic state was supported: Birds rearing enlarged broods showed subsequent increased rate of actuarial senescence, resulting in reduced residual life span.
The treatment induced a reproductive response in later seasons: Egg volume and nestling survival were higher in subsequent seasons in the increased versus reduced broods' treatment group. We detected these increases in egg volume and nestling survival despite the expectation that in the absence of a change in reproductive effort, the reduced somatic state indicated by the increased mortality rate would result in lower reproductive output. This leads us to conclude that the higher reproductive success we observed was the result of higher reproductive effort.
Our findings show that reproductive effort negatively covaries with remaining life expectancy, supporting optimality theory and confirming reproductive restraint as a key factor underpinning life‐history variation
Economic benefits of reducing aviation taxes in Latin America and the Caribbean.
IATA commissioned SEO Amsterdam Economics to prepare a study to independently quantify the economic benefits of reducing aviation taxes in Latin America and the Caribbean. The study provides evidence on the substantial economic benefits that a removal of aviation taxes and a reduction of passenger-based charges can bring to the economies of Latin America and the Caribbean for consumers and businesses. The study also shows that significant potential benefits of connectivity growth will be foregone for consumers and businesses if taxes remain at their current levels. Removing aviation taxes and reducing passenger based charges delivers immediate consumer benefits of 5.8-7.9 billion USD. By 2035, these consumer welfare benefits accumulate to 13.5-18.5 billion. In terms of macro-economic impact, removal of aviation taxes will results in a total GDP impact of 87 billion USD (+1.6%) and 912 thousand jobs (0.3% increase)
Experimentally increased brood size accelerates actuarial senescence and increases subsequent reproductive effort in a wild bird population
The assumption that reproductive effort decreases somatic state, accelerating ageing, is central to our understanding of life-history variation. Maximal reproductive effort early in life is predicted to be maladaptive by accelerating ageing disproportionally, decreasing fitness. Optimality theory predicts that reproductive effort is restrained early in life to balance the fitness contribution of reproduction against the survival cost induced by the reproductive effort. When adaptive, the level of reproductive restraint is predicted to be inversely linked to the remaining life expectancy, potentially resulting in a terminal effort in the last period of reproduction. Experimental tests of the reproductive restraint hypothesis require manipulation of somatic state and subsequent investigation of reproductive effort and residual life span. To our knowledge the available evidence remains inconclusive, and hence reproductive restraint remains to be demonstrated. We modulated somatic state through a lifelong brood size manipulation in wild jackdaws and measured its consequences for age-dependent mortality and reproductive success. The assumption that lifelong increased brood size reduced somatic state was supported: Birds rearing enlarged broods showed subsequent increased rate of actuarial senescence, resulting in reduced residual life span. The treatment induced a reproductive response in later seasons: Egg volume and nestling survival were higher in subsequent seasons in the increased versus reduced broods' treatment group. We detected these increases in egg volume and nestling survival despite the expectation that in the absence of a change in reproductive effort, the reduced somatic state indicated by the increased mortality rate would result in lower reproductive output. This leads us to conclude that the higher reproductive success we observed was the result of higher reproductive effort. Our findings show that reproductive effort negatively covaries with remaining life expectancy, supporting optimality theory and confirming reproductive restraint as a key factor underpinning life-history variation
Inclusive Higgs boson and dijet production via Double Pomeron exchange
We evaluate Higgs boson and dijet cross-sections at the Tevatron collider via
Double Pomeron exchange when accompanying particles in the central region are
taken into account. Such {\it inclusive} processes, normalized to the observed
dijet rate observed at run I, noticeably increase the predictions for tagged
(anti)protons in the run II with respect to {\it exclusive} ones, with the
potentiality of Higgs boson detection.Comment: 6pages, 4 figure
Diffractive SUSY particle production at the LHC
We give detailed predictions for diffractive SUSY Higgs boson and top squark
associated productions at the LHC via the exclusive double pomeron exchange
mechanism. We study how the SUSY Higgs cross section and the signal over
background ratio are enhanced as a function of tangent beta in different
regimes. The prospects are particularly promising in the ``anti-decoupling''
regime, which we study in detail. We also give the prospects for a precise
measurement of the top squark mass using the threshold scan of central
diffractive associated top squark events at the LHC.Comment: 14 pages, 6 fig
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